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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.

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