周期信号加上白噪声，通过在matlab中，用XCORR函数，求出周期信号，干扰信号，和观测信号的自相关函数，三者互相进行比较-Periodic signal plus white noise in matlab by using XCORR function, the autocorrelation function of a periodic signal is obtained, the interference signal, and the observed signals, compa