Filter
Top Products
Chapter 4 System Analysis
© National Instruments Corporation 4-9 Xmath Control Design Module
and orders for which the residue(s) should be found. If a user-specified
value for
pls is not actually a pole of the system or if the order requested
is greater than the multiplicity of the pole, the corresponding residue is
returned as zero.
C contains the value of the constant term.
Example 4-4 uses the transfer function from Example 2-10, Verifying a
Discretization Using makecontinuous( ).
Example 4-4 Calculating the Residues of a System
G= system(0.5*polynomial([-0.36]),
polynomial([-1,-1,-0.395+0.06305*jay,
-0.395-0.06305*jay]));
Rp=residue(G)
Rp (a pdm) =
Poles |
-------------------+-----------------------------
-0.395 - 0.06305 j | Order 1 0.738493 - 0.2277 j
| 2 0
-------------------+-----------------------------
-0.395 + 0.06305 j | Order 1 0.738493 + 0.2277 j
| 2 0
-------------------+-----------------------------
-1 | Order 1 -1.47699
| 2 -0.864864
-------------------+-----------------------------
combinepf( )
Sys = combinepf(Rp,C,{var})
combinepf( )
reverses the operation performed by residue( ),
combining partial fractions into a single transfer function. It expects a PDM
of the form shown in Example 4-4 as input.
Use
combinepf( ) to convert partial fractions to a transfer function.
Using the variable
Rp you obtained in Example 4-4:
G2=combinepf(Rp, {var = "s"})
G2 (a transfer function) =
0.5s + 0.18
---------------------------
2 2