PURPOSE: To prevent the symbol error that is caused by an immediate switching action of a switch when the receiving level is reduced by adding a 1-symbol delay circuit to the switch which is switched first and multiplying the output of this switch by the output of the switch which is switched later for execution of the delay detection.

CONSTITUTION: Two antenna changeover switches SW1 and SW2 are provided. The switching control of the SW1 is carried out by an antenna switching control circuit which observes the output signal of a band pass filter BPF. However it is supposed that the switching synchronization is correctly controlled by the antenna switching control circuit. Meanwhile the SW2 is switched to the same branch as the SW1 by interlocking the SW1 after an accurate symbol cycle (Ts) from the instance when the SW1 is switched. Under such conditions, an RF circuit and a BPF circuit are added to both switches SW1 and SW2 respectively. The BPF output signal of the SW1 passes through a 1-symbol delay circuit 22 and is multiplied by the BPF output signal of the SW2. Then the higher harmonic components of both output signals are eliminated by an LPF 26 and then both signals are decided.