Receiver automatic gain control (AGC)

Claim 1

In a receiver of the type wherein automatic gain control is provided by a closed loop including a gain-controlled amplification stage for adjusting the gain of a received signal, the gain of said gain-controlled amplification stage being controlled by a gain-control signal and an AGC generator for providing a gain-control signal to a gain-controlled amplification stage for controlling the gain based on the strength of the received signal, said AGC generator being coupled to the output signal of the gain-controlled amplification stage for sensing the strength of the output signal, the improvement comprising: (a) means for sampling the gain-control signal from said AGC generator to provide samples; (b) means for selecting the optimum gain-control signal from said samples based on the probability of acceptable AGC, P (k), according the following formula: ##EQU4## where n is the total number of samples collected, k is the selected order sample for the AGC setting, and F(x) and F(X) are the probability density function and the cumulative distribution function of the samples X i , respectively, the optimum gain-control signal being the sample having the highest probability of acceptable AGC; and (c) means for coupling said optimum gain control signal from said controller means to control the gain of said gain-controlled amplification stage.