Signal Detection in the Presence of Cochannel Interference and Noise

The problem of detection of a sinusoidal signal in the presence of white Gaussian noise and an interfering sinusoid at a nearby frequency is discussed. In the case of coherent detection, several possible receivers are analyzed and probability of error curves are calculated. In some cases it is possible to reduce the effect of cochannel interference significantly by proper choice of a receiver. In the case of incoherent detection, error probability curves have been calculated for the standard envelope detector for several values of frequency separation. The performance of the envelope detector can be degraded substantially by the presence of an interfering sinusoid.