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 [Search a list of Patent Appplications for class 324]   CLASS 324,ELECTRICITY: MEASURING AND TESTING
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SECTION I - CLASS DEFINITION

This is the residual home for all subject matter, not elsewhere classified, relating to the measuring, testing (or sensing) of electric properties, (e.g., determining ground resistivity, determining frequency of an alternating current, determining kilowatt hour demand), or the measuring, testing or sensing of nonelectric properties by electric means (e.g., determining moisture, a nonelectric property, by measuring conductance with a resistance bridge; determining speed, a nonelectric property by use of an electric tachometer).

(1) Note. Measuring and testing have been distinguished as being quantitative and qualitative, respectively, but in these definitions the terms are used synonymously.
(2) Note. This class was produced in 1953 by making official the unofficial digests which had been established by the Examiners of Class 175 (Division 48) during the period from about 1905 to 1952, and, in the case of subclasses 76+, by cursorily revising the unofficial digests which had been established by the Examiners of Classes 171 and 172 (Division 69) during the period from about 1902 to 1952. A caveat is given: While it is believed that the titles and definitions are reasonably correct, no assurance can be given that all of the patents, issued prior to the date of reclassification, are in the proper subclass, since only some of the individual patents were read during the reclassification project. Consequently, in making a thorough search in this class, it is advisable to investigate every subclass which may possibly be pertinent and not, in order to shorten the search, to rely upon the principle of superiority of subclass subject matter because of position in schedule, since the principle is applicable only in classes where each patent has been analyzed and placed in the schedule in accordance with that portion of the disclosed subject matter which is claimed.
(3) Note. Measuring and testing requires sensing and signaling or indicating to exhibit the result of the sensing. Sensing is synonymous with condition responsive. Sensing merely detects the presence and/or magnitude of the condition.
(4) Note. Since many other classes include condition responsive subclasses, often entitled automatically responsive or automatic, the search for sensing, in order to be complete, must extend to the class which relates to the environment in which the sensing occurs. Some of these classes are listed below under SEARCH CLASS.
(5) Note. Since Class 324 takes, under the class definition, only measuring and testing not elsewhere classified, the search, in order to be complete, must in appropriate instances extend to the other classes listed below under SEARCH CLASS.
(6) Note. The combination of the subject matter of this class (324) and an art environment is generally classified with the art environment where that environment is significant, either by virtue of a significant disclosed relationship or by virtue of a claimed relationship, as where a test is made of the condition of a portion of a telephone system without making said portion of the telephone system unavailable for use. Where the art environment is recited by name only the combination may be classified, in some instances, with the art environment, and in others, in this class (324). For a list of some of the other classes which contain pertinent subject matter, see the classes referred to under SEARCH CLASS.

SECTION II - LINES WITH OTHER CLASSES AND WITHIN THIS CLASS

Class 324, subclasses 870.01+ take telemetric-signaling means useful in transmitting a measured quantity, not limited to any particular measuring instrument provided for in other classes, while Class 324 takes such telemetric-signaling means in combination with a particular measuring means of the type provided for in Class 324.

LINE BETWEEN CLASS 340 AND CLASS 324

See Class 340, Communications: Electrical, appropriate subclasses, for subject matter sometimes similar to that in Class 324. Often, but not invariably, the line between these two classes is as follows: If the testing system is permanently associated with the environment being tested, as in a machine monitoring device or in a burglar alarm, classification is in Class 340, while if it is temporarily associated, as in a portable test set, such as used by linemen, classification is in Class 324. Note particularly subclasses 870.01+ for telemetering and subclasses 500+ for signaling, automatically responsive to a condition.

LINE BETWEEN CLASS 429 AND CLASS 324

See Class 429, Chemistry: Electrical Current Producing Apparatus, Product and Process, subclasses 61+ for automatic battery control means combined with the battery, and subclasses 90+ for battery having measuring, testing, and indicating means. See Class 324, subclasses 20+ and Class 340, subclasses 636.1-636.21 for this subject matter.

SECTION III - REFERENCES TO OTHER CLASSES

SEE OR SEARCH CLASS:

29, Metal Working,   subclass 25.35 for the electrical measuring, testing or sensing of piezoelectric crystals combined with the manufacture thereof, and subclass 25.41 for the electrical measuring, testing or sensing of condensers combined with the manufacture thereof.
33, Geometrical Instruments,   subclasses 125+ , for the determination of distance, and subclasses 300+, for magnetic field direction sensing and indicating.
73, Measuring and Testing,   appropriate subclasses for nonelectrical measuring and testing and for electrical measuring and testing of the following types: subclasses 26+ for gas analysis by electrical thermal determination,. subclass 75 for moisture determination by electrical thermal conductivity; subclass 760 for stress and strain gages, subclasses 104+ for surface and cutting edge determination by sliding pick-up, subclasses 112.01 - 112.06 for turbine engine testing, 114.01 - 114.81 for internal combustion engine measuring and testing, and especially 114.58 - 114.67 for electrical system testing of an internal combustion engine. Subclass 304 for liquid level gages; immersible electrode type; subclasses 305+ for float type, subclass 755 for fluid pressure (e.g., Pirani type), subclasses 488+ for speed.
100, Presses,   subclass 99 for presses having electrical measuring, testing or sensing means.
156, Adhesive Bonding and Miscellaneous Chemical Manufacture,   subclasses 47+ for methods of making or joining conductors of indefinite length.
178, Telegraphy,   appropriate subclasses particularly subclass 69 , for telegraphy combined with electrical measuring, testing or sensing.
181, Acoustics,   subclasses 101+ , for geophysical or subsurface exploration involving mechanically transmitting or receiving sound waves, subclasses 123+ for mechanical sound echo systems in general, and subclass 125 for mechanical sound location means.
204, Chemistry: Electrical and Wave Energy,   subclass 400 , for the analytical and testing apparatus related to the subject matter of that class, and subclass 242 for electrolytic cells, per se, (e.g., Beckmann cell).
205, Electrolysis: Processes, Compositions Used Therein, and Methods of Preparing the Compositions,   appropriate subclasses for electrolysis utilized for electrochemistry and especially subclasses 775+ as the residual home for a process of electrolytic analysis or testing, per se.
209, Classifying, Separating, and Assorting Solids,   for the subject matter of that class even if the basis of the separation is an electrical determination. Note subclasses 127.1+ for electrostatic separation and subclasses 212 and 213+ for magnetic separators, subclasses 511, 524+, 536, and 576 for photoelectric assorting.
250, Radiant Energy,   subclasses 200+ for miscellaneous photoelectric cell circuits, subclass 250 for wave meters for measuring the wavelength or frequency of radio and microwaves, subclass 281 for methods and apparatus for ionic separation or analysis, subclasses 302+ for fluorescent and radioactive tracer methods, subclasses 336.1+ for the detection of invisible radiation or the examination of material by invisible radiation using radiant energy responsive electric signalling means, subclasses 428+ for fluent material containing, support or transfer means with or without an irradiating source or radiating fluent material, subclasses 453.11+ for supports for objects of irradiation, subclasses 458.1+ for luminophor irradiation, subclasses 472.1+ for nonelectric invisible radiation detectors, subclasses 493.1+ for radiant energy generation and sources, subclasses 505.1+ for radiation controlling means and subclasses 522.1+ for source supports.
273, Amusement Devices: Games,   appropriate subclasses for games (e.g., pin-ball machines, target range) having electrical indicators.
307, Electrical Transmission or Interconnection Systems,   subclass 111 for systems which are nonresponsive to frequency change and subclass 152 for systems which are responsive to rate of change.
313, Electric Lamp and Discharge Devices,   subclass 10 for the subject matter of that class with integral temperature indicators.
314, Electric Lamp and Discharge Devices: Consumable Electrodes,   appropriate subclasses (note particularly subclass 9 ) for the subject matter of that class combined with measuring, testing or sensing.
315, Electric Lamp and Discharge Devices: Systems,   appropriate subclasses (note particularly subclasses 129+ ) for the subject matter of that class combined with measuring, testing or sensing.
318, Electricity: Motive Power Systems,   appropriate subclasses for automatically responsive motor systems and subclass 490 for motor systems having signals, meters, recorders or testing devices.
320, Electricity: Battery and Condenser Charging and Discharging,   subclass 48 for battery charging and discharging systems having indicating, signaling and/or testing means.
322, Electricity: Single Generator Systems,   subclasses 17+ for the subject matter of that class automatically responsive to a condition.
323, Electricity: Power Supply or Regulation Systems,   subclasses 234 through 303for the subject matter of that class automatically responsive to a condition.
329, Demodulators,   for amplitude frequency, phase or pulse demodulators which may include an indicator.
330, Amplifiers,   appropriate subclasses, for amplifiers, generally, which may be used in electrical measuring and testing circuits, particularly subclass 2 for amplifier condition testing or measuring. Where the amplifier is used merely as a part of an arrangement to measure or test a condition other than that of the amplifier, itself, classification is not in Class 330 but in the appropriate subclass of Class 324.
331, Oscillators,   subclass 44 for oscillator systems provided with frequency calibrating or testing means, and subclass 64 for oscillator systems provided with indicator, signal or alarm.
332, Modulators,   appropriate subclasses particularly subclasses 118 and 150 for the modulators having indicating, observing and/or signaling means.
333, Wave Transmission Lines and Networks,   appropriate subclasses, particularly subclasses 2+ , 14 and 17.1+ for the subject matter of that class automatically responsive to a condition.
336, Inductor Devices,   subclasses 30+ for the subject matter of that class automatically responsive to a condition.
340, Communications: Electrical,   appropriate subclasses, for subject matter sometimes similar to that in Class 324. (See Lines With Other Classes and Within This Class for a further discussion of the line).
343, Communications: Radio Wave Antennas,   subclasses 5+ for reflected and/or otherwise returned radio wave energy wave measuring, testing and sensing systems, such as RADAR and ponder systems, and subclasses 350+ for direction finding radio systems.
346, Recorders,   for recorders which record the operation of machines or workmen. Many of these recorders, especially in subclasses 33+ record the result of a measurement, test or sensing operation. Generally, but not invariably, a Class 324 disclosure, when combined with a recorder, is classified in Class 324.
348, Television,   subclasses 180+ for monitoring, testing, or measuring television signals or apparatus.
356, Optics: Measuring and Testing,   for measuring and testing light, materials and articles by means of visible light particularly subclasses 23+ for optical stroboscopes, subclasses 27+ for velocity or velocity and height measurements, subclasses 213+ for photometers, subclasses 237.1+ for apparatus for flaw detection subclasses 300+ for spectroscopic examination, subclasses 432+ for light transmission tests and subclasses 445+ for light reflection tests.
361, Electricity: Electrical Systems and Devices,   subclasses 1+ for safety systems responsive to an unsafe condition, such as circuit breaker systems, and subclasses 236+ for speed responsive electrical systems.
363, Electric Power Conversion Systems,   subclasses 74 , 164 and 165 for the subject matter of that class automatically responsive to a condition.
365, Static Information Storage and Retrieval,   subclass 200 wherein a defective memory device is used to store information, subclass 201 for specifics of a memory device which is tested for defects or erroneous information.
368, Horology: Time Measuring Systems or Devices,   subclasses 155+ for time measuring by clocks having electrical features.
374, Thermal Measuring and Testing,   appropriate subclasses for a measurement or test of a thermal quantity, whether performed electrically or nonelectrically, except for a measurement or test involving a particle spin determination.
376, Induced Nuclear Reactions: Processes, Systems, and Elements,   subclasses 245+ for processes or device for testing, measuring, etc., of a condition of a nuclear reactor during its operation.
378, X-Ray or Gamma Ray Systems or Devices,   appropriate subclasses, particularly subclasses 44+ , 51+ and 70+ for X-ray systems used in testing.
379, Telephonic Communications,   appropriate subclasses, particularly subclasses 1.01 through 35,for telephony combined with electrical measuring, testing or sensing.
422, Chemical Apparatus and Process Disinfecting, Deodorizing, Preserving, or Sterilizing,   subclasses 50+ and 105+ for apparatus for electrical measuring, testing, or sensing combined with significant chemical reaction or control.
429, Chemistry: Electrical Current Producing Apparatus, Product and Process,   subclasses 61+ for automatic battery control means combined with the battery, and subclasses 90+ for battery having measuring, testing, and indicating means. (See Lines With Other Classes and Within This Class for further discussion of the line between Class 429 and Class 324.)
434, Education,   and Demonstration appropriate subclasses, for electrical measuring, testing or sensing in combination with education.
436, Chemistry: Analytical and Immunological Testing,   subclasses 1+ for processes of electrical measuring, testing, or sensing combined with significant chemical reaction or control.
439, Electrical Connectors,   subclasses 488+ for a connector having indicating means or identifying means.
455, Telecommunications,   appropriate subclasses for radio systems having electrical measuring testing or sensing means for indicating the operative condition of the radio system.
473, Games Using Tangible Projectile,   and its incorporated class (273, Amusement Devices: Games), for a game device or apparatus (e.g., a pin-ball machine, target range, aerial projectile target device, bowling alley apparatus, golfing apparatus, simulated game apparatus, chance device, etc.) which may have an electrical indicator.
505, Superconductor Technology: Apparatus, Material, Process,   subclasses 150+ for high temperature (Tc greater than 30 K) superconducting device, and particularly subclasses 160+ for measuring or testing system or device; and subclass 310 for a process of measuring or testing a superconductive property.
702, Data Processing: Measuring, Calibrating, or Testing,   appropriate subclasses for data processing systems or calculating computers which are utilized for testing, measuring, or monitoring the operation of an external device or quantity where the external device or quantity must be only nominally claimed, particularly subclasses 6 through 13for well-logging, subclasses 14-18 for seismology, subclasses 57-80 for electrical signal parameter measurement, subclasses 85-107 for calibration, subclasses 108-126 for a testing system, subclass 141 for acceleration, subclasses 142-149 for speed or velocity, subclasses 176-178 for time duration or rate, and subclasses 191-195 for noise reduction in measured signal processing.
703, Data Processing: Structural Design, Modeling, Simulation, and Emulation,   subclass 4 for analog simulation of electrical device or system.
714, Error Detection/Correction and Fault Detection/Recovery,   appropriate subclasses for error detection, correction, recovery or prevention in pulse code data or computers.

