Signal Over- and Undershooting

Signal reflection occurs when a signal encounters an impedance mismatch along the transmission path. This impedance mismatch can arise from various factors, such as variations in trace impedance, connectors, and termination. When a signal encounters an impedance mismatch, a portion of the signal energy is reflected back towards the source. This reflected energy can interfere with the original signal, leading to distortions and potential signal integrity issues.

Overshoots and undershoots result from the superposition of the transmitted signal with a reflection of this signal. An overshot refers to the phenomenon where the voltage of a signal momentarily exceeds its desired amplitude before settling down to its intended level. On the other hand, an undershoot is when the voltage of a signal dips below its desired level before returning to its proper value. Both overshoots and undershoots can result in signal distortions and potentially cause erroneous data transfer or even system malfunctions.