User`s guide

2 LTI Models
2-44
balancing automatically when you convert any TF or ZPK model to state
space u s in g
ss.
• Conversions to the transfer function representation using
tf may incur a
loss of accuracy. As a result, t he transf er functio n poles may not ice ably differ
from the poles of the original zero-pole-gain or state-space model.
• Conversionsto statespace are notuniquely defined inthe SISO case, nor are
they guaran teed to pro duce a minimal r ealiz atio n in t he MIMO case . F or a
given state-space model
sys,
ss(tf(sys))
may return a mo de l with d iffe rent state-space mat rice s, or even a differe nt
number of state s in the M IMO cas e. There f ore, if possible, it i s best to avoid
converting back and forth between state-space and other model types.