# making different signals equal in length

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Lisa Justin on 3 Dec 2012
Commented: chaitanya on 27 Feb 2016
Hi, I am working with a set of data and i need all of them to be the same length. how can i do this?

Jan on 3 Dec 2012
It depends. As said already you can crop the longer ones, pad the shorter ones or apply an interpolation. For the latter there are linear, cubic, spline, bsline, trigonometric and more complicated interpolation methods.
aliya on 1 Jun 2015
Edited: aliya on 1 Jun 2015
What if we have multiple signals from a database of different sizes. how to make their length equal?
Walter Roberson on 1 Jun 2015
Find the maximum of their lengths, say maxlen. Then for each,
ifft(fft(TheSignal),maxlen)

Walter Roberson on 3 Dec 2012
S1 = size(FirstMatrix);
S2 = size(SecondMatrix);
MaxS = max(S1, S2);
if MaxS(1) > S1(1); FirstMatrix(end+1:MaxS(1), :) = 0; end
if MaxS(2) > S1(2); FirstMatrix(:, end+1:MaxS(2)) = 0; end
if MaxS(1) > S2(1); SecondMatrix(end+1:MaxS(1), :) = 0; end
if MaxS(2) > S2(2); SecondMatrix(:, end+1:MaxS(2)) = 0; end
You can simplify this a bit if you are using vectors and you know the orientation of the vectors.
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Lisa Justin on 3 Dec 2012
Edited: Lisa Justin on 3 Dec 2012
yes exactly. But then i lose some relevant part of the signal which is not good either. I am a bit unsure how best to make all the length equal. they are about 600 files
chaitanya on 27 Feb 2016
thanks..it is useful

Can you provide the data? you can do it by adding zeros, ones, any desirable data to the data having minimum sizes from data having maximum sizes by initializing max. data length caustiously..