| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a high-reliability system with a microphone/speaker for generating an acoustic wave corresponding to the input of data and acoustic wave communication equipment for processing an electric signal outputted from the microphone/speaker and responding to this signal. SOLUTION: The acoustic waves are received by a battery 106 for supplying power and a microphone/speaker 100 for converting the acoustic wave to the electric signal and converting the electric signal to the acoustic wave. At such a time, a start signal selection amplifier 120, to which power is always supplied, detects a starting frequency and operates a non-start signal selection amplifier 130 by supplying power to it. The non-start signal selection amplifier 130 detects and outputs only a non-starting frequency among the electric signals outputted from the microphone/dynamic speaker 100. Since a data amplifier inside a signal processing circuit 140 selectively amplifies only a data band signal, the influence of start signal is removed and the high-reliability system can be provided.</p> |
