中文说明：4FSK调制信号经过瑞利衰落信道和高斯信道之后利用matlab仿真的方法计算出接受信号的误码率和误比特率。并且绘制出发射信号和接收信号的星座图，绘制出误码率和误比特率的曲线
English Description：
4FSK modulation signals over Rayleigh fading channel and Gaussian channel using MATLAB simulation method to calculate received signal error rate and bit-error-rate. And draw a constellation of the transmitted signal and the received signal, draw the bit error rate and bit-error-rate curves