75 lines
1.8 KiB
Matlab
75 lines
1.8 KiB
Matlab
%%%%%%%%%%%%%%%%%%%%%%
|
|
% UNKNOWN SIGNAL
|
|
% Sampling frequency: 200 Hz
|
|
% Duration; 2 s
|
|
% First second: 6.25Hz, 13.28 Hz, 17.19 Hz
|
|
% Second second: 17.97Hz, 6.25 Hz, 8.59 Hz, 13.28 Hz
|
|
%%%%%%%%%%%%%%%%%%%%%%
|
|
|
|
% loads the signal package on Octave
|
|
% pkg load signal
|
|
|
|
% loads signal and its characteristics
|
|
signal = csvread('unknownsignal.csv');
|
|
|
|
%%%%%SIGNAL CHARACTERISTICS%%%%%
|
|
% sets sampling frequency
|
|
fps = 300; % -> freqMax of the signal should be < 150 Hz (Shannon-Nyquisit theorem), in practice freqMax < 60 Hz would be better
|
|
|
|
% computes the duration of the signal
|
|
duration = length(signal) / fps; % in s
|
|
|
|
% estimates its original frequency resolution
|
|
resolution = fps / length(signal); % in Hz
|
|
|
|
%%%%%STATIONARITY%%%%%
|
|
% temporal plot
|
|
figure;
|
|
plot(signal);
|
|
xticks(0:0.2*fps:length(signal)*fps);
|
|
xticklabels(0:0.2:length(signal)/fps);
|
|
xlabel('Time (s)');
|
|
ylabel('Amplitude (a.u.)');
|
|
|
|
% spectrogram
|
|
step_size = 50; %ms
|
|
window_size = 100; %ms
|
|
spectrogram(signal, fps, step_size, window_size);
|
|
|
|
% ccl: signal is not stationary, it is composed of 2 parts
|
|
|
|
%%%%%SPLIT SIGNAL INTO 2 PARTS%%%%%
|
|
% First part: [0 1s]
|
|
signal_1 = signal(1:end/2);
|
|
% Second part: [1s 2s]
|
|
signal_2 = signal(end/2+1:end);
|
|
|
|
%%%%%SPECTRAL ANALYSIS (RECTANGULAR WINDOW)%%%%%
|
|
%plots power spectrum with rectangular window
|
|
% 1st part of the signal with 1 Hz resolution
|
|
frequencySpectrum(signal_1, fps, 1);
|
|
|
|
|
|
% 2nd part of the signal with 1 Hz resolution
|
|
frequencySpectrum(signal_2, fps, 1);
|
|
|
|
|
|
|
|
|
|
%%%%%SPECTRAL ANALYSIS (BLACKMAN WINDOW)%%%%%
|
|
%plots power spectrum with blackman window
|
|
signal_1_win = blackmanWin(signal_1);
|
|
% 1st part of the signal with 1 Hz resolution
|
|
frequencySpectrum(signal_1_win, fps, 1);
|
|
|
|
|
|
signal_2_win = blackmanWin(signal_2);
|
|
% 2nd part of the signal with 1 Hz resolution
|
|
frequencySpectrum(signal_2_win, fps, 1);
|
|
|
|
|
|
|
|
|
|
|
|
|