Phase Noise to Period Jitter Calculator

Analyze integrated phase noise with flexible offset ranges. Estimate RMS jitter, period error, and stability. Built for engineers comparing oscillators, synthesizers, and reference clocks.

Calculator input

Enter carrier frequency and phase noise points. Use offset frequency in Hz, then SSB phase noise in dBc/Hz.

Carrier Frequency (MHz)

Lower Integration Bound (Hz)

Upper Integration Bound (Hz)

Phase Noise Data

One point per line. Example format: 1000,-90

Formula used

Single-sideband phase noise, L(f), is first converted from dBc/Hz into a linear power ratio density.

1. Linear phase noise density:

L_linear(f) = 10^(L(f)/10)

2. RMS phase variance from integrated phase noise:

σ_φ² = 2 ∫ L_linear(f) df

3. Convert phase error into time jitter:

σ_t = σ_φ / (2πf₀)

4. Compare jitter with the nominal period:

T = 1 / f₀ and Jitter % = (σ_t / T) × 100

This calculator uses logarithmic interpolation across offset frequency, then trapezoidal numerical integration over the selected range.

How to use this calculator

Enter the carrier frequency in MHz.
Set the lower and upper phase noise integration limits.
Paste offset frequency and phase noise pairs into the text area.
Keep integration bounds inside the entered offset range.
Press Calculate Period Jitter to generate the result.
Review RMS jitter, phase error, and period percentage.
Inspect the graph for phase noise trend and cumulative jitter growth.
Download CSV or PDF when you need a report.

Example data table

This example represents a notional 100 MHz source with decreasing phase noise over wider offset frequencies.

Offset Frequency (Hz)	Phase Noise (dBc/Hz)
1000	-90
10000	-110
100000	-130
1000000	-145
10000000	-155
20000000	-160

Default limits of 1 kHz to 20 MHz align with this sample dataset.

Frequently asked questions

1. What does this calculator convert?

It converts integrated single-sideband phase noise into RMS period jitter. The result helps you estimate timing uncertainty for clocks, oscillators, synthesizers, and reference sources.

2. Why are the integration bounds important?

Phase noise outside the selected offset range is excluded. Narrow limits usually reduce jitter. Wider limits capture more noise power and often produce larger timing uncertainty.

3. Why is the factor of two used?

Many phase noise plots show single-sideband noise. Total phase fluctuation includes both sidebands, so the integrated linear value is doubled before converting to RMS phase error.

4. Is the output peak-to-peak jitter?

No. The primary output is RMS jitter. Peak-to-peak jitter depends on distribution assumptions, observation time, and confidence level, so it is not fixed by RMS alone.

5. Why interpolate phase noise on a log scale?

Phase noise data is commonly measured at logarithmically spaced offsets. Log-frequency interpolation better follows real plots and reduces distortion between widely separated measurement points.

6. Can I use measured analyzer data?

Yes. Paste measured offset frequency and dBc/Hz values into the input area. Ensure the chosen integration limits stay within the measured range for accurate interpolation.

7. What does jitter as percent of period mean?

It compares RMS jitter with one ideal cycle. Smaller percentages indicate cleaner timing. This is useful when comparing sources that operate at different carrier frequencies.

8. When should I export CSV or PDF?

Use CSV for analysis, spreadsheets, and recordkeeping. Use PDF for reviews, design notes, and reports where you want a portable summary of inputs and results.