Adaptive two-channel automatic gain control system

A new method is proposed for enhancing the performance of automatic gain control systems coupled with analog-to-digital converters (ADCs). This approach is focused on increasing the dynamic range of software-defined radios in applications where high data rates and low-power requirements make increasing ADC resolution impractical. This novel approach utilizes two input channels in order to aggressively enhance sensitivity while remaining responsive to rapid changes in input signal power. For modest rates of input power change, signal- to error-power ratios (SER) can be enhanced by 6 dB or more. A methodology for selecting control parameters, algorithms for adjusting to input characteristics in real time, and results from a functional prototype are discussed.