摘要 |
PROBLEM TO BE SOLVED: To avoid occurrence of malfunction in a controller or the like by blocking an ASC output not required at application of power and its interruption in a demodulator for a digital microwave communication equipment. SOLUTION: An APC detection circuit 4 in a demodulator is normally operated through the supply of bipolar power supplies +E, -E and outputs an output signal (e) to an ASC circuit 5. The ASC circuit 5 is composed of an ASC circuit 51, an operational amplifier 52 setting an output level and a power supply voltage detection section 7, and the power supply voltage detection section 7 receives supply of a DC bias current by the same power supply as that of the APC detection circuit 4 and is operated and the input is inhibited when either of the bipolar power supplies is not supplied. |