Thesis (Ph.D.)--Washington State University, December 2005. / Includes bibliographical references (p. 79-85).

The use of uniformly distributed auxiliary random noise in the polarity-coincidence correlator has been described in the past. It has the advantage of constructional simplicity. It also gives an unbiased and consistent estimate of the correlation function. In this thesis, the method of using auxiliary random noise is extended to the multi-level digital correlator. It is found that any random noise of which the characteristic function has periodic zeros can be used as an auxiliary noise, that uniformly distributed noise is a special case, and that quantizing the auxiliary random noise has the same effect as directly quantizing the input signals. The mean-square error of this modified digital correlator is analyzed in detail. It differs from the mean-square error of the direct correlator only by a term which is inversely proportional to the total number of samples taken, provided that the power spectrum of the auxiliary noise is wide enough. This additional error is the combined effect of sampling, quantizing and adding auxiliary noise. It can be reduced to any desired value by taking a larger number of samples, by using a higher sampling rate, or by quantizing more finely. For completeness, the mean-square errors of the digital correlator, the Stieltjes correlator and the modified Stieltjes correlator are also derived. The mean-square error of the modified polarity-coincidence correlator, which is a special case of the modified digital correlator, is compared with the error of the multi-level modified digital correlator. Despite its constructional simplicity, the modified polarity-coincidence has a much larger error than the multi-level correlator. A small increase in the number of quantization levels reduces the error considerably. The implementation of a modified digital correlator with coarse quantization is also considered. A fast direct multiplier is designed to obtain high operation speed. Finally, the use of pseudo-random noise as an auxiliary noise is discussed. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

No description available.

Approved for public release, distribution is unlimited / The performance of coherent and noncoherent RAKE receivers over a fading channel in the presence of pulse-noise interference and additive white Gaussian noise is analyzed. Coherent RAKE receivers require a pilot tone for coherent demodulation. Using a first order phase-lock-loop to recover a pilot tone with additive white Gaussian noise causes phase distortions at the phase-lock-loop output, which produce an irreducible phase noise error floor for soft decision Viterbi decoding. Both coherent and noncoherent RAKE receivers optimized for additive white Gaussian noise perform poorly when pulse-noise interference is present. When soft decision convolutional coding is considered, the performance degrades as the duty cycle of the pulse-noise interference signal decreases. The reverse is true for hard decision Viterbi decoding, since fewer bits experience interference and bit errors with high noise variance cannot dominate the decision statistics. Soft decision RAKE receiver optimized for pulse-noise interference and additive white Gaussian noise performed the best for both the coherent and noncoherent RAKE receivers. This receiver scales the received signal by the inverse of the variance on a bit-by-bit basis to minimize the effect of pulse-noise interference. The efficacy is demonstrated by analytical results, which reveal that this receiver reduces the probability of bit error down to the irreducible phase noise error floor when pulse-noise interference is present. This demonstrates how important it is to design the receiver for the intended operational environment. / Civilian, Department of Defense

This thesis presents a comparative analysis of various low-frequency sonar signature representations and their ability to discriminate between proud targets of varying physical parameters. The signature representations used include: synthetic aperture sonar (SAS) beamformed images, acoustic color plot images, and bispectral images. A relative Mean-Square Error (rMSE) performance metric and an effective Signal-to-Noise Ratio (SNReff) performance metric have been developed and implemented to quantify the target differentiation. The analysis is performed on a subset of the synthetic sonar stave data provided by the Naval Surface Warfare Center - Panama City Division (NSWC-PCD). The subset is limited to aluminum and stainless steel, thin-shell, spherical targets in contact with the seafloor (proud). It is determined that the SAS signature representation provides the best, least ambiguous, target differentiation with a minimum mismatch difference of 14.5802 dB. The acoustic color plot and bispectrum representations resulted in a minimum difference of 9.1139 dB and 1.8829 dB, respectively / by Brenton Mallen. / Thesis (M.S.C.S.)--Florida Atlantic University, 2012. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2012. Mode of access: World Wide Web.

Thesis (Sc.D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1979. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaves 99-108. / by Marvin Stuart Keshner. / Sc.D.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / by John A. Cartelli. / M.S.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1979. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Vita. / Includes bibliographical references. / by Lawrence Howard Ozarow. / Ph.D.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / by Joseph A. Amram. / M.S.

Also issued as a Ph.D. thesis in the Dept. of Electrical Engineering, 1970. / Bibliography: p. 168-173.