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The (timing) jitter is defined as the “short-term variations of the significant instants of a timing signal from their ideal positions in time (where short-term implies that these variations are of a frequency greater than or equal to 10 Hz).”, while wander is defined as “The long-term variations of the significant instants of a digital signal from their ideal position in time (where long-term implies that these variations are of frequency less than 10 Hz)”
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With respect to jitter effects, IEEE 802.3, specifies objectives for the various interfaces in terms of BER (Bit Error Ratio). These objectives are never better than 10–12. As an example, in for a 1 Gbps link 10–12 corresponds to about 1 bit over about 15 minutes, or over 1.5 minutes in the case of 10 a10 Gbps linkslink.
When performing jitter measurements over periods longer than 60 seconds (e.g. several hours) isolated spikes may be recorded during the test measurement. These may be due to the System Under Test or to the measurement set up (e.g. environmental conditions, etc.).
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