Enhanced signal interception in the presence of interference

We consider the problem of intercepting a direct sequence spread spectrum waveform which is embedded in both narrowband interference and additive white Gaussian noise. The receiver we analyze is a broadband radiometer which has been enhanced in the following manner. Prior to entering the square-law device in the radiometer, the received waveform is passed through a transform domain processor which serves as a notch filter to null out the narrowband interference before it can contribute unwanted energy to the output of the radiometer. A central-limit theorem is established for the receiver´s output which forms the basis for analyzing the performance of the receiver. For various combinations of system parameters, numerical results are presented in the form of receiver operating characteristics.<>