UTD2000 Series User Manual 
26 
 
 
According to sin θ=A/B or C/D, θ is the angle difference of channels, the definition of A, B, 
C, D  is shown in figure above, so the angle difference is: θ=±arcsin (A/B) or θ=±arcsin 
(C/D). If the elliptical axis lies on I, III quadrant, then the phase difference of angle should 
lie on I, IV quadrant, that is within (0~π/2) or (3π/2~2π). If the elliptical axis lies on II、IV 
quadrant, the phase difference of angle should be within (π/2~π) or (π~3π/2). Additonally, 
users can also figure out the frequency and phase relation between two signals according 
to Lissajous figures below: 
 
Figure 3-4 Common Lissajous Figures 
 
Only when CH1 and CH2 are used simultaneously can this method be adopted. After 
selecting XY display mode, CH1 volatage is displayed on horizontal axis and CH2 voltage 
is displayed on vertical voltage. 
 
Figure 3-5 Waveform Display under XY Mode 
Note: To ensure a better dispay effect of lissajous figures, the waveform display under 
XY mode has a complete cycle at least. Below functions in XY display mode are 
ineffective. 
  Cursor Measurement Mode 
  Reference or Mathematical Operation Waveform 
  Window Extension Function 
  Trigger Control