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Chapter 3 Features and Functions
Pulse Width Modulation (PWM)
Width Deviation
The width deviation represents the variation in width (in seconds) in the
modulated waveform from the width of the original pulse waveform.
• Width deviation: 0 s to 1000 s (see below). The default is 10 µs.
• The width deviation cannot exceed the current pulse width.
• The width deviation is also limited by the minimum pulse width
(Wmin):
Width Deviation < Pulse Width – Wmin
and
Width Deviation < Period – Pulse Width – Wmin
where:
Wmin = 20 ns for period < 10 s.
Wmin = 200 ns for period > 10 s, but < 100 s.
Wmin = 2 µs for period > 100 s, but < 1000 s.
Wmin = 20 µs for period > 1000 s.
• The width deviation is limited by the current edge time setting.
Width Deviation < Pulse Width – (1.6 X Edge Time)
and
Width Deviation < Period – Pulse Width – (1.6 X Edge Time)
• Front-Panel Operation: After enabling PWM, press the Width Dev
softkey. Then use the knob or numeric keypad to enter the desired
deviation.
• Remote Interface Operation:
PWM:DEViation {< deviation in seconds>|MINimum|MAXimum}
Note: The pulse width and width deviation, and the pulse duty cycle and
duty cycle deviation are coupled in the front panel interface. If you select
Width for the pulse waveform and enable PWM, the Width Dev softkey is
available. On the other hand, if you select Dty Cyc for the pulse waveform
and enable PWM, the Dty Cyc Dev softkey is available.
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