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:
Apr. 06, 1976
Filed:
Dec. 31, 1974
Theodore S Rzeszewski, Lombard, IL (US);
Sotirios Sideris, Des Plaines, IL (US);
Quasar Electronics Corporation, Franklin Park, IL (US);
Abstract
A wide-band automatic fine tuning (AFT) circuit capable of a .+-.2 MHz pull-in range without false lockups responds to the output of a picture carrier discriminator, a sound carrier discriminator and a vertical synchronizing signal sensing means to operate a reversible digital counter in either its count up or count down direction depending upon the relationship of the outputs of the two discriminators and the synchronizing signal sensing circuit. The output of the counter is supplied to a digital-to-analog converter which produces a tuning control voltage used for controlling the frequency of operation of the local oscillator of the receiver. The output of the digital-to-analog converter is added to a conventional AFT voltage which maintains the desired tuning once it has been established by the wide-band AFT system.