| 摘要 |
PURPOSE:To prevent error detection caused by the transient response voltage of a BPF by providing an analog gate circuit to the output of an AGC circuit for multi- frequency signal reception and by equipping a circuit which outputs a control signal allowing the gate to open after the operation delay time of the AGC. CONSTITUTION:When a multi-frequency signal is applied to the AGC circuit, time response TIM applies a signal to gates of field effect transistors FET of analog gate circuits G1 to Gn after operation delay time (t) of the AGC circuit. As a result, FETs turn OFF, it is prevented that BPF1 to BPFn are applied with an excessive input within the operation delay time of the AGC circuit, and the transient response time becomes slight, so that it will not malfunction. Further, when a shortperiod signal such as a noise arrives, the signal attenuates before the gate circuit opens and, in cosequence, the shortperiod noise is not applied to BPF1 to BPFn, so that stable operation can be obtained. |
