HP 1660CS-Series User Manual page 220

Rise time The rise time of the first displayed rising edge is measured.
To obtain the best possible measurement accuracy, set the sweep speed
as fast as possible while leaving the full leading edge of the waveform on
the display. The rise time is determined by measuring time at the 10%
and 90% voltage points on the rising edge:
−t
Rise time = t
90% 10%
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
The Scope Auto Measure Menu
Automatic measurement algorithms
minimum
] ×100
− V
base
− V
top
] ×100
− V
base
− V
top
] ×100
− V
base
− V
minimum
] ×100
− V
base
7-101