soph2信號(hào)與系統(tǒng)同步來金梅課件

第4引用

變 系統(tǒng)函數(shù)(網(wǎng)絡(luò)函數(shù)由系統(tǒng)函數(shù)線性系統(tǒng)的穩(wěn)StateKeyLabofASIC&Systems,FudanUniversity,Jinmei用拉氏變換法分析電列s域方程（可以從兩方面入手求解s域方程F(sf(t，得到時(shí)域解StateKeyLabofASIC&Systems,FudanUniversity,Jinmei1、微分方程的拉氏變換 Ldf(t)sF(s)f(0 d

df2(t)

f0f(0 dt

ssF d

n(t)

s2F(s)sf(0)f(0 d

snF(s)

snr

f(r)(0 r狀態(tài)，得到s域方程。StateKeyLabofASIC&Systems,FudanUniversity,Jinmei2、利用元件的s域模型分析電電阻元件的s域模vRtRiRVR(s)RIR(s)或IR(s)

VR(s)R

IR(s) VR(s)StateKeyLabofASIC&Systems,FudanUniversity,Jinmei2、利用元件的s域模型分析電電感元件的s域模divLtL d

電壓源形式IL

0VL(s)IL(s)LsLiL(0

VL

I(s)

VL

1i(0

IL

1i0s VLStateKeyLabofASIC&Systems,FudanUniversity,Jinmei2、利用元件的s域模型分析電電容元件的stvt1it

d

ICV(s) (s)11v(0

電流源形式：Cv0 Cv0 VC111s 0VCIC(s)sCVC(s)CvC(0StateKeyLabofASIC&Systems,FudanUniversity,Jinmei2、利用元件的s域模型分析電i(t)I(s),v(t)V(s)

KCL:i(t)0I(s)0KVL:v(t)0V(s)StateKeyLabofASIC&Systems,FudanUniversity,JinmeiVC(0)StateKeyLabofASIC&Systems,FudanUniversity,JinmeiStateKeyLabofASIC&Systems,FudanUniversity,Jinmei第4 變換 StateKeyLabofASIC&Systems,FudanUniversity,Jinmei定義

rtethtRsEsH所 H(s)R(s)E(s)StateKeyLabofASIC&Systems,FudanUniversity,Jinmei2、H(s)的幾種單端網(wǎng)1單端網(wǎng)

H(s)

I1

H(s)

V1(s)

I1(s) I1

I2 雙端網(wǎng)V雙端網(wǎng)VH(s)I2(s)

H(s)V2I1(s)

2H(s)V2V1(s)

H(s)I2(s)I1(s)StateKeyLabofASIC&Systems,FudanUniversity,Jinmei求H(s)的方 htH

Ht tHStateKeyLabofASIC&Systems,FudanUniversity,Jinmei3．求H(s)3．求H(s)的方法H(s)求I1(s)求解法一：

t

v1(t

(R1)I(s)V(s 1

(R1)I(s)V(sH(s)(R

1H(s)(R StateKeyLabofASIC&Systems,FudanUniversity,Jinmei 方法一：Hs)h(tr(te(th(t方法二：Rs)Hs)Es)r(tStateKeyLabofASIC&Systems,FudanUniversity,Jinmei第4 變換 StateKeyLabofASIC&Systems,FudanUniversity,Jinmei一．H(s)零、極點(diǎn)與h(t)波形特征的系統(tǒng)函數(shù)的H(s)A(s) (sz1)(sz2)(szj)(szmB(s) (sp1)(sp2)(spk)(spnm(szjmK

z1,z2zn(spkkn(spkknn系統(tǒng)函數(shù)的極點(diǎn)：用×表示，零點(diǎn)：用○表StateKeyLabofASIC&Systems,FudanUniversity,JinmeiH(s)1 0在原點(diǎn) h(t)L1[H(s)]u(t H(s) ps a0,在左實(shí)軸 h(t)eatu(t),指數(shù)衰a0,在右實(shí)軸 h(t)eatu(t),a0,指數(shù)增H(s) pjω在虛軸s2 h(tsinωtu(t)，等幅振H(s) pαjω,pαj,共軛根(sα)2ω2 當(dāng)α0當(dāng)α0StateKeyLabofASIC&Systems,FudanUniversity,Jinmei二階H(s) 1,極點(diǎn)在原點(diǎn) h(t)tu(t),t,h(t)sH(s) ,極點(diǎn)在實(shí)軸上 (sa)2h(t)tetu(t),α0,t,h(t)H(s) ,在虛軸上，(s2ω2h(ttsintu(tth(t)增幅StateKeyLabofASIC&Systems,FudanUniversity,Jinmei2．H(s)極點(diǎn)分布與原函數(shù)的對(duì)應(yīng)

有實(shí)際物理意義的物理系統(tǒng)都是穩(wěn)定系統(tǒng)，即隨

強(qiáng)迫響應(yīng)形式取決于外加激勵(lì)。對(duì)應(yīng)于特解StateKeyLabofASIC&Systems,FudanUniversity,JinmeiStateKeyLabofASIC&Systems,FudanUniversity,JinmeiStateKeyLabofASIC&Systems,FudanUniversity,Jinmei穩(wěn)