PURPOSE: To reduce the time required for detecting a wave by dividing plural input signal in time and processing sampled signals at an arithmetic section provided with plural feedback capacities and feedback circuits, and then, separating the output of the arithmetic section into plural output signals.

CONSTITUTION: A multiplexing device 11 time-division multiplexes each signal from plural input terminals by using a clock from a control circuit 14 and sends the multiplexed signals to a transmitting device 12. The circuit 12 constitutes a switched capacitor integrator composed of MOS switches (SW) 21, 22, 26, and 27, sampling capacity 23, integration capacities 24 and 25, and operational amplifier 28, and performs sampling on input signals by means of the capacity 24 by alternately turning on and off the SWs 21 and 22 with 2-phase clocks which do not lie one upon another from the circuit 14. The sampled input signals are inputted into the amplifier 28. At the amplifier 28, the integrated value of an input signal which is obtained by feeding back the output through capacities 24 and 25 by alternately turning on and off the SWs 26 and 27 with 2-phase clocks which do not lie one upon another, is inputted into a reproducing device 13. At the device 13, the integrated value is separated into plural signals by means of the MOS SWs and a holding capacity and the separated signals are outputted.