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Centre for Neuroscience in Education


Calculation of PSI in MATLAB requires the installation of the Circular Statistics library from:

Philipp Berens (2022) Circular Statistics Toolbox (Directional Statistics) (, MATLAB Central File Exchange.

%% Script to Compute PSI from S-AMPH data tA

% Compute AM phase using Hilbert transform

for band = 1:5

    for AM = 1:3

        phase(:,AM,band) = angle(hilbert(tA(:,AM,band)));



% Compute PSI for 2 phase series with DIFFERENT frequencies (e.g. ratio of 2:1)

n = 1;

m = 2;

x = phase(:,2,1);   % choose desired AM (1=stress, 2=syll, 3=phoneme), choose desired frequency band (1-5)

y = phase(:,1,1);

nmPSI = abs(mean(exp(1i*(circ_dist(n*x,m*y)))));


Modulation Spectrum (MATLAB batch file)

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