| 摘要 |
PURPOSE:To suppress the generation of an incidental noise even if the length of chattering is varied in accordance with the car speed, by controlling a comparator signal passing to the change-over switch by means of a signal which has divided a pulse output of the frequency according to the car speed. CONSTITUTION:The receiving signals from the first and second antenna systems (neither of them is shown in the figure) are provided to the terminals 23a and 24a, respectively. And the receiving signals which have been detected by the level detectors 25, 26 are provided to the comparator 27, and the level comparison is performed. On the other hand, the divider 31 divides a pulse of the frequency according to the car speed by the car speed sensor 30, and sends out its output to the clock terminal CL of the D type flip flop 32 as a clock pulse. The chattering which gas been contained in an output 27a of the comparator 27 is removed by the flip flop 32, and an antenna change-over signal without chattering is sent out to the antenna change-over circuit (not shown in the figure) from the said output 32a. |
