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Aliasing Frequency Calculator and Formula

aliasing nyquist frequency sampling adc dac signal processing

This calculator determines the Nyquist frequency, also known as the aliasing frequency. It also explains the aliasing frequency formula used by this calculator. Additionally, it computes harmonic frequencies and their positions in the frequency spectrum.

As you know, Analog-to-Digital Converters (ADCs) convert analog signals into digital signals, while Digital-to-Analog Converters (DACs) perform the reverse process. Aliasing can occur when improper sampling techniques are used in ADCs or DACs.

Consider a signal with +B on the higher side and -B on the lower side, as illustrated below.

aliasing

When this signal is sampled using a sampling frequency (Fs) greater than 2B (Fs > 2B), spectral replications will appear at frequencies around +/-Fs/2. This frequency is known as the folding frequency or aliasing frequency.

The relationship Fs >= 2*B is known as the Nyquist Criteria.

Aliasing Frequency Calculator Example

Inputs

Outputs

INPUTS:

  • Fsample = 500 MHz
  • F Fundamental = 29.96 MHz
  • N = 2

OUTPUT:

  • Aliasing Frequency = 250 MHz
  • 2nd Harmonic = 59.93

Aliasing Frequency Formula or Equation

The following aliasing frequency formula is used in the calculator above:

Aliasing Frequency Formula