.~> With particular signal combining means (e.g., cavity mixer) {1}
DEFINITION
Classification: 331/37
(under the class definition) Subject matter comprising a signal producing system including a signal combining device (e.g., mixer, modulator) having signal input circuit means and a signal output circuit, at least two oscillators or a single oscillator simultaneously generating plural frequencies being connected to the input circuit means, the arrangement being such that the sum and/or difference frequencies (usually the difference frequency) of the oscillations generated by the respective oscillators or of the plural frequency oscillator appears in the output circuit of the signal combining means.
(1) Note. In addition to beat frequency oscillators the beat frequency principle is made use of in other systems. In general, beat frequency oscillators classified herein comprise means for beating two nonarbitrary sources of slightly different frequencies and of substantially equal amplitudes, the proximate purpose of the system being to produce a stable, high level, low frequency output wave (by selecting the lower side band). Modulators classified in Class 332 are directed to means for beating a source of carrier frequency of high amplitude with a signal wave of low amplitude, which signal wave varies arbitrarily in a continuous manner in accordance with some intelligence (e.g.,
sound). Radio receiver mixers or converters classified in Class 455, Telecommunications, are similar to the modulators of Class 332 except that the modulating signal wave contains, in addition to an arbitrary signal wave a large predictable component (the incoming carrier wave).
SEE OR SEARCH THIS CLASS, SUBCLASS:
19, for automatic frequency stabilized oscillators with a spectrum frequency reference source involving beat frequency generation in the stabilizing circuit.
22, for automatic frequency stabilized oscillators with signal comparator and having plural heterodyne stages in the stabilizing circuit.
30+, for automatic frequency stabilized oscillators with a stable heterodyne oscillator or source. 51, for frequency divider systems comprising plural oscillators in cascade.
53, for frequency multiplier systems comprising plural oscillators in cascade.
76, for oscillators combined with an output coupling network, with space discharge device or unilaterally conductive device therein, for harmonic producing or selecting.
SEE OR SEARCH CLASS
307, Electrical Transmission or Interconnection Systems,
424, for nonoptical parametric amplifier frequency converters, per se.
332, Modulators, see (1) Note above. Consult also the notes and search notes appended to the class and subclass definitions of Class 332 as to other fields of search for beat frequency systems.
359, Optics: Systems (Including Communication) and Elements,
326+, for optical frequency translators.
455, Telecommunications,
130+, for radio receivers using the beat frequency principle (in the form of autodyne, homodyne, superheterodyne and other types of beat reception), subclasses 313+ for radio receiver mixers or converters. See (1) Note above.
