RECEIVING EQUIPMENT AND AUTOMATIC GAIN CONTROLLING METHOD

摘要

PROBLEM TO BE SOLVED: To realize both AGC leading-in speed and AGC leading-in precision in AGC control. SOLUTION: An amplifier 151 amplifies a received signal. A level detecting part 104 detects the level of a base band signal. A level averaging part 105 switches time constant on the basis of a control signal from an AGC controller 10 and averages levels of detected results by using the time constant. In this case, a time constant is set to be a small value first and changed to a large value with passage of the number of times of renewal of AGC. A subtraction part 106 obtains the difference between a level averaging result and a reference value, and a multiplication part 107 multiplies the difference by a correction coefficient. An adding part 108 adds an output of the multiplication part 107 to an AGC control signal which is delayed by unit control term in a delay part 109 and produces an AGC control signal used in the present control term. Thereby an amplification gain of the amplifier 151 is controlled.