SUBCLASSES

[List of Patents for class 324 subclass 66]    66
 This subclass is indented under the class definition.  Subject matter for determining the location of a particular conductor or for identifying a particular conductor out of many.
(1) Note. This subclass includes, for example, the determination of a particular phase of polyphase conductors.

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379, Telephonic Communications,   subclasses 1.01 through 35,for testing devices used in telephony to identify or locate a particular line.
  
[List of Patents for class 324 subclass 67]    67
 This subclass is indented under subclass 66.  Subject matter for determining the location of a conductor at a point which is inaccessible.
(1) Note. The conductor, for example, may be located in a conduit inside a wall.

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326+,for similar subject matter utilized to determine the location of conductors which are buried in the earth.
  
[List of Patents for class 324 subclass 71.1]    71.1DETERMINING NONELECTRIC PROPERTIES BY MEASURING ELECTRIC PROPERTIES:
 This subclass is indented under the class definition.  Subject matter for determining a nonelectric property by measuring an electric property.

SEE OR SEARCH THIS CLASS, SUBCLASS:

61,for the determination of a nonelectric property by measuring capacity.
65,for the determination of a nonelectric property by measuring resistance.
  
[List of Patents for class 324 subclass 71.2]    71.2Erosion:
 This subclass is indented under subclass 71.1.  Subject matter where the nonelectric property measured relates to the amount of material removed from an object.
  
[List of Patents for class 324 subclass 71.3]    71.3Beam of atomic particles:
 This subclass is indented under subclass 71.1.  Subject matter where the property being measured is some characteristic of a beam of atomic particles.
  
[List of Patents for class 324 subclass 71.4]    71.4Particle counting:
 This subclass is indented under subclass 71.1.  Subject matter where the measurement means includes means for counting particles.
(1) Note. For classification in this subclass there should be recited significant details in regard to handling or preparing the particles to be counted.

SEE OR SEARCH CLASS:

377, Electrical Pulse Counters, Pulse Dividers, or Shift Registers: Circuits and Systems,   subclasses 10+ for particle counting, per se, and see also the search notes thereunder.
  
[List of Patents for class 324 subclass 71.5]    71.5Semiconductors for nonelectrical property:
 This subclass is indented under subclass 71.1.  Subject matter including semiconductive means for sensing variations in the nonelectrical property being measured.

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438, Semiconductor Device Manufacturing: Process,   subclasses 17+ for methods of making semiconductor electrical devices combined with measurement of an electrical condition.
  
[List of Patents for class 324 subclass 71.6]    71.6Superconductors:
 This subclass is indented under subclass 71.1.  Subject matter where the nonelectric properties being determined are those of superconductors.
  
[List of Patents for class 324 subclass 72]    72
 This subclass is indented under the class definition.  Subject matter for determining voltage, phase, current, power, frequency or a related quantity in a specific environment.
(1) Note. This subclass includes, for example, voltmeters, per se, in combination with a specific lightning rod.

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76+,for a measurement of electricity, per se, when not related to a specific environment. Note particularly subclass 157 for the measurement of electricity combined with some other feature. See (3) Note to the definition of subclass 76 for a statement of the line between subclasses 72 and 76.
  
[List of Patents for class 324 subclass 72.5]    72.5
 This subclass is indented under subclass 72.  Subject matter having a voltage probe.

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119,for volt meters and ammeters having rectifiers in a probe.
149,for voltmeters and ammeters having a probe.

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439, Electrical Connectors,   appropriate subclasses for probe conductor structure, per se.
  
[List of Patents for class 324 subclass 73.1]    73.1PLURAL, AUTOMATICALLY SEQUENTIAL TESTS:
 This subclass is indented under the class definition.  Subject matter for measuring or determining two or more electrical characteristics of an electrical circuit or circuit element, or for measuring or determining a single electrical characteristic of two or more electrical circuits or circuit elements, wherein the measurements or determinations are made one after another without human intervention.
(1) Note. This subclass is the residual locus of processes and apparatus which automatically perform sequential tests of the Class 324 type, none of which tests are provided for by subclasses preceding this one in the Class 324 schedule. Similar processes and apparatus in which one of the plural tests is provided for in a preceding subclass will be found in that subclass. For example, a patent claiming means for automatically testing a circuit for an "open circuit" caused by the failure of a circuit element, followed automatically by a test to determine the input/output characteristics of the circuit is classifiable as an "original" in subclasses 500+.
(2) Note. This subclass is the locus of processes and apparatus for performing, in automatic sequence, two or more Class 324 type tests which otherwise may be provided for in subclasses following this one in the Class 324 schedule. For example, a patent claiming a testing apparatus consisting of a combination of means to determine frequency, means to compare phase, and means to permit a human operator to switch from one means to another is classifiable as an "original" in subclasses 78+.
(3) Note. Subject matter for performing plural, Class 324 type tests simultaneously but not sequentially will be found in subclasses determined by the tests, per se.
(4) Note. Electrical characteristics measured by the subject matter of this subclass type include the response of a circuit or circuit element to a particular electrical input and includes such tests to determine the existence of miswired circuits. For similar subject matter used to detect the presence of short or open circuits caused by failures in circuit elements or their interconnections, see the reference below to subclasses 500+ in the search notes to other subclasses in this class.
(5) Note. The measurements of this subclass type may result in either quantitative or qualitative ("go-no-go") indications.
(6) Note. The automatic, sequential measurement of the analog responses of a circuit or circuit element to two different input levels is classifiable in this subclass. The response of a circuit or circuit element to a pattern of high and low digital input signals is classifiable in Class 371.
(7) Note. Testing means of this subclass type produce a distinct indication for each of the plural tests, Hence, testing means comprising plural transducers or detectors, each of outputs are combined to produce only on indication is not classifiable in this subclass unless the whole test is automatically repeated.

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114,for plural tests employing plural meters, which tests are not automatically sequenced.
115+,for plural tests employing plural meter ranges, which tests are not automatically sequenced.
133,for plural go-no-go tests which are not automatically sequenced.
140,for testing means having plural inputs, which means does not include automatic sequencing.
459+,for measuring or testing electrical parameters of printed circuits with an ionizable gas.
500+,for plural tests explicitly for the purpose of detecting failures in circuits or circuit elements consisting of open or short circuits.
754.01through 755.11 for test probe techniques.

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209, Classifying, Separating, and Assorting Solids,   especially subclass 556 , for diverse electrical test used to classify, separate or sort articles, and subclasses 571+ for sorting by sensing properties of articles by electrical testing means.
250, Radiant Energy,   subclasses 306+ for plural sequential tests involving testing by charged particles, especially subclass 310 for automatic sequential tests of printed circuits using an electron probe, and subclasses 363+ for automatic sequential tests of electrical circuits and devices using radiant energy and invisible-to-visible light converters.
340, Communications: Electrical,   subclass 653 for electrical alarms responsive to circuits for testing electrical circuits or components.
382, Image Analysis,   appropriate subclasses for automatic, sequential tests of printed circuits using image comparison.
455, Telecommunications,   subclasses 115.1 through 115.4and subclasses 226.1-226.4 for the testing of radio transmitters and receivers, respectively, which may include automatic sequential tests.
702, Data Processing: Measuring, Calibrating, or Testing,   subclasses 108+ for testing systems, particularly subclasses 117+ for testing of circuits, subclass 118 for testing multiple circuits, and subclass 121 for multiple test instruments.
714, Error Detection/Correction and Fault Detection/Recovery,   appropriate subclasses for error detection, correction, recovery or prevention in pulse code data or computers.
  
[List of Patents for class 324 subclass 74]    74
 This subclass is indented under the class definition.  Subject matter for testing and calibrating electric meters.

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130,for electric meters, per se, having self-calibrating features.

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73, Measuring and Testing,   subclasses 1.01+ , for the proving or calibrating of mechanical instruments.
374, Thermal Measuring and Testing,   subclasses 1+ for calibration or testing of a thermally responsive instrument.
702, Data Processing: Measuring, Calibrating, or Testing,   subclasses 85+ for calibration or correction system, subclasses 108+ for testing systems.
  
[List of Patents for class 324 subclass 75]    75
 This subclass is indented under subclass 74.  Subject matter in which the testing or calibrating is done by stroboscopic means.

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315, Electric Lamp and Discharge Devices: Systems,   appropriate subclasses, for flashing lamp systems.
356, Optics: Measuring and Testing,   subclasses 23+ for optical stroboscopes.
  
[List of Patents for class 324 subclass 76.11]    76.11MEASURING, TESTING, OR SENSING ELECTRICITY, PER SE:
 This subclass is indented under the class definition.  Subject matter relating to the measurement of electric voltages or currents, or combinations thereof, when said electric voltages and currents do not occur in a significantly recited external environment.
(1) Note. Measurement requires sensing and some indication of the result of the sensing. The indication can be quantitative, as in a calibrated voltmeter, or qualitative, as in an uncalibrated cathode-ray oscilloscope or a "hot line" indicator. No distinction is made in these subclasses between testing and measuring.
(2) Note. The definition is not limited to subject matter which indicates the result of the measurement, but covers the sensing subcombination as well. Such subcombinations, when disclosed as having utility only in the measurement of this subclass, are generally classified here, but when disclosed to a specific art device, are classified in one of the classes referred to under the search notes.
(3) Note. The recited external environment is significant to the measurement when there is a disclosed significant relation or when the claims recite, by more than name only, more of the environment than is necessary for the performance of the measurement. When the external environment is not significant, for example, a meter which indicates the phase difference between A-C voltages in different circuits, will be classified in this class even though one of the inputs is recited as being from a generator and the other as being from a power system.

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72,for this subject matter in combination with a specific environment. See (3) Note above.

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73, Measuring and Testing,   appropriate subclasses for nonelectrical measuring and testing and for electrical measuring and testing in combination with non-electrical measuring and testing. See the proceeding Class 324 definition notes for specific subclasses.
315, Electric Lamp and Discharge Devices: Systems,   subclasses 1+ for cathode-ray tube circuits of general application, including those for producing a visual grid on the face of the tube for calibration purposes.
340, Communications: Electrical,   subclasses 870.01+ for telemetering systems for indicating at a remote point the value of a local condition. Class 324 provides for significant measuring, testing, or sensing of electricity, per se, and the indication of the result, whether by a telemetering system or otherwise.
356, Optics: Measuring and Testing,   appropriate subclasses for measuring and testing light.
362, Illumination,   subclass 23 for illuminated dial or scale, some of which can be used as voltage or current indicators.
370, Multiplex Communications,   subclasses 241+ for testing (other than synchronization) of a multiplex communication element.
374, Thermal Measuring and Testing,   appropriate subclasses for thermal measuring and testing.
375, Pulse or Digital Communications,   subclasses 224+ for measuring and testing of pulse or digital communications device.
379, Telephonic Communications,   subclasses 1.01 through 35for diagnostic testing, malfunction indication, or electrical condition measurement of a telephonic communication device.
455, Telecommunications,   subclasses 115.1 through 115.4for measuring and testing of a transmitter and subclasses 226.1-226.4 for measuring and testing of a receiver in telecommunications.
714, Error Detection/Correction and Fault Detection/Recovery,   appropriate subclasses for error detection, correction, recovery or prevention in pulse code data or computers.
  
[List of Patents for class 324 subclass 76.12]    76.12Analysis of complex waves:
 This subclass is indented under subclass 76.11.  Subject matter whereby one or more components of a periodic wave made up of a combination of several frequencies or several sine waves superimposed on one another has components which are examined.
(1) Note. Such analysis as is found in this subclass is usually referred to as Fourier analysis.

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76.39+,for the measurement of frequency of a cyclic current or voltage, per se.
76.77+,for the measurement of phase of cyclic voltage or current.

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73, Measuring and Testing,   subclass 861.06 for volume or rate of flow meters measuring transit time of a tracer or tag by correlator means.
702, Data Processing: Measuring, Calibrating, or Testing,   subclasses 66+ for wave form analysis, particularly subclass 77 for Fourier analysis, subclass 112 for a testing system having sinusoidal signal stimulus, and subclasses 124+ for signal generation or waveform shaping.
704, Data Processing: Speech Signal Processing, Linguistics, Language Translation, and Audio Compression/Decompression,   subclasses 205+ for determination of the component frequencies in a speech signal.
  
[List of Patents for class 324 subclass 76.13]    76.13Amplitude distribution:
 This subclass is indented under subclass 76.12.  Subject matter comprising means to measure an extent of dispersion of magnitude variation in the component of the complex wave.
(1) Note. The amplitudes may be statistically analyzed.
  
[List of Patents for class 324 subclass 76.14]    76.14Radiometer (e.g., microwave, etc.):
 This subclass is indented under subclass 76.13.  Subject matter having means that detect and measure radiant energy either at separate wave lengths or integrated over a broad wavelength band in the complex wave.

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76.56,for microwave frequency detection in digital output used in determining the frequency of cyclic current or voltage.

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250, Radiant Energy,   subclass 250 for the measurement of radio or microwaves by an absorption wavemeter
342, Communications: Directive Radio Wave Systems and Devices (e.g., Radar, Radio Navigation),   appropriate subclasses for directive radio wave systems and devices used in communication.
  
[List of Patents for class 324 subclass 76.15]    76.15With sampler:
 This subclass is indented under subclass 76.13.  Subject matter including a device whose output is a series of discrete values representative of the values of an input at a series of points in time.

