信号与系统课件.pdf

Thenon-zeroareaof

convolution

ifx(t):ah(t):(b,b)

12

thenx(t)h(t):a

ifxn:nhn:m

thenxnhn:nm,nm

1122

Convolutionwithstep

x(t)h(t)(

x(t)u(t)h(t)u(t)

u(t)u(t)tu(t)

Convolutionwithstep

x(t)h(t)(

x(t)e−atu(t)h(t)e−btu(t)

−at−bt

e−atu(t)e−btu(t)e−e()

ut

b−a

Convolutionwithstep

x(t)h(t)(

x(t)e−atu(t)h(t)e−atu(t)

e−atu(t)e−atu(t)te−atu(t)

Convolutionwithstep

unun(n1)un

bn1−an1

nn

aunbunun

b−a

nn

aunaun

Convolutionwithconstant

x(t)

x(t)h(t)h()

xnA

xnhnhkAAhk

k=−k=−

Convolutionwithexponential

signal

x(t)est

st−

x(t)h(t)