Triggering the Oscilloscope

To use TV triggering

Example exercises The following are exercises to familiarize you with TV triggering.

To trigger on a specific line of video

TV triggering requires greater than 1/2 division of sync amplitude with any analog channel as the trigger source. Turning the trigger Level knob in TV 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 More key, then press the TV softkey.

2Press the Settings softkey, then press the Standard softkey to select the appropriate TV standard.

3Press 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.

4Press the Line # softkey and select the number of the line you want to examine.

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.

When using Generic as the TV standard, you can select a line number to trigger on when Mode is set to Line:Field1, Line:Field2 and Count:Vertical.

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Agilent Technologies 54621A, 54621D, 24A, 42A, 22A, 41A manual To trigger on a specific line of video, Alternate Triggering