AUTOMATIC GAIN CONTROL DEVICE

摘要

Provided is an automatic gain control device capable of preventing a sudden jump of a gain coefficient caused by a precipitous level modification of a reception level of a signal when updating a gain coefficient. The device includes: a square mean circuit unit (11) for performing a square mean process of a reception signal in a predetermined sample unit; a memory (2) for storing the square mean value; a gain coefficient generation circuit unit (3) which divides the preset reference output level by a value obtained by averaging a predetermined number of square mean values at a predetermined generation interval and generates a gain coefficient; a judgment circuit unit (5) for judging the fluctuation of the reception level of the reception signal; a control circuit unit (6) which decides the number of the square mean values and the generation interval when the fluctuation of the reception level of the reception signal is detected; a gain coefficient linear smoothing unit (8) which modifies the space between the gain coefficient before the update and the gain coefficient after the update from the gain coefficient generation circuit unit (3) linearly and/or non-linearly with a predetermined characteristic; and a multiplier (4) for multiplying the reception signal by the gain coefficient from the gain coefficient linear smoothing unit (8).