While specialized hardware description languages allow for maximum capability and efficiency in a design automation system, the use of a general purpose language in the same role can make the system more available or more available or more practical for a larger set of users. This project demonstrates the use of ADA* for the description and simulation of small digital signal processing systems. Building on conventions and primitives proposed by Denyer and Renshaw, a simple subsystem was described in ADA and then tested with a small simulator also written in ADA. * ADA is a trademark of the United States Department of Defense - ADA Joint Program Office (AJPO).

Polar Spectrum Coding is a novel speech coding algorithm for narrowband voice communications. A polar Fourier transform of the signal is computed, and the magnitude and phase of the speech spectrum is encoded for transmission. The correlation between frames of speech signals is exploited to minimize the transmission rate required for intelligible speech. At the receiver, the encoded words are decoded and the spectrum reconstructed. An inverse Fourier transform is performed, and the result is the reconstructed speech waveform. Polar Spectrum Coding theory is explained. The sensitivities of various parameters on performance are explored, and performance in the presence of channel noise is measured. Directions for future research in the realm of Polar Spectrum Coding is suggested.

Computer simulation of a control system is a valuable tool in design or performance evaluation. This is especially true when non-linear elements cannot be ignored and must be included within the model. A general purpose block diagram oriented simulation program will be developed which can utilize continuous, discrete and non-linear building blocks. The software tool will be demonstrated by means of an example.

No description available.

A small-signal analysis of a two-stage distributed power system is performed. Although the distributed power system is composed of conventional PWM converters, the analysis methods can be extended to systems using other converter topologies. The analysis focuses on two important features of a two-stage distributed power system: parallel power modules and cascaded regulators. The small-signal characteristics of parallel module regulators are analyzed, and an expression for the loop-gain of a parallel-module system is obtained. It is found that a parallel module system can be configured so that the loop-gain of the system is independent of the number of modules. The effects of placing switching regulators in cascade are analyzed. Of primary concern is the effect of the second stage's dynamic impedance on the first stage's control loops. It is found that the negative dynamic resistance of the second stage gives rise to right-half-plane poles in the opened-loop gains of the first stage. Fundamental loop-gain analysis is used to determine that stability of the system. It is found that the first stage of a cascaded regulator system must satisfy additional design constraints in order to be stable while driving a negative dynamic resistance. / Master of Science

The high performance method for obtaining an ARMA model spectral estimate of a wide-sense stationary time series has been found to provide typically superior performance when compared to such contemporary approaches as the Box-Jenkins and maximum entropy methods. In this dissertation, fast recursive algorithmic implementations of the high performance method are developed. They are recursive in the sense that as a new element of the time series is observed, the parameters characterizing an ARMA spectral estimate are algorithmically updated. The number of multiplications and additions required at each recursive stage are of the order p with p being the number of denominator coefficients of the ARMA model. Methods of modification of the data are applied to achieve a significant computational improvement. The development is predicated on utilization of various projection operators. / Ph. D.

Moving-average matched filters (MAMF's) are a class of digital filters used to detect the presence of a known signal in noise. Designing matched filters requires knowledge of the structure of the signal and the noise. If the spectral density of the noise is not known or is changing with time its spectral characteristics must be estimated. Since spectral estimators derive their estimates from a random process realization, the estimates themselves are probabilistic in nature. The performance of MAMF's based on these estimates must, in turn, be distributed in a probabilistic sense. This thesis investigates the performance of MAMF's designed on the basis of several different spectral estimators. Theoretical aspects of MAMF's and spectral estimators are reviewed and developed. A simulation system is used to exercise the spectral estimators and MAMF's and to provide comparative performance data. A graphical representation, using contour plots, is developed and can be used to predict the performance of a given MAMF/signal/spectral estimator combination. Finally, several methods of generating MAMF's whose output performance is relatively insensitive (or robust) to the probabilistic variations caused by the spectral estimators are developed and evaluated. The latter incorporates knowledge of the empirical distribution of the particular spectral estimator used, as well as the freedom of manipulating the signal. / M.S.

no abstract provided by author / Master of Science

Digital Signal Processing (DSP) is a technology-driven field which develops as early as mid-1960 when computers and other digital circuitry became fast enough to process large amounts of data efficiently. Since then techniques and applications of DSP have been expanding at a tremendous rate. With the development of large-scale integration, the cost and size of digital components are reducing, and speed of digital components is increasing. Thus the range of applications of DSP techniques is growing. Almost all current discussions of speech bandwidth compression systems are directed toward digital implementation, because these are now the most practical. The importance of DSP appears to be increasing with no visible signs of saturation. This thesis provides the description and results of designing laboratory experiments for the illustration of basic theory in the field of DSP. All experiments are written for the Texas Instruments TMS320I0 digital signal processing microcomputer and based on softwares provided by Atlanta Signal Process, Inc. (ASPI). The use of the 320/pc Algorithm Development Package (ADP) and Digital Filter Design Package (DFDP) developed by ASPI is introduced. The basic concepts, such as linear convolution, Finite Impulse Response (FIR) and Infinite Impulse Response (IIR) filter design, Fast Fourier Transform (FF1), are demonstrated. The IBM PC AT is interfaced with the TMS32010 processor. The experiments and their introductions in the thesis also serve as a manual for the DSP Laboratory; to complement the introductory signal processing course. / Master of Science

This thesis examines the use of a linear DC motor as a proof mass actuator for the control of large space structures. A model for the actuator, including the current and force compensation used, is derived. Because of the force compensation, the actuator is unstable when placed on a structure. Relative position feedback is used for actuator stabilization. This method of compensation couples the actuator to the mast in a feedback configuration. Three compensator designs are proposed. The physical limits of the LDCM place limits on the bandwidth of the closed loop actuator. A ten mode finite element model of a flexible space structure was used in simulations to examine all aspects of the actuator's performance. The performance of the actuator is compared for the three compensator designs. The actuator bandwidth is seen to be important in the actuator's effectiveness. Increasing actuator bandwidth resulted in a saturation nonlinearity in the actuator. The excitation capability of the actuator was examined to determine the authority of the actuator. The damping of the mast modes was examined to determine the effect of the feedback configuration of the actuator/mast system. Root locus techniques were used to explain changes in the vibrational modes of the structure due to the actuator compensation. Disturbance analysis was performed to quantify the effect of corrupted measurements on the purity of force generated by the actuator. / Master of Science