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76.24,for sampling in a frequency spectrum analyzer.
76.38,for sampling, per se, in analysis of complex waves.
76.42,for sampling by frequency comparison in frequency of cyclic current or voltage.
76.58,for sampling in digital output by phase comparison.
  
[List of Patents for class 324 subclass 76.16]    76.16With counter:
 This subclass is indented under subclass 76.13.  Subject matter including a device capable of changing stages in a specified sequence upon receiving appropriate signals.

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76.48,for counters in digital output by frequency comparison used to determine the frequency of cyclic current or voltage.
76.62,for counters in digital output by phase comparison used to determine the frequency of cyclic current or voltage.

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377, Electrical Pulse Counters, Pulse Dividers, or Shift Registers: Circuits and Systems,   subclass 19 where pulses are counted in systems for determining the value of some parameters.
  
[List of Patents for class 324 subclass 76.17]    76.17With integrator:
 This subclass is indented under subclass 76.13.  Subject matter whereby summing of a signal is derived.

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327, Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems,   subclasses 336+ for miscellaneous integrating circuits.
708, Electrical Computers: Arithmetic Processing and Calculating,   subclasses 823+ for analog integrators, per se.
  
[List of Patents for class 324 subclass 76.18]    76.18With slope detector:
 This subclass is indented under subclass 76.13.  Subject matter comprising means to monitor the rise over the run in a wave.

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76.25,for slope detection in frequency spectrum analyzers.

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327, Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems,   subclasses 14+ for miscellaneous slope detecting circuits and subclass 170 for slope control of a pulse waveform.
  
[List of Patents for class 324 subclass 76.19]    76.19Frequency spectrum analyzer:
 This subclass is indented under subclass 76.12.  Subject matter including means that show an energy distribution as a function of frequency for a given signal.

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702, Data Processing: Measuring, Calibrating, or Testing,   subclasses 76+ for frequency spectrum analysis.
  
[List of Patents for class 324 subclass 76.21]    76.21By Fourier analysis:
 This subclass is indented under subclass 76.19.  Subject matter wherein the energy distribution is taken at discrete harmonic components, i.e., harmonics, of the given signal.

SEE OR SEARCH CLASS:

702, Data Processing: Measuring, Calibrating, or Testing,   subclass 77 for Fourier analysis in a waveform measuring system.
708, Electrical Computers: Arithmetic Processing and Calculating,   subclasses 823+ for analog integrators, per se.
  
[List of Patents for class 324 subclass 76.22]    76.22Real-time spectrum analyzer:
 This subclass is indented under subclass 76.19.  Subject matter including a device which operates with sufficient speed that the energy distribution is determined within set timing limits.
  
[List of Patents for class 324 subclass 76.23]    76.23With mixer:
 This subclass is indented under subclass 76.19.  Subject matter including a circuit that generates output frequencies equal to the sum or difference of two input frequencies.

SEE OR SEARCH THIS CLASS, SUBCLASS:

76.43,for plural mixers used in frequency comparison for the determination of cyclic current or voltage.

SEE OR SEARCH CLASS:

455, Telecommunications,   subclasses 313+ for mixers, per se.
  
[List of Patents for class 324 subclass 76.24]    76.24With sampler:
 This subclass is indented under subclass 76.19.  Subject matter including a device whose output is a series of discrete values representative of the values of an input at a series of points in time.

SEE OR SEARCH THIS CLASS, SUBCLASS:

76.15,for sampling used in Amplitude distribution devices.
76.38,for sampling, per se, in analysis of complex waves.
76.42,for sampling by frequency comparison in determination of frequency of cyclic current or voltage.
76.58,for sampling in digital output by phase comparison in determination of frequency of cyclic current or voltage.
  
[List of Patents for class 324 subclass 76.25]    76.25With slope detector:
 This subclass is indented under subclass 76.19.  Subject matter comprising means to monitor the rise over the run in a wave.

SEE OR SEARCH THIS CLASS, SUBCLASS:

76.18,for slope detection in amplitude distribution.

SEE OR SEARCH CLASS:

327, Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems,   subclasses 14+ for miscellaneous slope detecting circuits and subclass 170 for slope control of a pulse waveform.
  
[List of Patents for class 324 subclass 76.26]    76.26Scanning-panoramic receiver:
 This subclass is indented under subclass 76.19.  Subject matter including a radio receiver that displays, on the screen of a cathode-ray tube, the presence and relative strength of all signals within a wide frequency range.

SEE OR SEARCH CLASS:

315, Electric Lamp and Discharge Devices: Systems,   subclasses 364+ for cathode-ray tube deflections circuits.
455, Telecommunications,   subclasses 145+ for panoramic display, per se.
  
[List of Patents for class 324 subclass 76.27]    76.27With particular sweep circuit:
 This subclass is indented under subclass 76.26.  Subject matter including a specific circuit which produces at regular intervals, an approximately linear, circular, or other movement of a beam in a cathode-ray tube.
  
[List of Patents for class 324 subclass 76.28]    76.28Digital filter:
 This subclass is indented under subclass 77.11.  Subject matter wherein an input signal is operated on by means of digital circuitry to alter the frequency spectrum of the input signal.

SEE OR SEARCH THIS CLASS, SUBCLASS:

76.29,for filtering in frequency spectrum analyzers.
76.31,for parallel filters in frequency spectrum analysis.
76.44,for filtering in frequency comparison used to determine the frequency of cyclic current or voltage.
76.68,for filtering in phase comparison used to determine the frequency of cyclic current or voltage.

SEE OR SEARCH CLASS:

333, Wave Transmission Lines and Networks,   appropriate subclasses for filters and filtering in wave transmission lines and networks.
702, Data Processing: Measuring, Calibrating, or Testing,   subclass 17 for filtering or noise removal in a seismic prospecting system, subclasses 190+ for measured signal extraction or separation (e.g., filtering).
  
[List of Patents for class 324 subclass 76.29]    76.29With filtering:
 This subclass is indented under subclass 77.11.  Subject matter including a network of resistors, inductors, or capacitors which offers comparatively little opposition to certain frequencies, while blocking or attenuating other frequencies.

SEE OR SEARCH THIS CLASS, SUBCLASS:

76.44+,for filtering in frequency comparison for determination of the frequency of cyclic current or voltage.
76.68,for filtering in phase comparison for the determination of the frequency of cyclic current or voltage.

SEE OR SEARCH CLASS:

333, Wave Transmission Lines and Networks,   appropriate subclasses for filters and filtering in wave transmission lines and networks.
702, Data Processing: Measuring, Calibrating, or Testing,   subclass 17 for filtering or noise removal in a seismic prospecting system, subclasses 190+ for measured signal extraction or separation (e.g., filtering).
  
[List of Patents for class 324 subclass 76.31]    76.31Parallel filters:
 This subclass is indented under subclass 76.29.  Subject matter including parallel connected network of resistors, inductors, or capacitors which offers comparatively little opposition to certain frequencies, while blocking or attenuating other frequencies.

SEE OR SEARCH THIS CLASS, SUBCLASS:

76.28,for digital filters in frequency spectrum analysis.
76.44,for filtering in frequency comparison used to determine the frequency of cyclic current or voltage.
76.68,for filtering in phase comparison used to determine the frequency of cyclic current or voltage.

SEE OR SEARCH CLASS:

333, Wave Transmission Lines and Networks,   appropriate subclasses for filters and filtering in wave transmission lines and networks.
702, Data Processing: Measuring, Calibrating, or Testing,   subclass 17 for filtering or noise removal in a seismic prospecting system, subclasses 190+ for measured signal extraction or separation (e.g., filtering).
  
[List of Patents for class 324 subclass 76.32]    76.32With space discharge device:
 This subclass is indented under subclass 76.31.  Subject matter comprising any device which is intended to have an electrical current flow between two spaced electrodes, at least part of the path followed by the discharge being constituted by a gas, vapor, or vacuum.

SEE OR SEARCH THIS CLASS, SUBCLASS:

76.76,for space discharge device in frequency of cyclic current or voltage devices.

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313, Electric Lamp and Discharge Devices,   for space discharge devices, per se.
  
[List of Patents for class 324 subclass 76.33]    76.33Correlation:
 This subclass is indented under subclass 77.11.  Subject matter including means to measure the similarity of two or more signals.

SEE OR SEARCH CLASS:

708, Electrical Computers: Arithmetic Processing and Calculating,   subclasses 422+ for correlation in electric digital calculating computers.
  
[List of Patents for class 324 subclass 76.34]    76.34With space discharge device:
 This subclass is indented under subclass 76.33.  Subject matter comprising any device which is intended to have an electrical current flow between two spaced electrodes, at least part of the path followed by the discharge being constituted by a gas, vapor, or vacuum.

SEE OR SEARCH THIS CLASS, SUBCLASS:

76.76,for space discharge device in frequency of cyclic current or voltage devices.

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313, Electric Lamp and Discharge Devices,   for space.
  
[List of Patents for class 324 subclass 76.35]    76.35With delay line:
 This subclass is indented under subclass 77.11.  Subject matter comprising a real or artificial transmission line or equivalent component that slows a signal for a predetermined length of time.

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76.54,for delay line in phase comparison in frequency of cyclic current or voltage.

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333, Wave Transmission Lines and Networks,   appropriate subclasses for delay lines in wave transmission lines and networks.
  
[List of Patents for class 324 subclass 76.36]    76.36With optics:
 This subclass is indented under subclass 77.11.  Subject matter comprising lenses, prisms, or mirrors to be used in the frequency spectrum analyzer.

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356, Optics: Measuring and Testing,   for optics measuring and testing, per se.
359, Optics: Systems (Including Communication) and Elements,   appropriate subclasses for optical systems and devices that may be used in measuring and testing.
  
[List of Patents for class 324 subclass 76.37]    76.37Bragg cell:
 This subclass is indented under subclass 76.36.  Subject matter comprising acousto-optic means to redirect light by the method of Bragg diffraction.
  
[List of Patents for class 324 subclass 76.38]    76.38With sampler:
 This subclass is indented under subclass 76.12.  Subject matter including a device whose output is a series of discrete values representative of the values of an input at a series of points in time.

SEE OR SEARCH THIS CLASS, SUBCLASS:

76.15,for sampling in amplitude distribution devices.
76.24,for sampling in a frequency spectrum analyzer.
76.42,for sampling by frequency comparison in frequency of cyclic current or voltage.
76.58,for sampling in digital output by phase comparison.
  
[List of Patents for class 324 subclass 76.39]    76.39Frequency of cyclic current or voltage (e.g., cyclic counting etc.):
 This subclass is indented under subclass 76.11.  Subject matter relating to the measuring of the frequency of an electric voltage or current which fluctuates in a periodic manner.
(1) Note. Generally, when an intangible electric voltage measurement occurs in a significant environment (for example, when the measurement is of the synchronizing frequency in a communication system) the class which provides for the environment also provides for the frequency measurement in that environment. The search should therefore, in appropriate instances, extend to other classes. An environment recited by name only is not considered to be significant.
(2) Note. The frequency measurement may be indicated in various manners, as in terms of frequency error, deviation, or average frequency over a period of time. The measurement and indication may be either qualitative or quantitative.
(3) Note. It is impossible to vary the frequency of a periodically varying voltage without concomitantantly varying its phase. Consequently, when the frequency changes slowly, it may be possible to indicate frequency by measuring phase angle. In those instances the search should extend to subclasses 76.77+, especially subclass 91, since synchronization is usually concerned with obtaining a zero phase angle rather than with obtaining a mere equality of frequency.

SEE OR SEARCH THIS CLASS, SUBCLASS:

160+,for electrical measuring of speed, for example, the speed of rotating shafts or bullets, and for measuring the average frequency of random events, such as the occurrence of random electrical impulses and for timing means utilized to electrically determine the time interval between points spaced in time, when said points are not determined by the fluctuations of a periodically varying voltage, as when the points are determined, for example, by a randomly varying voltage or by the events at a race track.
76.12+,for complex wave analysis, per se.

SEE OR SEARCH CLASS:

84, Music,   subclasses 454+ for tuning devices utilized in the tuning of musical instruments, some of which will measure the frequency of an unknown sound.
250, Radiant Energy,   subclass 250 for the measurement of radio or microwaves by an absorption wavemeter.
329, Demodulators,   subclasses 311+ for pulse demodulators or detectors; subclasses 315+ for frequency demodulators; and subclasses 345+ for phase demodulators.
331, Oscillators,   subclass 44 for oscillators provided with means or the method for calibrating the oscillator with respect to its generated frequency and subclass 64 for oscillators.
332, Modulators,   subclass 118 for frequency modulators having frequency measuring means and for the frequency meters, per se, when limited to use with modulation.
342, Communications: Directive Radio Wave Systems and Devices (e.g., Radar, Radio Navigation),   appropriate subclasses for radar systems. Note particularly subclasses 104+ for such systems (for example, by measuring the frequency shift due to the doppler effect) and subclasses 128+ for such systems which utilize frequency modulated waves.
361, Electricity: Electrical Systems and Devices,   subclasses 236+ for speed sensing and speed controlled systems, such as synchronizing systems.
368, Horology: Time Measuring Systems or Devices,   subclasses 15+ and 155+ for clocks which serve as standards in frequency measurements.
377, Electrical Pulse Counters, Pulse Dividers, or Shift Registers: Circuits and Systems,   appropriate subclasses for frequency of cyclic current or voltage in cycle counters or cycle counting.
702, Data Processing: Measuring, Calibrating, or Testing,   subclasses 75+ for frequency analysis, subclass 106 for signal frequency or phase correction.
  
