Agilent Technologies 54657A Specifikace stáhnout pdf (Strana 82)

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.

Select the TV display, TV as the trigger mode, and the appropriate TV

standard as described in the section, "To autoscale on a video signal."

2 Press Slope/Coupling in the TRIGGER section of the front

panel, then press the

Mode softkey until Field 1 or Field 2 appears.

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

Figure 3-5

Using Option 005 Enhanced TV/Video Trigger

To trigger on odd or even fields

3–10

1 2 ... 77 78 79 80 81 82 83 84 85 86 87 ... 187 188

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Agilent Technologies 54657A Specifikace Strana 82