RIGOL DS1000D - Manual (Page 143)

RIGOL
© 2008 RIGOL Technologies, Inc.
User’s Guide for DS1000E, DS1000D Series
3-9
Figure 3- 6
Ellipse method to observe the phase difference
Sin
θ = A/B or C/D, where θ = phase shift (in degrees) between the two signals.
From the formula above, you could get:
θ = ±arcsine (A/B) or ±arcsine (C/D)
If the main axis of the ellipse is at I and III quadrant, θ must be in the range of
(0~π/2) or (3π/2~2π). If the main axis is at II and IV quadrant, θ must be in the
range of (
π/2~π) or (π~3π/2).
A B
C
D
Signal must be
centered in X