Tektronix Waveform Monitors WFM700 Series - Manual (Page 71)

Reference
3- 22 WFM700 Series Waveform Monitors User Manual
3. Method 2 -- Use the percentage voltage cursors to measure rise time:
a. Turn on the voltage cursors and set the voltage cursor units to %.
b. Position the first voltage cursor to the top of the signal, and then position
the second voltage cursor to the bottom of the signal.
c. Touch the Set 100% soft key.
d. Position the first voltage cursor to where the readout lists 80%, and then
position the second voltage cursor to where the readout lists 20%.
e. Position the first timing cursor at the crossing of the rising edge of the
Eye waveform and the 20% voltage cursor.
NOTE. You can use the horizontal MAG control in the Sweep menu for greater
accuracy when adjusting the time cursors.
f. Position the second timing cursor at the crossing of the rising edge of the
Eye waveform and the 80% voltage cursor.
g. The Delta time readout indicates the 20 -- 80% rise time measurement.