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:
Sep. 14, 1976
Filed:
Aug. 13, 1975
Eric Breeze, Los Altos, CA (US);
Peter Alfke, Los Altos Hills, CA (US);
Fairchild Camera and Instrument Corporation, Mountain View, CA (US);
Abstract
A fine tunable electronic channel select system for controlling the varactor tuner of a television receiver or the like and including a dual mode prescaler for dividing the local oscillator (VCO) frequency of the tuner by a first divisor and then by a second divisor to produce a selectively variable average divide during a sample period, a programmable digital divider for dividing the output of the prescaler by a predetermined divisor corresponding to a selected television channel, a channel selection mechanism for controlling the programmable divider, a signal source for generating a stable reference frequency, a frequency/phase comparator for comparing the output of the programmable divider with the reference signal to develop an error signal, an integrator/amplifier for integrating the error signal to develop a biasing signal for controlling the tuner, and a fine-tune control circuit for selectively controlling the length of time the prescaler operates in each of its two modes, thereby enabling incremental variation of the biasing signal to provide fine tuning of the varactor tuner.