Agilent Technologies 42A, 54621D, 24A, 54621A, 22A, 41A manual To trigger on odd or even fields

Triggering the Oscilloscope

To use TV triggering

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.

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

3Press 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.

Triggering on Color Field 1 Alternating with Color Field 3

3-48