Tektronix TDS1000B Series Operator's Manual page 260

6
Using Menu Function Controls
10. On the Training 1 signal board, turn the ADJ knob to
display the XY signal as a circle.
The circle means that both of the signals are sine waves
and are 90º out of phase with respect to each other.
You will see a waveform similar to that shown in Figure 6.8.
Figure 6.8: XY Display of two sine waves with 90º phase shift
You can use the XY display format to set or measure the
phase shift between two synchronous signals with a phase
difference.
6-24 TDS1000B and TDS2000B Series Oscilloscopes – Operator Training Kit