US PATENT SUBCLASS 455 / 313
.~ Frequency modifying or conversion

Current as of: June, 1999
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130  DF  RECEIVER OR ANALOG MODULATED SIGNAL FREQUENCY CONVERTER {24}
313.~ Frequency modifying or conversion {4}
314  DF  .~.~> Plural separate successive conversions {1}
317  DF  .~.~> Unwanted oscillation or radiation prevention
318  DF  .~.~> With specified local oscillator structure or coupling {2}
323  DF  .~.~> Particular frequency conversion structure or circuitry {5}

DEFINITION

Classification: 455/313

Frequency modifying or conversion:

(under subclass 130) Subject matter including means whereby a modulated carrier wave signal is changed to another carrier frequency, e.g., an intermediate frequency signal, the frequency of which lies between that of the modulated input signal and the frequency of the lower frequency modulating signal.

(1) Note. In this and the indented subclasses the frequency conversion is usually accomplished by combining a modulated carrier wave input signal with the output of a local oscillator means (i.e., by mixer means).

SEE OR SEARCH THIS CLASS, SUBCLASS:

196.1+, for variation of local oscillator frequency combined with signal frequency selection.

255+, for local oscillator frequency control.

SEE OR SEARCH CLASS

307, Electrical Transmission or Interconnection Systems,

424, for nonoptical parametric amplifier frequency converters, per se.

324, Electricity: Measuring and Testing,

76.41, for systems for measuring, testing, or sensing of electricity by heterodyning; and subclass 85 for phase comparison systems utilizing frequency conversion.

327, Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems,

113+, for miscellaneous frequency conversion or control.

331, Oscillators,

37+, for beat frequency oscillators.

332, Modulators, appropriate subclasses for modulators in general.

343, Communications: Radio Wave Antennas,

6+, for radar receivers which may utilize frequency conversion means; and subclasses 100+ for directional receivers utilizing frequency converters.

348, Television, appropriate subclasses for television systems which may include frequency conversion.

359, Optics: Systems (Including Communication) and Elements, 326+, for optical frequency translators.

370, Multiplex Communications, appropriate subclasses for multiplex systems which may include frequency conversion.