Diversity receiving apparatus for a mobile unit

摘要

In a first diversity receiving apparatus, during an antenna selection operation, one of antennas are selected such that each of antennas successively connected to a receiver for consecutive horizontal retrace periods but for horizontal scanning periods following the horizontal retrace period, the selected antenna showing a largest level at the previous antenna selection operation is connected to the receiver to detect levels derived from respective antennas. The antenna showing a largest level is selected at the current antenna selection operation to receive a radio wave television signal for the following M (a natural number) horizontal scanning cycles. M is changed in accordance with the phasing condition. For example, M is changed according to a speed of vehicle, a field intensity, a frequency of the received television signal, etc. The switching circuit and tuner may be provided doubly to prevent the affection of switching noise. A second apparatus determines the selected antenna by further detecting noise levels derived from the respective antennas during a vertical retrace period. A frequency of switching of antennas for determining the selected antenna is reduced to reduce a switching noise on the reproduced image or in the reproduced sound.