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lsim不支持符号运算。' G! o3 V! `/ |4 P- Q! i+ G' W+ j
syms s t;
, P7 e; s$ M* ^) Eh = exp(-t) + exp(-2 * t);7 c2 B4 P! ~$ K" F& w
hs = laplace(h);" I1 `6 v7 J+ w& w9 F, C7 y) d
[num,den]=numden(hs);
* O: h v( x* D9 l' y# Jn=sym2poly(num);4 p- u8 A% K8 i$ R7 o, Z
d=sym2poly(den); E8 a, x4 t7 I1 y' Z" a. m3 f5 Y
hs=tf(n,d);
* p9 s8 N4 A! [t = 0: 0.01:10;0 E2 K( M& S/ B+ W9 Z' [
f = exp(-t);3 ?1 i/ X8 n9 h
y2 = lsim(hs,f,t);+ C4 S" D! s. Q# e
figure(2); d8 M* a* ]: \$ {8 L2 D' r. S; \
plot(y2); |
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