# Do I need equally paced values to do a Fourier Cosine Transform?

I am gathering data from a sensor, but the data gathering depends on a code running, so the timing is not precise to make it equally paced.

What I mean is this, the time it takes to do measurement #1 and #2 is not exactly the same between measurement #2 and #3 and so one.

I may have data like this:

value = 20 taken at t=0s
value = 21 taken at t=0.2s
value = 44 taken at t=0.44s
value = 22 taken at t=0.67s
value = 33 taken at t=0.9s
value = 32 taken at t=1.3s


As you can see the time between measurements is not exactly the same and can vary slightly.

The idea is to perform a Fourier Cosine Transform on the discreet values.

First question is:

1. will this not equally time between the measurements affect the DCT?
2. what can be done to "normalize" the data to have constant times?

• Your sampling frequency is 5 Hz., hence your DCT frequency separation will be $5/(2N)$ with $N$ being the number of samples... Commented Feb 8, 2019 at 19:03