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:
Jul. 31, 1990
Filed:
Feb. 17, 1989
Jean-Marc Merval, Saint Egreve, FR;
Danika Perrin, Grenoble, FR;
SGS-THOMSON Microelectronics S.A., Gentilly, FR;
Abstract
A detection circuit of a line synchronization signal in a video signal wherein the synchronization signal is sent to a phase locked loop (PLL) comprises a voltage controlled oscillator (8), for supplying a line scanning signal to a display. The following steps are provided: inhibiting the operation of the loop and setting the VCO to its free frequency, in the absence of the line synchronization signal; supplying a detection window in relation with the oscillations of the VCO; and detecting the presence of the synchronization signal in this window for supplying either an enabling signal after the detection of a determined number of synchronization tops, this enabling signal connecting again the VCO in the loop, or an inhibiting signal if the detection is interrupted during the determined number of synchronization tops.