Television – Synchronization – Automatic phase or frequency control
Patent
1993-02-11
1995-09-12
Groody, James J.
Television
Synchronization
Automatic phase or frequency control
348524, 348497, 331 1A, 331 20, 331 25, H04N 506, H04N 512
Patent
active
054501377
ABSTRACT:
This specification concerns signal processing apparatus for processing line synchronization pulses in a line synchronization signal that define an analog video signal line period. The apparatus comprises a phase locked loop (40) for generating a clock signal of a frequency that is a multiple of the line synchronization signal frequency. The phase locked loop (40) comprises a counter (100) for dividing the clock signal by said multiple. The apparatus further comprises logic (110,50) for resetting the counter (100) upon detection of a spurious pulse introducing a time interval into the line synchronization signal of less than the line period of the video signal. The apparatus is particularly useful in image processing systems for digitizing analog video signals that have been replayed via a conventional, domestic video tape player, and therefore may comprise spurious line sync pulses introduced by playback head skip.
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patent: 4942472 (1990-07-01), Imbert et al.
patent: 4996596 (1991-02-01), Hirao et al.
Patent Abstracts of Japan vol. 010, No. 061 (E-387) 11 Mar. 1986 & JP-A-60 213 184 (Sony) 25 Oct. 1985 * abstract *.
Patent Abstracts of Japan vol. 015, No. 121 (E-1049) 25 Mar. 1991 & JP-A-30 09 615 (Toshiba) 17 Jan. 1991 * abstract *.
Brown David J.
Conway-Jones David C.
Rickard Thomas W.
Smith Peter M.
Bogdon Bernard D.
Groody James J.
International Business Machines - Corporation
Lee Michael H.
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