Agilent Technologies 22D Guide de l'utilisateur télécharger pdf (Page 112)

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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.

Th e t ri gg er ci rc ui ts lo ok fo r t he po si ti on o f t he st art of Ve rt ic al S yn c t o de term ine

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

1 2 ... 107 108 109 110 111 112 113 114 115 116 117 ... 275 276

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Agilent Technologies 22D Guide de l'utilisateur Page 112