Statistical Properties of the Output of Receivers under Interference Conditions

interference mechanisms in receivers frequently entail nonlinear phenomena which alter the information sidebands of unwanted signals admitted to the receiver. Methods are discussed for obtaining useful statistical properties of the output of double-sideband receivers in such cases, when the original unwanted signals are double-sideband modulated with "Gaussian process" information. The solution is carried out in two stages. The statistical properties at the output of the nonlinear device, where the information sidebands are no longer Gaussian, are first obtained. A method is then developed for conveniently determining the pertinent quantities at the output of the filter and detector. The firstorder moments of the output are given emphasis. From these the first-order probability densities can frequently be approximated, as they are here. Specific attention is given to second harmonic interference caused by square-law nonlinearity, and to intermodulation interference caused by cube-law nonlinearity. An example of each is worked out to show the effect of bandwidth on the moments and on the probability densities.