HP 16534A User Reference page 104

The Auto-Measure Menu
Measurement Algorithms
Fall time
Fall time is measured between the 10% and 90% points of the falling edge.
To obtain the best possible measurement accuracy, set the sweep speed as
fast as possible while leaving the falling edge of the waveform on the display:
−t
Fall time = t
10% 90%
Preshoot and Overshoot
Preshoot and Overshoot measure the perturbation on a waveform above or
below the top and base voltages (see the "Top and Base Voltages" section
earlier in this chapter). These measurements use all data displayed on the
screen; therefore, it is very important that only the data of interest be
displayed. If you want to measure preshoot and overshoot on one edge of a
waveform, then only display that edge. If you want to measure the maximum
preshoot and overshoot on a waveform, then display several cycles of the
waveform.
Preshoot is a perturbation before a rising or a falling edge and is measured
as a percentage of the top-base voltage.
Overshoot is a perturbation after a rising or a falling edge and it is measured
as a percentage of the top-base voltage.
If the measured edge is rising, then
− V
V
base
Preshoot = [
V
top
and,
V
maximum
Overshoot = [
V
top
If the measured edge is falling, then
V
maximum
Preshoot = [
V
top
and,
V
base
Overshoot = [
V
top
8-10
.
minimum
] ×100
− V
base
− V
top
] ×100.
− V
base
− V
top
] ×100
− V
base
− V
minimum
] ×100.
− V
base