Rise time Rise and fall time measurements are commonly used when validating the signal integrity of square waves, pulses, and clocks in digital systems. Rise time characteristics are important in electronics because they indicate the ability of a circuit to respond to fast input signals. As a rule of thumb, the following formula can be used to estimate the rise time of an oscilloscope: tR = 0.35 / BW where tR is rise time and BW is bandwidth of the oscilloscope.  So, for a 100 MHz oscilloscope the rise time can be calculated as: tR = 0.35 / 100 MHz = 3.5 ns The 0.35 relationship between bandwidth and rise time assumes a single-pole resistor-capacitor (RC) roll-off response of the oscilloscope and 10%-90% rise time measurement. Real-world examples may differ, especially at high frequencies, where the constant can reach 0.45 or higher. More information on Rise time >>