# Implementing FFT in Matlab

I am facing a trouble implementing the fft and appreciate your advice. My data structured as follow: The data are retrieved from the share market for one day change in the share price. The time range from (11:00:00 to 15:00:00) this means 16200 Sec. In matlab its represented as serial so it will be from 0.4584 to 0.6458. Data are not sampled in fixed freqency. Price is sampled only when there is a change in price. For example ( it can be sampled in each second and sometimes in 30 Seconds interval).

• What you're asking for is the DFT of a non-uniformly sampled signal. I suggest you change the title of the question accordingly. The votes to close this question are presumably because of the words 'implement' and 'Matlab'. You should rather ask questions about signal processing in general.
– Deve
Sep 29 '13 at 11:10

• Interpolate the data in order to obtain evenly spaced samples before taking the FFT as suggested by Hasan. Use the Matlab function interp1. If you have the Data Analysis toolbox, the resample function of the timeseries class might be worth a look.