通信电子线路 (谢沅清 邓钢 著) 电子工业出版社 课后答案 05.pdf

5.2 ( ) cos U cos t a t = A ω t Ω 0 0 Ω ∆ω = S U cos Ω t f Ω ( ) cos( cos ) a t = A ω + S U Ω t t 0 0 f Ω t 5.4 1 1 1 1 课后答案网 5.9 mf 1 t=0 5.2-11 A J (m )cos[(ω + Ω ) + ϕ ] −A J (m )cos[(ω − Ω )t + ϕ ] 0 1 0 0 0 1 0 0 t=0 5.10 u u 6 Ω(t)=cos(2π 400t)(V) s(t)=4cos(2π 25 10 t) f =15 kHz ∆ (1) (2) (1) 6 3 ω(t)=ω0+∆ωcosΩt=2π 25 10 +2π 15 10 cos2π 400t 6 ϕ (t) = ∫ω (t) =2π 25 10 t+37.5sin2π 400t u 6 FM(t)=4cos2π 25 10 t+37.5sin2π 400t (2) m =m =37.5 p f 6 uPM(t)=4cos2π 25 10 t+37.5cos2π 400t 37 7 4 2 5.11