Example 6: Video Signal Trigger - Owon MSO5022 User Manual

User's Manual of OWON Color Mixed Signal Digital Storage Oscilloscope
6. Push down the DISPLAY button and recall the DISP SET menu.
7. Press the F3 menu selection button and choose XY for Format.
The oscilloscope will display the input and terminal characteristics of the network
in the Lissajous graph form.
8. Adjust the VOLTS/DIV and VERTICAL POSITION knobs, optimizing the
wave form.
9. With the elliptical oscillogram method adopted, observe and calculate the phase
difference (see Fig. 95).
Based on the expression sinq =A/B or C/D, where, 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
The signal must be
centered and kept in the
horizontal direction.
Fig. 95 Lissajous Graph
98