I am sampling voltage values. I need to convert it to the frequency domain using FFT . As I understand the frequency steps after FFT will be the integer multiples of Fs/N (where Fs is the data sample rate in Hz, and N is the FFT length). How can I have sub-Hz frequency steps? Do I use use long sampling times and long FFT lengths, for instance, Sampleing at 1 kHz and using 10000 FFT length will produce 0.1Hz frequency steps, and the sample stream will be 10 seconds long? Am I on the right track? Thanks Peter, pr20@cornell.edu pls, also e-mail copy of your reply.
sub-Hz FFT
Started by ●October 9, 2008
Reply by ●October 9, 20082008-10-09
Peter123 wrote: > I am sampling voltage values. I need to convert it to the frequency domain > using FFT . > As I understand the frequency steps after FFT will be the integer > multiples of Fs/N (where Fs is the data sample rate in Hz, and N is the FFT > length). > How can I have sub-Hz frequency steps? Sample for a longer time. > Do I use use long sampling times and long FFT lengths, for instance, > Sampleing at 1 kHz and using 10000 FFT length will produce 0.1Hz frequency > steps, and the sample stream will be 10 seconds long? > Am I on the right track? Yes. > Thanks > Peter, pr20@cornell.edu pls, also e-mail copy of your reply. Jerry -- Engineering is the art of making what you want from things you can get. ����������������������������������������������������������������������� ** Posted from http://www.teranews.com **
Reply by ●October 9, 20082008-10-09
Thanks Jerry!>Peter123 wrote: > > I am sampling voltage values. I need to convert it to the frequency >domain > > using FFT . > > As I understand the frequency steps after FFT will be the integer > > multiples of Fs/N (where Fs is the data sample rate in Hz, and N is >the FFT > > length). > > How can I have sub-Hz frequency steps? > >Sample for a longer time. > > > Do I use use long sampling times and long FFT lengths, for instance, > > Sampleing at 1 kHz and using 10000 FFT length will produce 0.1Hz >frequency > > steps, and the sample stream will be 10 seconds long? > > Am I on the right track? > >Yes. > > > Thanks > > Peter, pr20@cornell.edu pls, also e-mail copy of your reply. > >Jerry >-- >Engineering is the art of making what you want from things you can get. >����������������������������������������������������������������������� >** Posted from http://www.teranews.com ** >
