RADIO COMMUNICATION SYSTEM

PURPOSE:To prevent a radio communication system where the SN ratio is never deteriorated after demodulation despite the reduction of the reception power in an FM communication system. CONSTITUTION:In a bidirectional radio communication system where two points are connected together by a frequency modulated wave, at least one of both radio stations measures the reception power of the signal received from the radio station of the opposite party side (22). The modulation index of the radio wave sent from a radio station to the opposite party side is controlled based on the measured reception power so that the signal received from the opposite party station has a prescribed SN ratio. Then the band widths of the variable BPF 18 and 30 which transmit transmission/reception modulated waves of the relevant radio station are properly controlled in response to the modulation index.