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. 03, 1996
Filed:
Mar. 31, 1994
Steven J Kommrusch, Ft. Collins, CO (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
A voltage shift feedback system offsets the signal amplitude of an incoming analog video signal so that a more accurate analog-to-digital conversion of the analog video signal can be achieved in an analog-to-digital convertor. The voltage shift feedback system comprises an input capacitor for isolating the system from the analog video signal and a feedback loop. The feedback loop comprises a separator mechanism in the preferred embodiment for determining when the analog video signal exhibits a particular amplitude, such as a blank level or a synchronization level, and for generating a separator output indicative thereof. An offset control logic monitors the digital pixel data output from the ADC and the separator output. A variable current mechanism is connected to the offset control logic and the ADC input connection for supplying a continuous current i.sub.c to the ADC input. When the analog video signal exhibits the particular amplitude, the offset control logic compares the digital pixel data from the ADC to a predetermined range, preferably a desired synchronization or blank amplitude range, and adjusts the current so that the digital pixel data converges toward the predetermined range.