Receiver with multiple antennas

Claim 1

A VHF radio receiver adapted for mobile use, having: first (1) and second (2) antenna input lines; first (6) and second (8) oscillators; a plurality of configuration switches (S1-S5) for selectively applying respective output signals of said oscillators (6,8) to other portions of said receiver; first (3) and second (4) mixers coupled respectively to said first and second input lines (1, 2) for mixing, in a first configuration of said switches, respective antenna signals with a signal generated: by said first oscillator (6); and means (10), coupled to respective outputs of said mixers, for adding resulting mixed signals, with controllable phase position, to form a summation signal, further comprising, a Radio Data System demodulator (18) coupled to an output of one (4) of said mixers; memory means for storing alternate frequencies of a plurality of different transmitters carrying an identical program; control circuit means (19), connected to control inputs of said configuration switches (S1-S5), for momentarily setting said switches to a second configuration in which an output signal of said second mixer (4) is fed to an evaluation circuit (16, 17, 18, 19), said evaluation circuit including a multipath reception recognition circuit (16) having an input connected to outputs of said first (3) and second (4) mixers, and having an output connected to an input of said control circuit means; and an oscillator input of said second mixer (4) is connected to an output of said Second oscillator (8) which tunes said second mixer to one of said alternate frequencies, in order to evaluate quality of reception at said alternate frequency, said control circuit means (19), upon return to said first switch configuration, monitoring quality of reception and triggering switchover to an alternate frequency whenever quality of reception at a current frequency drops below a predetermined level.