| 摘要 |
PROBLEM TO BE SOLVED: To provide a train detection system high in resistance against noise. SOLUTION: In a method for judging a train with the presence or absence of demodulation owing to the drop of a reception signal level by the short circuit of an axle by using a frequency modulation signal as a train detection signal, a gain processing amplifying the amplitude of the signal, a limitter 32 limiting the amplitude of the output signal of the gain processing to a prescribed value and a filter processing removing higher harmonics by the limitter processing are combined in the front stage of a demodulation processing at the time of applying the demodulation processing with amplitude dependency as a method for arbitrarily setting the threshold of train judgment. Thus, a processing for arbitrarily setting the threshold of train judgment is realized by arbitrarily setting the lower limit value of the signal level that can be demodulated with a gain.
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