Automatic gain compression detection and gain control for analog front-end with nonlinear distortion

摘要

An analog front-end (AFE) circuit has at least one AFE stage to generate a conditioned analog signal, and a gain control block to set a gain of the AFE stages. A finite state machine (FSM) block sets the gain to a baseline set gain without gain compression, or a current set gain with gain compression. An amplitude block determines amplitudes of the inner and outer eyes of a signal eye of the conditioned analog signal at the baseline set gain and the current set gain. A compression calculation block determines a gain compression of the conditioned analog signal at the current signal gain based on the relative changes in the respective amplitudes of the inner and outer signal eyes between the baseline and current set gains. The FSM block increases the current set gain until the gain compression ratio reaches a predefined limit.