When a signal passes through a serpentine trace with coupling between the legs, there is an apparent speed-up of the signal. That is, the signal appears to pass through the serpentine section faster than the trace length would otherwise indicate. This apparent speed-up is caused by crosstalk coupling between the legs of the serpentine traces. The amount of apparent speed-up is directly related to the coupling strength between the legs and inversely related to the rise time of the signal passing through the section. The apparent speed-up of the signal is not directly related to the coupled length. For long coupled lengths (those longer than the critical length) signals may become distorted as they pass through the serpentine section, but the degree of distortion is a complex function of the frequency of the signal. Signals pass relatively undistorted through short coupled serpentine sections.

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