AUTOMATIC GAIN CONTROLLER

摘要

PURPOSE:To provide the automatic gain controller which can realize the high- speed gain control and the stable reception at the time of the rise of burst and the high-speed gain recovery at the time of the fall of burst by a reset signal. CONSTITUTION:A detector 2 outputs the detection output (c) according to the level of an amplifier output (b). A non-signal state detecting device 4 generates a non-signal state detection signal (f) from the detection output (c). A data end discrimination device 6 generates the data end signal from a decoded data string (h) from a decoder 5. A gain control signal generation circuit 3 inputs the OR between the non-signal state detection signal (f) and the data end signal (e) as a reset signal (g). When the reset signal (g) is turned off, the gain control signal (d) is generated according to the detection output (c). In this case, the operational point of the detection output (c) in the normal state is set low. When the reset signal (g) is turned on, the gain control signal (d) which increases the gain of the variable gain amplifier 1 is generated.