The Nyquist data sampling rate in pulse code modulation (PCM) is twice the highest frequency component in the original analog signal. This means that the sample rate must be high enough to accurately capture all the details of the original signal. According to the Nyquist theorem, the minimum sampling rate required to avoid aliasing (the phenomenon where high-frequency components in the original signal are misinterpreted as low-frequency components in the sampled signal) is twice the highest frequency component in the original signal.

In PCM, the analog signal is sampled at regular intervals, and each sample is quantized and encoded into a digital value. The quantization step determines the number of bits used to represent each sample, and thus the dynamic range and accuracy of the digital representation of the analog signal. The Nyquist rate determines the minimum number of samples required to accurately represent the original analog signal in the digital domain.