[List of Patents for class 324 subclass 76.41]    76.41Frequency comparison (e. g., heterodyne, etc.):
 This subclass is indented under subclass 76.39.  Subject matter having means to compare two frequencies with each other.
(1) Note. The two frequencies are usually, but not necessarily, sinusoidal.
(2) Note. One frequency, for example, may serve as a time base for an oscilloscope upon which the other frequency is displayed, or the two frequencies may be heterodyned to make a beat which has a mathematically determinable frequency with respect to the two frequencies.

SEE OR SEARCH THIS CLASS, SUBCLASS:

76.77+,especially subclass 91, for this subject matter when the frequency comparison is for synchronizing purposes. See also (3) Note to subclass 76.39.

SEE OR SEARCH CLASS:

315, Electric Lamp and Discharge Devices: Systems,   subclasses 1+ for cathode-ray tube circuits that can be used in frequency comparison (e.g., oscilloscopes, etc.).
331, Oscillators,   for oscillators whose generated frequency can be varied or which can serve as frequency standards. By way of example, subclasses 37+ of Class 331 provides for beat frequency oscillator systems, and subclass 44 provides for oscillators with frequency calibration of oscillator.
334, Tuners,   appropriate subclasses for tuned networks for use in wave energy apparatus and comprising inductance and capacitance elements in circuit arrangement to form a resonant circuit and in which structure is provided for adjusting one or both of these elements for changing the mean resonant frequency of the circuit. Note especially subclasses 30+ for tuners combined with resonant indicators.
455, Telecommunications,   for this subject matter in combination with a radio receiving system, particularly subclasses 145+ for panoramic receivers.
  
[List of Patents for class 324 subclass 76.42]    76.42With sampler:
 This subclass is indented under subclass 76.41.  Subject matter including a device whose output is a series of discrete values representative of the values of an input at a series of points in time.

SEE OR SEARCH THIS CLASS, SUBCLASS:

76.15,for sampling in amplitude distribution devices.
76.24,for sampling in a frequency spectrum analyzer.
76.38,for sampling, per se, in analysis of complex waves current, or voltage.
76.58,for sampling in digital output by phase comparison.
  
[List of Patents for class 324 subclass 76.43]    76.43With plural mixers:
 This subclass is indented under subclass 76.41.  Subject matter including more than one circuit that generates output frequencies equal to the sum and the difference of two input frequencies.

SEE OR SEARCH THIS CLASS, SUBCLASS:

76.23,for mixers in frequency spectrum analyzers

SEE OR SEARCH CLASS:

455, Telecommunications,   subclasses 313+ for mixers, per se.
  
[List of Patents for class 324 subclass 76.44]    76.44With filtering:
 This subclass is indented under subclass 76.41.  Subject matter including a selective network of resistors, inductors, or capacitors which offers comparatively little opposition to certain frequencies,while blocking or attenuating other frequencies.

SEE OR SEARCH THIS CLASS, SUBCLASS:

76.28,for digital filters in frequency spectrum analysis.
76.29+,for filtering in frequency spectrum analyzer.
76.31,for parallel filters in frequency spectrum analysis.
76.68,for filtering in phase comparison used to determine the frequency of cyclic current or voltage.
  
[List of Patents for class 324 subclass 76.45]    76.45Bandpass:
 This subclass is indented under subclass 76.44.  Subject matter that limits the range of frequencies that will be passed through a device.
  
[List of Patents for class 324 subclass 76.46]    76.46Plural:
 This subclass is indented under subclass 76.44.  Subject matter including more than one filter.
  
[List of Patents for class 324 subclass 76.47]    76.47Digital output:
 This subclass is indented under subclass 76.41.  Subject matter comprising an output signal which represents the size of a stimulus or input signal in the form of a series of discrete quantities which are coded to represent digits in a system of numerical notation.

SEE OR SEARCH THIS CLASS, SUBCLASS:

76.55+,for digital output by phase comparison in frequency of cyclic current or voltage.
76.82+,for digital output in phase comparison, per se.
  
[List of Patents for class 324 subclass 76.48]    76.48With counter:
 This subclass is indented under subclass 76.47.  Subject matter including a device capable of changing stages in a specified sequence upon receiving appropriate signals.

SEE OR SEARCH THIS CLASS, SUBCLASS:

76.16,for counters in amplitude distribution devices.
76.62,for plural counters in digital output by phase comparison.

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377, Electrical Pulse Counters, Pulse Dividers, or Shift Registers: Circuits and Systems,   subclass 19 where pulses are counted in systems for determining the value of some parameters.
  
[List of Patents for class 324 subclass 76.49]    76.49Tuned mechanical resonator (e.g., reed, piezocrystal, etc.):
 This subclass is indented under subclass 76.39.  Subject matter having a mechanical resonating system and an electromechanical transducer to drive the mechanical resonating system in accordance with the electric voltage or current.
(1) Note. The mechanical resonator is usually a reed and its vibration can be visually observed, but it may be a quartz crystal whose motion is not visible or some other resonator.

SEE OR SEARCH CLASS:

333, Wave Transmission Lines and Networks,   subclasses 141+ and 186+ for electromechanical filters utilizing mechanical resonating systems.
  
[List of Patents for class 324 subclass 76.51]    76.51By tuning (e.g., to resonance, etc.):
 This subclass is indented under subclass 76.39.  Subject matter having circuit which may be adjusted for resonance at a particular frequency or other predetermined condition.

SEE OR SEARCH THIS CLASS, SUBCLASS:

76.41+,for this subject matter in combination with heterodyning means.
76.49+,for this subject matter where the tuned current has a tuned mechanically resonant element.

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250, Radiant Energy,   subclass 250 for this subject matter in combination with a radio or carrier wave communication frequency
334, Tuners,   appropriate subclasses for tuned networks for use in wave energy apparatus and comprising inductance and capacitance elements in circuit arrangement to form a resonant circuit and in which structure is provided for adjusting one or both of these elements for changing the mean resonant frequency of the circuit.
455, Telecommunications,   subclasses 154.1+ for indicator means combined with frequency selection means in a radio receiver.
  
[List of Patents for class 324 subclass 76.52]    76.52By phase comparison:
 This subclass is indented under subclass 76.39.  Subject matter having angle relationship means as a part thereof, in order to perform the frequency measurement.

SEE OR SEARCH THIS CLASS, SUBCLASS:

76.77+,for the phase comparison means, per se.
  
[List of Patents for class 324 subclass 76.53]    76.53With phase lock:
 This subclass is indented under subclass 76.52.  Subject matter comprising means of making the phase of an oscillator signal follow exactly the phase of a reference signal.
  
[List of Patents for class 324 subclass 76.54]    76.54With delay line:
 This subclass is indented under subclass 76.52.  Subject matter comprising a real or artificial transmission line or equivalent component that slows a signal for a predetermined length of time.

SEE OR SEARCH THIS CLASS, SUBCLASS:

76.35,for delay line in frequency spectrum analyzer.

SEE OR SEARCH CLASS:

333, Wave Transmission Lines and Networks,   appropriate subclasses for delay lines in wave transmission lines and networks.
  
[List of Patents for class 324 subclass 76.55]    76.55Digital output:
 This subclass is indented under subclass 76.52.  Subject matter comprising an output signal which represents the size of a stimulus or input signal in the form of a series of discrete quantities which are coded to represent digits in a system of numerical notation.

SEE OR SEARCH THIS CLASS, SUBCLASS:

76.47+,for digital output in frequency comparison.
76.82,for digital output in phase comparison, per se.
  
[List of Patents for class 324 subclass 76.56]    76.56With microwave frequency detection:
 This subclass is indented under subclass 76.55.  Subject matter comprising means to detect frequencies of 1000mhz plus.

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76.14,for radiometers in amplitude distribution used in analysis of complex waves.

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250, Radiant Energy,   subclass 250 for the measurement of radio or microwaves by an absorption wavemeter.
342, Communications: Directive Radio Wave Systems and Devices (e.g., Radar, Radio Navigation),   appropriate subclasses for directive radio wave systems and devices used in communication.
  
[List of Patents for class 324 subclass 76.57]    76.57With tone detection:
 This subclass is indented under subclass 76.55.  Subject matter comprising means to detect a sound sensation having pitch.
  
[List of Patents for class 324 subclass 76.58]    76.58With sampler:
 This subclass is indented under subclass 76.55.  Subject matter including a device whose output is a series of discrete values representative of the values of an input at a series of points in time.

SEE OR SEARCH THIS CLASS, SUBCLASS:

76.15,for sampling in amplitude distribution devices.
76.24,for sampling in a frequency spectrum analyzer.
76.38,for sampling used in analysis of complex waves.
76.42,for sampling in frequency comparison used in determination of frequency of cyclic current or voltage.
  
[List of Patents for class 324 subclass 76.59]    76.59With multiplexing:
 This subclass is indented under subclass 76.55.  Subject matter including a device for simultaneous transmission of two or more signals in either or both directions over the same transmission path.

SEE OR SEARCH CLASS:

370, Multiplex Communications,   for multiplex communications, per se.
  
[List of Patents for class 324 subclass 76.61]    76.61With memory:
 This subclass is indented under subclass 76.55.  Subject matter comprising means to collect and hold information until it is needed.

SEE OR SEARCH CLASS:

365, Static Information Storage and Retrieval,   for memories, per se.
  
[List of Patents for class 324 subclass 76.62]    76.62With counter:
 This subclass is indented under subclass 76.55.  Subject matter including devices capable of changing stages in a specified sequence upon receiving appropriate signals.

SEE OR SEARCH THIS CLASS, SUBCLASS:

76.16,for counters in amplitude distribution devices.
76.48,for counters in digital output by frequency comparison used in determining the frequency of cyclic current or voltage.

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377, Electrical Pulse Counters, Pulse Dividers, or Shift Registers: Circuits and Systems,   subclass 19 where pulses are counted in systems for determining the value of some parameters.
  
[List of Patents for class 324 subclass 76.63]    76.63Using register:
 This subclass is indented under subclass 76.62.  Subject matter including a device in which information is stored in and serially transferred through a storage medium.

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235, Registers,   for mechanical registers, per se.
377, Electrical Pulse Counters, Pulse Dividers, or Shift Registers: Circuits and Systems,   for electrical registers, per se.
  
[List of Patents for class 324 subclass 76.64]    76.64Plural:
 This subclass is indented under subclass 76.62.  Subject matter comprising more than one counter.
  
[List of Patents for class 324 subclass 76.65]    76.65With space discharge device:
 This subclass is indented under subclass 76.55.  Subject matter comprising any device which is intended to have an electrical current flow between two spaced electrodes, at least part of the path followed by the discharge being constituted by a gas, vapor, or vacuum.

SEE OR SEARCH THIS CLASS, SUBCLASS:

76.76,for space discharge device in frequency of cyclic current or voltage devices.

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313, Electric Lamp and Discharge Devices,   for space discharge devices, per se.
  
[List of Patents for class 324 subclass 76.66]    76.66With capacitive energy storage:
 This subclass is indented under subclass 76.52.  Subject matter comprising conductors and dielectrics that store electrical energy.
  
[List of Patents for class 324 subclass 76.67]    76.67With space discharge device:
 This subclass is indented under subclass 76.66.  Subject matter comprising any device which is intended to have an electrical current flow between two spaced electrodes, at least part of the path followed by the discharge being constituted by a gas, vapor, or vacuum.

SEE OR SEARCH THIS CLASS, SUBCLASS:

76.76,for space discharge device in frequency of cyclic current or voltage devices.

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313, Electric Lamp and Discharge Devices,   for space discharge devices, per se.
  
[List of Patents for class 324 subclass 76.68]    76.68With filtering:
 This subclass is indented under subclass 76.52.  Subject matter including a network of resistors, inductors, or capacitors which offers comparatively little opposition to certain frequencies, while blocking or attenuating other frequencies.

SEE OR SEARCH THIS CLASS, SUBCLASS:

76.28,for digital filters in frequency spectrum analysis.
76.29+,for filtering in frequency spectrum analyzer.
76.31,for parallel filters in frequency spectrum analysis.
76.44,for filtering in frequency comparison used to determine the frequency of cyclic current or voltage.

SEE OR SEARCH CLASS:

333, Wave Transmission Lines and Networks,   appropriate subclasses for filters and filtering in wave transmission lines and networks.
702, Data Processing: Measuring, Calibrating, or Testing,   subclass 17 for filtering or noise removal in a seismic prospecting system, subclasses 190+ for measured signal extraction or separation (e.g., filtering).
  
[List of Patents for class 324 subclass 76.69]    76.69Current output proportional to frequency:
 This subclass is indented under subclass 76.52.  Subject matter whereby the current is related to the frequency by a constant.
  
[List of Patents for class 324 subclass 76.71]    76.71Nulling circuit:
 This subclass is indented under subclass 76.52.  Subject matter comprising a circuit that indicates when current, voltage, or power is zero.
  
[List of Patents for class 324 subclass 76.72]    76.72Qualitative output:
 This subclass is indented under subclass 76.52.  Subject matter whereby an output indicates conformance to specifications of a device.
(1) Note. This is usually a go or no situation.
  
[List of Patents for class 324 subclass 76.73]    76.73With saturable device:
 This subclass is indented under subclass 76.52.  Subject matter comprising a magnetic-core reactor, the reactance of which is controlled by changing the saturation of the core by varying a superimposed unidirectional flux.

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76.75,for inductive sensing used in determining the frequency of cyclic current or voltage.

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307, Electrical Transmission or Interconnection Systems,   subclasses 401+ for Nonlinear Reactors Systems (e.g., Saturable), per se.
  
[List of Patents for class 324 subclass 76.74]    76.74Deviation measurement:
 This subclass is indented under subclass 76.52.  Subject matter comprising a device that measures the difference between the actual and specified values of a quantity.
  
[List of Patents for class 324 subclass 76.75]    76.75Having inductive sensing:
 This subclass is indented under subclass 76.39.  Subject matter comprising detecting means which senses an inductance or detects the inducing of a voltage through mutual or electrostatic induction.

