Facsimile and static presentation processing – Facsimile – Specific signal processing circuitry
Patent
1985-04-24
1987-07-14
Chin, Tommy P.
Facsimile and static presentation processing
Facsimile
Specific signal processing circuitry
358154, H04N 504, H04N 516
Patent
active
046806334
ABSTRACT:
A composite video signal is input to a DC restore circuit and a sync separator circuit, the output of which is connected to a sync decoder circuit. The DC restore circuit includes a negative sensing peak sample and hold circuit that generates a first reference voltage equal to the sync tip voltage. A first differential amplifier substracts the composite video signal from the reference voltage and produces an inverted, level shifted replica, the sync tip voltage of which is zero. A second differential amplifier having an output clamping circuit, in conjunction with a comparator, produces a composite sync voltage that is used to strobe a sample and hold circuit to produce a second reference voltage. The replica is inverted by a second differential amplifier that subtracts the replica from the second reference voltage to produce the DC restored video signal, a "back porch" portion of which is accurately referenced to zero volts.
REFERENCES:
patent: 4097896 (1978-06-01), Avery
patent: 4233629 (1980-11-01), Dayton
patent: 4254435 (1981-03-01), Dayton et al.
patent: 4387396 (1983-06-01), Tanaka et al.
patent: 4516042 (1985-05-01), Nakamura
patent: 4550342 (1985-10-01), Buchanan et al.
Roland J. Turner; DC Restorer for Video Use Offers Ultra Stability, 12/73; pp. 114-115; Electronics, 178-7.3 DC.
Gerdes Richard C.
Vokac Peter R.
Chin Tommy P.
Third Domain, Inc.
LandOfFree
Circuit and method for producing accurate dc restored video wave does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Circuit and method for producing accurate dc restored video wave, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Circuit and method for producing accurate dc restored video wave will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1430703