h = tf(10, [0.2 1 0])
h =
10
-----------
0.2 s^2 + s
Continuous-time transfer function.
>> zh = c2d(h, 0.2,'zoh')
[num den] = tfdata(zh, 'v')
zh =
0.7358 z + 0.5285
----------------------
z^2 - 1.368 z + 0.3679
Sample time: 0.2 seconds
Discrete-time transfer function.
num =
0 0.7358 0.5285
den =
1.0000 -1.3679 0.3679
>> [z, p, k] = tf2zpk(num, den)
z =
-0.7183
p =
1.0000
0.3679
k =
0.7358
如上述变换,分别可以求出系数NUM和DEN.
但是,看Z域的Z,P,K(零点,极点,增益)却和S域大相径庭,S域增益为10,无零点,两个极点(一个初始极点);
造成这样的结果,是由于离散系统会引入所谓的延时环节和0阶保持器么?
两组数值是一个概念,只是不同域的不同表达么?