| 摘要 |
PURPOSE:To improve the dynamic range of the receiver, by controlling the AGC so that the gain is reduced more if the antenna input of a prescribed value or more exists. CONSTITUTION:If the signal of a strong electric field is input, switch 31 is operated to transfer output information of synchronizing signal detecting circuit 12 to AGC voltage correcting circuit 32. When switch 31 is closed, AGC voltage correcting circuit 32 sets the AGC voltage to a prescribed potential, which is determined by power source voltage B and resistances R10, R11 and R20, independently of the output of comparator 8. This potential functions to attenuate the gain for high frequency amplifier 2 more. As a result, high frequency amplifying circuit 2 is prevented from exceeding the dynamic range. |
