US PATENT SUBCLASS 324 / 76.77
.~ Phase comparison (e.g., between cyclic pulse voltage and sinusoidal current, 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}
76.77.~ Phase comparison (e.g., between cyclic pulse voltage and sinusoidal current, etc.) {11}
76.78  DF  .~.~> Quadrature sensing
76.79  DF  .~.~> Feedback control, electrical
76.81  DF  .~.~> Feedback control, mechanical
76.82  DF  .~.~> Digital output
76.83  DF  .~.~> Analog output
84  DF  .~.~> With waveguide (e.g., coaxial cable)
85  DF  .~.~> With frequency conversion
86  DF  .~.~> Polyphase (e.g., phase angle, phase rotation or sequence)
87  DF  .~.~> With nonlinear device (e.g., saturable reactor, rectifier), discharge device (e.g., gas tube) or lamp {2}
90  DF  .~.~> Electrodynamometer instrument
91  DF  .~.~> Synchroscope type

DEFINITION

Classification: 324/76.77

Phase comparison (e.g., between cyclic pulse voltage and sinusoidal current, etc.):

(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,

311+, for pulse demodulators using locally generated oscillations, subclasses 336+ for frequency demodulator employing phase shift, and subclass 346 for using locally generated oscillations.