Abstract: A gas sensor comprises a gas separation membrane comprising substituted polyacetylene where a substituent group is combined to a double-bonded carbon atom in the backbone chain of the substituted polyacetylene and a sensing element configured to detect gas permeated through the gas separation membrane.

Abstract: A multiplex transmitter-receiver system comprising a synchronizing signal generator for producing a plurality of multiplex transmission-receiving synchronizing signals from a three-phase alternating current, and a signal processor for effecting signal processing based on the synchronizing signals for transmitting and/or receiving a plurality of signals through a single signal transmission line. The signal generator comprises a polyphase rectangular wave generator for producing polyphase rectangular waves by shaping the waveform of the three-phase alternating current, and an arithmetic logic unit for producing a plurality of multiplex transmission-receiving synchronizing signals by logic elements based on combinations of the polyphase rectangular waves.