东南大学信号与系统课件 Section 8-9

2-8+∞∞−ttftf),(),(21∫+∞∞−∆−=τττdtfftftf)()()(*)(2121)(1τf)(2τ−tf)()(21ττ−tff1)(),(21tftf)(*)()(21tftfty=X-AxisX-AxisY-AxisY-Axis1100tt1t2t)(1tf)()(2tetftε−=X-AxisY-Axis01)(2τ−tfY-Axis01)()(21ττ−tffX-Axis1t2ttττ∫+∞∞−−=τττdtffty)()()(2110)(,1=∞−tytt2)()(211111)(,tttttedetyttt−−−−−=∗=≤∫ττ3)()()(21221)1()(,ttttttteedetytt−−−−−−−=−=∞≤∫ττ40)(,→∞→tytt12f22ft34tty⇐⇐)()(][)]()(][1[)(2)()(21)(121tteettttetytttttt−−+−−−−=−−−−−−εεε)(][1[)(]1[2)(1)(21ttettetttt−−−−−=−−−−εε11)(*)()(*)(1221tftftftf=⇒2)(*)()(*)())()((*)(3121321tftftftftftftf+=+⇒)(1th)(2th)(te)(*)(1thte)(*)(2thte)(tr))((1sH))((2sH))((sE))((sR)]()([)()()()()()(2121ththtethtethtetr+∗=∗+∗=)()()(21ththth+=)(te)(tr))()((21sHsH+3321321*)*()*(*ffffff=⇒)(1th)(2th)(te)(*)(1thte)*(**)*(2121hhehher==))((1sH))((2sH))((sE))((sR)(*)()(21ththth=)(te)(tr))()((21sHsH⋅11221**hhhh=21,hh21dtdfffdtdfffdtd212121**]*[==2])([*)()(*])([)(*)(212121∫∫∫∞−∞−∞−==tttdxxftftfdxxfdxxfxf3dtdfdxxfdxxfdtdftftftt212121*)()(*)(*)(∫∫∞−∞−==0)(1=−∞f0)(2=−∞f3)()(*)(21trtftf=)()(*)(212211tttrttfttf−−=−−4)(tδ1)()(*)(tfttf=δ2)()(*)(00ttftttf−=−δ3))((*)()(*)()()(ttfttfnnδδ=4dxxfdxxtfntnt)()()()(*)(∫∫∞−∞−=δ∫∞−=tdxxfttf)()(*)(ε)()(*)(ttttεεε=5)(1tf),(21ttt∈)(2tf),(43ttt∈),(,*)(423121tttttffty++∈=6][*2121FFff⋅=1-L21Y-Axis01)()(21tftf∗X-Axis1t−2t−1tt−2tt−τ)(1τ−f)(2τff1(t-)10)(,1=∞−tytt2)1(02111)(,1ttttedetyttt−−−−−=⋅=≤∫ττ3)1()2(2121)(,tttttttteedetytt−−−−−−−−=⋅=∞≤∫ττ40)(,→∞→tyt3X-AxisX-AxisY-AxisY-Axis1100tt1t2t)()()(211tttttf−−−=εε)()(2tetftε−=)(][1[)(]1[)]()([*)()(*)(2)(1)(211221ttettetttttetftfttttt−−−−−=−−−=−−−−−εεεεε)()1()(*)()tettettεεε−−−=4(12)X-AxisX-AxisY-AxisY-Axis0tt1t2t)(1tfAB)(2tf3t4t1τ2τ0Y-Axis0)()(21tftfy∗=tX-Axis2τ31tt+42tt+2τABk=ABk=-AB21ττ−1--5221ττ=X-AxisY-Axis00tt1t2t)(1tf′(A)∫∞−tdxxf)(23t4t(A)2τBY-Axis0)()(21tftfy∗=tX-Axis12Y-Axis0X-Axisf2(t-)f1()342-9)()()()(tepNtrpD=)()()()()()(tepDpNtepHtr==1)(trzi0,)(≥=⇒∑tectrtiziiiλλ2)(*)()(thtetrzs=1)]([)(sHth-1L=)(trzi(2))(tu)()1()(3tetetε−−=C=1F+-)(tu)(te+-Ω=1RVu1)0(=−+-)()()1(tetupRC=+ppHtetup+=⇒=+11)()()()1(1)()()(,1tetcetuttziεελ−−==−=2)()(tethtε−=3)(]21211[*)(3teehetuttzsε−−−−==)()()()1(tututuzsziC+=⇒+−=−−)(]21[teettε)(]211[3tetε−−)2(=+)()()(213tteettεε+−=−−)3(=+∑→)(tectiiελ→→=herzs*~EndofChapter2~~EndofChapter2~