Tektronix 684A User Manual

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Specifications
1–4
TDS 684A, TDS 744A, & TDS 784A Service Manual
The delayed display (or the intensified zone) may also be delayed by a selected
number of events. In this case, the events source is the delayed-trigger source.
The delayed trigger can also be set to occur after a number of events plus an
amount of time.
Trigger System
The triggering system supports a varied set of features for triggering the
signal-acquisition system. Trigger signals recognized include:
H Edge (main- and delayed-trigger systems): This familiar type of triggering is
fully configurable for source, slope, coupling, mode (auto or normal), and
holdoff.
H Logic (main-trigger system): This type of triggering can be based on pattern
(asynchronous) or state (synchronous). In either case, logic triggering is
configurable for sources, for boolean operators to apply to those sources, for
logic pattern or state on which to trigger, for mode (auto or normal), and for
holdoff. Time qualification may be selected in pattern mode. Another class
of logic trigger, setup/hold, triggers when data in one trigger source changes
state within the setup and hold times that you specify relative to a clock in
another trigger source.
H Pulse (main-trigger system): Pulse triggering is configurable for triggering
on runt or glitch pulses, or on pulse widths or periods inside or outside limits
that you specify. It can also trigger on a pulse edge that has a slew rate faster
or slower than the rate you specify. The pulse trigger is also configurable for
source, polarity, mode, and holdoff.
H Video (with option 05: Video Trigger): Video triggering is compatible with
standard NTSC, PAL, SECAM, and HDTV formats. An additional feature
called FlexFormat
TM 
(flexible format) allows the user to define the video
format on which to trigger.
You can choose where the trigger point is located within the acquired waveform
record by selecting the amount of pretrigger data displayed. Presets of 10%,
50%, and 90% of pretrigger data can be selected in the horizontal menu, or the
general purpose knob can be assigned to set pretrigger data to any value within
the 0% to 100% limits.
Acquisition Control
You can specify a mode and manner to acquire and process signals that matches
your measurement requirements.