说明：  随机信号通过平方根升余弦滤波器滤波后，进入AWGN信道，接收机采用的是LMS算法，通过循环找到最佳的截止频率
(The random signal is filtered through the square root cosine filter and enters the AWGN channel. The receiver uses the LMS algorithm to find the best cut-off frequency through the loop.)