Example 6: Video Signal Trigger - Owon SDS6062 User Manual

waveform.
(8) With the elliptical oscillogram method adopted, observe and calculate the phase
difference (see Fig.6-6).
Based on the expression sin q =A/B or C/D, thereinto, q is the phase difference angle,
and the definitions of A, B, C, and D are shown as the graph above. As a result, the
phase difference angle can be obtained, namely, q =± arcsin (A/B ) or ± arcsin (C/D).
If the principal axis of the ellipse is in the I and III quadrants, the determined phase
difference angel should be in the I and IV quadrants, that is, in the range of (0 ～π /2)
or (3π / 2 ～2π). If the principal axis of the ellipse is in the II and IV quadrants, the
determined phase difference angle is in the II and III quadrants, that is, within the
range of (π / 2 ～π) or (π ～3π /2).

Example 6: Video Signal Trigger

Observe the video circuit of a television, apply the video trigger and obtain the stable
video output signal display.
Video Field Trigger
For the trigger in the video field, carry out operations according to the following
steps:
(1) Press the Trigger Menu button to display the trigger menu.
User Manual of Smart Digital Storage Oscilloscope
The signal must be
centered and kept in the
horizontal direction.
Fig.6-6 Lissajous Graph
6. Demonstration
78