FFT is a mathematical tool commonly used in digital signal processing, and is characterized by fast operational speed and low SNR threshold value.
快速傅里叶变换是数字信号处理的常用数学工具，以运算速度快和信噪比阈值低为特点。
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The basic factors related with photonic information processing are ultrahigh response speed, low photon power threshold, high conversion efficiency and relatively low device cost.