Facsimile and static presentation processing – Facsimile – Specific signal processing circuitry
Patent
1989-11-14
1990-09-25
Peng, John K.
Facsimile and static presentation processing
Facsimile
Specific signal processing circuitry
358 10, 358148, H04N 1700, H04N 504, H04N 1702
Patent
active
049597167
ABSTRACT:
A T.V. input source identifying circuit for determining whether a video signal is from a videotape player or a broadcast signal by measuring jitter of vertical synchronization pulses and by measuring noise. The video signal includes a plurality of frames with each frame including a plurality of fields. In one embodiment of the present invention, timing data is generated corresponding to the period of at least one selected field in each of a plurality of selected frames. From this timing data, a maximum number is stored that corresponds to the greatest period and a minimum number is stored that corresponds to the least period of the selected fields. The minimum number is subtracted from the maximum number and the difference is compared to a threshold to determine the type of video signal. In an alternate embodiment, numbers corresponding to fields from successive frames are compared by a subtraction and the difference is compared to a threshold in order to make a decision as to the type of video signal. In both of the aforementioned embodiments, the noise level of the video signal is constantly monitored. When the noise is above a threshold, the local signal is generated regardless of the information derived from the timing data.
REFERENCES:
patent: 3904823 (1975-09-01), Van Straaton
patent: 3916102 (1975-10-01), Merrell
patent: 4158857 (1979-06-01), Hiraguri
patent: 4180829 (1979-12-01), Pires
patent: 4298890 (1981-11-01), Vai
patent: 4335403 (1982-06-01), Srivastava
patent: 4425581 (1984-01-01), Schwappe
patent: 4562457 (1985-12-01), Salvia
patent: 4665437 (1987-06-01), Nicholson
patent: 4683495 (1987-07-01), Brock
patent: 4729023 (1988-03-01), Srivastavoa
Bugni Anthony R.
Burdick William S.
Darby Ted A.
Naimpally Saiprasad V.
Phillips Larry G.
Goodman Edward W.
North American Philips Corporation
Peng John K.
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