音频库，包括短时傅里叶变换，信干比计算等-Audio library, including the short-time Fourier transform, signal to interference ratio calculation

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.