Tidsjitter

Tidsjitter, or time jitter, is the short‑term variation in the timing of a clock edge or periodic signal from its ideal position. It describes deviations in time from the expected transition moments and is a key parameter in electronic timing, data communications and synchronization systems.

Causes of tidsjitter include phase noise of oscillators, thermal and flicker noise, power‑supply fluctuations, and propagation delays in cables and interconnects. In networks, jitter can also arise from queueing, scheduling, and varying processing times along the path.

Common categories of tidsjitter are deterministic (periodic) jitter, random jitter, burst jitter, and long‑term wander. Cycle‑to‑cycle jitter describes variation between consecutive cycles; period jitter refers to variation in the length of the signal period; phase jitter concerns the offset of the signal’s phase.

Measurement and metrics for tidsjitter include RMS jitter, peak‑to‑peak jitter, and time deviation (TDEV), as well as Allan deviation in precision timing contexts. For high‑speed serial interfaces, jitter budgets and jitter transfer functions are used to characterize how jitter propagates through a system.

Impact and applications: in digital communications and data networks, excessive tidsjitter can cause sampling or bit errors and degrade synchronization. In audio and video, it can degrade perceived quality. Standards for interfaces such as Ethernet, PCIe, and USB specify allowable jitter budgets to ensure reliable operation.

Mitigation and design considerations: use low phase‑noise oscillators and careful clock distribution, employ phase‑locked loops with appropriate bandwidth, consider jitter cleaners or attenuators, improve power‑supply conditioning and PCB layout, and design systems with adequate jitter tolerance. Performing a jitter budget and tolerance analysis is a common practice in timing‑critical designs.