Hilbert Envelope Extraction

%% Read in sound sample

[y,FSamp] = audioread('Ex1_Mary.wav');

%% Extract wholeband Hilbert envelope, low-pass filter and plot

env = abs(hilbert(y));

cutoff = 50; % cutoff for low-pass filter, typically 40 Hz or 50 Hz

[a,b] = bilinear([0 0 0 15], [1 6 15 15], FSamp/(2*pi*cutoff)); % filter coefficients

LPenv = filtfilt(a,b,env); % perform zero-phase filtering (no phase distortion)

figure,

plot([1:length(y)]/FSamp,y,'k'),hold on

plot([1:length(y)]/FSamp,LPenv,'r','LineWidth',2)

axis tight

xlabel('Time (s)','FontName','Times','FontSize',18,'FontWeight','bold')

ylabel('Amplitude','FontName','Times','FontSize',18,'FontWeight','bold')

title('Wholeband Amplitude Envelope','FontName','Times','FontSize',24,'FontWeight','bold')

Compute PSI

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