Package: dsp
Single section or cascaded allpass filter
Note:
MATLAB^{®} code with 
The AllpassFilter
object filters each channel
of the input using Allpass filter implementations. This System object™ supports
code generation. To import this object into Simulink^{®}, use the MATLAB System
block.
To filter each channel of the input:
Define and set up your Allpass filter. See Construction.
Call step
to filter each channel
of the input according to the properties of dsp.AllpassFilter
.
The behavior of step
is specific to each object in
the toolbox.
Note:
Starting in R2016b, instead of using the 
Allpass = dsp.AllpassFilter
returns
an Allpass filter System object, Allpass
, that
filters each channel of the input signal independently using an allpass
filter, with the default structure and coefficients.
Allpass = dsp.AllpassFilter('
returns an Allpass filter System object, PropertyName
',PropertyValue
,
...)Allpass
,
with each property set to the specified value.

Internal allpass filter structure You can specify the internal allpass filter implementation structure
as one of  

Allpass polynomial coefficients Specify the real allpass polynomial filter coefficients. This
property is applicable only when the 

Wave Digital Filter allpass coefficients Specify the real allpass coefficients in the Wave Digital Filter
form. This property is only applicable when the 

Lattice allpass coefficients Specify the real or complex allpass coefficients as lattice
reflection coefficients. This property is applicable only if the 

Indicate if last section is first order Indicate if last section is first order or second order. When
you set 
reset  Reset internal states of a System object 
step  Process inputs using allpass filter 
For additional methods, see Analysis Methods for Filter System Objects.
For a complete list of analysis methods supported for the dsp.AllpassFilter
object,
enter dsp.AllpassFilter.helpFilterAnalysis
at the MATLAB command
prompt.
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 
[1] Regalia, Philip A. and Mitra Sanjit K. and Vaidyanathan, P. P. (1988) "The Digital AllPass Filter: AVersatile Signal Processing Building Block." Proceedings of the IEEE, Vol. 76, No. 1, 1988, pp. 19–37
[2] M. Lutovac, D. Tosic, B. Evans, Filter Design for Signal Processing Using MATLAB and Mathematica. Prentice Hall, 2001