EXFO PSO-100 Series Optical Sampling Oscilloscopes - Manual (Page 79)

Setting up and Using the Optical Sampling Oscilloscope
Optical Sampling Oscilloscope 71
Managing Measurement Parameters
To set the thresholds for rise and fall times:
1. From the main window, select the Measure menu.
2. Select Thresholds, then the desired value (10-90 % or 20-80 %).