making different signals equal in length

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?

Answer 1

[Jan]

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]

What if we have multiple signals from a database of different sizes. how to make their length equal?

[Walter Roberson]

Find the maximum of their lengths, say maxlen. Then for each,

ifft(fft(TheSignal),maxlen)

Answer 2

[Walter Roberson]

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.

[Walter Roberson]

Ah... did you want to do this by clipping the longer ones to the length of the shorter?

[Lisa Justin]

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]

thanks..it is useful

Answer 3

[Muruganandham Subramanian]

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..