基带信号s(t)为正弦滚降信号，其带宽$B=\frac{1+r}{2T_s}$
ASK信号频谱宽度为基带信号的两倍$B_{ASK}=2B=\frac{1+r}{T_s}$
频移键控FSK
发1时载频$\omega_1$，发0时载频为$\omega_2$
$\omega_1=\omega_c-\Delta \omega$
$\omega_2=\omega_c+\Delta \omega$
频偏$2\Delta \omega=\omega_1-\omega_2$
二进制FSK信号可视为两个ASK信号的叠加
$B_{FSK}=2B+|f_2-f_1|$
调频指数$m_f=\frac{2\Delta \omega}{\omega_s}$, 频偏$2\Delta \omega=\omega_1-\omega_2$
移相键控PSK