Nyquist theorem and Anti-aliasing

Harry Nyquist, after whom the Nyquist Theory is named, was an electrical engineer at Harvard University. He made significant contributions to signal processing and information theory in the early 20th century.

Known as a pioneer in the field of sampling theory and information theory, Nyquist presented the concept of sampling frequency in his 1928 paper “Certain Topics in Telegraph Transmission Theory.” This concept later became known as the “Nyquist Theory.”

What is Sampling rate? Why 44.1kHz or 48kHz?

The sampling rate refers to the frequency of the sampling process in hertz (Hz).
For instance, a 44.1kHz sampling rate means that 44,100 samples are taken per second. Higher sampling rates can capture a wider frequency range, thus more accurately reproducing higher frequency components. CD-quality audio typically has a sampling rate of 44.1kHz.