第5章 数字基带传输系统.pdf

㄀㄀㄀5ゴゴゴ᭄ᄫ෎ᏺӴ䕧㋏㒳5.1ᓩ㿔ᓩ㿔ᓩ㿔
᭄ᄫ෎ᏺֵো5.2
5.1ᓩ㿔ǂǂǂ
5.2.1Ѡܗⷕ
᭄ᄫ෎ᏺֵো5.2
˖˖˖˖᭄ᄫ෎ᏺֵোⱘࡳ⥛䈅ᆚᑺǂǂǂᐌ㾕᭄ᄫ෎ᏺֵো㉏ൟᐌ㾕᭄ᄫ෎ᏺֵো㉏ൟ5.3
5.4᮴ⷕ䯈ᑆᡄⱘ᭄ᄫ෎ᏺ㋏㒳
ⶽᔶ㛝ކ
5.5䚼ߚડᑨ㋏㒳
ϝ㾦⊶
5.6᭄ᄫ෎ᏺӴ䕧㋏㒳ⱘᡫాໄᗻ㛑ǂǂǂ
5.7ⴐⴐⴐ೒೒೒催ᮃ㛝ކ
5.8ᯊඳഛ㸵
छԭᓺ㛝ކ
᭄ᄫֵোⱘᡄхϢ㾷ᡄ5.9

1.ऩᵕᗻϡᔦ䳊⊶ᔶऩᵕᗻϡᔦ䳊⊶ᔶǂ3.ऩᵕᗻᔦ䳊⊶ᔶ

10100111010011
ˇE
ˇE

0

0

2.ঠᵕᗻϡᔦ䳊⊶ᔶ4.ঠᵕᗻᔦ䳊⊶ᔶঠᵕᗻᔦ䳊⊶ᔶǂǂǂǂ

10100111010011

ˇEˇE

ˉEˉE

−−
g1(tnTs)s(t)g2(tnTs)
5.Ꮒߚ⊶ᔶ
t
1010011−−
2TsTs0Ts2Ts
ˇE
∞
s(t)=ag(t−nT)
ˉE∑ns
n=−∞
g(t−nT)㸼⼎ヺোĀ0ā
g(t−nT)=1s
s−
6.໮⬉ᑇ⊶ᔶǂǂǂg2(tnTs)㸼⼎ヺোĀ1ā

ेˈ⼎ϟˈ᭄ᄫ෎ᏺֵোৃ⫼䱣ᴎᑣ߫㸼މϔ㠀ᚙ
0000
+3E
010101
+∞
E10
−=
E1111s(t)∑sn(t)
−3En=−∞

1
−−
g1(tnTs)s(t)g2(tnTs)
〇ᗕ⊶˖ᰃ䱣ᴎᑣ߫s(t)ⱘ㒳䅵ᑇഛߚ䞣ˈᅗপއѢ↣
t
ݙߎ⦄g1(t)ǃg2(t)ⱘὖ⥛ࡴᴗᑇഛDŽܗϾⷕ−−
2TsTs0Ts2Ts

∞∞
=−+−−
=v(t)∑[Pg1(tnTs)1(P)g2(tnTs)]
s(t)∑sn(t)5.3᭄ᄫ෎ᏺֵোⱘࡳ⥛䈅ᆚᑺ
n=−∞
n=−∞
=−+−−
g(t−nT)ҹὖ⥛Pߎ⦄vn(t)Pg1(tnTs)1(P)g2(tnTs)
s(t)=1s
n−−
g2(tnTs)ҹὖ⥛1(P)ߎ⦄
Ѹব⊶˖=−
∞u(t)s(t)v(t)
=+=
s(t)v(t)u(t)v(t)∑vn(t)=−
n=−∞un(t)sn(t)vn(t)
〇Ѹ∞
ᗕব=
u(t)∑un(t)
⊶⊶n=−∞

g(t−nT)ҹὖ⥛Pߎ⦄
=1s1ǃ〇ᗕ⊶ⱘࡳ⥛䈅Pv(f)
sn(t)
g(t−nT)ҹὖ⥛1(−P)ߎ⦄∞
2s=−+−−
v(t)∑[Pg1(tnTs)1(P)g2(tnTs)]
v(t)=Pg(t−nT)+1(−P)g(t−nT)n=−∞
n1s2s=+
v(t)v(tTs)
〇ᗕ⊶ᰃϔϾ਼ᳳЎTsⱘ਼ᳳֵোDŽ−=
un(t)snt)(vn(t)
∞
−−−−ҹὖ⥛j2πmft
1(P)[g1(tnTs)g2(tnTs)]P=s
=vt)(∑Cme
−−−−−m=−∞
P[g1(tnTs)g2(tnTs)]ҹὖ⥛1(P)
T2/
=−−−1s−jm2πft
an[g1(tnTs)g2(tnTs)]=s
Cmv(t)edt
∫−T2/
Tss

Ts2/−π
1(−P)ҹὖ⥛P=f[Pg(t)+1(−P)g(t)]ejm2fstdt
=s∫−12
aTs2/
n−−
Pҹὖ⥛1(P)=[]ω+−ω
fsPG1(ms)1(P)G2(ms)

∞
j2πmft1
v(t)=Cesδ(ω)=δ2(πf)=δ(f)P(f)
∑mπ2ǃѸব⊶ⱘࡳ⥛䈅u
m=−∞2
E[U(f)2
=[+−]=T
CmfsPG1(mfs)1(P)G2(mfs)Pu(f)lim
N→∞+
2(N)1TS
∞−π
G(mf)=g(t)ej2mfsdt=+↔
1s∫−∞1T2(N)1TsuT(t)UT(f)
∞
−πNN
=j2mfs
G2(mfs)g2(t)edt==−−−
∫−∞uT(t)∑un(t)∑an[g1(tnTs)g2(tnTs)]
n=−Nn=−N
∞
2j2πmft∞
=s−j2πft
R(t)∑Cme=
UT(f)uTt)(edt
m=−∞∫−∞
∞N∞
=[]+−2δ−=a[g(t−nT)−g(t−nT)]e−j2πftdt
Pv(f)∑fsPG1(mfs)1(P)G2(mfs)(fmfs)∑n∫−∞1S2S
m=−∞n=−N
∞N
2−π
P(ω)=2πf[]PG(mω)+1(−P)G(mω)δ(ω−mω)=j2fnTs−
v∑s1s2ss∑ane[G1(f)G2(f)]
m=−∞n=−N

2
2
E[U(f)P(f)
=T3ǃs(t)ⱘࡳ⥛䈅s
Pu(f)lim
N→∞+
2(N)1TS
=+
Ps(f)Pv(f)Pu(f)
N
−j2πfnT∞
=s−2
UT(f)∑ane[G1(f)G2(f)]=[]+−δ−
∑fsPG1(mfs)1(P)G2(mfs)(fmfs)
n=−N
m=−∞
+−−2
∞fsP1(P)G1(f)G2(f)
G(f