In digital signal processing, what does "aliasing" refer to?

Aliasing refers to the distortion that occurs when a signal is sampled below its Nyquist frequency, which is half of the sampling rate. When a continuous signal is sampled, if the sampling rate is insufficient to capture the changes in the signal—specifically, if it is below this critical frequency—higher frequency components of the signal can misrepresent themselves as lower frequencies in the resulting digital representation. This misrepresentation leads to a phenomenon where different signals become indistinguishable or "alias" one another, resulting in inaccuracies in digital signal processing.

Understanding this concept is crucial for anyone working with digital signals, as choosing an appropriate sampling rate is essential to preserve the integrity of the original signal when converting it to a digital format. Moreover, it highlights the necessity of proper signal processing techniques to prevent aliasing, which can obscure important information.