Why do I receive an error when I run this code?
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Why do I receive an error when I run this code?
sys=tf([1],[1 1],'InputDelay',2)
sysd=c2d(sys,0.5)
[num,den]=tfdata(sysd)
num=num2str(num{:})
den=num2str(den{:})
num=poly2sym(num,z)
den=poly2sym(den,z)
num=char(num)
den=char(den)
采纳的回答
Paulo Silva
2011-6-9
Bad use of the poly2sym function, you give a string for the first argument but the function expects one array.
Also the z should be like this 'z'
doc poly2sym
Just a tip: num{:} gives you one array, that array can be used by poly2sym
sys=tf([1],[1 1],'InputDelay',2)
sysd=c2d(sys,0.5)
[num,den]=tfdata(sysd)
num=vpa(poly2sym(num{:},'z'),4)
den=vpa(poly2sym(den{:},'z'),4)
nums=char(num)
dens=char(den)
There were some errors, I had to edit the answer several times but I think that now it's all working.
5 个评论
sadel
2011-6-9
Paulo Silva
2011-6-9
Because it's the exact value.
Paulo Silva
2011-6-9
you can see the same behavior in the documentation example
doc poly2sym
Paulo Silva
2011-6-9
ok I fixed the code again, no more big and precise values, happy now?
sadel
2011-6-9
更多回答（1 个）
Julián Francisco
2011-6-9
0 个投票
My Matlab program says that you have not defined the variable z.
1 个评论
Paulo Silva
2011-6-9
it should be like this 'z' instead of just z
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