FFT on time series error message

Im attempting to run a FFT for a time series I created, however I keep getting an error message saying invalid data type. What am I doing wrong? Thanks.

T=1 %delta t

L=64 %length of vector

t=0:T:L-1

for i=1:L

      if t(i)==8

          y(i)=1

      else y(i)=0

      end

end

plot(t,y)

Y = fft(y);

Answer 1

[Walter Roberson]

? You do not show a timeseries ?

fft() cannot be done directly on a timeseries object.

If the times are regular intervals the extract the Data property from the timeseries and fft() that; if you end up plotting that then you can use the Time property of the timeseries to figure out delta-time to figure out sampling frequency.

If the times are not regular intervals then there are no Mathworks-provided routines to do the calculations, but you can see https://www.mathworks.com/matlabcentral/fileexchange/25135-nufft--nfft--usfft NUFFT from the File Exchange