说明：  自己写的信噪比计算工具snr2.m snr2(s2ana,fs,f0,fl,fh,bl,bh) s2ana: 待分析信号 fs:采样频率 f0:信号频率 [fl,fh]:信号能量分散带
(Their signal to noise ratio calculation tool written in snr2.m snr2 (s2ana, fs, f0, fl, fh, bl, bh) s2ana: to be analyzed signal fs: sampling frequency f0: signal frequency [fl, fh]: the signal with energy dispersive)