Nyquist Sampling Check

Enter a signal frequency and sample rate to check Nyquist compliance, estimate alias frequency, and compute a safer target sample rate.

How to Use

  1. Enter your highest signal frequency (f).
  2. Enter your sampling rate (fs).
  3. Set a safety margin to recommend a more robust sample rate.
  4. Open “Show Work” to see the math and alias estimate (if any).
Sampling Status
Nyquist threshold, margin, and alias estimate (when undersampled).
Signal
—
Sample rate
—
Nyquist
—
Alias
—
Status: —
Inputs & Settings
Enter frequency and sampling rate. Margin recommends a safer fs.
Use your highest frequency of interest (or bandwidth edge) that must be captured.
Common: 44.1 kHz, 48 kHz, 1 MS/s, 100 MS/s, etc.
Example: 20% means target = Nyquist × 1.20. Or set multiplier directly (e.g., 2.5× Nyquist).
Show Work (step-by-step)
—
Work is shown in base units (Hz) for clarity. Aliasing estimate shown when undersampled.

Nyquist Reference

For a real-valued signal with highest frequency component f, the Nyquist criterion is: fs ≥ 2f.

  • Nyquist frequency: fN = fs / 2
  • Ratio: r = fs / (2f)
  • Simple alias estimate (when f > fN): folds into [0, fN]

In practice, filters, noise, and non-sinusoidal waveforms often require sampling significantly above 2×f.

FAQ

What should I use for “highest signal frequency”?

Use the highest frequency you must preserve after sampling. For non-sine waveforms, that may be a bandwidth target or harmonic content you care about.

Why do I still see distortion above Nyquist?

Nyquist is a theoretical minimum. Without anti-alias filtering (and with real-world noise), you often need more margin.

Is aliasing always “one number”?

For a pure tone, you can estimate a folded tone. For complex spectra, aliasing folds many components into baseband.

Tool Info

Last updated:

Updates may include additional sampling modes, better alias explanations, and more presets.