| 摘要 |
PROBLEM TO BE SOLVED: To provide an FM demodulation method and device therefor at a low cost and with satisfactory resistance against interference under interference environment without recognizing interference conditions and without using a BPF (band-pass filter) for suppressing interference waves. SOLUTION: The FM demodulation device is provided with an outer product operation part 2 that demodulates frequencies and obtains a first demodulated waveform by performing an outer product operation of two digital signals before and after minute changes of time based on the frequency-modulated digital signals, a delay detection circuit 3 that performs delay detection to the first demodulated waveform based on the first demodulated waveform from the outer product operation part 2 and obtains a second demodulated waveform, an interference judging part 4 that judges presence/absence of the interference waves to be superposed on the digital signals by comparing the first demodulated waveform from the outer product operation part 2 and the second demodulated waveform from the delay detection circuit 3 and a demodulated waveform selection part 5 that selects the first demodulated waveform when no interference wave is judged to exist and selects the second demodulated waveform when the interference waves are judged to exist. COPYRIGHT: (C)2003,JPO
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