7.1 XY Mode 
The XY mode display is also called Lissajous graph.
When XY 1&2 are selected, the CH1 signal will be entered on the horizontal 
axis (X), and the CH2 on the vertical axis (Y). In X-Y mode, when CH1 is 
activated, use the horizontal POSITION knob to adjust the graph horizontally. 
When CH2 is activated, use the horizontal POSITION knob to adjust the 
graph vertically.The vertical SCALE knob to be used to adjust each channel’s 
amplitude level. The horizontal SCALE knob can be used to adjust the time 
position in order to obtain a well displayed Lissajous graph.
XY Display Mode
7.2 Application of XY Mode
The phase difference between the two signals of the same 
frequency can be easily observed by Lissajous method. 
The following chart gives the observation of phase 
difference.
Since sinθ = A/B or C/D, theta (θ) is the angle between 
the two signals, the definition of A, B and C, D is shown 
above. We can draw a difference angle θ = ± arcsin(A/B) 
or θ = ± arcsin(C/D). If the principal axis of an ellipse is 
in quadrants I and III, then the phase angle should be 
in I, IV quadrant, in 0 to (π / 2) or (3 π / 2) to 2 π. If the 
principal axis of an ellipse in II, IV quadrant, then the 
phase angle should be (π /2) to π or π to (3 π/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 .
UTD2000CEX-II User Manual