M进制，$k=log_2M$
$$S_{MPSK}=A\cos(w_ct+\varphi _i) \\ \varphi _ i=\frac{2\pi i}{M} \qquad i=0,1,\cdots,M-1$$
$$S_{MPSK}=g(t)\cos(w_ct+\varphi _i)=g(t)a_{ic}\cos\omega_ct - g(t) a_{is} \sin \omega_s t $$
MPSK 调制信号的产生
原文：https://www.cnblogs.com/htj10/p/8933464.html
