●●● ●●●● ●●●● ●●●0 ●●●● V(t)=Acos(ot+0) ●●●● ●●●● Amplitude Frequency Phase 幅度 频率 相位 AM FM PM 调幅 调频 调相 Analog modulation (vary continuously) 模拟调制(连续变化) Digital modulation (change in discrete steps) 数字调制(离散阶跃变化) 8Amplitude Frequency Phase 幅度 频率 相位 Vt A t ( ) cos( ) AM FM PM 调幅 调频 调相 Analog modulation (vary continuously) 模拟调制 (连续变化 ) Digital modulation (change in discrete steps) 数字调制(离散阶跃变化) 8