Television – Synchronization – Locking of video or audio to reference timebase
Patent
1993-11-30
1996-01-23
Groody, James J.
Television
Synchronization
Locking of video or audio to reference timebase
348572, 375294, 327 78, H04N 504
Patent
active
054868670
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.
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patent: 4831378 (1989-05-01), Baars et al.
patent: 4959558 (1990-09-01), Kay et al.
patent: 5293369 (1994-03-01), Melas et al.
TRW LSI Products, Inc. TMC22070 Advance Information, "Genlocking Video Digitizer", Jan. 21, 1992, pp. 1-4.
Hsu De D.
Liu Wendy L.
Williams Frederick A.
Clark William R.
Groody James J.
Murrell Jeffrey S.
Raytheon Company
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