A Smart Hybrid AGC Scheme for Satellite System

Satellite communication (SATCOM) has experienced increasingly rapid development in recent years due to its safety and reliability. Automatic gain control (AGC) is an essential regulating part in satellite communication systems with the aim of maintaining a suitable output amplitude as the input varies. In this paper, we propose a hybrid Automatic Gain Control (AGC) approach which combines the signal amplitude ratio technique and the signal amplitude difference technique in existing feedback and feedforward AGC schemes. The proposed AGC scheme is robust to different input signal amplitude variations and is applicable to other systems besides SATCOM system. The proposed AGC scheme can maintain the input signal within the desired range in the conditions of jamming with shorter response time compared to conventional AGC. To demonstrate the effectiveness of the proposed AGC scheme, simulations have been carried out based on the typical satellite transponder link. Jamming signals are considered in the simulation to evaluate the performance of the system with QPSK input signals.