Resampling/Interpolate Data

Hello,

How can i resample/interpolate the signal (Sig1). Sig1 has approx.99 Hertz and Sig2 has 500 Hertz.

First Column is the time. Second Column is the distance.

Thank you.

Answer 1

[Aabha]

Hi Philipp,

You can downsample “Sig2” to match the sampling frequency of “Sig1”. This can be done using the “resample” function in MATLAB. Here is a reference code to help you with it.

distance = Sig2(:, 2); 
time = Sig2(:, 1); 
fs1 = 99; 
fs2 = 500; 
[p, q] = rat(fs1 / fs2); %resampling factor

distanceResampled = resample(distance, p, q); 
timeResampled = linspace(time(1), time(end), length(distanceResampled))';     

Sig2Resampled = [timeResampled, distanceResampled]; 

If you would like to interpolate the signals instead of resampling, you can use the “interp1” function in MATLAB. Here is a reference code for interpolation

timeSig1 = Sig1(:,1)'; 
distanceSig1 = Sig1(:, 2)'; 
timeSig2 = Sig2(:,2)'; 
distanceSig2 = Sig2(:, 2)'; 

interpolSig = interp1(timeSig1, distanceSig1, timeSig2, 'linear');

This code will interpolate “Sig1” such that the new signal “interpolSig” will have the same time vector “time1”.

You can also refer to the following documentation for more details.

https://www.mathworks.com/help/releases/R2021a/matlab/ref/timeseries.resample.html

https://www.mathworks.com/help/releases/R2021a/matlab/ref/interp1.html