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Signal Correlation is a digital signal processing technique which has a wide variety of applications, ranging from geophysical exploration to acoustic signal enhancements, or beamforming. This dissertation will consider this technique in an underwater acoustics perspective, but the algorithms illustrated here can be readily applied to other areas. Although beamforming techniques have been studied for the past fifty years, modern beamforming systems still have difficulty in operating in noisy environments, especially in shallow water.

Wigner distribution is considered to be one of the most powerful tools for time-frequency analysis of rumvstationary signals. Wigner distribution is a bilinear signal transformation which provides two dimensional time-frequency characterization of one dimensional signals. Although much work has been done recently in signal analysis and applications using Wigner distribution, not many synthesis methods for Wigner distribution have been reported in the literature. This thesis is concerned with signal synthesis from discrete-time Wigner distribution and from discrete-time pseudo-Wigner distribution and their applications in noise filtering and signal separation. Various algorithms are developed to reconstruct signals from the modified or specified Wigner distribution and pseudo-Wigner distribution which generally do not have a valid Wigner distributions or valid pseudo-Wigner distribution structures. These algorithms are successfully applied to the noise filtering and signal separation problems. / Master of Science

A major break-through in the real-time digital simulation of dynamic models has occurred with the introduction of the Intel 2920 digital signal processing chip. The problems and potentials for this new device are demonstrated by implementing an elliptic function digital low pass filter via the bilinear z-transform approach. The software implementation is presented. Debugging and software verification are accomplished via manufacturer's simulation software tools. The hardware performance is verified in the laboratory. The results of these efforts point to much promise for wide scale applications, however, problems associated with performance indicate early version chip problems.

This research report is devoted to an investigation of finite impulse response (FIR) filters and their implementation via windowing techniques. Analysis is restricted to those FIR filters that possess both a nonrecursive structure and a linear phase response. Initially an informative yet concise overview of FIR filters is presented. Some knowledge of "discrete – time" systems is assumed. Next, the concepts associated with FIR filter implementation through the utilization of window functions is developed. Analysis is performed in both the time and frequency domains. Results obtained define optimal window function criteria. The last design technique is devoted to computer aided FIR filter design via windows. The purpose of this section is to demonstrate the advantages of using the computer to solve the FIR filter – window design problem. An example problem supplements this section. Conclusions, along with a brief summary are documented.