Statistical description of non-coherent automatic gain control

In many systems automatic gain control (AGC) is an important system function prior to analog-to-digital conversion (ADC), for instance. The authors analyze the tracking performance of noncoherent AGCs. The gain fluctuation is described by stochastic differential equations. For typical operational cases the physical probability density functions of the AGC gain variation are compared with different approximation techniques, i.e. the Fokker-Planck (F-P) approach and the assumption of Gaussian distributions; the limitations of the approximation methods are emphasized.<>