In 1980, Namias introduced the theory of fractional power of Fourier transform, a generalized Fourier transform, called FrFT ( Fractional Fourier transform), which is a new Time-Frequency analysis tool. Fourier变换的分数幂理论最早由Namias于1980年建立,他将这种推广的Fourier变换称为FrFF。FrFF是一种新的信号时频分析工具。