Package: phased
Matched filter
The MatchedFilter
object implements matched
filtering of an input signal.
To compute the matched filtered signal:
Define and set up your matched filter. See Construction.
Call step
to perform the matched
filtering according to the properties of phased.MatchedFilter
.
The behavior of step
is specific to each object in
the toolbox.
Note:
Starting in R2016b, instead of using the 
H = phased.MatchedFilter
creates a matched
filter System object, H
. The object performs
matched filtering on the input data.
H = phased.MatchedFilter(
creates
a matched filter object, Name
,Value
)H
, with each specified
property Name set to the specified Value. You can specify additional
namevalue pair arguments in any order as (Name1
,Value1
,...,NameN
,ValueN
).

Source of matched filter coefficients Specify whether the matched filter coefficients come from the
Default:  

Matched filter coefficients Specify the matched filter coefficients as a column vector.
This property applies when you set the Default:  

Window for spectrum weighting Specify the window used for spectrum weighting using one of Default:  

Userdefined window for spectrum weighting Specify the userdefined window for spectrum weighting using
a function handle or a cell array. This property applies when you
set the If If Default:  

Spectrum window coverage region Specify the spectrum region on which the spectrum window is
applied as a 1by2 vector in the form of Note that both Default:  

Coefficient sample rate Specify the matched filter coefficients sample rate (in hertz)
as a positive scalar. This property applies when you set the Default:  

Window sidelobe attenuation level Specify the sidelobe attenuation level (in decibels) of a Chebyshev
or Taylor window as a positive scalar. This property applies when
you set the Default:  

Kaiser window parameter Specify the parameter that affects the Kaiser window sidelobe
attenuation as a nonnegative scalar. Please refer to Default:  

Number of nearly constant sidelobes in Taylor window Specify the number of nearly constant level sidelobes adjacent
to the mainlobe in a Taylor window as a positive integer. This property
applies when you set the Default:  

Output gain To obtain the matched filter gain, set this property to Default: 
clone  Create matched filter object with same property values 
getNumInputs  Number of expected inputs to step method 
getNumOutputs  Number of outputs from step method 
isLocked  Locked status for input attributes and nontunable properties 
release  Allow property value and input characteristics changes 
step  Perform matched filtering 
Construct a matched filter for a linear FM waveform.
hw = phased.LinearFMWaveform('PulseWidth',1e4,'PRF',5e3); x = step(hw); hmf = phased.MatchedFilter(... 'Coefficients',getMatchedFilter(hw)); y = step(hmf,x); subplot(211),plot(real(x)); xlabel('Samples'); ylabel('Amplitude'); title('Input Signal'); subplot(212),plot(real(y)); xlabel('Samples'); ylabel('Amplitude'); title('Matched Filter Output');
Apply the matched filter, using a Hamming window to do spectrum weighting.
hw = phased.LinearFMWaveform('PulseWidth',1e4,'PRF',5e3); x = step(hw); hmf = phased.MatchedFilter(... 'Coefficients',getMatchedFilter(hw),... 'SpectrumWindow','Hamming'); y = step(hmf,x); subplot(211),plot(real(x)); xlabel('Samples'); ylabel('Amplitude'); title('Input Signal'); subplot(212),plot(real(y)); xlabel('Samples'); ylabel('Amplitude'); title('Matched Filter Output');
Apply the matched filter, using a custom Gaussian window for spectrum weighting.
hw = phased.LinearFMWaveform('PulseWidth',1e4,'PRF',5e3); x = step(hw); hmf = phased.MatchedFilter(... 'Coefficients',getMatchedFilter(hw),... 'SpectrumWindow','Custom',... 'CustomSpectrumWindow',{@gausswin,2.5}); y = step(hmf,x); subplot(211),plot(real(x)); xlabel('Samples'); ylabel('Amplitude'); title('Input Signal'); subplot(212),plot(real(y)); xlabel('Samples'); ylabel('Amplitude'); title('Matched Filter Output');
The filtering operation uses the overlapadd method.
Spectrum weighting produces a transfer function
$$H\text{'}(F)=w(F)H(F)$$
where w(F) is the window and H(F) is the original transfer function.
For further details on matched filter theory, see [1]or [2].
[1] Richards, M. A. Fundamentals of Radar Signal Processing. New York: McGrawHill, 2005.
[2] Skolnik, M. Introduction to Radar Systems, 3rd Ed. New York: McGrawHill, 2001.
phased.CFARDetector
 phased.StretchProcessor
 phased.TimeVaryingGain
 pulsint
 taylorwin