说明：  能实现傅里叶快速变换 很好用很实用能实现傅里叶快速变换 很好用很实用能实现傅里叶快速变换 很好用很实用能实现傅里叶快速变换 很好用很实用
(Fast Fourier transform to achieve good to very practical to achieve fast Fourier transform is very useful to achieve good use of fast Fourier transform is very useful with good fast Fourier transform to achieve good to very practical)