吉他调弦，相当于ap guitar tuner-This article shows how to use a Fast Fourier Transform (FFT) algorithm to calculate the fundamental frequency of a captured audio sound. Also, we will see how to apply the algorithm to analyze live sound to build a simple guit

数字信号处理中简单的音频特效处理，回声，变调、低通滤波、高通滤波-Digital signal processing simple audio effects processing, echo, pitch, low pass, high pass filter