Measurement Computing WavePort rev.3.0 - Manual (Page 41)

WavePort User’s Manual 09-29-00 Hardware and Operation Reference 4-13
Triggers
This section discusses the following topics:
•
Pulse Trigger
• Digital-Pattern Trigger
• Multi-Channel Triggering
• External Clock and Timer
Pulse Trigger
In addition to the standard “single-channel” trigger-on-level functions, the WavePort system supports
pulse trigger. With pulse trigger, you can define both the amplitude and the duration of the pulse that will
be used to trigger the acquisition. Pulse trigger can be used to detect spurious transients that can be missed
by simple level triggers.
WavePort includes a BNC connector labeled “PULSE.” This connector located on the cover plate (just
below the WaveBook Channel 8 BNC).
Pulse Trigger allows the use of a high-
bandwidth input for triggering, and the
correlation of lower-speed waveforms with
the occurrence of a high-speed pulse. You
can set a pulse amplitude between
±5 V and
a pulse width in the range of
100 ns and 800 ms.
Pulse Trigger Selected
This option allows you to trigger on analog level “pulses” on either the Channel 1 input or the Pulse Trigger
input. This trigger type is similar to the Channel 1 Analog trigger but places an additional time-based
condition on the signal. Depending on whether the pulse width is set as a minimum or a maximum, the
signal either must or must not cross the threshold again within the given amount of time.
The red horizontal line (Threshold) and blue vertical lines (defining maximum width) will vary according to
the parameter settings. You can specify either one or two thresholds for the level and width settings. The
number of labels matches the number of thresholds and the placement follows the polarity.
• For positive polarity, the text is “Rise Above... Stay Below.”
• For negative polarity, the text is “Fall Below and Stay Above.”
Note: When used as a maximum, the pulse width setting can capture signal pulses.
As a minimum, it is useful for ignoring pulses.