采用java画出啊音频信号的时域图和频域图，先对采集到的音频信号傅里叶变换-audio signal

用JAVA写的带通滤波代码，实现思路很简单，没有采用各种数字滤波的方法。而是通过傅里叶变换到频域，将要求外的频率均置0，再逆傅里叶变换得到的。效果还不错。-Written using JAVA bandpass filtering code to achieve the idea is very simple, without using a variety of digital filtering approach. But through the Fourier transform to t

java平台下的FFT变换，实现通过RR间期计算HRV频域分析-FFT transform java platform, to achieve a frequency domain HRV calculated by the RR interval analysis