What is Jitter in Data Communication ?

Data communication system depends on the four fundamental characteristics 1.delivery 2. accuracy 3.timeliness 4.jitter please describe me briefly about jitter,its working and its purpose.

Data propagates in form of signals over the communication link; these signals are expected to travel with defined periodicity. But these signals may cause deviation from original specified periodicity during this communication. This deviation is termed as jitter. Jitter may be caused by electromagnetic interference (EMI) and crosstalk with carriers of other signals.

 Jitter can cause a display monitor to flicker, affect the performance of processors in personal computer and loss of transmitted data between network devices.

It is also defined as delay in the packet receiving time than usual. If packet latency across the network is greater than the average it means there is jitter on netwrok.so this comes in timeliness criteria of network effectiveness.