Agilent Technologies 2000 X-Series, Руководство пользователя

Страница: 137 / 352

Triggers
10
Agilent InfiniiVision 2000 X-Series Oscilloscopes User's Guide 137
• "To trigger on all sync pulses" on page 138
• "To trigger on a specific field of the video signal" on page 139
• "To trigger on all fields of the video signal" on page 140
• "To trigger on odd or even fields" on page 141
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).
4
Press the
Mode
softkey and select the TV field of the line you want to
trigger on. You can choose
Line:Field1
,
Line:Field2
, or
Line:Alternate
.
5 Press the Line # softkey and select the number of the line you want to
examine.
N O T E
Alternate Triggering
If Line:Alternate is selected, the oscilloscope will alternately trigger on the selected line
number in Field 1 and Field 2. This is a quick way to compare the Field 1 VITS and Field 2
VITS or to check for the correct insertion of the half line at the end of Field 1.