Computer Science – Text, sound and images | e-Consult

Aliasing occurs when a signal's frequency is higher than half the sampling rate. In digital sound reproduction, this leads to the higher frequencies being incorrectly represented as lower frequencies, resulting in a distorted and unpleasant sound.

Aliasing occurs when the sample rate is insufficient to capture the full range of frequencies present in the original sound. Specifically, if a frequency is greater than the Nyquist frequency (which is equal to half the sample rate), it will alias.

Two methods to prevent aliasing are:

• Anti-aliasing filters: These filters are applied to the analog signal before sampling. They attenuate (reduce the amplitude of) frequencies above the Nyquist frequency, preventing them from aliasing. This is a crucial step in any digital audio system.
• Increase the sample rate: Increasing the sample rate raises the Nyquist frequency, allowing for a wider range of frequencies to be accurately represented without aliasing. This is a straightforward way to avoid aliasing, but it requires more storage space and processing power.