Computer graphics processing and selective visual display system – Display driving control circuitry
Reexamination Certificate
2003-12-17
2008-10-07
Hjerpe, Richard (Department: 2629)
Computer graphics processing and selective visual display system
Display driving control circuitry
C345S089000, C345S213000, C348S689000, C348S694000, C348S697000, C358S409000, C358S443000, C358S445000
Reexamination Certificate
active
07432918
ABSTRACT:
The video signal processing circuit has a clamp circuit for clamping a composite video signal including a copy guard signal with amplitude of from white to black as well as a pseudo horizontal synchronization signal, a brilliant signal, and a synchronization signal. The circuit also has a synchronization signal separation circuit, which separates the synchronization signal from the composite video signal and a synchronization signal discrimination circuit, which identifies if the synchronization signal coming from the synchronization signal separation circuit has the same cycle as that of a horizontal synchronization signal, and which blocks the signal with the cycle shorter than the cycle of the horizontal synchronization signal, letting only the signal with the cycle of the horizontal synchronization signal pass. The clamping of the composite video signal is performed correctly even during the period when clamp pulse based on the pseudo horizontal synchronization signal with a shorter pulse width in the copy guard signal period is used.
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patent: 4398215 (1983-08-01), Osaka
patent: 5461489 (1995-10-01), Ohara et al.
patent: 03-057967 (1991-03-01), None
patent: 11-239281 (1999-08-01), None
Hjerpe Richard
Morrison & Foerster / LLP
Nguyen Jennifer T
Sanyo Electric Co,. Ltd.
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