实现了在matlab下音频信号的dct(离散余弦)和fft(傅里叶变换)相对matlab工具箱，有快速准确的效果。-Realized the dct (discrete cosine) of the audio signal in matlab fft (Fourier transform) relative matlab toolbox, fast and accurate results.

该代码可做快速傅里叶转换以及离散傅里叶转换以及绘制三维时频图(The code can do fast Fourier transform, as well as discrete Fourier transform, and to draw three-dimensional time-frequency map)