Adaptive Digital Automatic Gain Control
Original Publication Date: 1985-Mar-01
Included in the Prior Art Database: 2005-Feb-18
A technique is described whereby an adaptive digital automatic gain control provides digital implementation of the automatic gain control (AGC) function when a modem is implemented using a digital signal processor. In the past, modems which used digital signal processing techniques for filtering, modulation, demodulation, etc., would often implement the AGC function with an analog circuit because low level signals are digitized with limited precision, resulting in loss of information required to demodulate the signal. To overcome this situation, a higher resolution analog-to-digital converter (ADC) is usually used if the AGC is to be done digitally. To implement the AGC function digitally, a signal may be rectified and low-pass filtered to find the root mean square (RMS) average value.