熟练掌握拉氏正变换.pptVIP

要求：熟练掌握拉氏正变换(定义、性质、定理)熟练掌握拉氏反变换运算法解电路网络函数状态方程的列写拉氏变换套题（八）

一.练习题1 2(3)f(t)1t1.求下列函数的象函数2.求下列象函数的原函数

解:1.

2.法2:

1H-11e(t)t求u.二.S1 +1 uE(S)e(t)

法2:分段拉氏变换11e(t)t求u.1He(t)+R u-S+1 U(S)-

R+U(S)-Se-1

, C1=C2=C3=2FR1us1us2C3ic1ic2ic3C1+uc1-+uc2C2-k2解:uc3(0-)=2V,运算电路为:三.已知us1=10V,us2=2V,R=2uc1(0-)=uc2(0-)=5V

10/S21/2S5/S1/2S2/SU(S)5/SI2(S)I3(S)1/2SI1(S)

10/S21/2S5/S1/2S1/2S5/S2/SU(S)2I(S)3I(S)I1(S)543.52tc2u 、uc3

R1us1us2C3ic1ic2ic3C1+uc1-+u C2c2-k2C1=C2=C3=2F讨论:哪个对？10V

若需响应则电压激励us应为什么函数？零状态+us_i(t)四.已知时响应

五.网络如下图(a)所示,其网络函数U(S)I(S) RLC(a)的极、零点图如图(b)示,且已知Z(j0)=2,试求R、L、C参数值。。(2)求冲激响应h(t).j2-2-1-2(b)解:由图(b)零点为z=-2，极点为

U(S)I(S) RLC(a)零点为z=-2,极点为C=0.2F

(2)

六。列写图示电路的状态方程解:(1)iL1usu c1uc2iL2iR2iR1(2)(3)L1L2+ uc2-usR1R+uc1-* *M

(4)(5)

法2:(1)令iL1=1,其余均为0L1L2+uc2--R1010usR1R+uc1-**M1AuL2ic2ic1uL1R1R2

(2)令iL2=1,其余均为01AuL2ic2ic1uL1R1R2001-1-R1010L1L2+uc2-usR1R2+uc1-**M

(3)令uc1=1,其余均为0(4)令uc2=1,其余均为0(5)令uS=1,其余均为0ic2iuL1R1R2uL21VuL2ic2ic1uL1R1R21VuL2R1R21VuL1-1-1-1/R2ic11/R201-1/R2c11/R2-12L1L2+uc2-usR1R+uc1-**M求uL1,uL2,ic1,ic2. ic2

-R10 -1 00 0 -1 11 1-1/R21/R20 -1/R2 -1/R2-1000