RIGOL DS1000B - Manual (Page 147)

RIGOL
User’s Guide for DS1000B Series 3-9
Figure 3-6
Ellipse method to observe the phase difference
Sinθ = 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)
θ must be in the range of (0~π/2) or (3π/2~2π) if the main axis of the ellipse is at I
and III quadrant, If the main axis is at II and IV quadrant, θ must be in the range of
(π/2~π) or (π~3π/2).
Note:
[1] For DS1204B, the standard probe is RP3300A which attenuation ratio is fixed at 10X and does
not need to be adjusted.
A B
C
D
Signal must be
centered in X