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TDS 684A, TDS 744A, & TDS 784A Service Manual
4–47
Set upper
and lower
limits that
ensure
triggering.
Then change
limits until
triggering
stops.
Figure 4–14: Measurement of Time Accuracy for Pulse and Glitch Triggering
3. Confirm the trigger system is within time-accuracy limits for pulse-glitch or
pulse-width triggering (horizontal scale >1 ms):
a. Set upper and lower limits that ensure triggering at 250 kHz:
H Press the side-menu button Upper Limit. Use the keyboard to set
the upper limit to 4 ms.
H Press the side-menu button Lower Limit. Use the keypad to set the
lower limit to 500 ns.
b. Display the test signal:
H Set the horizontal SCALE to 5 ms.
H Set the output of the sine wave generator for a 250 kHz,
five-division sine wave on screen. Set the vertical SCALE to 20 mV
(the waveform will overdrive the display).
H Press SET LEVEL TO 50%.
c. Check against limits: Do the following subparts in the order listed.
H Use the general purpose knob to increase Lower Limit readout until
triggering is lost.