Oscillators – Automatic frequency stabilization using a phase or frequency... – Plural oscillators controlled
Patent
1977-07-20
1978-06-13
Kominski, John
Oscillators
Automatic frequency stabilization using a phase or frequency...
Plural oscillators controlled
331 16, 331 31, H03B 304
Patent
active
040951901
ABSTRACT:
A system is disclosed for generating a plurality of preselected frequencies in a radio frequency device such as a receiver, transmitter or transceiver. It comprises two crystal-controlled reference signal oscillators. First and second controllable variable-frequency oscillators (VCO's), first and second mixers, and a programmable frequency divider, together generate first and second output signals, with the first mixer being coupled to the first crystal oscillator and to the first VCO to generate the first output signal having a frequency corresponding to the difference between the frequency of the first reference signal and that of the first VCO. The second mixer is coupled to the second crystal oscillator and to the second VCO to generate the second output signal which has a frequency corresponding to the difference between the frequency of the second reference signal and the frequency of the second VCO. A phase comparator is selectively coupled to the mixers by a switch for selectively comparing the first reference signal with one of the output signals and developing a corresponding control signal which varies systematically in accordance with the frequency difference therebetween, with the control signal being applied to both VCO's to vary the oscillation frequencies thereof until the frequency of the selected output signal is substantially equal to the predetermined frequency of the first reference signal, whereby the output signal of the corresponding VCO has a frequency which corresponds to one of the plurality of predetermined receiver frequencies as selected by both the programmable frequency divider and the mixer output signal selected by the switch.
REFERENCES:
patent: 3863174 (1975-01-01), Klinger
Imazeki Kazuyoshi
Kazami Koichi
General Research of Electronics Inc.
Kominski John
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