Facsimile and static presentation processing – Facsimile – Specific signal processing circuitry
Patent
1989-03-23
1992-09-01
Chin, Tommy P.
Facsimile and static presentation processing
Facsimile
Specific signal processing circuitry
455343, H04N 563
Patent
active
051444410
ABSTRACT:
A receiver comprises a tuner circuit for detecting a selected input signal and an audio circuit for reproducing the audio content in the detected signal. The tuner circuit includes a local oscillator, a prescaler, a phase detector and an integrator, and has a tendency to uncontrollably detune during AC power interruption responsive to a spurious tuning control signal generated in the tuner circuit and generate audible noise during the detuning. The audible noise is introduced into the audio content of the detected signal. An AC power interruption detector monitors a run power supply and generates a power loss control signal when the run supply falls below a predetermined threshold. A control circuit responsive to the power loss control signal, absent a user command, first disables normal operation of the tuner circuit and then disables the audio circuit, thereby reducing the audible noise. The tuner circuit may be disabled by decoupling the output of the phase detector from the input to the integrator, enabling the input to float. In the absence of a corrective signal from the phase detector, which may be the spurious tuning control signal, the integrator maintains a substantially constant output tuning voltage and prevents sudden detuning.
REFERENCES:
patent: 3882400 (1975-05-01), Hamada
patent: 4031549 (1977-06-01), Rast et al.
patent: 4110693 (1978-08-01), Evans
patent: 4207530 (1980-06-01), Gallagher
patent: 4227257 (1980-10-01), Sato
patent: 4355422 (1982-10-01), Paschen
patent: 4405947 (1983-09-01), Tults et al.
patent: 4532457 (1985-07-01), Haferl
patent: 4546388 (1985-10-01), Williams, Jr.
patent: 4641064 (1987-03-01), Testin et al.
patent: 4641190 (1987-03-01), Testin et al.
patent: 4656399 (1987-04-01), Testin et al.
patent: 4716463 (1987-12-01), Stacy et al.
patent: 4743864 (1988-05-01), Nakagawa et al.
patent: 4750040 (1988-06-01), Hakamada
patent: 4763195 (1988-08-01), Tults
CTC 140 Color TV Chassis Technical Training Manual, first published by GE Consumer Electronics, pp. 34-39, 1987.
SL-HF750 Operation Manual, published by Sony, Aug., 1986, pp. 127-131.
Morris Robert E.
Sparks Bradley A.
Chin Tommy P.
Fried Harvey D.
Laks Joseph J.
Thomson Consumer Electronics Inc.
Tripoli Joseph S.
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