The effect of spectral shaping on the probability of detection of a DS-SS in the presence of CW interference

Direct sequence spread spectrum (DS-SS) modulation is employed in digital communication systems to provide low probability of detection and reduce the effects of interference. A radiometer can be used to detect the presence of the SS signal within some bandwidth. The presence of CW (continuous wave) interference severely degrades the performance of the radiometer. An interference excision filter can be used to improve the performance of the radiometer. Here, the received signal is weighted using a windowing function, and its frequency-domain representation is obtained using the discrete Fourier transform. The interference is detected and notched out by zeroing appropriate frequency components. The effects of using various windows as part of the excision filter on the performance of the system are analyzed. Numerical results are presented.<
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