SEE OR SEARCH THIS CLASS, SUBCLASS:

76.73,for a saturable device in by phase comparison used in determining the frequency of cyclic current or voltage.
200+,for devices and methods to sense and indicate the sensing of a magnetic field, per se.
  
[List of Patents for class 324 subclass 76.76]    76.76With space discharge device:
 This subclass is indented under subclass 76.39.  Subject matter comprising any device which is intended to have an electrical current flow between two spaced electrodes, at least part of the path followed by the discharge being constituted by a gas, vapor, or vacuum.

SEE OR SEARCH THIS CLASS, SUBCLASS:

76.65,for space discharge device in digital output by phase comparison.

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313, Electric Lamp and Discharge Devices,   for space discharge devices, per se.
  
[List of Patents for class 324 subclass 76.77]    76.77Phase comparison (e.g., between cyclic pulse voltage and sinusoidal current, etc.):
 This subclass is indented under subclass 76.11.  Subject matter relating to the measuring of a phase relationship between an electric voltage or current which fluctuates in a periodic manner and another electric voltage or current which fluctuates in the same manner.
(1) Note. Generally, when the measurement of an intangible phase relationship occurs in a significant environment (for example, when the measurement is of the phase difference between voltages produced by two generators in an electric generating system) the search is in this class which provides for the phase measurement in that environment. The search should therefore, in appropriate instances, extend to other classes. An environment recited by name only is not considered to be significant.
(2) Note. The voltage or current usually fluctuates in a sinusoidal manner, but may fluctuate in any other periodic manner.
(3) Note. The phase measurement may be indicated in various manners, as in terms of phase angle, power factor, time lag or advance, or otherwise. The measurement and indication may be either quantitative or qualitative (as, for example, "lead" and "lag").
(4) Note. The two periodic voltages or currents need not be supplied to the system as inputs. For example, one of these periodic voltages may be supplied to the system as the unknown input while the other can be derived from the unknown input by an averaging process or can be supplied by a stable oscillator which is part of the system, or it can be supplied by a mechanically moving standard.
(5) Note. It is impossible to vary the phase of a periodically fluctuating voltage or current without concomitantly varying its frequency. Consequently, especially when phase angles vary rapidly, it may be possible to indicate phase angle by measuring frequency. In those instances the search should extend to subclasses 76.39+ of this class.
(6) Note. One of the voltages or currents may be of a different type than the other voltage or current; for example, one may be a sinusoidal voltage while the other may be a pulse current, or one of the voltages may be a harmonic of the other voltage and the measurement may be of the phase relationship between harmonics of the same frequency.

SEE OR SEARCH THIS CLASS, SUBCLASS:

76.52,for phase comparison in frequency of cyclic current or voltage devices.
141,and 142, for watt meters and voltmeters which do not indicate phase angle but respond to it.
160+,for the measurement of phase angle between an electrical voltage or current and the angular position of a rotating machine which generates or is supplied by said voltage or current.

SEE OR SEARCH CLASS:

329, Demodulators,   subclasses 311+ for pulse demodulators using locally generated oscillations, subclasses 336+ for frequency demodulator employing phase shift, and subclass 346 for using locally generated oscillations.
  
[List of Patents for class 324 subclass 76.78]    76.78Quadrature sensing:
 This subclass is indented under subclass 76.77.  Subject matter comprising means to detect the state or condition of two related periodic functions or two related points separated by a quarter of a cycle, or 90 electrical degrees.
  
[List of Patents for class 324 subclass 76.79]    76.79Feedback control, electrical:
 This subclass is indented under subclass 76.77.  Subject matter having electrical means to control a return path from an output terminal to an input terminal of at least one functional circuit device or circuit.

SEE OR SEARCH CLASS:

330, Amplifiers,   appropriate subclasses for feedback, per se.
  
[List of Patents for class 324 subclass 76.81]    76.81Feedback control, mechanical:
 This subclass is indented under subclass 76.77.  Subject matter having mechanical means to control a return path from an output terminal to an input terminal of at least one functional circuit device or circuit.

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330, Amplifiers,   appropriate subclasses for feedback, per se.
  
[List of Patents for class 324 subclass 76.82]    76.82Digital output:
 This subclass is indented under subclass 76.77.  Subject matter comprising an output signal which represents the size of a stimulus or input signal in the form of a series of discrete quantities which are coded to represent digits in a system of numerical notation.

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76.47,for digital output in frequency comparison in frequency of cyclic current or voltage.
76.55,for digital output in by phase comparison in frequency of cyclic current or voltage.
  
[List of Patents for class 324 subclass 76.83]    76.83Analog output:
 This subclass is indented under subclass 76.77.  Subject matter having an output quantity which varies smoothly over a continuous range of values rather than in discrete steps.
  
[List of Patents for class 324 subclass 77.11]    77.11Nonscanning:
 This subclass is indented under subclass 76.19.  Subject matter wherein the frequency components of the spectrum are acquired simultaneously.
  
[List of Patents for class 324 subclass 84]    84
 This subclass is indented under subclass 83.  Subject matter having a wave guide.

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333, Wave Transmission Lines and Networks,   subclasses 239+ , for wave guides, per se. Also consult the search notes to that subclass for the other classes which make provision for wave guides.
  
[List of Patents for class 324 subclass 85]    85
 This subclass is indented under subclass 83.  Subject matter having means to change the frequency of a voltage or current into another frequency which varies in correspondence therewith.

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79,for frequency measuring using zero or countable beat heterodyne.
82,for the subject matter of this subclass (85) used to measure frequency.
  
[List of Patents for class 324 subclass 86]    86
 This subclass is indented under subclass 83.  Subject matter in which one of the electric voltages or currents is obtained from a polyphase source.
(1) Note. In order that a disclosure be classified in this subclass, the polyphase source must be significantly related to the phase measurement. For example, the average phase angle of three phases of a three phase circuit may be compared with the phase of a single phase circuit. A polyphase source which supplies only a single phase voltage or current to the measuring equipment, without more, is not significantly related to the phase measurement.

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108,for the measurement of positive, negative and zero sequence components of a three phase system.
  
[List of Patents for class 324 subclass 87]    87
 This subclass is indented under subclass 83.  Subject matter having a lamp or space discharge device or nonlinear device.
(1) Note. The lamp and space discharge device of this subclass are of the type which are classified elsewhere (see the Search Notes below) The nonlinear device is one whose voltage-current relationship is significantly nonlinear, as, for example, a thermistor, contact rectifier, thyrite resistor, transistor, saturable reactor or nonlinear condenser.

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313, Electric Lamp and Discharge Devices,   see the Class Definition of Class 313 for lamp and space discharge device of this subclass (324/87). See (1) Note above.
  
[List of Patents for class 324 subclass 88]    88
 This subclass is indented under subclass 87.  Subject matter having a cathode ray tube.
(1) Note. The cathode-ray tube usually serves as an indicator, but not necessarily so.

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313, Electric Lamp and Discharge Devices,   subclasses 364+ , for cathode-ray tubes, per se.
315, Electric Lamp and Discharge Devices: Systems,   subclasses 1+ for cathode-ray tube circuits of general application.
  
[List of Patents for class 324 subclass 89]    89
 This subclass is indented under subclass 87.  Subject matter having a space discharge device of the discharge control type.
(1) Note. The discharge may be controlled, for example, by means of a grid or by means of a magnetic field. The space discharge device may be of either the vacuum, gas or vapor type.
  
[List of Patents for class 324 subclass 90]    90
 This subclass is indented under subclass 83.  Subject matter having an indicating instrument of the type which has a stator element which produces a magnetic field by means of a supplied current.
(1) Note. The electrodynamometer instruments usually do not have a permanent magnetic field, but not necessarily so. They are, for example, of the ratio-meter type.

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144,for the electrodynamometer instrument, per se.
  
[List of Patents for class 324 subclass 91]    91
 This subclass is indented under subclass 83.  Subject matter for indicating if two voltages or currents are in phase.
(1) Note. The indication may be quantitative or qualitative, as, for example, "lead" and "lag". The measurement must be of a phase angle and not of some unrelated quantity. Thus, for example, a mere voltmeter, even though designated a "synchroscope", is not classified here but is classified with the appropriate art.

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84,through 90, for this subject matter where the synchroscope is of the type set forth in subclasses 84 through 90.
  
[List of Patents for class 324 subclass 92]    92
 This subclass is indented under subclass 76.  Subject matter having fluid means as a part thereof.
(1) Note. The fluid means must be significant to the electrical measurement or to the apparatus used in the measurement, and may be used, for example, as an expansible means in a thermal meter, as a lubricant, or as a cooling means.

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155,for meter pivots and bearings.

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73, Measuring and Testing,   subclasses 861+ for fluid rate of flow or volume meters, 290+ for fluid depth gages, and 700+ for fluid pressure gages.
137, Fluid Handling,   appropriate subclasses, for the subject matter of that class. Note subclasses 123+ for syphons, and subclasses 334+ for fluid handling with heating.
  
[List of Patents for class 324 subclass 93]    93
 This subclass is indented under subclass 92.  Subject matter in which the fluid is electrically conductive and having means to cause electricity to flow through the fluid.
(1) Note. The fluid is usually mercury, but may be any other conductive fluid, such as a molten alloy. Herein are found, inter alia, mercury type ampere hour meters.
  
[List of Patents for class 324 subclass 94]    94
 This subclass is indented under subclass 93.  Subject matter in which the fluid is electrolytic and having means to cause an electrolytic action to take place.

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205, Electrolysis: Processes, Compositions Used Therein, and Methods of Preparing the Compositions,   appropriate subclasses for electrolysis utilized for electrochemistry and especially subclasses 775+ as the residual home for a process of electrolytic analysis or testing, per se.
252, Compositions,   subclass 62.2 for electrolytes utilized in electrical devices, such as electrolytic condensers and rectifiers.
  
[List of Patents for class 324 subclass 95]    95
 This subclass is indented under subclass 76.  Subject matter having a wave guide or electrically long line.
(1) Note. A cavity resonator is a special case of a wave guide.

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94+,for similar subject matter utilized in electrical testing other than the measuring of electricity, per se.

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333, Wave Transmission Lines and Networks,   subclasses 236+ , for long lines and wave guides, per se, and consult the class notes of Class 333 and the subclass definition notes for a definition of these terms.
  
[List of Patents for class 324 subclass 96]    96
 This subclass is indented under subclass 76.  Subject matter utilizing radiant energy means as a part thereof.
(1) Note. A voltage being measured may, for example, be applied to an electric light and the luminuous flux produced by the light may be taken as a measure of the voltage being measured.

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250, Radiant Energy,   appropriate subclasses for the detections of nuclear or invisible radiant energy particularly subclasses 336.1+ for invisible radiant energy responsive electric signalling devices.
343, Communications: Radio Wave Antennas,   subclass 703 for antenna combined with structure which tells the magnitude of the signal energy flowing in, to or from the antenna, a significant relationship existing between the antenna and the measuring structure.
356, Optics: Measuring and Testing,   subclass 46 for incandescent standards, and subclasses 213+ for photometers.
  
[List of Patents for class 324 subclass 97]    97
 This subclass is indented under subclass 96.  Subject matter having means to direct the radiant energy in beams.
(1) Note. This subclass includes, for example, reflection galvanometers of the mirror type and pointer instruments having optical means to project an enlarged image of the pointer onto a scale.

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154,for rotors that are mounted on filar suspensions.
  
[List of Patents for class 324 subclass 98]    98
 This subclass is indented under subclass 76.  Subject matter having means for actively bringing a state of balance between mechanical or electrical forces into existence.
(1) Note. This subclass includes, for example, potentiometers in which the potential of an unknown voltage is balanced against the potential of a standard cell.
(2) Note. The mere passive balancing that occurs in an instrument such as the D"Arsonval meter, where the spring restoring torque equals the rotor torque, is not the type of balancing which is the subject matter of this subclass. But balancing without deflection, for example, is found here.
  
[List of Patents for class 324 subclass 99]    99
 This subclass is indented under subclass 98.  Subject matter having automatic means for bringing about the state of balance.

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318, Electricity: Motive Power Systems,   subclasses 560+ , and the classes referred to in the search notes to these subclasses for follow-up electric motor systems, also known as rebalancing and servo motor systems.
330, Amplifiers,   subclasses 144+ for amplifier systems including automatically variable impedance in the signal path.
  
[List of Patents for class 324 subclass 100]    100
 This subclass is indented under subclass 99.  Subject matter in which the result of the balancing operation is recorded.

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113,for similar subject matter not having automatic balancing means.

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346, Recorders,   subclass 31 and 32 for this subject matter.
  
[List of Patents for class 324 subclass 101]    101
 This subclass is indented under subclass 76.  Subject matter having a Wheatstone bridge and having means to indicate the current which results because of the unbalance.

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57+,for Wheatstone bridges used to measure impedance.
98+,for this subject matter having a Wheatstone bridge which is balanced.

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323, Electricity: Power Supply or Regulation Systems,   subclass 365 , for miscellaneous Wheatsone bridge circuits and consult the search notes to that subclass for a list of the other classes which have provision for Wheatstone bridges.
330, Amplifiers,   subclasses 72 , 146 and 175, for amplifier systems wherein series arranged vacuum tubes are in the arms of a bridge, wherein at least one arm of a Wheatstone bridge, and wherein there is a Wheatstone bridge in the signal coupling circuit, respectively.
  
[List of Patents for class 324 subclass 102]    102
 This subclass is indented under subclass 76.  Subject matter which is responsive to a transient or which is used to determine some characteristic of a transient or some characteristic of a portion of a wave form of a cyclic wave.
(1) Note. This subclass includes, for example, the determination of the complete wave form of a transient, such as results when a short circuit occurs on a transmission line.

