中文说明：
实现信号处理中QAM调制、过信道、解调部分。其中QAM调制部分可改符号点数，M阶数，信道加高斯白噪声、时延、多径，调制解调均有星座图。通过本代码，可学习QAM调制解调，或者通信系统的知识。
English Description：
Realize QAM modulation, over channel and demodulation in signal processing. QAM modulation part can change the number of symbols, m-order, channel plus Gaussian white noise, delay, multipath, modulation and demodulation have constellation. Through this code, you can learn QAM modulation and demodulation, or communication system knowledge.