soph2信號與系統(tǒng)-同步來金梅課件

離散時(shí)間信號——離散時(shí)間系統(tǒng)的數(shù)學(xué)模型—常系數(shù)線性差分離散時(shí)間系統(tǒng)的單位樣值（單位沖激）卷積（卷積和解卷積（反卷積StateKeyLabofASIC&Systems,FudanUniversity,Jinmei 離散時(shí)間信號——離散時(shí)間系統(tǒng)的數(shù)學(xué)模型—常系數(shù)線性差分離散時(shí)間系統(tǒng)的單位樣值（單位沖激）卷積（卷積和解卷積（反卷積StateKeyLabofASIC&Systems,FudanUniversity,Jinmei離散時(shí)間系統(tǒng)的StateKeyLabofASIC&Systems,FudanUniversity,Jinmei離散時(shí)間系統(tǒng) 和缺

構(gòu)筑“ ”的“引領(lǐng)工程StateKeyLabofASIC&Systems,FudanUniversity,Jinmei混合續(xù)時(shí)間信號.。StateKeyLabofASIC&Systems,FudanUniversity,Jinmei系統(tǒng) 經(jīng)典法：齊次解時(shí)域分析零輸入響應(yīng) StateKeyLabofASIC&Systems,FudanUniversity,Jinmei 卷積（卷積和解卷積（反卷積StateKeyLabofASIC&Systems,FudanUniversity,JinmeixxtxnT等間隔 n 數(shù)字序列如

有規(guī)則的,可以用函數(shù)表示 與xn概念上有區(qū)別，但為了書寫方便，常以表示整個序列，在 用場合一般不 StateKeyLabofASIC&Systems,FudanUniversity,Jinmei序列的三種

On有限長序列：n1OnStateKeyLabofASIC&Systems,FudanUniversity,Jinmei 卷積（卷積和解卷積（反卷積StateKeyLabofASIC&Systems,FudanUniversity,Jinmei相加相乘

z(n)x(n)z(n)x(n)z(n)移位x

z(n)x(nm)z(n)x(nm)右

2

x移

31

1 倒置z(nx(n)差分：前向差分：x(nx(n1后向差分：x(n)x(nx(nz(nx(kk a減少或增加的運(yùn)算（零點(diǎn)），分別稱為抽取StateKeyLabofASIC&Systems,FudanUniversity,JinmeiStateKeyLabofASIC&Systems,FudanUniversity,Jinmei 卷積（卷積和解卷積（反卷積StateKeyLabofASIC&Systems,FudanUniversity,Jinmei單位樣值(n)

0,n1O1n1O1n(n1(n1O1n

(nj)1,n比例性c(nc(n

f(n)(n)f(0)注意：(t)用面 (n)在n0取有限值不是面積StateKeyLabofASIC&Systems,FudanUniversity,Jinmei利用單位樣值信號表示任意x(n)x(m)(nm)mff2o134n fn

11.5

StateKeyLabofASIC&Systems,FudanUniversity,Jinmei單位階躍

u(n)

nn

11

12 u(nu(n)樣值之和u(n)(n)(n1)(n2)(n3)(nkk(n)u(n)u(nStateKeyLabofASIC&矩形 R(n)

0nNn0,nRRN1o NnN(n)u(n)u(nNStateKeyLabofASIC&Systems,FudanUniversity,Jinmei斜變x(n)11123nStateKeyLabofASIC&Systems,FudanUniversity,Jinmei單邊指數(shù)0a0a1aa1

a

1a1

StateKeyLabofASIC&Systems,FudanUniversity,Jinmei正弦01sin0t01sin0tO1510

余弦序列：xncosn :正弦序列的頻率,序列值依次周期性當(dāng) 0 ,則序列每10個重復(fù)一次正弦包00離散正弦序列0xnNxnN稱為序列的周期，為任意正整數(shù)StateKeyLabofASIC&Systems,FudanUniversity,Jinmei正弦序列周期性①2πN，N是正整

2π0

sin0nsin0n2πsin0

0②0②0 ，為有m m

2π nmsin0nm

0 sin0n仍為周期③2π為無理

周期：N0找不到滿足xNxn的N值，為非周StateKeyLabofASIC&Systems,FudanUniversity,JinmeiStateKeyLabofASIC&Systems,FudanUniversity,Jinmei復(fù)指數(shù)xnej0 cosnjsin xn

xn1argxn0nStateKeyLabofASIC&Systems,FudanUniversity,Jinmei StateKeyLabofASIC&Systems,FudanUniversity,Jinmei 離散時(shí)間信號——離散時(shí)間系統(tǒng)的數(shù)學(xué)模型—常系數(shù)線性差分卷積（卷積和解卷積（反卷積StateKeyLabofASIC&Systems,FudanUniversity,Jinmei一．用差分方程描述線性時(shí)不變離統(tǒng)離散時(shí)間系統(tǒng)離散時(shí)間系統(tǒng)離散時(shí)間系x2 y2統(tǒng)離散時(shí)間系c1x1(n)c2x2

c1y1(n)c2y2StateKeyLabofASIC&Systems,FudanUniversity,Jinmei一．用差分方程描述線性時(shí)不變離時(shí)不變111O23n1 34nx(nNy(n111O23n1 34nx(nNy(nN111 3n1 3nStateKeyLabofASIC&Systems,FudanUniversity,Jinmei離散時(shí)間StateKeyLabofASIC&Systems,FudanUniversity,JinmeiStateKeyLabofASIC&Systems,FudanUniversity,Jinmeib(常數(shù) =(a-StateKeyLabofASIC&Systems,FudanUniversity,Jinmeidytaytfyt輸出

時(shí)間間隔:dytytytTytytTdyt StateKeyLabofASIC&Systems,FudanUniversity,Jinmei列差分ytytTaytft若 ytynTftfnTfynyn1aynfT

yn 1 1

fStateKeyLabofASIC&Systems,FudanUniversity,Jinmeix1x1x1nx2x2x1x1nx2x2xx1x1nx2x2StateKeyLabofASIC&Systems,FudanUniversity,Jinmeia

EStateKeyLabofASIC&Systems,FudanUniversity,Jinmei akynkbrxnrk rStateKeyLabofASIC&Systems,FudanUniversity,Jin