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100,and 113, for recorders which are equally responsive to transients and steady state voltages.
103+,for peak voltmeters or maximum current ammeters.
121,for cathode ray oscilloscopes which are equally responsive to steady state and transient voltages.
  
[List of Patents for class 324 subclass 103]    103
 This subclass is indented under subclass 76.  Subject matter having means for indicating the demand for electricity, averaged over a set period of time, or having means for indicating the consumption of electricity exceeding a set minimum or having means for indicating the maximum or minimum value of the electricity.
(1) Note. The demand may be indicated in various manners, as by average demand over a period of time larger than the set period of time, maximum demand, integrated demand, or otherwise, and may be expressed in terms of watts, voltamperes or otherwise. The excess consumption may likewise be expressed in various manners, such as integrated excess or excess demand.

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102,for the measurement of some characteristic of a transient, other than mere maximum or minimum.
116,for multi-rate registering meters which register at different rates depending upon demand.
139,for time controlled meters which do not measure demand.
  
[List of Patents for class 324 subclass 104]    104
 This subclass is indented under subclass 103.  Subject matter having means whose temperature is varied in accordance with the electricity being measured and having means, responsive to said temperature variation for indicating the demand, excess consumption, maximum, or minimum.

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92,for this subject matter having fluid means, such as thermal expansion meters.
  
[List of Patents for class 324 subclass 105]    105
 This subclass is indented under subclass 76.  Subject matter having means which are significant because of some thermal relationship.
(1) Note. This subclass includes, for example, cooling features and means for compensating an instrument for changes in the ambient temperature. Thermally actuated meters are in indented subclass 106.
  
[List of Patents for class 324 subclass 106]    106
 This subclass is indented under subclass 105.  Subject matter having means whose temperature is varied in accordance with the electricity being measured and having means, responsive to said temperature variation, for indicating the result of the measurement.
(1) Note. This subclass includes, for example, hot wire ammeters of both the expansion or bimetallic type and the thermocouple type.

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92,for this subject matter having fluid means, such as thermal fluid expansion meters.
104,for this subject matter for indicating demand, excess, maximum or minimum.

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374, Thermal Measuring and Testing,   subclasses 100+ , for thermometers, per se.
  
[List of Patents for class 324 subclass 107]    107
 This subclass is indented under subclass 76.  Subject matter responsive to the voltages or currents in a polyphase system.
(1) Note. A polyphase system is a group of alternating current circuits, usually interconnected, which enter or leave a region at more than two points of entry or exit, and which are so energized that in the steady state the alternating currents through the point of entry or exit and the alternating potential differences between them all have substantially equal periods, but have differences in phase and may have differences in wave form.

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140+,for single phase systems of the three wire type, having means to measure the energy in such systems. Note that some of such metering systems are inherently capable of also measuring polyphase energy. Also consult the search notes to subclass 140.
  
[List of Patents for class 324 subclass 108]    108
 This subclass is indented under subclass 107.  Subject matter for measuring the positive, negative or zero sequence of current of voltage in the polyphase system or responsive to one of these factors.
  
[List of Patents for class 324 subclass 109]    109
 This subclass is indented under subclass 76.  Subject matter having means for utilizing electrostatic attraction or repulsion or piezo-electric action in order to respond to the electricity.

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78+,and 83+, for this subject matter when utilized to measure frequency or compare phase as, for example, in synchroscopes.

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310, Electrical Generator or Motor Structure,   subclass 309 for electrostatic motors and subclasses 311+ for piezo-electric devices and systems, per se.
361, Electricity: Electrical Systems and Devices,   subclasses 271+ for electrostatic condensers, per se.
  
[List of Patents for class 324 subclass 110]    110
 This subclass is indented under subclass 76.  Subject matter for protecting the electric measuring apparatus or for combating attempts to cause the meter to read inaccurately.
(1) Note. This subclass includes, for example, meters combined with fuses to protect the meter against accidental overloads and meters that are provided with special circuit means to cause the meter to continue to register if the potential coil is disconnected by a customer of a utility company who is attempting to defraud the company.

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156,for meters having casings which serve to protect the meter mechanically.

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361, Electricity: Electrical Systems and Devices,   subclasses 659+ for meters having casings and similar structures to protect the meters mechanically.
  
[List of Patents for class 324 subclass 111]    111
 This subclass is indented under subclass 76.  Subject matter having means to store the electricity which is being measured.
(1) Note. This subclass relates to storage means, such as condenser banks, which store the electricity in such a manner that the original wave form can be recovered, and also relates to condensers which are used to integrate the electricity.

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178, Telegraphy,   subclass 17.5 , for telegraph systems having storage means for temporarily holding signals.
315, Electric Lamp and Discharge Devices: Systems,   subclasses 8.51+ for cathode ray tube systems for accumulating or storing electrical pulse energy for later retrieval, and subclasses 84.51+ for similar electrical pulse storage systems utilizing electric space discharge devices of the gaseous type.
365, Static Information Storage and Retrieval,   appropriate subclass for the storage and retrieval of information. This class excludes the mere storage of control signals.
  
[List of Patents for class 324 subclass 112]    112
 This subclass is indented under subclass 111.  Subject matter in which the electricity is stored in an extended tape or wire or in a sheet medium.
(1) Note. This subclass relates to, for example, the storage of the electricity in a disk, similar to a phonograph record, and to the storage of the electricity in magnetic wire or tape.

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360, Dynamic Magnetic Information Storage or Retrieval,   for magnetic recording or reproducing.
365, Static Information Storage and Retrieval,   appropriate subclass for the storage and retrieval of information. This class excludes the mere storage of control signals.
369, Dynamic Information Storage or Retrieval,   for dynamic storage of information signals.
  
[List of Patents for class 324 subclass 113]    113
 This subclass is indented under subclass 76.  Subject matter for recording the result of the measurement of the electricity.
(1) Note. Many of the Classes have provision for their own recording systems, consequently, in appropriate instances, the search for a recorder should extend to the class relating to the environment in which the recorder might be found.

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346, Recorders,   appropriate subclasses, for this same subject matter. In Class 346 there is no subclass which relates specifically to the recording of electricity, per se, but the recorders are classified on the basis of the manner in which the record is made. Note subclass 150.2 in which an electric spark is utilized to mark a phenomenal record.
347, Incremental Printing of Symbolic Information,   subclasses 111+ for electric recorders comprising means for applying electricity to a medium for recording an image.
  
[List of Patents for class 324 subclass 114]    114
 This subclass is indented under subclass 76.  Subject matter having plural meters.
(1) Note. The meters may be of the same or of different kinds and may be separated or may be combined to one case.

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115,for single meters which have plural ranges or plural scales.

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340, Communications: Electrical,   subclasses 870.41 and 870.15 for telemetering systems having plural receivers or meters.
361, Electricity: Electrical Systems and Devices,   subclass 660 for switchboards having plural meters.
  
[List of Patents for class 324 subclass 115]    115
 This subclass is indented under subclass 76.  Subject matter having plural ranges, plural scales, or plural registration rates.

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114,for meters having plural scales or plural ranges where both scales or both ranges are simultaneously usable, (i.e., where there are plural meters).
  
[List of Patents for class 324 subclass 116]    116
 This subclass is indented under subclass 115.  Subject matter having a register.
(1) Note. This subclass includes, for example, watt hour meters which register at one rate for an initial period and then register at a different rate for other periods.

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103,for demand meters, per se, i.e., meters that indicate purely demand and not some quantity of which demand is but a factor.
139,for time controlled meters of the registering type which do not register at plural rates.
  
[List of Patents for class 324 subclass 117]    117
 This subclass is indented under subclass 76.  Subject matter having magnetic means in which a significant amount of saturation occurs during the operation thereof.
(1) Note. This subclass relates, for example, to metering systems having magnetic amplifiers and to meters having saturated pole tips.

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323, Electricity: Power Supply or Regulation Systems,   subclasses 249 , 302, 310, and 329, for magnetic amplifiers of the nonlinear type.
330, Amplifiers,   subclass 10 for amplifier systems wherein the active element is a saturable core reactor.
  
[List of Patents for class 324 subclass 118]    118
 This subclass is indented under subclass 76.  Subject matter having means to modulate the voltage or current being measured onto a carrier wave and having further means to demodulate the resulting modulating carrier wave into a replica of the original voltage or current.
(1) Note. This subclass relates, for example, to direct current voltmeters which measure a very small direct current voltage which small voltage is amplified in the modulator-demodulator apparatus so that it is large enough to actuate a conventional meter.

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329, Demodulators,   appropriate subclasses for demodulators, per se.
330, Amplifiers,   subclass 10 for modulator-demodulator amplifiers, per se.
332, Modulators,   appropriate subclasses, for modulators.
  
[List of Patents for class 324 subclass 119]    119
 This subclass is indented under subclass 76.  Subject matter having a rectifier.
(1) Note. The rectifier may be used, for example, to change an alternating current input into a direct current output, or the rectifier may be used merely as a nonlinear element.

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363, Electric Power Conversion Systems,   appropriate subclasses for miscellaneous rectifying systems.
  
[List of Patents for class 324 subclass 120]    120
 This subclass is indented under subclass 76.  Subject matter having means to transform the voltage or current to be measured into a different current or voltage and having means to measure said different voltage or current.
(1) Note. This subclass contains, for example, systems where a DC voltage is changed into an AC voltage which is measured as an AC voltage, systems wherein the input voltage is converted into a pulse voltage and systems wherein the input voltage is converted from one frequency into another frequency.

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118,for this subject matter wherein the input voltage or current is first modulated and then demodulated.
119,for this subject matter having a rectifier.

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340, Communications: Electrical,   subclasses 870.01+ for telemetering systems having no significant measuring, testing or sensing of the condition to be telemetered. Some telemetering systems utilize current conversion means. Note indented subclasses 870.19+ for telemetering systems in which the value of the condition is represented by a pulse code.
  
[List of Patents for class 324 subclass 121]    121
 This subclass is indented under subclass 76.  Subject matter having a cathode-ray tube.
(1) Note. The cathode-ray tube may be an indicator as, for example, a cathode ray oscilloscope or a "magic eye" tube, or the cathode-ray tube may be a control tube of some type.

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88,for this subject matter utilized to measure phase displacement between two voltages.

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313, Electric Lamp and Discharge Devices,   subclasses 364+ , for cathode-ray tubes, per se.
315, Electric Lamp and Discharge Devices: Systems,   subclasses 1+ , for cathode- ray tubes circuits of general application. Note that Class 315 includes, among its cathode-ray tube systems, those systems in which an unknown voltage is applied to the deflecting means of the cathode-ray tube so that the unknown voltage may be observed. The system is not excluded from Class 315 unless some means is claimed to enable the desired information to be derived other than merely observing the trace of the ray on an unchartered luminous screen.
  
[List of Patents for class 324 subclass 122]    122
 This subclass is indented under subclass 76.  Subject matter having a gaseous discharge device.
(1) Note. A gaseous discharge device is defined as being a device having two spaced electrodes between which electricity flows and having either gas or vapor in the space between the electrodes.
(2) Note. This subclass includes, for example, spark gap volt meters and metering systems using a gaseous discharge device as a nonlinear impedance.

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313, Electric Lamp and Discharge Devices,   subclasses 567+ for gaseous discharge devices, per se.
315, Electric Lamp and Discharge Devices: Systems,   appropriate subclasses for miscellaneous gas discharge device systems.
  
[List of Patents for class 324 subclass 123]    123
 This subclass is indented under subclass 76.  Subject matter having an amplifier or having a space discharge device.

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117,for this subject matter utilizing magnetic saturation type amplifiers.
121,for this subject matter when the space discharge device is a cathode-ray tube.
122,for this subject matter when the space discharge device is a gaseous discharge device.

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330, Amplifiers,   for amplifiers, per se.
  
[List of Patents for class 324 subclass 124]    124
 This subclass is indented under subclass 123.  Subject matter having an inverted amplifier.
(1) Note. An inverted amplifier is defined as one having an amplification factor which is less than unity. Usually this is achieved by connecting the input circuit to the plate of a vacuum tube and taking the output from the grid of a vacuum tube. The inverted amplifier acts as an attenuating circuit to couple the meter to the source of voltage or current being measured.

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330, Amplifiers,   subclass 250 for inverted transistor amplifiers, and subclasses 160+ and 162+ for inverted amplifiers of the vacuum tube type.
  
[List of Patents for class 324 subclass 125]    125
 This subclass is indented under subclass 76.  Subject matter having means to control the mechanical vibrations which result because of inertia, elasticity, and damping or having means to control vibrations which arise outside or inside the measuring means.
(1) Note. This subclass includes, for example, instruments having "dead beat" characteristics.

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123,for this subject matter having amplifier means with negative feed back control, for the purpose of controlling the inertia effects.

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73, Measuring and Testing,   subclass 430 for instrument mechanism dampening, per se, subclasses 514.12+ for fluid or fluent material dampening of an inertial member in an acceleration measuring apparatus, and subclass 514.14 for vibration dampening in an inertial-type acceleration measuring apparatus.
248, Supports,   subclasses 560+ for resilient supports.
  
[List of Patents for class 324 subclass 126]    126
 This subclass is indented under subclass 76.  Subject matter having means for coupling the measuring device to the source of current or voltage being measured.
(1) Note. Such means, for example, may be an attenuator or an instrument shunt.

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115,for this subject matter in instruments having plural ranges.
149,for measuring instruments having mere prods, probes or other terminal structure without circuit elements other than conductors.

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333, Wave Transmission Lines and Networks,   subclasses 24+ for coupling networks, per se.
338, Electrical Resistors,   subclass 49 for electrical resistors of the shunt type.
  
[List of Patents for class 324 subclass 127]    127
 This subclass is indented under subclass 126.  Subject matter in which the coupling means is a transformer.
(1) Note. The transformer, for example, may be of the type having a core which can be opened to admit a current carrying conductor.

