通信系统中数字调制信号分析 包括时域、频域、误码率、信噪比、谱分析、加性高斯白噪声，实现一个完整的系统分析的MATLAB程序-Communication systems digital modulation signal analysis including time domain, frequency domain, bit error rate, SNR, spectrum analysis, additive white Gaussian noise, to achieve a compl