Tektronix TBS2072, Руководство пользователя

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Sampling oscilloscope concepts
Auto mode, when forcing triggers in the absence of valid triggering events, does not synchronize the waveform on the
display. The waveform will appear to roll across the screen. If valid triggers occur, the display will become stable.
Normal trigger mode.
Normal mode sets the oscilloscope to acquire a waveform only when a trigger condition occurs.
If no trigger occurs, the last waveform record acquired remains on the display. If no last waveform exists, no waveform
is displayed.
Holdoff trigger mode.
The Holdoff trigger mode lets you set a time period during which the oscilloscope ignores trigger
events. For example, to trigger on the fi rst pulse of a pulse burst, you would set the trigger conditions to trigger on a positive
edge, and set the holdoff value so that the trigger is disabled for a period of time after the trigger event but before the next
bust occurs. Using Holdoff in this case prevents the oscilloscope from triggering on any positive signal edge.
Use Set Holdoff to minimum to set the holdoff value to the minimum value.
NOTE. The trigger mode does not set the trigger conditions; those are set with the trigger Type controls. (See page 27,
Available trigger types.)
Trigger delay (acquisition mode)
In normal acquisition modes, the trigger point is located at the center of the waveform record, and is positioned at the
center-screen expansion point so that horizontal scale changes are centered around the trigger point. The
Delay function
in the Acquire menu disconnects the trigger point from the center-screen expansion point. This feature lets you use the
Horizontal Position knob to reposition (delay) the trigger point from the expansion point by a speci fi ed amount.
The most common use for
Delay is to acquire and display waveform detail that is separated after the trigger event by a
signi fi cant interval of time. For example, you can trigger on a pulse that occurs once every 10 ms and then use Delay to look
at the signal characteristics that occur 6 ms after the trigger point.
TBS2000 Series User Manual 29