How to cut the desired signal?
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Muhammad Hammad Malik
le 16 Nov 2022
Modifié(e) : Muhammad Hammad Malik
le 17 Nov 2022
Hello All. I need your guidance on how can i cut the signal and keep my desired signal only. I have a physiological signal. I just want to keep the part of the signal when it goes up and remove the begining and the end of the signal. I am attaching the signal image and the code used to generate it. Could you please guide me how to do this or is there any code to do. Looking forward to hearing from you. Thanks
cd 'D:\Research\TFR classification\DATI'
filenames=dir('*.txt');
Fs=500;
TextSize=24;
time_FIF=zeros(1,length(filenames));
for i= 24 %length(filenames)
%% Signal
%close all
fprintf(['\n\n\n *******************************************\n\n'...
' CODICE data set = ' filenames(i).name(1:end-4) '\n\n'...
' We are assuming a sampling rate of 500 Hz\n\n'...
' *******************************************\n\n'])
%% Import data from text file
opts = delimitedTextImportOptions("NumVariables", 25);
% Specify range and delimiter
opts.DataLines = [1, Inf];
opts.Delimiter = "\t";
% Specify column names and types
opts.VariableNames = ["Var1", "Var2", "Var3", "Var4", "Var5", "Var6", "Var7", "Var8", "Var9", "Var10", "Var11", "Var12", "Var13", "Var14", "Var15", "Var16", "Var17", "Var18", "Var19", "Var20", "Var21", "Var22", "Var23", "VarName24", "Var25"];
opts.SelectedVariableNames = "VarName24";
opts.VariableTypes = ["string", "string", "string", "string", "string", "string", "string", "string", "string", "string", "string", "string", "string", "string", "string", "string", "string", "string", "string", "string", "string", "string", "string", "double", "string"];
% Specify file level properties
opts.ExtraColumnsRule = "ignore";
opts.EmptyLineRule = "read";
% Specify variable properties
opts = setvaropts(opts, ["Var1", "Var2", "Var3", "Var4", "Var5", "Var6", "Var7", "Var8", "Var9", "Var10", "Var11", "Var12", "Var13", "Var14", "Var15", "Var16", "Var17", "Var18", "Var19", "Var20", "Var21", "Var22", "Var23", "Var25"], "WhitespaceRule", "preserve");
opts = setvaropts(opts, ["Var1", "Var2", "Var3", "Var4", "Var5", "Var6", "Var7", "Var8", "Var9", "Var10", "Var11", "Var12", "Var13", "Var14", "Var15", "Var16", "Var17", "Var18", "Var19", "Var20", "Var21", "Var22", "Var23", "Var25"], "EmptyFieldRule", "auto");
opts = setvaropts(opts, "VarName24", "DecimalSeparator", ",");
% Import the data
s = readtable(filenames(i).name, opts);
s = table2array(s);
s = s(1420:3358);
%s = s(4.1*Fs:7.4*Fs);
%% Clear temporary variables
clear opts
%%
Fig=figure;
plot((1:length(s))/Fs,s,'k')
xlabel('time (s)')
title(['Signal ' filenames(i).name(1:end-4)])
set(gca,'fontsize', TextSize);
set(Fig,'Units', 'Normalized', 'OuterPosition', [0 0 1 1]);
4 commentaires
Mathieu NOE
le 16 Nov 2022
well , the simplest approach is to define the time boundaries of the valid data to plot
assuming your data are t (time) and y (data), create the logical array idx :
% create dummy data
t = (0:0.25:4)
y = zeros (size(t));
y(7:end) = 1-exp(-3*t(1:end-6));
% extract portion between 1.5 and 2.5 s
idx = (t>=1.5 & t <=2.5)
plot(t,y,'b',t(idx),y(idx),'-*r');
Réponse acceptée
Fangjun Jiang
le 16 Nov 2022
In general,
t=0:0.1:3.5;
signal=0:35;
index=and(t>=1.5, t<=2.0);
new_t=t(index);
new_signal=signal(index);
plot(new_t, new_signal)
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