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22 March 1996 Pulsed interference immunity of a wavelet-based modulation scheme
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Modulation in which binary data is mapped by a discrete wavelet transform and then communicated as pulse amplitude modulation (PAM) is studied for its immunity to pulsed interference. The presentation is in terms of two specific examples in which the input mappers are a Hadamard transform and a two-stage Haar multirate synthesis filter bank, respectively. The input data stream is segmented into contiguous blocks of four bits (plus or minus 1 s) that are linearly block-transformed into four PAM coefficients whose dependencies can be used to correct some single and multiple erasures resulting from pulsed interference within the block. The encoding transformations are rate 1, nonredundant mappings describable by trellis diagrams and the language of partial response signaling. For pedagogical purposes the example is carried through in the noiseless case where erasures are the sole channel impairment. Noise-fee results for the identity mapping are also given; a comparison reveals that the Haar mapping is the best of the three. Some results for the additive white Gaussian noise case follow, in which case no one method proves uniformly superior to the others.
© (1996) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Richard S. Orr "Pulsed interference immunity of a wavelet-based modulation scheme", Proc. SPIE 2762, Wavelet Applications III, (22 March 1996);

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