SOFTWARE-BASED DIGITAL AUDIO ON PCs


Copyright (C) 1990  David T. Chappell
All Rights Reserved


                            ABSTRACT


     Digital audio techniques were investigated with special

concentration on computer applications.  Experimentation showed

that the Intel 8253 programmable interval timer, found on all IBM

PCs and compatibles, can output digitized sound.  The

relationship between pulse amplitude modulation and pulse width

modulation signals was found to be significant to this process.

Feeding digitized sound data to the chip results in an inherent

transfer from pulse amplitude modulation to pulse width

modulation encoding.  The relationship in signal modulation

allows IBM PCs to play digitized sound without the use of extra

hardware.

                           Biography:

     David T. Chappell is a senior in the computer science

curriculum at North Carolina State University.  In addition, he

participates in the co-op program and works for IBM.  His

interests are in the areas of advanced input/output,

technological research, and scientific applications.  David plans

to attend graduate school in computer science or a related field.