# getMatchedFilter

Matched filter coefficients for pulse waveform

Since R2021a

## Syntax

``coeff = getMatchedFilter(pulselib,idx)``
``coeff = getMatchedFilter(pulselib,idx,pidx)``

## Description

example

````coeff = getMatchedFilter(pulselib,idx)` returns matched filter coefficients, `coeff`, for the waveform specified by the index, `idx`, in the waveform library, `pulselib`.```

example

````coeff = getMatchedFilter(pulselib,idx,pidx)` also specifies the pulse index, `pidx`, of a stepped FM waveform.```

## Examples

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This example shows how to put two waveforms into a waveform library and how to extract and plot their matched filter coefficients.

Create a pulse library consisting of a rectangular and a linear FM waveform.

```waveform1 = {'Rectangular','PRF',10e3 'PulseWidth',50e-6}; waveform2 = {'LinearFM','PRF',10e3,'PulseWidth',50e-6,'SweepBandwidth',1e5, ... 'SweepDirection','Up','SweepInterval', 'Positive'}; pulsesib = pulseWaveformLibrary('SampleRate',1e6,... 'WaveformSpecification',{waveform1,waveform2});```

Retrieve the matched filter coefficients for each waveform and plot their real parts.

```coeff1 = getMatchedFilter(pulsesib,1,1); subplot(2,1,1) stem(real(coeff1)) title('Matched filter coefficients, real part') coeff2 = getMatchedFilter(pulsesib,2,1); subplot(2,1,2) stem(real(coeff2)) title('Matched filter coefficients, real part')``` ## Input Arguments

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Pulse waveform library, specified as a `phased.PulseWaveformLibrary` System object.

Waveform index, specified as a positive integer. The index specifies which waveform coefficients to return.

Data Types: `double`

Pulse index, specified as a positive integer. The index specifies which pulse matched-filter coefficients to return. This argument applies only to stepped FM waveforms.

Data Types: `double`

## Output Arguments

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Matched filter coefficients, specified as a complex-valued vector or complex-valued matrix. For the stepped FM pulse, the output is a complex-valued matrix. Each matrix column corresponds to a step in the waveform. For all other waveforms, the output is a column vector.

Data Types: `double`
Complex Number Support: Yes

## Version History

Introduced in R2021a