Digital Automatic Gain Control Design for Optical Sin/Cos Scale Signals

This paper utilizes a Field Programmable Gate Array (FPGA) in conjunction with an Analog to Digital Converter (ADC) converter to design an Automatic Gain Control (AGC) circuit for the output signal of an Analog Optical Scale. The analog Sin/Cos orthogonal signals from the optical scale are first converted into digital signals using an ADC converter, which serves as input to the AGC circuit. A digital Schmidt trigger circuit designed using the FPGA determines the quadrant of the digital Sin/Cos signals. By detecting the peaks of the Sin/Cos signals, a series of peak values are obtained to determine the maximum and minimum values of Sin/Cos, thereby determining the required amplifier gain for the AGC circuit. Finally, the digitally processed Sin/Cos signals from the AGC circuit are output, and the performance of the AGC circuit is validated using the output results of a digital-to-analog converter (DAC).