Matched filter
Detection
phaseddetectlib
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.
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 . |
Specify the matched filter coefficients as a column vector.
This parameter appears when you set Source of coefficients to Property
.
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.
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
and EndFrequency
are
measured in baseband. That is, they are within [-Fs/2,Fs/2]
,
where Fs
is the sample rate specified in any of
the waveform library blocks. The parameter StartFrequency
must
be less than EndFrequency
.
This parameter appears when you set Spectrum window to Chebyshev
or Taylor
.
Specify the sidelobe attenuation level, in dB, of a Chebyshev or Taylor
window as a positive scalar.
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 function kaiser
for more details.
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.
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.
Block simulation method, specified as Interpreted Execution
or Code
Generation
. If you want your block to use the MATLAB® interpreter,
choose Interpreted Execution
. If you want your
block to run as compiled code, choose Code 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).
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 |