Nyquist theorem
Nyquist’s theorem relates to the sampling of an analogue signal to create a digital signal.
It states that:
To accurately sample an analogue signal, the sampling rate must be at least twice the highest frequency present in the analogue signal.
For music and voice audio, the highest frequency is usually around 20,000 Hz (20 kHz), which is why CD quality audio has a sample rate of 44,100 samples per second! It’s designed to be about double the highest frequency in the audio, to make sure that we can accurately capture the sound without losing any important information.
Example
Section titled “Example”If the highest frequency in an audio track is 12kHz, the minimum sample rate needed to produce an accurate digital sound is 24kHz - twice as high.