Wide band automatic gain control with limiting amplifiers

TL;DR: In this article, a high speed communication receiver has a preamplifier stage, an IF stage which includes an attenuation stage having a variable attenuator and a limiting amplifier, a power splitter, an automatic gain control (AGC) circuit having a full-wave detector connected to the power spitter and supplying an amplitude adjusting signal to a mixer where it is mixed with a bias control signal for connection to the variable attenuation with the bias control voltage fixing the operating range mid-point of the attenuators.

Abstract: A high speed communication receiver has a preamplifier stage, an IF stage which includes an attenuation stage having a variable attenuator and a limiting amplifier, a power splitter, an automatic gain control (AGC) circuit having a fullwave detector connected to the power splitter and supplying an amplitude adjusting signal to a mixer where it is mixed with a bias control signal for connection to the variable attenuator with the bias control voltage fixing the operating range mid-point of the variable attenuator and the limiter amplifier for limiting the initial high amplitude portion of the signal pulse resulting from the AGC control voltage reaction time to a level just beyond the top of the dynamic range for enhacing the response time of the receiver and a data processor means including an amplifier connected to the power splitter for restoring the IF stage output signals, a downconverter for converting the frequency to that compatible with an A/D converter, an A/D converter for digitizing the signals and a data processor for processing the information of the digitized signals.