Rapid settling automatic gain control with minimal signal distortion

摘要

An apparatus and method of automatic gain control (AGC) useful for a detector of a digital radio providing rapid settling and minimal distortion is described. The automatic gain control includes a plurality of modular AGC elements each having a unique bias. The AGC elements may also be switched from an open loop operating mode with a unique initial gain voltage to a closed loop operating mode. A matched filter is applied to the output of each of the AGC elements to filter out all but the signal constituents that match the reference symbol. The output of the matched filters having the greatest signal to noise ratio is the selected as the detector output. The output with the greatest signal to noise ratio corresponds to the output of the AGC element that has settled with the least distortion.