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Pulse Width Violation Mode and Commands
Use Pulse Width Violation Mode to find pulses that are wider than the
rest of the pulses in your waveform. You can also use this mode to find
pulses that are narrower than the rest of the pulses in the waveform.
The oscilloscope identifies a pulse width trigger by looking for a pulse
that is either wider than or narrower than other pulses in your waveform.
You specify the pulse width and pulse polarity (positive or negative) that
the oscilloscope uses to determine a pulse width violation. For a positive
polarity pulse, the oscilloscope triggers when the falling edge of a pulse
crosses the trigger level. For a negative polarity pulse, the oscilloscope
triggers when the rising edge of a pulse crosses the trigger level.
When looking for narrower pulses, pulse width less than (Width <)
trigger is the same as glitch trigger.
Use Source to select the oscilloscope channel used to trigger the
Source
oscilloscope.
Use the Level control to set the voltage level through which the pulse
Level
must pass before the oscilloscope will trigger.
When setting the trigger level for your waveform, it is usually best to
choose a voltage value that is equal to the voltage value at the mid point
of your waveform. For example, if you have a waveform with a minimum
value of 0 (zero) volts and a maximum value of 5 volts, then 2.5 volts is
the best place to set your trigger level. The reason this is the best choice
is that there may be some ringing or noise at both the 0-volt and 5-volt
levels that can cause false triggers.
When you adjust the trigger level control, a horizontal dashed line with
a T on the right-hand side appears showing you where the trigger level
is with respect to your waveform. After a period of time the dashed line
will disappear. To redisplay the line, adjust the trigger level control
again, or activate the Trigger dialog. A permanent icon with arrow
(either T, T
, or T
) is also displayed on the right side of the waveform
L
H
area, showing the trigger level.
Use the Polarity control to specify positive or negative pulses.
Polarity
Use Direction to set whether a pulse must be wider (Width >) or
Direction
narrower (Width <) than the width value to trigger the oscilloscope.
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