IDLE CHANNEL DETECTION SYSTEM

摘要

PURPOSE:To detect an idle channel efficiently with respect to the idle channel detection system in the time division multiplex communication system for an inter-radio station frame phase asynchronization using plural same carrier frequencies. CONSTITUTION:A reception level measurement system is provided with a mixer 3 converting each carrier into an intermediate frequency, a local oscillator 4 giving a local signal to the mixer 3 and deciding a frequency at which the mixer 3 makes a frequency, a detector 6 detecting the level of an intermediate frequency output of the mixer 3, a detector 6 detecting the level of the intermediate frequency output of the mixer 3, a storage circuit 7 storing the oscillating frequency of the oscillator 4 and the level output of the detector 6 and a control circuit 5 deciding newly the sequence of frequencies to be detected except the prescribed level of the frequency or over in the output of the detector 6 based on the information of the storage circuit 7 and sending sequentially the relevant oscillating frequency designation signal to the local oscillator 4.