Conventional detection and demodulation rules are not ideally suited for use with discrete Fourier transform (DFT) based narrow-band interference suppression, if the DFT incorporates time-weighting to localize the interference spectrally. Detection rules which are adapted to the time-weighting are introduced here and shown to o er signi cant improvements in performance, but their implementation is complex. It is found that if a spectrally-contained orthogonal transform (SCOT) is employed in place of the windowed DFT however, the conventional detection rules have a level of performance comparable to that obtained with DFT based suppression and the adapted rules. In addition to yielding good interference localization, SCOTs bene t from the fact that they provide a Karhunen-Loeve like transform for each component of the observation. The primary focus of the paper is the application of interference suppression for the detection of the presence of covert signals; however, it is also demonstrated that SCOT based suppression is potentially better suited than DFT based suppression for data demodulation in commercial code-division multipleaccess (CDMA) network overlays.
A4D-A250 519 W1ENTATION PAGE OM o17408"Vtiatea to average I iour Der 'esoorse. nciudn the tim'e for reviewing instrr'Tis sea.rmo -st 5o3 Sur'is g "nro reviewing thle collection o 4 intrMatin Send comhimerits regarding t01s b,.irclen es rate or 3n, Al'.er
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92-12938. Detailed study results are presented in section 3.3 on page 53.
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