What is aliasing?

Alias, in the context of signal processing and digital media, refers to the phenomenon where a high frequency signal is sampled at a lower rate, causing distortions or errors in the representation of the original signal.

Aliasing occurs when the input signal frequency exceeds the Nyquist frequency, which is half the sampling rate. When this happens, the high frequency components of the signal are incorrectly represented as lower frequencies, leading to inaccuracies and artifacts in the reconstructed signal.

In digital media, aliasing can manifest as jagged edges or moiré patterns in images, or as distortion or artifacts in audio. Anti-aliasing techniques such as low-pass filtering or oversampling are commonly used to reduce aliasing effects and improve the quality of digital signals.

Overall, understanding aliasing is important in the design and implementation of digital systems to ensure accurate representation and processing of signals.