UNI-T UPO2000E Series, Руководство пользователя

Страница: 46 / 66

Picture 7-1 Waveform display in XY mode
8.3 Application of XY Mode
The Lissajous method makes it easy to observe the phase difference between two signals of the same frequency.
The following figure shows the observation of phase difference.
According to sinθ = A/B or C/D, θ is the phase difference angle between channels, and the definition of A, B and C, D are
shown above, it can be calculated that the phase difference angle θ = ± arcsin (A/B) or θ = ± arcsin (C/D). If the main axis
of the ellipse is in the quadrants I, III, then the calculated phase difference angle should be in the quadrants I, IV, i.e. within
(0~π/2) or (3π/2~2π); If the main axis of the ellipse is in the quadrants II, IV, then the calculated phase difference angle
should be within (π/2~π) or (π~3π/2).
In addition, if the frequency or phase difference of the two detected signals is an integer, the frequency and the phase
relationship between the two signals can be calculated according to the pattern in the following chart:
46