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. 20, 2005
Filed:
Jun. 14, 2002
Applicant:
Wai Cheong Chan, Sunnyvale, CA (US);
Inventor:
Wai Cheong Chan, Sunnyvale, CA (US);
Assignee:
National Semiconductor Corporation, Santa Clara, CA (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G01R019/00 ;
U.S. Cl.
CPC ...
Abstract
In a polarity detector circuit for detecting the polarity of monitor sync signals, a clock generator and counter circuit are provided to count clock cycles during the positive and negative portions of the signal. Comparators are used to compare the counter values to predetermined values to determine when one or both of the counters has reached a predefined value. With the proper choice of sampling clock, this digital implementation can be easily optimized for small size and simplicity.