Frequency Domain Adaptive filter
The dsp.FrequencyDomainAdaptiveFilter
computes
output, error, and coefficients using a frequency domain FIR adaptive
filter.
To implement the adaptive FIR filter object:
Define and set up your adaptive FIR filter object. See Construction.
Call step
to implement
the filter according to the properties of dsp.FrequencyDomainAdaptiveFilter
.
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.
fdaf = dsp.FrequencyDomainAdaptiveFilter
returns
a frequency domain FIR adaptive filter System
object, fdaf
.
This System
object is used to compute the filtered output and
the filter error for a given input and desired signal.
fdaf = dsp.FrequencyDomainAdaptiveFilter('
returns
an PropertyName
', PropertyValue
,...)FrequencyDomainAdaptiveFilter
System
object, fdaf
,
with each specified property set to the specified value.
fdaf = dsp.FrequencyDomainAdaptiveFilter(LEN,'
returns
an PropertyName
',PropertyValue
,...)FrequencyDomainAdaptiveFilter
System
object, fdaf
,
with the Length property set to LEN
and other specified
properties set to the specified values.

Method to calculate filter coefficients Specify the method used to calculate filter coefficients as
one of 

Length of filter coefficients vector Specify the length of the FIR filter coefficients vector as a positive integer value. This property is nontunable. The default value is 32. 

Block length for coefficient updates Specify the block length of the coefficients updates as a positive
integer value. The length of the input vectors must be divisible by
the 

Adaptation step size Specify the adaptation step size factor as a positive numeric
scalar less than or equal to 

Adaptation leakage factor Specify the leakage factor used in leaky adaptive filter as
a scalar numeric value between 0 and 1, both inclusive. When the value
is less than 1, the System
object implements a leaky adaptive
algorithm. The default is 

Averaging factor of energy estimator Specify the averaging factor used to compute the exponentially windowed FFT input signal
powers for the coefficient updates as a scalar positive numeric value less
than or equal to 1. The default value is 

Offset for normalization terms Specify the offset for the normalization terms in the coefficient
updates as a scalar nonnegative numeric value. Use this property to
avoid divide by zero or divide by very small numbers. This situation
occurs if any of the FFT input signal powers becomes very small. The
default value is 

Initial FFT input signal power Specify the initial common value of all of the FFT input signal
powers as a scalar positive numeric value. The default is 

Timedomain initial coefficients of the filter Specify the initial timedomain coefficients of the adaptive
filter as a scalar or a vector of length equal to the 

Locked status of coefficient updates Specify whether to lock the filter coefficient values. By default,
the value of this property is This property is tunable. 

Current FFT coefficients of the filter This property stores the current discrete Fourier transform
of the filter coefficients as a row vector. The length of this vector
is equal to the sum of the 
reset  Reset filter states for Frequency Domain Adaptive filter 
step  Apply Frequency Domain Adaptive filter to input 
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] Shynk, J.J.“FrequencyDomain and Multirate Adaptive Filtering.” IEEE Signal Processing Magazine, Vol. 9, No. 1, pp. 14–37, Jan. 1992.