Automatic Gain Control Circuit Design for Wireless RF Receiver

Abstract

Due to the limitation of communication environment, the change of communication distance and the attenuation and superposition of signals in the transmission process, the range of wireless signal strength received by the receiver fluctuates greatly, which seriously affects the accurate demodulation of signals by the receiver. The radio frequency receiver with Automatic Gain Control (AGC) circuit only needs a low-bit Analog-to-Digital Converter (ADC) to quantize the received signal, which reduces the accuracy requirement of ADC circuit. Moreover, image suppression and signal demodulation in digital domain can be more accurate and flexible. In this paper, by analyzing and comparing the common circuit structures of closed-loop feedback type, open-loop feedforward type and sampling data feedback type, an open-loop feedforward digital-analog hybrid AGC circuit is designed according to the application environment requirements of the wireless communication system in the Internet of Things mode, which has the advantages of fast establishment and high linearity.