Diversity device for VHF car radio having several antennae - synchronises oscillator to antenna noise signals in mixer using automatic search stage and converts output of adder to carry frequency

摘要

The diversity device (2) for a VHF car radio (1) drives several car aerials (3) connected in different positions on the same vehicle, to process all the antenna signals simultaneously. A preamplification and a mixing stage (18) are connected to each antenna (3). The output signals of the mixing stage (18) are vectorially added in a summation stage via controllable phase rotating members. The second signal input to the mixing stage (18) is derived from an auxiliary oscillator (9). The oscillator (9) is synchronised through the interference outputs of the radio mixer oscillator (6) at the output of the radio (1), via an automatic search function (13). The output of the summation stage (19) is fed back via the auxiliary oscillator (9) to a feed back mixer (15). USE/ADVANTAGE - Enables readily available car radios to be modified to operate to process signals simultaneously from several antennas.