sweeptone

Create a sweep tone excitation signal by using the sweeptone function.

excitation = sweeptone(2,1,44100);

plot(excitation)
title('Excitation')

Pass the excitation signal through an infinite impulse response (IIR) filter and add noise to model a real-world recording (system response).

[B,A] = butter(10,[.1 .7]);
rec = filter(B,A,excitation);
nrec = rec + 0.12*randn(size(rec));

plot(nrec)
title('System Response')

Pass the excitation signal and the system response to the impzest function to estimate the impulse response. Truncate the estimate to 100 points. Use impz to determine the true impulse response of the system. Plot the true impulse response and the estimated impulse response for comparison.

irEstimate = impzest(excitation,nrec);
irEstimate = irEstimate(1:101);

irTrue = impz(B,A,101);
plot(0:100,irEstimate, ...
     0:100,irTrue,'ro')

legend('True impulse response','Estimated impulse response')

Generate an exponential swept sine (ESS) signal with a 3-second sweep that goes from 20 Hz to 20 kHz, and ends with a 2-second silence. Specify the sample rate as 48 kHz.

fs = 48e3;
excitation = sweeptone(3,2,fs,'SweepFrequencyRange',[20 20e3]);

Visualize the excitation in time and time-frequency.

t = (0:numel(excitation)-1)/fs;
plot(t,excitation)
xlabel('Time (s)')

spectrogram(excitation,512,0,1024,fs,'yaxis')