Abstract: In an adaptive antenna system, the output of the discriminator of an FM receiver is synchronously rectified, in synchronism with commutation of the input thereof between a pair of antennas, to provide an output signal. When the inputs of the receiver are coupled directly to the antennas, the system may be employed in a homing mode. The output of the rectifier may alternatively be employed to control amplitude and/or phase controls connected between a pair of antennas and the input circuits of the receiver, for the use of the receiver in an adaptive system. For control of amplitude, a quadrature hybrid may be connected between the antennas and the input circuit of the receiver, in order to balance the amplitude of the received signals.