基于最大平均功率算法的符号定时恢复算法。输入参数：RtfSig过采样的待恢复信号，信号中的N符号总数，dS升采样率，N_T升余弦滚降滤波器系数-Symbol timing recovery algorithm based on maximum average power algorithm. Input parameters: RtfSig be over-sampled signal recovery, the total number of N-symbol signal, the sampling rate dS l, N_T raised cosine filter coefficients