| 摘要 |
<p>PURPOSE:To eliminate the disturbance to a receiving channel in a fixed base station by providing an electric field detecting part for detecting the receiving electric field strength by obtaining a detection signal from a prescribed stage of a receiving part, controlling an automatic gain control amplifier in accordance with an output of the electric field detecting part and also, controlling a transmitting output level of a transmitting part. CONSTITUTION:An electric field detector 17 outputs an electric field detection value being in inverse proportion to an input voltage. This electric field detection value is amplified by a DC amplifier 18, and thereafter, applied to an AGC amplifier 3 and a power amplifier(PA) 15. The AGC amplifier 3 becomes the gain of a roughly prescribed value when the input voltage exceeds some value. Accordingly, when a receiving electric field which has exceeded some prescribed level is inputted, the gain of the AGC amplifier 3 is suppressed. Simultaneously, by an electric field detection value given to a transmitting part 15, a transmitting output is controlled. In such a way, a strong electric field is inputted to an antenna 1, the gain of the AGC amplifier 3 is suppressed, and a cross modulation in a receiving system is suppressed. In such a way, it does not occur that a disturbance is given to a receiving channel of a fixed base station.</p> |
