| 摘要 |
<p>Automatic switching circuitry (1) comprises means to process input signals of more than one frequency incorporating information for the derivation of one or more audio channels. The processing means includes selectively variable bandpass means (11, 12) which may be one of several values corresponding to the frequency of an input signal. Means (14) are provided to apply a demultiplex operation on signals output from the bandpass means (11, 12). Control logic (15) monitor the demultiplex means (14) to determine if a demultiplex operation has been achieved and instruct selection of another value for the bandpass means (11, 12) if no demultiplex operation was achieved for a given value of the bandpass means (11, 12).</p> |
