What is the Nyquist frequency?

The Nyquist frequency is half of the sampling rate of a digital system. For example, a system sampling at 44,100 Hz has a Nyquist frequency of 22,050 Hz — the highest frequency it can accurately represent without aliasing.

Aliasing occurs when a signal is sampled at a rate lower than twice its highest frequency component. The undersampled high-frequency content "folds back" and appears as a false lower-frequency signal in the digital output.

What is the Nyquist rate (minimum sampling rate)?

The Nyquist rate is 2 × the signal's maximum frequency. A signal containing frequencies up to 10 kHz must be sampled at a minimum of 20,000 samples per second (20 kHz) to avoid aliasing.

Why do real systems sample faster than the Nyquist minimum?

Practical anti-aliasing filters are not ideal — they have a roll-off transition band. Engineers typically use an oversampling ratio of 1.5× to 10× the Nyquist rate to give the filter room to attenuate frequencies above the band of interest before they alias.

Does the calculator account for anti-aliasing filter design?

It calculates the theoretical Nyquist minimum and flags any sampling rate below that threshold. Filter transition-band design (guard band) is not computed here, but the oversampling ratio field helps you evaluate margin.

Nyquist Frequency Calculator

Enter a signal bandwidth to instantly get the Nyquist frequency, minimum sampling rate, and aliasing risk analysis.

Signal Parameters

Signal Bandwidth (max frequency)

Your Actual Sampling Rate (optional — for aliasing check)

Quick Presets

Enter a signal bandwidth and press Calculate

Summary

The Nyquist Frequency Calculator applies the Nyquist-Shannon sampling theorem to determine the minimum sampling rate required to accurately represent an analog signal in digital form. Given a signal's maximum frequency component, it computes the Nyquist frequency (equal to half the sampling rate) and flags aliasing risk when your actual sampling rate falls below the required minimum. It supports frequency inputs from Hz to GHz and lets you test any proposed sampling rate against the Nyquist criterion.

How it works

Enter the maximum frequency component (bandwidth) of your signal.
Select the appropriate unit: Hz, kHz, MHz, or GHz.
The Nyquist frequency is calculated as exactly half the minimum sampling rate.
The minimum sampling rate (Nyquist rate) is computed as 2 × signal bandwidth.
Optionally enter your actual sampling rate to check for aliasing.
Results show whether your system satisfies the Nyquist criterion.

Use cases

Designing ADC (analog-to-digital converter) circuits for audio or RF systems.
Verifying oscilloscope or data-acquisition sample rates meet signal requirements.
Audio engineering: confirming 44.1 kHz CD standard covers 20 kHz human hearing.
Communications: checking RF receiver sampling against carrier bandwidth.
Embedded systems: sizing microcontroller ADC clock for sensor data.
DSP education: exploring aliasing effects interactively.
Medical devices: ensuring ECG or EEG digitizers capture all relevant frequencies.
Radar and sonar: validating pulse repetition and sampling configurations.

Frequently Asked Questions

Last updated: 2026-05-23 · Reviewed by Nham Vu