Digital automatic gain control method and device

Abstract

An automatic gain control device () includes a peak detector () configured to receive a current output of an ADC () and to compare it to a previous output to produce a peak value. The automatic gain control device () also includes an out-of-range indicator () configured to receive an out-of-range signal if an input to the ADC exceeds the dynamic range of the ADC. The out-of-range indicator () increases the peak value if the out-of-range indicator () receives the out-of range signal. An error detector () is coupled to the out-of-range indicator () and the peak detector () and produces an error level that is the difference of an output of the out-of-range indicator () and a pre-selected target value. The pre-selected target value is chosen to attenuate interference signals that exceed the dynamic range of the ADC () but minimizes the attenuation of communication signals. An integrator () is coupled to the error detector () and sums the error level with an integrator value to determine a new integrator value. A quantizer (), coupled to the integrator (), receives the new integrator value and determines a new level of attenuation.