Sampling Theorem Calculator
A signal up to 4 kHz needs a Nyquist rate of 8 kHz; sampled at only 6 kHz, a 5 kHz tone aliases down to 1 kHz.
8 kHz
- Nyquist frequency fₛ/2
- 3 kHz
- This sampling rate
- is too low: frequencies above fₛ/2 alias
- Tone of 5 kHz appears at
- 1 kHz
- Sampling interval Tₛ = 1/fₛ
- 166.6666667 µs
Step-by-step solution
- Nyquist rate = 2 × 4 kHz = 8 kHz
- Alias: |f − k fₛ| with k = round(f/fₛ) = 1 → 1 kHz
Sampling Theorem Formula
fₛ ≥ 2f_max
alias frequency f_a = |f − k fₛ| with k the nearest integer to f/fₛ
Worked Example
A 4 kHz signal sampled at 6 kHz, and a 5 kHz tone in the same system:
- Nyquist rate = 2 × 4 kHz = 8 kHz
- Alias: |f − k fₛ| with k = round(f/fₛ) = 1 → 1 kHz
This sampling rate: is too low: frequencies above fₛ/2 alias · Tone of 5 kHz appears at: 1 kHz · Sampling interval Tₛ = 1/fₛ: 166.6666667 µs
GATE tip
For x(t) = cos(2π·f₁t) + cos(2π·f₂t)·…, the Nyquist rate is twice the HIGHEST frequency present after expanding products: cos A cos B makes sum and difference frequencies.
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Frequently asked questions
Why do audio systems use 44.1 kHz?
Hearing extends to about 20 kHz, so the Nyquist rate is 40 kHz; the extra margin lets a practical anti-alias filter roll off between 20 and 22.05 kHz.
What about band-pass signals?
A band-limited signal of bandwidth B can be sampled at as little as 2B with the right choice of fₛ (band-pass sampling), not 2f_max.
Sources
- The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures .
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
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APA
Scientific Converters. (2026, October 15). Sampling Theorem Calculator. Retrieved October 25, 2026, from https://scientificconverters.com/calculators/sampling-theorem-calculator/
IEEE
Scientific Converters, "Sampling Theorem Calculator," scientificconverters.com. Accessed: Oct. 25, 2026. [Online]. Available: https://scientificconverters.com/calculators/sampling-theorem-calculator/