How to interpolate data from an excel file

I have an excel file with data collected from 8 runs of 1000 time points each. I want to interpolate the data to get 1024 data points for each of the 8 runs. I have attached a sample excel file as well as a script a colleague suggested we use but is still incomplete.

[Bob Thompson]

Have you tried using MATLABs 1d linear interpolator?

https://www.mathworks.com/help/matlab/ref/interp1.html

Answer 1

[Deepak Sarath]

Hi Alex, At first you need to specify the time doamin or query points to which you want to extrapolate . So let me assume from your question, you jus wanna convert 1000 samples to 1024 samples irrespective of time stamps. So.

   %read the time column in excel to variable 'time'
   %read the Values column in excel to variable 'Data'
   y=0;
   x=0;
   for i =1 :999
        y=y+0.9765; % 1000/1024
        x=[x;y];
   end
   %so now you have the time instances at which you wanna extrapolate the data.
   output=interp1(time,Data,x,'linear','extrap');

[Jan]

Letting an array grow iteratively is inefficient. This is nicer to create x:

x = (1:999) * 0.9765

[Deepak Sarath]

Hey Jan, This will create an array of length 999 not 1024. Probably ,

    x= (1:1024)*.9765

Will do, Thanks for your piece of logic.