SELECTION CIRCUIT IN A SPACE DIVERSITY RECEPTION SYSTEM FOR A MOBILE RECEIVER

摘要

A selection system in a space diversity system of a mobile receiver combines the ultra high frequency signals after they have been frequency shifted to an intermediate frequency. The system combines the intermediate frequency signals depending on the ratio of the magnitudes of these signals. If the ratio of the magnitude of the received signals is equal to or greater than a preset magnitude level, for example, 5 db, a control unit selects only the received signal having the largest magnitude. Otherwise, the control unit linearly combines both received signals. Specifically, if the absolute value of the difference in received phase signals is less than 90.degree., the output of a phase detector causes the control unit to pass both received signals to a summer that linearly combines them prior to demodulation. Otherwise, the control unit inverts the phase of one of the received signals prior to passing both received signals to the summer.