i am working on a FFT processor. i need to know that if i need to take the 1024 point FFT of a voltage time series then what should i do. i mean which one is correct way. 1) wait for 1024 samples and take their FFT. then wait for another 1024 samples and take their FFT and so on.... 2) wait for 1024 samples for the first time only and take their FFT. then after the computation of this FFT, immediately start taking FFT of the currrently available 1024 samples in the input buffer and so on.. please tell me which on is the right way of taking FFT of a voltage time series. plz reply early Regards Aamir
FFT processor - some issues
Started by ●July 7, 2006
Reply by ●July 7, 20062006-07-07
aamir.nedian wrote:> i am working on a FFT processor. i need to know that if i need to take the > 1024 point FFT of a voltage time series then what should i do. i mean > which one is correct way. > > 1) wait for 1024 samples and take their FFT. then wait for another 1024 > samples and take their FFT and so on.... > > 2) wait for 1024 samples for the first time only and take their FFT. then > after the computation of this FFT, immediately start taking FFT of the > currrently available 1024 samples in the input buffer and so on.. > > please tell me which on is the right way of taking FFT of a voltage time > series. plz reply earlyIt all depends on what is to be done with the result. Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
Reply by ●July 7, 20062006-07-07
"aamir.nedian" <aamir.nedian@gmail.com> wrote in message news:hu2dnXA0_fppUzPZnZ2dnUVZ_oGdnZ2d@giganews.com...>i am working on a FFT processor. i need to know that if i need to take the > 1024 point FFT of a voltage time series then what should i do. i mean > which one is correct way. > > 1) wait for 1024 samples and take their FFT. then wait for another 1024 > samples and take their FFT and so on.... > > 2) wait for 1024 samples for the first time only and take their FFT. then > after the computation of this FFT, immediately start taking FFT of the > currrently available 1024 samples in the input buffer and so on.. > > please tell me which on is the right way of taking FFT of a voltage time > series. plz reply early > > Regards > Aamir >They are both valid approaches and it really depends on the application. The second approach (sliding FFT) gives you greater resolution but at a much higher processing cost.1022 times.
Reply by ●July 10, 20062006-07-10
aamir.nedian wrote:> i am working on a FFT processor. i need to know that if i need to take the > 1024 point FFT of a voltage time series then what should i do. i mean > which one is correct way. > > 1) wait for 1024 samples and take their FFT. then wait for another 1024 > samples and take their FFT and so on.... > > 2) wait for 1024 samples for the first time only and take their FFT. then > after the computation of this FFT, immediately start taking FFT of the > currrently available 1024 samples in the input buffer and so on.. > > please tell me which on is the right way of taking FFT of a voltage time > series. plz reply early > > Regards > AamirThe second aproach is more convenient if you want to obtain a good spectral estimation, but maybe is not necessary to make another FFT for every new sample. You can search about STFT (Short Time Fourier Transform) in google because there are lots of techniques depending on the aplication.