Tektronix CSA7154, User Manual

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Triggering
CSA7000 Series, TDS7000 Series, & TDS6000 Series Instruments User Manual
3- 77
Horizontal position is adjustable and defines where on the waveform record the
trigger occurs. It lets you choose how much the instrument acquires before and
after the trigger event. The part of the record that occurs before the trigger is the
pretrigger portion. The part that occurs after the trigger is the posttrigger portion.
When horizontal delay is off, the reference marker shows the trigger position in
the waveform.
Displaying pretrigger information can be valuable when troubleshooting. For
example, if you are trying to find the cause of an unwanted glitch in your test
circuit, you can trigger on the glitch and make the pretrigger period large enough
to capture data before the glitch. By analyzing what happened before the glitch,
you may uncover clues about its source.
The slope control determines whether the instrument finds the trigger point on
the rising or the falling edge of a signal. (See Figure 3--24.)
You set trigger slope by pushing the SLOPE button on the front panel to toggle
between the positive-going and negative-going edge.
The level control determines where on that edge the trigger point occurs. (See
Figure 3--24.) You can set the trigger level with the LEVEL knob on the front
panel. Push the LEVEL knob to automatically set the trigger level to the 50%
amplitude point of the signal.
Positive-going edge Negative-going edge
Trigger slope can be positive or negative.
Trigger level
can be adjusted
vertically.
Figure 3- 24: Slope and level controls help define the trigger
Horizontal Position
Slope and Level