Tektronix TDS 200-Series, User Manual

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Application Examples
TDS 200-Series Digital Oscilloscope User Manual
59
15. Push the Trig knob menu box button to select Holdoff.
16. Adjust the HOLDOFF knob to 21 ms for NTSC and PAL video.
NOTE
. To make a large adjustment to the holdoff period, adjust the
SEC/DIV knob to 50 ms, adjust the HOLDOFF knob to 21 ms, and
readjust the SEC/DIV back to the previous value.
Now the oscilloscope only triggers on an odd or an even field (but
not both), and the line information is stable.
With 500 ns of holdoff time, you cannot
see any line information because the
alternating fields overlap
With 21 ms of holdoff time you can
easily see one clear line