| 摘要 |
An automatic gain control apparatus that can prevent jumps in the gain coefficient when the gain coefficient is altered, due to a sharp change in the level of the received signal before and after the alteration, having a mean square circuit (11) for performing mean square processing on the received signal over prescribed sampling intervals, a memory (2) for storing the mean square values, a gain coefficient generating circuit (3) for generating a gain coefficient at predetermined generating intervals by dividing a preset reference output level by a mean value of a predetermined number of the mean square values, a decision circuit (5) for deciding whether the received level of the received signal has changed, a control circuit (6) for, when a change in the received level of the received signal is detected, determining the number of mean square values and the generating interval, a gain coefficient linear smoother (8) for altering the gain coefficient over an interval between the gain coefficients received from the gain coefficient generating circuit (3) before and after an alteration linearly and/or nonlinearly with a predetermined characteristic, and a multiplier (4) for multiplying the received signal by the gain coefficient obtained from the gain coefficient linear smoother (8).
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