designHighpassFIR

Create a dsp.FIRFilter object, and set the NumeratorSource property to 'Input port' so that you can vary the coefficients of the FIR filter through the input port during simulation.

firFilt = dsp.FIRFilter(NumeratorSource="Input port")

firFilt = 
  dsp.FIRFilter with properties:

            Structure: 'Direct form'
      NumeratorSource: 'Input port'
    InitialConditions: 0

  Use get to show all properties

Create a spectrumAnalyzer object to visualize the spectra of the input and output signals.

spectrumScope = spectrumAnalyzer(SampleRate=44100,PlotAsTwoSidedSpectrum=false,...
    ChannelNames=["Input Signal","Filtered Signal"]);

Create a dsp.DynamicFilterVisualizer object to visualize the magnitude response of the varying filter.

filterViz = dsp.DynamicFilterVisualizer(NormalizedFrequency=true);

Stream in random data and filter the signal using the dsp.FIRFilter object. Use the designHighpassFIR function to design the filter coefficients. By default, this function returns a vector of FIR filter coefficients. Assign these coefficients to the dsp.FIRFilter object.

Vary the cutoff frequency of the filter during simulation. The designHighpassFIR function redesigns the coefficients based on the updated filter specifications. Pass these updated coefficients to the FIR filter. Visualize the spectra of the input and filtered signals using the spectrum analyzer.

Fcut = 0.5;
for idx = 1:500
    num = designHighpassFIR(FilterOrder=30,CutoffFrequency=Fcut,Window="hann");
    x = randn(1024,1);
    y = firFilt(x,num);
    spectrumScope(x,y);
    filterViz(num);
    Fcut = Fcut + 0.0001;
end

Design and implement a highpass FIR filter object using the designHighpassFIR function. The function returns a dsp.FIRFilter object when you set the SystemObject argument to true.

firFilt = designHighpassFIR(FilterOrder=30,CutoffFrequency=0.5,Window="hann",...
        SystemObject=true)

firFilt = 
  dsp.FIRFilter with properties:

            Structure: 'Direct form'
      NumeratorSource: 'Property'
            Numerator: [0 -2.1297e-19 -0.0011 1.8613e-18 0.0048 -4.8729e-18 -0.0122 8.7270e-18 0.0251 -1.2757e-17 -0.0477 1.6267e-17 0.0960 -1.8649e-17 -0.3148 0.5000 -0.3148 -1.8649e-17 0.0960 1.6267e-17 -0.0477 -1.2757e-17 0.0251 ... ] (1x31 double)
    InitialConditions: 0

  Use get to show all properties

Create a dsp.DynamicFilterVisualizer object to visualize the magnitude response of the filter.

filterViz = dsp.DynamicFilterVisualizer(NormalizedFrequency=true);
filterViz(firFilt)

Create a spectrumAnalyzer object to visualize the spectra of the input and output signals.

spectrumScope = spectrumAnalyzer(SampleRate=44100,PlotAsTwoSidedSpectrum=false,...
    ChannelNames=["Input Signal","Filtered Signal"]);

Stream in random data and filter the signal using the dsp.FIRFilter object. Visualize the spectra of the input and filtered signals using the spectrum analyzer.

for idx = 1:500
    x = randn(1024,1);
    y = firFilt(x);
    spectrumScope(x,y);
end