Agilent Technologies InfiniiVision DSO6014L, Руководство пользователя

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Triggering the Oscilloscope 4
6000 Series Oscilloscope User’s Guide 193
To trigger on odd or even fields
To check the envelope of your video signals, or to measure worst
case distortion, trigger on the odd or even fields. When Field 1
is selected, the oscilloscope triggers on color fields 1 or 3. When
Field 2 is selected, the oscilloscope triggers on color fields 2 or
4.
1 Press the Trigger More key, then press the TV softkey.
2
Press the
Settings
softkey, then press the
Standard
softkey to
select the appropriate TV standard.
3
Press the
Mode
softkey and select
Field1
or
Field2
.
The trigger circuits look for the position of the start of Vertical
Sync to determine the field. But this definition of field does not
take into consideration the phase of the reference subcarrier.
When Field 1 is selected, the trigger system will find any field
where the vertical sync starts on Line 4. In the case of NTSC
video, the oscilloscope will trigger on color field 1 alternating
with color field 3 (see the following figure). This setup can be
used to measure the envelope of the reference burst.