For example, if a signal has a highest frequency of 1kHz, it can be perfectly reconstructed from its samples if the sampling rate is greater than 2kHz.
The Nyquist rate has many applications in digital signal processing, such as audio and video encoding and decoding, image processing, speech recognition, and communications systems. It is also used in analog-to-digital and digital-to-analog converters.
The Nyquist rate is determined by the highest frequency component of the signal.
It states that a signal can be accurately reconstructed from its samples if the sampling rate is at least double the highest frequency component of the signal.