Agilent Technologies InfiniiVision 3000 User Manual page 171

10
Triggers
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.
Figure 31 Triggering on Color Field 1 Alternating with Color Field 3
If a more detailed analysis is required, then only one color field should be
selected to be the trigger. You can do this by using the Field Holdoff softkey
in the Video Trigger Menu. Press the Field Holdoff softkey and use the Entry
knob to adjust the holdoff in half- field increments until the oscilloscope
triggers on only one phase of the color burst.
A quick way to synchronize to the other phase is to briefly disconnect the
signal and then reconnect it. Repeat until the correct phase is displayed.
When holdoff is adjusted using the Field Holdoff softkey and the Entry knob,
the corresponding holdoff time will be displayed in the Trigger Mode and
Coupling Menu.
Agilent InfiniiVision 3000 X-Series Oscilloscopes User's Guide 171