说明：  设定码元速率、载波频率、采样速率、码元个数等，先仿真bpsk信号，然后对其求循环谱。采用频域平滑的方法。
(Set the symbol rate, carrier frequency, sampling rate, number of symbols and so on, first simulate the BPSK signal, and then calculate the cyclic spectrum. The frequency domain smoothing method is adopted.)