Jitter
Jitter is an unwanted variation of one or more characteristics of a periodic signal in electronics and telecommunications. Jitter may be seen in characteristics such as the interval between successive pulses, or the amplitude, frequency, or phase of successive cycles. Jitter is a significant factor in the design of almost all communications links (e.g. USB, PCI-e, SATA, OC-48). In clock recovery applications it is called timing jitter. [1] Jitter can apply to a number of signal qualities (e.g. amplitude, phase, pulse width or pulse position), and can be quantified in the same terms as all time-varying signals (e.g. RMS, or peak-to-peak displacement). Also like other time-varying signals, jitter can be expressed in terms of spectral density (frequency content). Jitter period is the interval between two times of maximum effect (or between two times of minimum effect) of a jitter characteristic that varies regularly with time.
