Fall time

In telecommunication, fall time is the time required for the amplitude of a pulse to decrease (fall) from a specified value (usually 90 percent of the peak value exclusive of overshoot or undershoot) to another specified value (usually 10 percent of the peak value exclusive of overshoot or undershoot).

Note: Limits on undershoot and oscillation, i.e., hunting, may need to be specified when specifying fall time limits. Synonym pulse decay time.

Source: from Federal Standard 1037C and from MIL-STD-188