The sampling theorem shows that aliasing can be avoided if the Nyquist frequency is greater than the bandwidth, or maximum component frequency, of the signal being sampled.

采样定理表明，如果奈奎斯特频率大于样本的带宽或样本成分的最高频率，系统的采样失真可以避免。

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Contrarily, if the frequency bandwidth of signal is finite, the time length of signal will be infinite when sampling in frequency domain, the time folding phenomenon will certainly happen.

反之，若信号的频带宽度有限，当进行频域抽样时，时域必然发生混叠。

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