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added spectrogram

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Paul EWING 2024-03-18 09:38:17 +01:00
parent 42144d3bdc
commit 8b53aa2734
1 changed files with 36 additions and 0 deletions
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spectrogram.m Normal file
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function spectrogram(signal, samplingFreq, step_size, window_size)
%%%%%%%%%%%%%%%%%%%%%%%
%function spectrogram(signal, samplingFreq, step_size, window_size)
% ex.: spectrogram(signal, 300, 50, 1000)
%
% Task: Plot the spectrogram of a given signal
%
% Inputs:
% -signal: temporal signal to analyse
% -samplingFreq: sampling frequency of the temporal signal
% -step_size: how often the power spectrum will be computed in ms
% -window_size: size of the analysing window in ms
%
% Ouput: None
%
% author: Guillaume Gibert (guillaume.gibert@ecam.fr)
% date: 14/03/2023
%%%%%%%%%%%%%%%%%%%%%%%
figure;
subplot(2,1,1);
t=0:1/samplingFreq:length(signal)/samplingFreq-1/samplingFreq;
plot(t, signal');
xlim([0 length(signal)/samplingFreq-1/samplingFreq]);
ylabel('Amplitude (norm. unit)');
subplot(2,1,2);
step = fix(step_size*samplingFreq/1000); % one spectral slice every step_size ms
window = fix(window_size*samplingFreq/1000); % window_size ms data window
[S, f, t] = specgram(signal);
specgram(signal, 2^nextpow2(window), samplingFreq, window, window-step);
xlabel('Time (s)');
ylabel('Frequency (Hz)');
title('hello');