Year: 1970
Type: article
Abstract: The programmable pulse-width modulated signal generator de scribed was designed and constructed to serve as a versatile source of various types of pulse-width-modulated signals.Typical signals generated are unipolar and bipolar PWM signals with single-edge, or double-edge, modulation.This signal generator can be used as a driver for the development of PWM power amplifiers, or as a source of WM signals for studies of their spectral content and of filter requirements for low-distortion signal recovery.The basic characteristics of unipolar and bipolar PWM ampli fiers and signals are discussed.The design of the circuit modules utilized in the signal generator is presented.All of the modules are built on plug-in circuit boards.The signal generator incorporates an active low-pass filter with a Butterworth characteristic having a roll-off of 6, 12 or 18 db per octave.The cut-off frequency is variable from 1 kHz to 50 kHz.The triangular carrier signal frequency is variable from 10 kHz to I MHz and can be modulated with input signals from DC to 50 kHz.iii The system is conveniently arranged for the application of negative feedback to assist in stability studies and to study the effect of negative feedback on signal distortion and on carrier ripple.The unfiltered carrier output signal can supply 200 mA to a 50-ohm load which is sufficient to drive high-power switching-mode output amplifier stages.A complete circuit diagram and a parts list are included.Photo graphs of typical signals generated are presented.
Author: M. A. Honnell
Institution: Auburn University
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W65059871