Patent ID: 6708025
Filing Date: 2004-03-16
Classification: H03G

Abstract:
An automatic gain controller comprising:a gain control amplifier which variably amplifies an input signal based on a gain control signal to output a signal of a predetermined level; a gain control signal generator which generates an automatic gain control signal based on the difference between the level of the output signal from the variable gain amplifier and a target value; a sweep signal generator which outputs a sweep signal for sweeping across the minimum value and the maximum value of a variable gain range of the variable gain amplifier; a gain voltage value detector which detects a control voltage value of the sweep signal obtained when the level of the output signal from the variable gain amplifier coincides with the target value; and a gain control signal provider which provides the gain control signal to the variable gain amplifier, wherein the sweep signal is used as the gain control signal in the initial stage of operation, wherein the control voltage value obtained when the level of the output signal coincides with the target value is used as the gain control signal after the sweep operation via the sweep signal, wherein the automatic gain control signal based on the difference is used as the gain control signal after output of the control voltage value.