采样定理
As stated by the Nyquist–Shannon sampling theorem, to prevent aliasing, the audio signal must be sampled at a rate at least twice that of the highest frequency component in the signal. For recording music-quality audio, the following PCM sampling rates are the most common: 44.1, 48, 88.2, 96, 176.4, and 192 kHz, each with an upper-frequency limit half the sampling frequency.