Step-Tune Method for Digital Automatic Gain Control System of SAR

This paper studies the step-tune method used in Digital Automatic Gain Control (DAGC) system in depth, and presents an improved method named shift-step-tune which is bases on double-threshold step-tune. Subsequently, we derive the regions for gain stability and provide the criteria for both single-threshold and double-threshold step-tune method through statistic calculation and performance analysis. And then validate them by computer simulation and SAR data image.