中文说明：本程序采用MATLAB编程实现如何计算信号的信噪比signal_to_noise，计算公式是信号功率比上噪声功率，并对比值进行分贝转换，最终得到想要的信噪比，主程序为snr_singlech.m，
English Description：
This procedure using MATLAB to realize signal_to_noise how to calculate the signal to noise ratio, the calculation formula is the noise power on signal power ratio, and the DB conversion ratio, eventually getting the signal to noise ratio, the main program for the snr_singlech.m,