| 摘要 |
PURPOSE:To detect a switching noise when the antenna is switched, so that a malfunction does not occur, by selecting the time constant of the antenna switching circuit to smaller than that of the noise detector. CONSTITUTION:When receiving by the antenna 8, if a multipath noise component appears in the detection output C, its output is transferred to the antenna switching circuit 1 as an antenna switching signal F through an HPF101, a noise amplifier 102, a noise detector 103, and a bistable multivibrator circuit 105. The circuit 1 switches the antenna 9 from 8 by the signal F. In this case, at the time of switching, a switching noise is generated, but when the time constant of the circuit 1 is selected in advance to smaller than the detection time constant of the detector 103, the noise detection output E is not induced by the switching noise. Accordingly, a malfunction caused by a switching noise can be prevented. |
