Digital Audio
An anti-aliasing filter removes frequencies above the Nyquist limit before analogue-to-digital conversion, preventing unwanted artefacts in digital recordings.
The anti-aliasing filter is a low-pass filter placed before the A/D converter to ensure that only frequencies below half the sampling rate are captured. By eliminating content that cannot be accurately represented, it prevents the creation of spurious tones or distortions during digitisation.
Early digital recorders used steep analogue filters, which sometimes affected high-frequency response, but modern oversampling converters employ gentler digital filters with far fewer phase issues. The anti-aliasing filter is essential for producing clean, accurate digital recordings.
