jittering

Jittering is the occurrence of small, rapid, irregular variations in a signal or process, typically in time or position. It can degrade the reliability of systems that assume regularity, such as clocks, video frames, or data packets. Jitter can be deliberate (as an anti-aliasing technique) or unintentional due to noise, interference, or system dynamics.

In electronics and communications, timing jitter refers to deviation of a waveform’s edges from their ideal times. It is quantified as jitter amplitude in seconds or as a phase or period jitter. Sources include clock instability, propagation delays, or network congestion. Effects include sampling errors, bit-errors, degraded synchronization. Mitigation includes using stable reference oscillators, phase-locked loops, jitter buffers, enhanced clock recovery, and proper timing budgets.

In computer graphics and rendering, jittering describes perturbing sample positions between frames to reduce aliasing (temporal anti-aliasing and stochastic sampling). It can also refer to small random displacements of geometry or texture coordinates to avoid shimmering. In Monte Carlo rendering, jittered sampling helps to break regular patterns and improve convergence.

In networking and data transmission, packet jitter is the variation in inter-arrival times of packets. High jitter harms real-time applications such as voice and video. Mitigation uses jitter buffers, quality-of-service mechanisms, and traffic shaping; accurate time synchronization protocols also help.

In metrology and electronics, phase or period jitter describes fluctuations in oscillator output, which can propagate through systems that rely on precise timing such as synthesizers, radios, and digital circuits. Jitter is typically summarized with metrics such as RMS jitter and peak-to-peak jitter.