Clock jitter is the deviation from the ideal timing of clock transition events. Because such deviation can be detrimental to high-speed data transfer and can degrade performance, jitter must bekept to a minimum in a high-speed system.
High-speed signaling is very sensitive to jitter. As signals toggle faster and faster, tighter restrictions fall on the signal transmitter and receiver. In many high-speed data applications, the clock edge must fall within a tight margin of time to capture data correctly. The more jitter in a system, the more often the clock edge will fall outside the margin. The frequency of clock edge deviations from theacceptable margin translates to the system's bit error rate (BER).
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