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Chapter 4 Remote Interface Reference
Pulse Width Modulation (PWM) Commands
4
• The duty cycle deviation is also limited by the current edge time
setting.
Duty Cycle Dev < Duty Cycle – (160 X Edge Time) ÷ Period
and
Duty Cycle Dev <
100 – Duty Cycle – (160 X Edge Time) ÷ Period
•
If you select the
External
modulating source (
PWM:SOUR EXT
command
), the deviation is controlled by the ±5V signal level present
on the rear-panel Modulation In connector. For example, if you have
set the duty cycle deviation to 5 percent, a +5V signal level
corresponds to a 5 percent deviation, that is an additional 5% of
period added to the pulse duty cycle. Lower external signal levels
produce less deviation, and negative signal levels reduce the duty
cycle.
Note: The operation of the PWM:DEV:DCYC command is affected by the
FUNC:PULS:HOLD command (see “Pulse Configuration Commands” on
page 192 for further information). The FUNC:PULS:HOLD command
determines whether pulse width (the default) or pulse duty cycle values
are to be held constant as the period is varied. If the width is held, so is
the width deviation. If the duty cycle is held, so is the duty cycle deviation.
If pulse width and width deviation are being held, duty cycle deviation
values specified with the PWM:DEV:DCYC command are automatically
converted to the equivalent width deviation in seconds.
PWM:STATe {OFF|ON}
PWM:STATe?
Disable or enable PWM. To avoid multiple waveform changes, you can
enable PWM after you have set up the other modulation parameters.
The default is OFF. The :STAT? query returns “0” (OFF) or “1” (ON).
• The function generator will allow only one modulation mode to be
enabled at a time. For example, you cannot enable PWM and AM at
the same time. When you enable PWM, the previous modulation
mode is turned off.
• The function generator will not allow PWM to be enabled at the same
time that sweep or burst is enabled. When you enable PWM, the
sweep or burst mode is turned off.
• PWM is allowed only when pulse is the selected function.
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