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. 05, 1989
Filed:
Mar. 31, 1988
Yves C Faroudja, Los Altos, CA (US);
Jack J Campbell, San Francisco, CA (US);
Faroudja Laboratories, Inc., Sunnyvale, CA (US);
Abstract
An improved comb filter extracts at least one of chroma and luminance from a quadrature modulated subcarrier color television input signal. The described method implemented by the described apparatus includes the steps of delaying the input signal through a plurality of predetermined delay periods wherein the duration of each delay period is related to line scan period or picture frame period, filtering the undelayed and delayed signals so that energy components of the input signal lying in the vicinity of the chroma subcarrier frequency are passed, thereby providing bandpass filtered undelayed and delayed signals, detecting amplitude and sense of periodic transitions lying in the chroma energy passband, multiplying two of the undelayed and delayed signals by the continuously variable coefficients to produce an error correction signal corresponding substantially to the following approximation: