Computer Science – 1.2 Multimedia | e-Consult

The Nyquist-Shannon sampling theorem states that to accurately reconstruct a continuous-time signal from its samples, the sampling rate must be at least twice the highest frequency component present in the signal. This minimum sampling rate is known as the Nyquist rate.

If the sampling rate is below the Nyquist rate, aliasing occurs. Aliasing is a phenomenon where high-frequency components in the original signal are incorrectly interpreted as lower frequencies in the sampled signal. This results in distortion and artifacts in the reconstructed audio.

Consequences of aliasing:

• Distortion: Aliasing introduces unwanted frequencies into the audio signal, leading to a distorted sound.
• Incorrect pitch perception: High-pitched sounds can be perceived as lower-pitched sounds, altering the perceived pitch of the audio.
• Unwanted artifacts: Aliasing can create audible artifacts, such as buzzing or humming sounds.

To avoid aliasing, it is crucial to ensure that the sampling rate is sufficiently high to meet the Nyquist rate for the audio signal being sampled. Anti-aliasing filters are often used before sampling to attenuate high-frequency components that could cause aliasing.