What does rise time measure in a signal?

Rise time specifically measures the duration it takes for a signal to transition from a lower threshold to a higher threshold, capturing the dynamic behavior of the signal during its upward movement. The typical definition of rise time is the time taken for the signal to rise from 10% of its maximum value to 90% of its maximum value. This range is used because it provides a clear indication of how rapidly the signal can change, encompassing the effects of various factors such as bandwidth and signal integrity.

By focusing on the specified percentages, rise time effectively reflects the significant part of the signal's transition while ignoring the potential inaccuracies that could arise from the extremes (0% and 100%). This measurement is crucial in designing and assessing circuits and systems that rely on precise timing and performance characteristics.