SPACE DIVERSITY RECEIVING SYSTEM WITH PHASE- CONTROLLED SIGNAL COMBINING AT INTERMEDIATE FREQUENCY STAGE

摘要

Disclosed is a space diversity receiving system for combining a plurality of reception antenna outputs at an intermediate frequency stage with an in-phase relationship maintained among them. A phase-shifter phaseshifts at least one of the antenna outputs after being converted into intermediate frequency signals. A first combiner combines the output of the phase-shifter and non-phase-shift intermediate frequency signals. A first branching circuit branches out the output of the phase-shifter. A second branching circuit branches out the non-phase-shift intermediate frequency signals. A phase-modulator phase-modulates either one of the outputs of the first and second outputs of the branching circuits with a low frequency signal. A second combiner combines the output of the phase-modulator and the non-phase-modulation output. The amount of phase shift at the phaseshifter is controlled in response to the output of the second combiner.