IIR Filter with no zeros
The AllpoleFilter
object filters each channel
of the input using Allpole filter implementations.
To filter each channel of the input:
Define and set up your Allpole filter. See Construction.
Call step
to filter each channel
of the input according to the properties of dsp.AllpoleFilter
.
The behavior of step
is specific to each object in
the toolbox.
Starting in R2016b, instead of using the step
method
to perform the operation defined by the System
object™, you can
call the object with arguments, as if it were a function. For example, y
= step(obj,x)
and y = obj(x)
perform
equivalent operations.
allpole = dsp.AllpoleFilter
returns
an Allpole filter System
object, allpole
, which
independently filters each channel of the input over successive calls
to the step
method. This System
object uses a
specified Allpole filter implementation, and it supports variablesize
input.
allpole = dsp.AllpoleFilter('
returns an Allpole filter System
object, PropertyName
',PropertyValue
,
...)allpole
,
with each property set to the specified value.

Filter structure Specify the filter structure.
 

Filter denominator coefficients Specify the denominator coefficients as a real or complex numeric
row vector. This property is applicable when the Structure property
is set to one of  

Lattice filter coefficients Specify the lattice filter coefficients as a real or complex
numeric row vector. This property is applicable when the Structure
property is set to  

Initial conditions for the filter states Specify the initial conditions of the filter states. The default
value is You can specify the initial conditions as a scalar, vector, or matrix. If you specify a scalar value, this System object initializes all delay elements in the filter to that value. You can also specify a vector whose length equals the number of delay elements in the filter. When you do so, each vector element specifies a unique initial condition for the corresponding delay element. The object applies the same vector of initial conditions to each channel of the input signal. You can also specify a matrix with the same number of rows as the number of delay elements in the filter and one column for each channel of the input signal. In this case, each element specifies a unique initial condition for the corresponding delay element in the corresponding channel. This property is tunable.  

Denominator coefficients word and fractionlength designations Specify the denominator coefficients fixedpoint data type as
one of  

Reflection coefficients word and fractionlength designations Specify the reflection coefficients fixedpoint data type as
one of 
freqz  Frequency response 
fvtool  Open filter visualization tool 
impz  Impulse response 
phasez  Unwrapped phase response 
reset  Reset internal states of Allpole filter 
step  Filter input with Allpole filter object 
More Analysis Methods for Filter System Objects.
In AllpoleFilter, analysis methods are not supported for fixedpoint
processing if the structure is Direct form
or Direct
form transposed
.
Common to All System Objects  

clone  Create System object with same property values 
getNumInputs  Expected number of inputs to a System object 
getNumOutputs  Expected number of outputs of a System object 
isLocked  Check locked states of a System object (logical) 
release  Allow System object property value changes 
This object implements the algorithm, inputs, and outputs described on the Allpole Filter block reference page. The object properties correspond to the block parameters.