注意这显然一场评分考试分数相同并不意味着付出努力或难度tlc examsolns.pdfVIP

Note:Thisisclearlyagradedexam,equalmarksdonotimplyequaleffortordifficulty.

Q1andQ2covertheminimumbasicsofthemodule,Q3-5themorechallengingaspects.

Q1

2

a)K(1+mS)cos(t)wherek/2=10[2marks]

c

b)Still10W[2marks]

c)K(1+mS)cos(t)*cos(t)=K(1+mS)(cos(2t+1)/2

ccc

-LPF_DCblock-kmS[2marks]

d)Pro:betterpowerefficiency,conmorecomplexdemodulation[2marks]

e)KeypointistheQrequiredoffilter

Q2

FM(t)=(a)t+cosdt))S(t[2marks]

k

cf

b)

c)

kf

FM(t)=(t+cos(sint))

cm

m

ifk/ωissmallthenwehavethecaseofnarrowbandFM,suchthat

fm

kfkf

FM(t)=