| 摘要 |
PURPOSE:To always monitor the operations of switches within a multiplexer, by comparing an input analog signal of an analog multiplexer with the output analog signal of a sample holding circuit provided at the output side. CONSTITUTION:When the sampling is carried out, analog switches 3 and 6 close the same channel to plural analog signals. An input analog signal is fed to the switch 3 from a terminal 1 via a comparator 2 and held at a holding circuit 41. The output of the circuit 41 is fed via the switch 6 to an input terminal of the other side of the comparator 2 to which the signals of the same channel are fed. The output of the comparator 2 is set at a prescribed level when the switches 3 and 6 have normal operations. Thus a discriminating circuit 7 has no operation. When the switches 3 and 6 have an out-of-synchronism, the output of the comparator 2 increases. Then a signal is delivered from the circuit 7. |
