Development of AGC and channel equalization algorithm for multi-channel RF system in FPGA

In this paper, design and development of algorithm for automatic gain control (AGC) as an attenuator have been proposed and thereafter a channel equalizing algorithm has also been developed. TOAT R512+ digital step attenuator is used for attenuation where 3 control bits adjust the attenuation level and the attenuators are controlled through FPGA which runs the AGC algorithm checking the input level and controlling the same in real time. Due to the different path lengths and RF signal variation, the multi-channel (here 4 channels) system has channel mismatch which is taken care by a channel equalization algorithm which is based on the idea that one to one mapping has best output and keeping that as reference, the same input is channelized through other channels where the fractional gain is calculated and multiplied with the original input for channel equalization.