Keysight 81160A - Page 643

Tutorial
81150A and 81160A User’s Guide 643
Pulse Width Modulation (PWM)
Introduction
PWM is used in digital audio applications, motor control circuitry, switching
power supplies, and other control applications. The Keysight 81150A /
81160A provides PWM for pulse waveforms, and PWM is the only type of
modulation supported for pulse waveforms. For PWM, the amplitude of the
modulating waveform is sampled digitally and used to control the pulse
width or duty cycle of the pulse waveform.
Pulse Width Modulation
Width Deviation
The variation of pulse width in the modulated waveform from the pulse
width of the pulse waveform is called the width deviation. The deviation can
also be expressed in terms of duty cycle (as a percentage referenced to the
period of the pulse waveform), which is called the duty cycle deviation. In
PWM the deviation of width or duty cycle is symmetrical around the pulse
width or duty cycle of the original pulse waveform. For example, if you
specify a pulse waveform with a 10% duty cycle, and then specify PWM
with a duty cycle deviation of 5%, the modulated waveform will have a pulse
that varies in duty cycle from 5% to 15% under control of the modulating
waveform.