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129,for instruments having pole pieces which will admit a nonunitary input conductor without disconnecting or cutting said implement conductor.

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336, Inductor Devices,   appropriate subclasses for the structure of transformers, per se. Of special interest are subclass 172 , for "Fractional turn" type inductive devices (including transformers), and subclasses 173+ and 175+ which include current transformers.
  
[List of Patents for class 324 subclass 128]    128
 This subclass is indented under subclass 126.  Subject matter in which the coupling means is a selective filter.
(1) Note. The filter may be a high pass, low pass or band pass filter.

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333, Wave Transmission Lines and Networks,   subclasses 167+ , for wave filters, per se.
  
[List of Patents for class 324 subclass 129]    129
 This subclass is indented under subclass 76.  Subject matter having pole piece means so constructed that they will admit an input conductor without cutting or disconnecting said conductor.
(1) Note. This subclass includes, for example, "hook on" ammeters of the type not equipped with an integral transformer.

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127,for similar subject matter utilizing a transformer of the split core type.
  
[List of Patents for class 324 subclass 130]    130
 This subclass is indented under subclass 76.  Subject matter having means for self-calibrating the instrument.

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74+,for calibrating means for electric instruments, per se.
  
[List of Patents for class 324 subclass 131]    131
 This subclass is indented under subclass 76.  Subject matter in which the measuring instrument indications are of the suppressed zero type.
(1) Note. Suppressed zero refers to that condition of instrument in which the scale reading does not extend from zero to an upper value but rather from an intermediate value to an upper value.
  
[List of Patents for class 324 subclass 132]    132
 This subclass is indented under subclass 76.  Subject matter in which the measuring instrument indications are of the nonlinear type.
(1) Note. The instrument deflection, for example, may be related to the input current or voltage in a logarithmic manner.
  
[List of Patents for class 324 subclass 133]    133
 This subclass is indented under subclass 76.  Subject matter for giving a nonquantitative indication.
(1) Note. This subclass includes, for example, polarity testers and "hot-line" indicators.
(2) Note. A quantitative instrument may be modified into a nonquantitative instrument by merely omitting the scale. Consequently, in appropriate instances, the search should extend to the pertinent quantitative type subclass.

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340, Communications: Electrical,   appropriate subclasses for similar subject matter. Also see the search note to Class 340 in the class definition of this class (324).
362, Illumination,   appropriate subclasses, for electric lamp luminaries, many of which could be used as nonquantitative indicators.
  
[List of Patents for class 324 subclass 134]    134
 This subclass is indented under subclass 76.  Subject matter having a commutator or having a reversing switch or having a pulsating switch.
(1) Note. This subclass includes, for example, DC watt hour meters.

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200, Electricity: Circuit Makers and Breakers,   appropriate subclasses for the structure of switches, per se.
310, Electric Generator or Motor Structure,   appropriate subclasses, for motors having commutators.
361, Electricity: Electrical Systems and Devices,   subclasses 139+ for relay systems, per se.
  
[List of Patents for class 324 subclass 135]    135
 This subclass is indented under subclass 134.  Subject matter having a rotor which oscillates between two positions.

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73, Measuring and Testing,   subclass 430 for instrument mechanism dampening, per se, subclasses 514.12+ for fluid or fluent material dampening of an inertial member in an acceleration measuring apparatus, and subclass 514.14 for vibration dampening in an inertial-type acceleration measuring apparatus.
310, Electrical Generator or Motor Structure,   subclasses 36+ for oscillating motors, per se.
  
[List of Patents for class 324 subclass 136]    136
 This subclass is indented under subclass 76.  Subject matter having a rolling ball or a rolling wheel.
(1) Note. The ball or wheel are usually part of an integrating mechanism, but may be part of a speed transmission.

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33, Geometrical Instruments,   subclass 121 for area integrators, per se.
235, Registers,   appropriate subclasses, particularly subclasses 65 , 66 and 68, for calculating devices and machines having integrating features.
  
[List of Patents for class 324 subclass 137]    137
 This subclass is indented under subclass 76.  Subject matter having a rotor upon which torque is exerted by means of an electo-magnetic field which produces eddy current in the rotor.
(1) Note. This subclass includes, for example, the familiar AC integrating watt hour meter. The rotor is often known as a Ferraris disk.
(2) Note. The rotor in this subclass may rotate continuously or may rotate through only a certain angle as determined by the stiffness of a spring which restrains further rotation.

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152,for this subject matter where the eddy current rotor is merely a drag disk.

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310, Electrical Generator or Motor Structure,   subclasses 166+ for eddy current motors of general application.
318, Electricity: Motive Power Systems,   subclasses 727+ for eddy current motor systems of general application. Note particularly indented subclasses 781+, for eddy current motors which operate from a single phase source.
  
[List of Patents for class 324 subclass 138]    138
 This subclass is indented under subclass 137.  Subject matter having means to vary the time-phase relationship between two alternating magnetic fields.
(1) Note. The time-phase relationship, for example, may be adjusted so as to bring the alternating magnetic fields into time quadrature, or it may be adjusted so that they are slightly out of quadrature.

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148,for other measuring means having phase shift means.

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318, Electricity: Motive Power Systems,   subclass 729 for power-factor control of induction motor systems including eddy current motor systems.
323, Electricity: Power Supply or Regulation Systems,   subclasses 212 through 219for phase shifting means, per se.
  
[List of Patents for class 324 subclass 139]    139
 This subclass is indented under subclass 76.  Subject matter having rotary motor driving means which rotate constantly, independently of the electricity being measured, or having time control means or having means which oscillate.
(1) Note. Time control means may be, for example, a clock which rotates at a constant speed or an electric synchronous motor which rotates at a constant speed. Oscillating means may be means such as an anchor escapement or a stepping ratchet.
(2) Note. This subclass relates, for example, to integrating meters wherein an element periodically oscillates at an amplitude which is determined by the quantity to be integrated (variable stroke) or at a radius which is determined by that quantity (variable radius).

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103+,for demand, excess, maximum or minimum meters which provide a final indication of which time is but a factor.
116,for multi-rate registering meters which register at different rates in accordance with a function of time.
135,for oscillating measuring means in which a pulsating or reversing switch is associated with the oscillating means.
136,for variable radius type meters which utilize a rolling ball or wheel.

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74, Machine Element or Mechanism,   appropriate subclasses, for ratchet mechanisms.
368, Horology: Time Measuring Systems or Devices,   for clocks and watches. Note subclasses 155+ , for those having electrical features.
  
[List of Patents for class 324 subclass 140]    140
 This subclass is indented under subclass 76.  Subject matter having plural inputs to the measuring means.
(1) Note. A single circuit can furnish plural inputs to the measuring means, since a single circuit can carry a voltage and a current independently of each other. Thus, the indented subclasses contain watt meters and volt-ampere meters of the type which are not found in subclasses above.
(2) Note. This subclass includes, for example, ratio meters and summation meters.

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62+,for complete resistance measuring systems including, as a part thereof, ratio meters.

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340, Communications: Electrical,   subclasses 870.01+ for telemetering systems for indicating at a remote point the value of a local condition. Note subclasses 870.11+ where the condition at plural localities is sensed. Note subclasses 870.19+ where the value of the condition is coded into a pulse type code.
  
[List of Patents for class 324 subclass 141]    141
 This subclass is indented under subclass 140.  Subject matter for measuring volt amperes.
(1) Note. The volt amperes may be either real or reactive. Reactive volt amperes are often referred to as volt vars,

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137+,for this subject matter having an eddy current rotor.
  
[List of Patents for class 324 subclass 142]    142
 This subclass is indented under subclass 140.  Subject matter for measuring watts.
(1) Note. This subclass contains, for example, watt meters of the dynamometer type.

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134,for this subject matter having a commutator or a reversing or pulsating switch.
137+,for this subject matter having an eddy current rotor.
  
[List of Patents for class 324 subclass 143]    143
 This subclass is indented under subclass 76.  Subject matter having plural active motor elements.
(1) Note. The plural active motor element may be mounted on a single shaft to operate a single indicator, or they may be mounted on two shafts to operate two rotary arms whose variable point of intersection determines the final indication.

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114,for plural meters.
115,for a single meter having plural ranges or scales.
  
[List of Patents for class 324 subclass 144]    144
 This subclass is indented under subclass 76.  Subject matter having a stationary means to produce a magnetic field by the flow of electricity through a winding.
(1) Note. This subclass includes, for example, electrodynamometer type instruments having only a single input.

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134+,for this subject matter having a rotor with a commutator or reversing or pulsating switch.
137+,for this subject matter having an eddy current rotor.
140+,for this subject matter having plural inputs.

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310, Electrical Generator or Motor Structure,   subclasses 10+ , for dynamo electric structure of general application.
  
[List of Patents for class 324 subclass 145]    145
 This subclass is indented under subclass 144.  Subject matter having a core armature which is attracted by the magnetic field and which moves, under said attraction, along its own axis.

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335, Electricity: Magnetically Operated Switches, Magnets, and Electromagnets,   subclasses 255+ for plunger type solenoids, per se.
  
[List of Patents for class 324 subclass 146]    146
 This subclass is indented under subclass 144.  Subject matter having a permanent magnet.
(1) Note. The permanent magnet may supplement the magnetic field produced by the electromagnet or it may be acted upon by the electromagnetic field.

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147,for similar subject matter having soft instead of hard iron.

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335, Electricity: Magnetically Operated Switches, Magnets, and Electromagnets,   subclasses 299+ for similar subject matter, not restricted to the measurement of electricity.
  
[List of Patents for class 324 subclass 147]    147
 This subclass is indented under subclass 144.  Subject matter having an iron rotor.

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146,for this subject matter where the iron rotor is or becomes a permanent magnet under any conditions of operation.
  
[List of Patents for class 324 subclass 149]    149
 This subclass is indented under subclass 76.  Subject matter having a probe, a prod or a specific terminal.

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72.5,for similar subject matter in combination with a high frequency testing device.
119,for this subject matter having a rectifier in the probe.

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361, Electricity: Electrical Systems and Devices,   subclass 668 for meter terminal or connector arrangements.
439, Electrical Connectors,   appropriate subclasses for an electrical terminal, per se.
  
[List of Patents for class 324 subclass 150]    150
 This subclass is indented under subclass 76.  Subject matter having a rotor which has a coil which is eccentrically mounted with respect to the axis of the rotor.
(1) Note. The coil, for example, may be of rectangular shape and the axis of the rotor may correspond with one of the sides of the rectangle.

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140,for this subject matter having plural inputs, as in ratio-meters.
  
[List of Patents for class 324 subclass 151]    151
 This subclass is indented under subclass 76.  Subject matter having a permanent magnet.
(1) Note. This subclass relates, for example, to D"Arsonval type instruments and to magnetic suspensions for instrument rotors.

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146,for this subject matter also having a magnetic field produced by an electromagnet.
171+,for similar subject matter not restricted to the measurement of electricity.

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310, Electrical Generator or Motor Structure,   subclass 90.5 for a bearing having a magnetic suspension.
335, Electricity: Magnetically Operated Switches, Magnets, and Electromagnets,   subclasses 302+ for permanent magnets, per se.
  
[List of Patents for class 324 subclass 152]    152
 This subclass is indented under subclass 151.  Subject matter in which the permanent magnet is associated with an eddy current means and the permanent magnet acts as a drag for the eddy current means.
(1) Note. The eddy current means usually is a disk rotor.

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103,for excess type meters which utilize a hysteresis type brake (which has a constant counter-torque at all speeds) having a permanent magnet and for meters in which the torque on the drag magnet actuates an indicator by movement of the drag magnet.
137+,for similar subject matter where an eddy current disk acts both as a motive element and a drag element.
139,for meters having a rotor which is driven by a constant torque device and having a brake whose drag is determined by the electricity to be measured.

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310, Electrical Generator or Motor Structure,   subclasses 103+ , for magnetic field type torque transmitting brakes and clutches.
  
[List of Patents for class 324 subclass 153]    153
 This subclass is indented under subclass 76.  Subject matter having a register.
(1) Note. A registering means is herein defined as being a device which converts a linear or rotational movement into a number which corresponds to the movement and is a measure thereof. Generally the register is provided with means for separately indicating the value of the several digits which go to make up the number that is a measure of the indication.
  
[List of Patents for class 324 subclass 154]    154
 This subclass is indented under subclass 76.  Subject matter having a rotor.
(1) Note. This subclass includes, for example, rotors provided with filar suspensions, rotors having means for setting them to zero, and rotors having means to balance them.
  
[List of Patents for class 324 subclass 155]    155
 This subclass is indented under subclass 154.  Subject matter having significant bearing or pivot structure.
(1) Note. A bearing or pivot is significant when it is claimed by more than name only or when it is disclosed as being significant.

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151,for magnetic suspensions which decrease friction by decreasing bearing load.
403+,for meters with fluid means, such as lubricating means.

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310, Electrical Generator or Motor Structure,   subclass 90.5 for a bearing having a magnetic suspension.
  
[List of Patents for class 324 subclass 156]    156
 This subclass is indented under subclass 76.  Subject matter having a casing for the instrument.

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73, Measuring and Testing,   subclass 431 , for this subject matter.
312, Supports: Cabinet Structure,   for miscellaneous casings.
361, Electricity: Electrical Systems and Devices,   subclasses 659+ for special meter casings, and subclasses 664+ for meter mounting arrangements.
  
[List of Patents for class 324 subclass 157]    157
 This subclass is indented under subclass 76.  Subject matter combined with some other type of subject matter.
(1) Note. The meter, for example, may be combined with a specific type of distribution system.
(2) Note. A meter in a specific environment, generally, but not invariably, is classified with the specific environment. Consequently, in appropriate instances, the search should extend to the class which relates to the environment.

