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:
Jan. 23, 1996
Filed:
Nov. 30, 1993
De D Hsu, San Diego, CA (US);
Frederick A Williams, Bellevue, WA (US);
Wendy L Liu, San Diego, CA (US);
Raytheon Company, Lexington, MA (US);
Abstract
A high resolution digital phase detector adapted to receive a threshold value and a sequence of digital samples of a substantially linear portion of an analog video signal. A first output signal is provided when a digital sample is detected as having crossed the threshold value. An interpolation is done between the value of the digital sample to first cross the threshold value and the immediately preceding digital sample on the opposite side of the threshold value. In such manner, the time of the crossing within the sample interval is resolved to a subpixel level. A second output signal represents a fractional phase error between the actual crossing and a desired crossing point within the sample interval. The first and second signals are added in a phase locked loop to adjust the output of a voltage controlled oscillator to be synchronized to the incoming analog video signal in both integer and subpixel phase.