Integrate phase noise across offset bands accurately. Convert results into seconds, radians, and unit intervals. Built for lab verification, timing studies, and design reviews.
| Carrier | Lower Offset | Upper Offset | Offset Point | Phase Noise |
|---|---|---|---|---|
| 100 MHz | 1 kHz | 10 MHz | 100 Hz | -72 dBc/Hz |
| 100 MHz | 1 kHz | 10 MHz | 1 kHz | -92 dBc/Hz |
| 100 MHz | 1 kHz | 10 MHz | 10 kHz | -112 dBc/Hz |
| 100 MHz | 1 kHz | 10 MHz | 100 kHz | -128 dBc/Hz |
| 100 MHz | 1 kHz | 10 MHz | 1 MHz | -142 dBc/Hz |
| 100 MHz | 1 kHz | 10 MHz | 10 MHz | -152 dBc/Hz |
1. Convert each phase-noise point from dBc/Hz to linear form:
Llinear(f) = 10^(L(f)/10)
2. Integrate the single-sideband spectrum over the selected offset range:
σφ2 = 2 × ∫ Llinear(f) df
3. Convert RMS phase jitter to time jitter:
σt = σφ / (2πf0)
4. Convert time jitter to unit intervals:
UI = σt × data rate
This page uses exact piecewise log-log integration between entered points. That approach matches the common straight-line slope assumption used on phase-noise plots.
Phase noise jitter connects spectral purity with timing stability. Engineers use it when they verify oscillators, PLL outputs, reference clocks, converters, and high-speed links. A low spot-noise number at one offset is not enough. The integrated range controls the final RMS jitter result.
Every offset band adds some phase variance. Close-in noise often dominates slow timing wander. Far-out noise can dominate serial links and wideband sampling systems. That is why the integration limits matter so much. A 1 kHz to 10 MHz result can differ greatly from a 10 Hz to 100 MHz result.
Measured phase-noise plots are usually read at decade offsets. Designers then assume straight slopes between those points. This calculator follows that common practice. It integrates each segment exactly in linear power while preserving the straight-line trend on the logarithmic plot. That makes the output more realistic than a rough average.
RMS phase jitter in radians shows total angular uncertainty. RMS time jitter converts that uncertainty into seconds. UI jitter is useful for serial channels because it compares timing error with the data period. The percent-of-period figure is helpful for clock tree analysis and timing budgets.
Use the results during oscillator selection, PLL loop optimization, ADC clock cleanup, DAC spectral planning, and RF source comparison. The segment table also shows where the biggest contributors sit. That helps you decide whether to improve close-in flicker noise, loop bandwidth, reference quality, or far-out broadband noise. Better insight leads to better clock design, cleaner spectra, and stronger timing margins.
It is the RMS timing uncertainty derived from the integrated phase-noise spectrum. It turns frequency-domain noise data into a time-domain jitter value.
Single-sideband phase noise represents one side of the carrier. Total phase variance uses both sidebands, so the integral is multiplied by two.
Jitter depends on the total area under the noise curve. Changing the lower or upper offset boundary changes that area, sometimes by a large amount.
Use UI jitter for serial links, data recovery analysis, and eye-diagram work. It compares RMS timing error with the bit period.
Yes. Two points create one integrated segment. More points improve realism because they capture bends in the measured spectrum.
Only when you must integrate beyond measured data. Extrapolation follows the end slope, which is convenient but less trustworthy than actual measurements.
Usually yes, but the required limit depends on the system. Clocks for RF synthesis, converters, and links all have different jitter budgets.
Enter single-sideband phase-noise values in dBc/Hz at known offset frequencies. Those values normally come from a datasheet or lab measurement plot.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.