setExtractorParameters

Create a signalFrequencyFeatureExtractor object to extract the Welch power spectral density (PSD) estimate of a signal consisting of a 100 Hz sinusoid in additive N(0,1) white noise. The sample rate is 1 kHz and the signal has a duration of 5 seconds.

fs = 1000;
t = 0:1/fs:5-1/fs;
x = cos(2*pi*100*t) + randn(size(t));

sFE = signalFrequencyFeatureExtractor(SampleRate=fs,WelchPSD=true);

For the PSD computation, set the OverlapLength to 25 samples and the FFTLength to 512 samples. Call the getExtractorParameters function on the object to view the PSD parameters.

setExtractorParameters(sFE,"WelchPSD",OverlapLength=25,FFTLength=1024)
params = getExtractorParameters(sFE,"WelchPSD")

params = struct with fields:
          FFTLength: 1024
    FrequencyVector: []
      OverlapLength: 25
             Window: []

Use the extract function to extract the Welch's PSD estimate of the signal. Plot the result.

feature = extract(sFE,x);

fvec = linspace(0,fs/2,length(feature));
plot(fvec,pow2db(abs(feature)))

xlabel("Frequency (Hz)")
ylabel("PSD (dB/Hz)")
grid