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72,for the measurement of electricity in a specific environment.
116,for multi-rate registering meters which may, for example, be combined with two load circuits having loads of different tariff rates.

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307, Electrical Transmission or Interconnection Systems,   appropriate subclasses for systems for distributing electricity.
  
[List of Patents for class 324 subclass 160]    160
 This subclass is indented under the class definition.  Subject matter wherein are provided processes or means to produce an electrical signal representative of the time rate of change of position (speed) of a physical element and to indicate, in response to said signal, said time rate.

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73, Measuring and Testing,   subclasses 178+ , for navigational speed measuring devices such as ship’s logs, leeway incidence or rate of climb; subclasses 861+, for volume or rate of flow meters; subclasses 488+, for mechanical speed measuring devices and indented subclasses 519.01+, for permanent magnet type speedometers.
340, Communications: Electrical,   subclasses 441 and 446, for vehicle speed actuated signals and subclasses 670+, for speed actuated signals and alarms in general.
342, Communications: Directive Radio Wave Systems and Devices (e.g., Radar, Radio Navigation),   subclasses 104+ for radar type systems which determine the velocity of an object.
346, Recorders,   subclass 18 , for recorders combined with a speed indicator or alarm.
356, Optics: Measuring and Testing,   subclasses 27+ , for velocity or velocity/height measuring systems including optical sighting systems.
361, Electricity: Electrical Systems and Devices,   subclass 51 and subclasses 236+ for control systems responsive to speed.
700, Data Processing: Generic Control Systems or Specific Applications,   subclass 304 for speed control.
702, Data Processing: Measuring, Calibrating, or Testing,   subclasses 141 and 142+ for acceleration and speed measuring systems, respectively.
  
[List of Patents for class 324 subclass 161]    161
 This subclass is indented under subclass 160.  Subject matter in which means are provided for comparing one speed signal with another speed signal or a reference signal.
(1) Note. The comparison means is not necessarily electrical.

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79,for comparison of the frequencies of two electrical signals.

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307, Electrical Transmission or Interconnection Systems,   subclass 123 , for switching systems responsive to the differential speed between two bodies.
361, Electricity: Electrical Systems and Devices,   subclasses 243+ for the synchronization of rotating shafts which requires a comparison of the speeds of the shafts. Also consult the search notes to that subclass for a compilation of other pertinent classes.
  
[List of Patents for class 324 subclass 162]    162
 This subclass is indented under subclass 160.  Subject matter including means producing an electrical signal representative of the time rate of change of speed or a physical object.
(1) Note. This subclass relates to electrical accelerometers other than, for example, those which sense acceleration by means of an inertial element.
(2) Note. The means of this subclass may include means responsive to acceleration, per se, or means responsive to a speed signal to derive the acceleration.

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73, Measuring and Testing,   subclasses 514.01+ , for means indicating acceleration including an inertial element. See (1) Note above.
307, Electrical Transmission or Interconnection Systems,   subclass 121 , for switching systems responsive to acceleration.
340, Communications: Electrical,   subclass 669 , for acceleration or deceleration responsive signals or alarms.
700, Data Processing: Generic Control Systems or Specific Applications,   subclass 304 for speed control.
702, Data Processing: Measuring, Calibrating, or Testing,   subclasses 141 and 142+ for acceleration and speed measuring system, respectively.
  
[List of Patents for class 324 subclass 163]    163
 This subclass is indented under subclass 160.  Subject matter in which means for producing a signal representative of speed includes means to convert mechanical motion into an electrical signal whose output amplitude is a function of the speed being measured, and in which the indicating means measures said amplitude.

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166+,for electrical generators of speed signals whose frequency is a function of the speed being measured.

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310, Electrical Generator or Motor Structure,   subclasses 10+ , for dynamoelectric generator structure.
322, Electricity: Single Generator Systems,   appropriate subclasses, for single dynamoelectric generator systems.
  
[List of Patents for class 324 subclass 164]    164
 This subclass is indented under subclass 163.  Subject matter in which the electrical generator includes a conductive, nonferromagnetic armature whose movement is representative of the speed being measured, means to induce an electric current in said armature and means responsive to the current to indicate the speed of the armature.

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310, Electrical Generator or Motor Structure,   subclass 171 , for induction generator structure.
322, Electricity: Single Generator Systems,   subclass 47 , for induction generator systems.
  
[List of Patents for class 324 subclass 165]    165
 This subclass is indented under subclass 163.  Subject matter combined with means to indicate the sense of motion (e.g., forward or backward, clockwise or counter clockwise) within a given path, of the object whose speed is being measured.

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33, Geometrical Instruments,   subclass 204 , for direction indicators in general which are responsive to some force.
116, Signals and Indicators,   subclasses 200+ , for mechanically actuated shaft rotation indicators.
307, Electrical Transmission or Interconnection Systems,   subclass 122 , for switching systems responsive to direction of rotation.
340, Communications: Electrical,   subclass 465 , for signal means for automatically indicating the direction of movement of a vehicle, and subclasses 671+, for signal means for indicating machine shaft rotation or direction.
  
[List of Patents for class 324 subclass 166]    166
 This subclass is indented under subclass 160.  Subject matter in which the signal producing means produces a periodic electrical signal whose frequency is a function of the speed being measured.
(1) Note. This subclass includes, for example, apparatus in which an electrical pulse is produced each time the moving object traverses a fixed increment of distance. The movement thus sensed may be either linear or angular (e.g., rotary).

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78+,for the measurement of the frequency of cyclic electric currents of voltages.
  
[List of Patents for class 324 subclass 167]    167
 This subclass is indented under subclass 166.  Subject matter including electro-magnetic, indicator driving means energized by the speed signal to produce a rotating magnetic field whose rotation is synchronized with the frequency of the speed signal.
(1) Note. The rotating magnetic field may drive freely rotating armature or a restrained armature either of which is, in turn, connected to some means to indicate the speed of the rotating field and, thus, the object whose speed is being measured.
  
[List of Patents for class 324 subclass 168]    168
 This subclass is indented under subclass 166.  Subject matter in which the means for producing a signal includes an electrical circuit breaker actuated at a frequency representative of the speed being measured.

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200, Electricity: Circuit Makers and Breakers,   subclasses 19.01+ , for periodically actuated switches.
  
[List of Patents for class 324 subclass 169]    169
 This subclass is indented under subclass 168.  Subject matter in which the switch is also a component of an internal combustion engine ignition system.
  
[List of Patents for class 324 subclass 170]    170
 This subclass is indented under subclass 169.  Subject matter wherein the speed measuring means is connected to the secondary circuit of the ignition system; the voltage fluctuations of the secondary circuit thereby producing the speed signal.
  
[List of Patents for class 324 subclass 171]    171
 This subclass is indented under subclass 168.  Subject matter combined with means to indicate the distance the object whose speed is being measured has traveled during the speed measuring interval.
(1) Note. This subclass includes revolution counters as well as odometers.

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73, Measuring and Testing,   subclass 490 , for mechanical speed and distance measuring systems.
  
[List of Patents for class 324 subclass 172]    172
 This subclass is indented under subclass 166.  Subject matter in which means for producing a speed signal includes a recording medium and means to move it at a speed proportional to speed being measured.
  
[List of Patents for class 324 subclass 173]    173
 This subclass is indented under subclass 166.  Subject matter in which the means for producing a speed signal included means producing a magnetic field and further means sensitive to changes in the field to produce an electrical signal.

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200,for magnetic detectors and systems therefor.

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73, Measuring and Testing,   subclass 519.01 for a speed measuring device using a magnetic drag cup.
310, Electrical Generator or Motor Structure,   subclasses 40+ , for rotary dynamoelectric generator structure.
322, Electricity: Single Generator Systems,   appropriate subclasses for single dynamoelectric generator systems.
  
[List of Patents for class 324 subclass 174]    174
 This subclass is indented under subclass 173.  Subject matter in which the means for producing a magnetic field includes a permanent magnet.

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310, Electrical Generator or Motor Structure,   subclasses 152+ for rotary, dynamoelectric generator structure including permanent magnets.
322, Electricity: Single Generator Systems,   subclass 46 , for single dynamoelectric permanent-magnet generator systems.
  
[List of Patents for class 324 subclass 175]    175
 This subclass is indented under subclass 166.  Subject matter in which means for producing a speed signal includes means responsive to radiant energy (i.e., electromagnetic or atomic radiation) to produce or alter an electric current.
  
[List of Patents for class 324 subclass 176]    176
 This subclass is indented under subclass 160.  Subject matter in which the means for producing the electric speed signal includes a variable circuit element whose impedance varies as a function of the position of the object in the path along which its speed is being measured.
(1) Note. The impedance of the circuit element of this subclass being a function of displacement, the current through the element may, for example, be differentiated with respect to time to produce the speed signal.

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178,and the subclasses indented thereunder for systems including an element whose electrical characteristics change in response to the passage of an object.

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73, Measuring and Testing,   subclasses 514.39+ , for apparatus including a mechanical speed indicating device with electrical means for sensing its indication, for example, a flyball governor with electrical means for sensing the radial displacement of the flyball.
  
[List of Patents for class 324 subclass 177]    177
 This subclass is indented under subclass 160.  Subject matter in which the means producing an electric speed signal is responsive to the supply voltage or current of an electric motor.

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318, Electricity: Motive Power Systems,   and subclass 490 , for electric motors with signals, meters, recorders or testing devices.
388, Electricity: Motor Control Systems,   appropriate subclasses, together with art collection 928.1, for running-speed and acceleration control systems for responsive to terminal electromotive force.
  
[List of Patents for class 324 subclass 178]    178
 This subclass is indented under subclass 160.  Subject matter wherein the means for producing a speed signal includes means responsive to the passage (event) of an object past a plurality spaced locations.
(1) Note. This subclass includes, for example, systems for measuring the time taken by an object such as projectile or vehicle to move through a measured distance. The "event" being the passage of the object past the ends of the measured distance.

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181+,for systems for measuring the duration of time intervals.

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73, Measuring and Testing,   subclass 167 , for apparatus for testing ordinance and projectiles.
346, Recorders,   subclass 38 , for recorders actuated responsive to ordinance.
  
[List of Patents for class 324 subclass 179]    179
 This subclass is indented under subclass 178.  Subject matter in which the means responsive to the passage of an object is sensitive to magnetic field variations caused by passage of the object through magnetic field.
  
[List of Patents for class 324 subclass 180]    180
 This subclass is indented under subclass 178.  Subject matter in which the means responsive to the passage of an object includes an electrical switch actuated directly by the object.
(1) Note. The switch of this subclass may be frangible.

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200, Electricity: Circuit Makers and Breakers,   appropriate subclasses for switches or particular structure or type, particularly subclass 47 , for limit switches adapted to be actuated by the motion of a machine part, and subclass 61.41, for stationary switch structure having an actuator responsive to the passage of a transient object
  
[List of Patents for class 324 subclass 200]    200MAGNETIC:
 This subclass is indented under the class definition.  Subject matter which includes apparatus to sense and indicate the sensing of a magnetic field and elements or subcombinations of apparatus to sense and indicate the sensing of the magnetic field where not elsewhere provided.
(1) Note. Method claims pertaining to the subject matter of this group of subclasses will be placed with the corresponding apparatus subclasses.
(2) Note. The term "elements" includes magnetic sensors, per se, and energized sensors not provided for in another class.
(3) Note. The apparatus to indicate includes a visible or latent recording of the result of a magnetic field sensing.
(4) Note. The magnetic field sensed may be a portion of a magnetic field or a portion of a magnetic field in a material.
(5) Note. Included in this group of subclasses are: the measuring or testing of magnetic fields, the measuring, testing, or sensing of material of metal or nonmetal by means of magnetic fields for electrical, magnetic, and other properties of the material, subcombinations of the apparatus to measure or test magnetic fields or materials by magnetic fields not provided for elsewhere, magnetic field sensors not classified elsewhere, supports for material tested by magnetic fields, and supports for magnetic field sensing devices.
(6) Note. This is the generic subclass for the location, identification, or testing of (1) metal ores, (2) unwanted metals, or (3) the presence of metal in a nonmetal environment. In these cases the metal is located, identified, or tested by its interaction with a magnetic field.

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51,for short or open coil tests, the number of coil turns tests, and coil polarity tests.
55,for transformer properties testing. 300+, for nuclear or electronic testing. 323+, for geophysical subsurface and surface testing. 376+, for core sample magnetic orientation testing.

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164, Metal Founding,   subclass 450.5 for a metal casting apparatus including control means influenced by a magnetic sensor.
209, Classifying, Separating, and Assorting Solids,   subclass 8 for magnetizing or demagnetizing precedent to a separation, subclasses 38+ for the combination of a magnetic separation with another physical separation of a solid from a solid, subclasses 72+ for the magnetic testing and separation of objects from other objects, and subclasses 212+ for the separation of material by magnetic separation.
250, Radiant Energy,   subclasses 250+ for the detection of invisible electromagnetic energy and the testing of material by invisible electromagnetic radiation, subclasses 493.1+ for radiant energy generation and sources, and subclasses 505.1+ for radiation controlling means.
331, Oscillators,   subclass 44 for oscillators with frequency calibration or testing.
343, Communications: Radio Wave Antenna,   subclass 17.7 for radar systems with testing or calibrating, and subclass 703 for antennas with means to measure radiated antenna signal energy.
356, Optics: Measuring and Testing,   subclasses 33+ for the measurement of distance by light, subclasses 300+ for the examination of visible light by spectros copy, subclasses 138+ for angle or axial alignment testing, subclass 625 for menstruation or conation comparison, subclasses 401+ for color tests, and subclasses 213+ for the examination of visible light generally.
360, Dynamic Magnetic Information Storage or Retrieval,   subclass 31 for monitoring or testing the progress of recording.
455, Telecommunications,