The Nyquist frequency is the highest frequency that can be accurately represented in a digital signal. It is equal to half the sampling rate of the signal. For example, if a signal is sampled at 1000 Hz, the Nyquist frequency is 500 Hz. Any frequency above the Nyquist frequency will be aliased, meaning it will appear as a lower frequency in the digital signal. Therefore, it is important to ensure that the sampling rate is high enough to accurately represent the frequencies of interest in a signal. In practical terms, the Nyquist frequency sets a limit on the highest frequency that can be recorded or analyzed in a digital signal. For example, if a signal contains frequencies above the Nyquist frequency, those frequencies will be distorted or lost in the digital representation of the signal. This can lead to errors in analysis or interpretation of the signal. To avoid aliasing, it is important to choose a sampling rate that is at least twice the highest frequency of interest in the signal. This is known as the Nyquist-Shannon sampling theorem. For example, if a signal contains frequencies up to 100 Hz, a sampling rate of at least 200 Hz is required to accurately represent the signal. In summary, the Nyquist frequency is a fundamental concept in digital signal processing that sets a limit on the highest frequency that can be accurately represented in a digital signal. It is important to choose a sampling rate that is high enough to avoid aliasing and accurately represent the frequencies of interest in a signal.