An all digital automatic gain control

A digitally implemented automatic gain control (AGC) technique developed for a modem receiver design is described. The modem´s signal-processing software is integrated with the AGC, thereby allowing the designer to have control over the overall performance and characteristic features of the modem at a lower cost. Such features include complex functions such a equalization freeze, data carrier, and voice detect. By eliminating a hardware-implemented AGC, an overall system cost reduction is accomplished. The AGC has been incorporated in a commercial QAM/DPSK/FSK modem design, where its performance has been shown to be comparable to that of current approaches