192 Keysight InfiniiVision 3000T X-Series Oscilloscopes User's Guide
11 Triggers
 
2 In the Trigger Menu, press the Trigger softkey; then, turn the Entry knob to 
select Video.
3 Press the Source softkey and select any analog channel as the video trigger 
source.
The selected trigger source is displayed in the upper-right corner of the display. 
Turning the Trigger Level knob does not change the trigger level because the 
trigger level is automatically set to the sync pulse. Trigger coupling is 
automatically set to TV in the Trigger Mode and Coupling Menu.
4 Press the sync polarity softkey to set the Video trigger to either positive ( ) or 
negative ( ) sync polarity.
5 Press the Settings softkey.
Provide Correct Matching
Many video signals are produced from 75 Ω sources. To provide correct matching to these 
sources, a 75 Ω terminator (such as a Keysight 11094B) should be connected to the 
oscilloscope input.