The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 27, 1978
Filed:
Jul. 20, 1977
Kazuyoshi Imazeki, Tokyo, JA;
Koichi Kazami, Tokyo, JA;
General Research of Electronics, Inc., Tokyo, JA;
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 means for generating a first reference signal having a predetermined frequency and means, including at least two voltage controlled oscillators (VCO), a mixer, a programmable frequency divider, and a switch, for generating a second reference signal, with the mixer being coupled to the first reference signal generating means and being selectively coupled on one of the VCO's by the switch to generate an output signal having a frequency corresponding to the difference between the frequency of said first reference signal and the frequency of the selected variable-frequency oscillator. Means are coupled to the first reference signal generating means and to the second reference signal generating means for comparing the first and second reference signals and developing a control signal which varies systematically in accordance with the frequency difference between the first and second reference signals, with the control signal being applied to both the VCO's to vary the oscillation frequencies thereof until the frequency of the second reference signal is substantially equal to the predetermined frequency of the first reference signal, whereby the output signal of the selected 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 VCO selected by the switch.