Tenma 72-14520 Instructions Manual page 32

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 according to the pattern in the following chart:
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