Bring some signals to the same start value and end value

Hello,

I need some help. I want to bring some Signals to the same start end value. How I can do this quickly and easy?

Here is our code to plot the signals in one plot:

clear all
close all
F = 2000;
load('Spiro_4.mat');
data4 = data; 
Atemfluss4 = data(1:end,1); 
Volumen4 = data(1:end,2); 
F = 2000; % sampling frequency
T4= 1/F;     %Periodendauer
t4= ([0:T4:25.889]); % time vector

load('Spiro_3.mat');
data3 = data; 
Atemfluss3 = data(1:end,1); 
Volumen3 = data(1:end,2); 
F = 2000; % sampling frequency
T3= 1/F;     %Periodendauer
t3= ([0:T3:28.444999]); % time vector

load('Spiro_2.mat');
data2 = data; 
Atemfluss2 = data(1:end,1); 
Volumen2 = data(1:end,2); 
F = 2000; % sampling frequency
T2= 1/F;     %Periodendauer
t2= ([0:T2:25.979999]); % time vector

load('Spiro_1.mat');
data1 = data; 
Atemfluss1 = data(1:end,1); 
Volumen1 = data(1:end,2); 
F = 2000; % sampling frequency
T1= 1/F;     %Periodendauer
t1= ([0:T1:33.414]); % time vector

figure;
plot(t1,Volumen1,t2,Volumen2,t3,Volumen3,t4,Volumen4);
ylabel('Volume in litres');
xlabel('Zeit in s');

Thank you for support.

[EDITED, Jan, Code formatted]

[dpb]

What does "... bring some Signals to the same start end value" mean, precisely?

[Daniel Sedlaczek]

Hello,

the signals should start and end at the same point, so that the start and

Endpoints lie on one point.

[dpb]

OK, that depends on what the definition of "point" is -- we talking in time or magnitude or both?

Since at least for the time they all start a 0, it's only a scaling to one end time.

The question then is "What time is the desired one?"

[Daniel Sedlaczek]

Hello,

the signal should start at the y-axis value 0 and should end at the y-axis value 0 for each signal.

Thanks.

[Daniel Sedlaczek]

Hello,

Solution has been found.

thanks

[dpb]

Well then, post the Answer, don't just leave it hanging...altho never did fully define the solution wanted.

[Daniel Sedlaczek]

I have solve it with a Best fit line like this:

x1=1;

x2=length(VolumenDeTrend);

y1=VolumenDeTrend(x1);

y2=VolumenDeTrend(x2);

m = (y2-y1)/(x2-x1);

b = y1-(m*x1);

x=[x1:1:x2];

z = m*x+b;

g = z';

VolumenDA = VolumenDeTrend - g;

Answer 1

[Mathieu NOE]

hello

if you want all data to start and stop at the same values , you can do that : it works even sampling rates are different

if it 's ok for you I'll be glad if you would accept my answer

% define common start and stop time values
start = 0;
stop = 1; % for example
ind1 = find(t1>=start & t1<=stop)
ind2 = find(t2>=start & t2<=stop)
ind3 = find(t3>=start & t3<=stop)
ind4 = find(t4>=start & t4<=stop)

figure;
plot(t1(ind1),Volumen1(ind1),t2(ind2),Volumen2(ind2),t3(ind3),Volumen3(ind3),t4(ind4),Volumen4(ind4));
ylabel('Volume in litres');
xlabel('Zeit in s');

Answer 2

[dpb]

Presuming it is to just stretch the shorter to the same time as the longest, something like:

y1=randn(size(t1)); Y1=movmean(y1,6000);
y4=randn(size(t4)); Y4=movmean(y4,6000);
plot(t1,Y1,t4,Y4)

% sample data completed, "stretch" Y4 to length/time of Y1
Y4adj=resample(Y4,numel(t1),numel(t4));
% and show result
hold on
plot(t1,Y4adj)
legend('Y1','Y4','Y4adj')

produced

A little noisy signal but can see stretched the original red curve out to same length as the blue one. Rinse and repeat.