| 摘要 |
PROBLEM TO BE SOLVED: To detect electric field intensity of not less than 120 dBμ. SOLUTION: The output signal of an RF-AGC circuit 7 is added with that of a differential amplifier circuit 9 by an adding circuit 11. When the receiving electric field intensity of more than 100 dBμ is detected according to the output level of the circuit 11, the output of a forcedly driving circuit 10 in an RF-AGC loop is fixed to obtain the attenuation quantity of 100 dB in a receiving line. Then, when the output signal of an electric field intensity detection circuit 6 is higher than a prescribed level, the gain of an RF amplifier circuit 1 is reduced as it is. |
