Abstract: A space diversity receiving system is described which eliminates the low frequency phase modulation component at the intermediate frequency stage output. Received signals from two antennae are converted to intermediate frequency signals and then combined after one signal has been passed through a variable phase shifter. Branching amplifiers are provided in each intermediate frequency channel so that all phase modulation, phase detection and production of the control signal necessary for controlling the variable phase shifter are achieved outside of all main intermediate frequency channels that are to be combined to obtain an intermediate frequency output.

Abstract: A diversity receiving system having a hysteresis switching characteristic has first and second signal receiver portions supplied with at least one radio frequency signal for producing a pair of received signals, a level detection circuit provides a pair of voltages representative of the levels of the received signals, the outputs of the level detection circuit are compared to determine which one is at a higher level, a switching circuit selectively leads the higher level one of the received signals to an output terminal of the receiving system, and the level of the higher level one of the received signals is raised with respect to the lower level one which has not been led to said output terminal. In the present system, the higher level signal is selected while the reference level for detection with respect to the higher level signal is relatively lowered so that the higher level signal is more stably selected.