| 摘要 |
PROBLEM TO BE SOLVED: To provide a demodulation circuit capable of stably demodulating an ASK signal having a small modulation rate with a circuit of comparatively simple configuration. SOLUTION: One part of the ASK signal including any one of an upper envelope and a lower envelope is amplified in an amplifier 101. Then, the signal component of the envelope of the ASK signal included in the amplified signal is extracted in a signal extractor 110. Since the envelope of the ASK signal is equivalent to a baseband signal, the component of the baseband signal is amplified in the amplifier 101, and the component of the amplified baseband signal is extracted in the signal extractor 110. Accordingly, since the baseband signal having a large amplitude can be extracted by amplifying the minute baseband signal included in the ASK signal, the ASK signal having a small modulation rate can be stably demodulated. COPYRIGHT: (C)2007,JPO&INPIT
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