| 摘要 |
PROBLEM TO BE SOLVED: To provide an interphone system capable of reducing a consumption current when performing processing of modulation and demodulation. SOLUTION: In the conventional example, since a timing synchronization unit 12 determines symbol synchronization timing using a digital audio signal having been decoded, all components of a demodulating means have to be always operated and then the current consumption increases. According to the present invention, however, since the timing synchronization unit 13 of a demodulating means 26 determines symbol synchronization timing of a decoding unit 10 using a digital signal output from a delay detection unit 8, the decoding unit 10 and a parallel/serial conversion unit 11 in post-stages can stop operating before the symbol synchronization timing is determined. Consequently, when the processing for modulation and demodulation is performed, the current consumption before the determination of the symbol synchronization timing can be reduced. COPYRIGHT: (C)2009,JPO&INPIT
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