Matched Filter
Matched filter
Library
Detection
phaseddetectlib
Description
The Matched Filter block implements matched filtering of an input signal. Matched filtering is an FIR filtering operation with the coefficients equal to the time reversed samples of the transmitted signal. The filter can improve SNR before detection.
Parameters
- Source of coefficients
Specify whether the matched filter coefficients come from Coefficients or from an input port.
Property
Matched filter coefficients are specified by Coefficients. Input port
Matched filter coefficients are specified via the input port Coeff
.- Coefficients
Specify the matched filter coefficients as a column vector. This parameter appears when you set Source of coefficients to
Property
.- Spectrum window
Specify the window used for spectrum weighting using one of
None
Hamming
Chebyshev
Hann
Kaiser
Taylor
Spectrum weighting is often used with linear FM waveforms to reduce sidelobe levels in the time domain. The block computes the window length internally to match the FFT length.
- Spectrum window range
This parameter appears when you set the Spectrum window parameter to any value other than
None
. Specify the spectrum region, in hertz, on which the spectrum window is applied as a 1-by-2 vector in the form of[StartFrequency,EndFrequency]
.Note that both
StartFrequency
andEndFrequency
are measured in baseband. That is, they are within[-Fs/2,Fs/2]
, whereFs
is the sample rate specified in any of the waveform library blocks. The parameterStartFrequency
must be less thanEndFrequency
.- Sidelobe attenuation level
This parameter appears when you set Spectrum window to
Chebyshev
orTaylor
. Specify the sidelobe attenuation level, in dB, of a Chebyshev or Taylor window as a positive scalar.- Kaiser shape parameter
This parameter appears when you set the Spectrum window parameter to
Kaiser
. Specify the parameter that affects the Kaiser window sidelobe attenuation as a nonnegative scalar. Please refer to the functionkaiser
for more details.- Number of constant level sidelobes
This parameter appears when you set the Spectrum window parameter to
Taylor
. Specify the number of nearly-constant-level sidelobes adjacent to the mainlobe in a Taylor window as a positive integer.- Enable SNR gain output
Select this check this box to obtain the matched filter SNR gain via the output port
G
. The output port appears only when this box is selected.- Simulate using
Block simulation method, specified as
Interpreted Execution
orCode Generation
. If you want your block to use the MATLAB® interpreter, chooseInterpreted Execution
. If you want your block to run as compiled code, chooseCode Generation
. Compiled code requires time to compile but usually runs faster.Interpreted execution is useful when you are developing and tuning a model. The block runs the underlying System object™ in MATLAB. You can change and execute your model quickly. When you are satisfied with your results, you can then run the block using
Code Generation
. Long simulations run faster than they would in interpreted execution. You can run repeated executions without recompiling. However, if you change any block parameters, then the block automatically recompiles before execution.When setting this parameter, you must take into account the overall model simulation mode. The table shows how the Simulate using parameter interacts with the overall simulation mode.
When the Simulink® model is in
Accelerator
mode, the block mode specified using Simulate using overrides the simulation mode.Acceleration Modes
Block Simulation Simulation Behavior Normal
Accelerator
Rapid Accelerator
Interpreted Execution
The block executes using the MATLAB interpreter. The block executes using the MATLAB interpreter. Creates a standalone executable from the model. Code Generation
The block is compiled. All blocks in the model are compiled. For more information, see Choosing a Simulation Mode (Simulink).
Ports
Note
The block input and output ports correspond to the input and
output parameters described in the step
method of
the underlying System object. See link at the bottom of this page.
Port | Supported Data Types | |
---|---|---|
X | Input signal matrix. The size of the first dimension of the input matrix can vary to simulate a changing signal length. A size change can occur, for example, in the case of a pulse waveform with variable pulse repetition frequency. | Double-precision floating point |
Coeff | Matched filter coefficients. | Double-precision floating point |
Y | Filter output. | Double-precision floating point |
G | Matched-filter gain. | Double-precision floating point |