Facsimile and static presentation processing – Facsimile – Specific signal processing circuitry
Patent
1989-06-20
1992-06-16
Chin, Tommy P.
Facsimile and static presentation processing
Facsimile
Specific signal processing circuitry
4551881, 4551911, 4551801, H04N 562, H04B 106, H04B 116
Patent
active
051228785
ABSTRACT:
An input circuit and a television tuner for at least two frequency bands. The television tuner has a joint pre-amplifier whose output is connected to two independent, switchable and tunable band-pass filter circuits for the two frequency bands, preferably extending from VHF band I up to and including the hyperband. To achieve a high selection effect with a simple circuit structure and low space requirement, a two-stage switching device is connected to the output of the pre-amplifier, to which device separate inputs of the independent band filters are connected. The input circuit has a pre-circuit filter comprising a frequency-determining capacitor, and a series circuit connected parallel thereto including three frequency-determining coils. The first coil, like the capacitor, is connected at one end to ground and the third coil, like the capacitor, has its output end connected to the pre-amplifier input. A single range switch is connected parallel to two of the coils while a further coil array is connected between an antenna connection and a pickup of the series circuit. To achieve a good pre-selection and power match with minimal circuitry between the antenna connection and the input of the pre-amplifier, the coil array in the pre-circuit filter is a matching coil between the antenna connection and the connection point of the second and third coils.
REFERENCES:
patent: 3962643 (1976-06-01), Ma
patent: 3980957 (1976-09-01), Puitzer
patent: 4132952 (1979-01-01), Hongu
patent: 4419768 (1983-12-01), Yamashita et al.
patent: 4470071 (1984-09-01), Rindal
patent: 4736457 (1988-04-01), Kupfer
patent: 4756024 (1988-06-01), Kupfer
Schematic diagram dated Jul. 26, 1984 for Tuner 260-82370 of the Firm Loewe Opta GmbH Industriestrasse 11, 8640 Kronach, Germany.
Data Sheet dated Apr. 1985 for VHF/UHF Television Tuner UV 617, UV 618,256 of the Firm Valvo, Hamburg, Germany.
Philips Development Data Sheet dated Jun. 1985 for VHF/UHV Television Tuners, UV 615, UV 616/256.
Heigl Franz
Kuspert Ludwig
Chin Tommy P.
Telefunken electronic GmbH
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