US PATENT SUBCLASS 324 / 76.39
.~ Frequency of cyclic current or voltage (e.g., cyclic counting etc.)

Current as of: June, 1999
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324 /   HD   ELECTRICITY: MEASURING AND TESTING

76.11  DF  MEASURING, TESTING, OR SENSING ELECTRICITY, PER SE {46}
76.39.~ Frequency of cyclic current or voltage (e.g., cyclic counting etc.) {6}
76.41  DF  .~.~> Frequency comparison, (e.g., heterodyne, etc.) {4}
76.49  DF  .~.~> Tuned mechanical resonator (e.g., reed, piezocrystal, etc.)
76.51  DF  .~.~> By tuning (e.g., to resonance,etc.)
76.52  DF  .~.~> By phase comparison {10}
76.75  DF  .~.~> Having inductive sensing
76.76  DF  .~.~> With space discharge device

DEFINITION

Classification: 324/76.39

Frequency of cyclic current or voltage (e.g., cyclic counting etc.):

(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,

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,

250, for the measurement of radio or microwaves by an absorption wavemeter.

329, Demodulators,

311+, for pulse demodulators or detectors; subclasses 315+ for frequency demodulators; and subclasses 345+ for phase demodulators.

331, Oscillators,

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,

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

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,

236+, for speed sensing and speed controlled systems, such as synchronizing systems.

368, Horology: Time Measuring Systems or Devices,

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,

75+, for frequency analysis, subclass 106 for signal frequency or phase correction.