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:
Aug. 25, 1987
Filed:
Oct. 27, 1986
Alvin R Balaban, Lebanon, NJ (US);
Steven A Steckler, Clark, NJ (US);
RCA Corporation, Princeton, NJ (US);
Abstract
A digital phase-lock-loop circuit includes a generator that produces a horizontal rate output signal at a controlled frequency and a phase detector responsive to the output signal and to an incoming synchronizing signal. The phase detector is coupled to the generator control port via a loop filter. When the phase between the output signal and the synchronizing signal that synchronizes the phase-lock-loop circuit changes as a result of, for example, head switching in a two-head VTR that supplies the synchronizing signal, a signal representative of such phase change is produced. The phase change representative signal is fed forward to the generator, by bypassing the loop filter of the phase-lock-loop circuit. The phase change representative signal produces an immediate phase shift of the output signal such that the loop filter is not affected by the head switching.