Main Content

Fall time of negative-going bilevel waveform transitions

returns a vector `f`

= falltime(`x`

)`f`

containing the time each transition of the
bilevel waveform `x`

takes to cross from the 10% reference level
to the 90% reference level (See Percent Reference Levels). To determine the transitions,
`falltime`

estimates the state levels of the input waveform
using a histogram method. `falltime`

identifies all regions that
cross the lower-state boundary of the high state and the upper-state boundary of the
low state. The low-state and high-state boundaries are expressed as the state level
plus or minus a multiple of the difference between the state levels (See State-Level Tolerances). Because `falltime`

uses
interpolation, `f`

may contain values that do not correspond to
sampling instants of the bilevel waveform `x`

.

specifies the sample rate in hertz. The sample rate determines the sample instants
corresponding to the elements in `f`

= falltime(`x`

,`fs`

)`x`

. The first sample instant in
`x`

corresponds to *t*=0. Because `falltime`

uses interpolation,
`f`

may contain values that do not correspond to sampling
instants of the bilevel waveform `x`

.

`[___] = falltime(___,`

returns the fall times with additional options specified by one or more
`Name,Value`

)`Name,Value`

pair arguments.

`falltime(___)`

plots the signal and darkens the
regions of each transition where fall time is computed. The plot marks the lower and
upper crossings and the associated reference levels. The state levels and the
associated lower- and upper-state boundaries are also displayed.

[1] *IEEE ^{®} Standard on Transitions,
Pulses, and Related Waveforms*, IEEE Standard 181, 2003,
pp. 15–17.