| 摘要 |
PURPOSE:To eliminate an reception insensible region by utilizing a vertical antenna signal and a horizontal antenna signal as reception signals and using a deciding signal based on the amplitude and phase of both the signals so as to control a switch circuit, thereby controlling the system in a way that the inverting point of the phase of the antenna signal is eliminated. CONSTITUTION:An amplitude comparator 15 compares the quantity of the amplitude of the vertical antenna signal from a vertical antenna 10 with a horizontal antenna signal from a horizontal antenna 11 and gives the result of comparison as 1st and 2nd amplitude comparison signals. A phase comparator 16 compares the phases of the vertical antenna signal with the horizontal signal and gives the result of comparison as 1st and 2nd phase comparison signals. A decision circuit 17 decides whether or not the phase of the horizontal antenna signal is inverted based on each amplitude comparison signal and each phase comparison signal and outputs the result of decision as the deciding signal. A switch circuit 19 outputs the vertical antenna signal and the horizontal antenna signal while switching them selectively in response to each amplitude comparisom signal. A switch circuit 20 gives the horizontal antenna signal to the switch circuit 19 directly or via a phase inverting circuit in response to the deciding signal.
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