Siemens Aktiengesellschaft

Erich Mayerhofer

Guenter Beyer

Klaus Weis

August Weber

A circuit arrangement for a frequency-dependent analysis of received signals which lie in a wide overall frequency band utilizes a filter bank which cooperates with an evaluation circuit. The filter bank has frequency-dependent band filters connected thereto and comprises an evaluation frequency range which exhibits only a few small band width in relation to the overall frequency band. The received signals are processed by means of a filter circuit having adjoining pass ranges, the signals being modulated by a number of frequency modulators into an evaluation frequency range and an addition of the individual heterodyning frequency values is performed. The frequency-dependent successive partial frequency bands of the received signals, after conversion in the filter circuit, are respectively connected to another of two transmission channels in such a manner that the first transmission channel only transmits the even numbered partial frequency bands in the frequency-dependent succession, and the second transmission channel only transmits the uneven numbered partial frequency bands in the frequency-dependent succession. The transmission channels are coupled to one of two respective equally structured filter banks and all outputs of the filter circuit, engaged by means of received signals, supply the output signal which characterizes engagement. Each received signal, if it falls in only one pass range, passes only one overlapping-free transmission path; if it falls into two adjoining pass ranges, it passes two overlapping-free transmission paths and thereby results in unequivocal frequency values for evaluation.

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Taufkirchen, Germany

Erich Mayerhofer