Masters Theses

Date of Award

12-1985

Degree Type

Thesis

Degree Name

Master of Science

Major

Electrical Engineering

Major Professor

Robert E. Bodenheimer

Committee Members

Donald Boldin, Robert W. Rochelle

Abstract

Digital Signal Processing (DSP) is fast becoming the desired method for measurement and control operations due to the increased use of computers in these applications and the advantages of performing operations on digital signals as opposed to analog signals. As the use of Analog-to-Digital converters (ADC) and Digital-to-Analog converters (DAC) increase, the graduating student is faced with a need to understand these systems and have some experience in the operation of these devices in DSP applications.

The specific objectives of this thesis were: 1) to explore the capabilities of the DAC and ADC systems on the TI 990, 2) to explore the diagnostic procedures necessary for proper maintenance and calibration of the ADC and DAC subsystem, and 3) to provide sample DSP programs that can be written by the student in the laboratory in conjunction with coursework.

To achieve the first objective, an Input/Output (I/O) panel was constructed to allow access to the many channels on the ADC and DAC modules. This panel was then used in the diagnostic procedure and the sample DSP programs required of the second and third objectives.

FORTRAN was chosen as the language to use in all software development because it was available on the TI computer, it has several support packages available that accessed the ADC and DAG system, and it is a common language in the engineering curriculum. The example programs that were developed are discussed in Chapter II, and the source code is available in the appendix. These programs consisted of 1) a digital oscilloscope, 2) a Fourier Series analysis program, 3) a program to characterize lesser resolution ADC's, and 4) a program to perform Fast Fourier Transforms and filtering. An operation amplifier summing junction was constructed for the third laboratory and an eight bit ADC for the fourth laboratory. The schematic for these devices is available in the appendix.

Results indicate that the TI system can be used very effectively in the laboratory analysis of some DSP applications. The only limitations that were evident were those due to the nature of the TI 990 being a multi-user system, some time shifting of the sampled signal was observable due to the system scheduling and running other users during the sampling process. Also, to use the system for analysis of high frequency signals, an assembly language routine would need to be developed.

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