| 摘要 |
An FM receiver includes an IF unit followed by an LF unit, the IF unit having an IF filter arrangement. The center frequency of the IF filter arrangement, which is relatively narrowbanded with respect to the channel bandwidth, is controlled as a function of the receiving conditions. The receiver has circuitry for changing the signal transmission characteristic of the IF and/or LF unit, including a detector module with detector circuits for detecting values characteristic of receiving or interference states, with the inputs of these circuits each being connected with a circuit point of the IF or LF unit carrying the signal to be processed and with the outputs of these circuits providing signals characterizing receiving or interference states. The circuitry for changing the signal transmission characteristic also includes an evaluation circuit for processing the signals characteristic of receiving or interference states, the evaluation circuit having an input portion with at least one amplitude and/or time threshold circuit connected with the detector module and having a logic unit which is connected to the input portion and which provides processed signals characteristic of receiving and interference states as control signals for influencing individual stages of the IF or LF unit.
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