Empfangsfrequenzbandfilterung

摘要

The invention relates to the filtering of a sub-frequency band from a receive frequency band. A carrier frequency for prefiltering the receive frequency band and an intermediate frequency for demodulating the frequency band filtered during prefiltering and for generating a basic frequency band are coupled into the signalling path. The desired sub-frequency band is filtered out of the basic frequency band by post-filtering. The carrier frequency, intermediate frequency and post-filtering are tuned to each other.