Demodulator for FSK signals - uses digital comb filter for dividing input signal into partial signals of differing frequency

摘要

The demodulator has a digital filter (F) which divides the frequency shift keying signals into partial signals (Y1, Y2) of different frequency. Th frequency shift keying signals are fed to the digital filter via an A-D converter, the filter comprising a comb filter which uses a sampling frequency related to the frequencies of the obtained partial signals by a defined equation. Pref. a polyphase filter is used, with the output signals having a sampling frequency which is half that of the input signal (X1). ADVANTAGE - Reduced complexity relative to previous bandpass filter demodulator for separation of FSK frequencies.