Keysight DSOX3012T, Руководство пользователя

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196 Keysight InfiniiVision 3000T X-Series Oscilloscopes User's Guide
11
Triggers
1 Press the Time > softkey; then, turn the Entry knob to set the time to
greater-than the sync-pulse width so that the oscilloscope synchronizes to the
vertical sync.
2 Press the Edge # softkey; then, turn the Entry knob to select the Nth edge after
after vertical sync to trigger on.
3 To enable or disable the horizontal sync control, press the first Horiz Sync
softkey.
• For interleaved video, enabling the Horiz Sync control and setting the
Horiz Sync adjustment to the sync time of the probed video signal allows the
Edge # function to count only lines and not double count during equalization.
Additionally, the Field Holdoff can be adjusted so that the oscilloscope
triggers once per frame.
• Similarly, for progressive video with a tri-level sync, enabling the Horiz Sync
control and setting the Horiz Sync adjustment to the sync time of the probed
video signal allows the Edge # function to count only lines and not double
count during vertical sync.
When the horizontal sync control is enabled, press the second Horiz Sync
softkey; then, turn the Entry knob to set the minimum time the horizontal sync
pulse must be present to be considered valid.
To trigger on a specific line of video
Video triggering requires greater than 1/2 division of sync amplitude with any
analog channel as the trigger source. Turning the trigger Level knob in Video
trigger does not change the trigger level because the trigger level is automatically
set to the sync pulse tips.
One example of triggering on a specific line of video is looking at the vertical
interval test signals (VITS), which are typically in line 18. Another example is
closed captioning, which is typically in line 21.
1 Press the [Trigger] key.
2 In the Trigger Menu, press the Trigger softkey; then, turn the Entry knob to
select Video .
3 Press the Settings softkey, then press the Standard softkey to select the
appropriate TV standard (NTSC).