My first response to your question that I posted is in error. When Iwrote it, I was thinking that you were implementing the FFT on a 16-bit machine, but the 563xx is a 24-bit architecture. Given that, I don't think you should have any difficulty realizing an FFT dynamic range in excess of 100 dB. I wouldn't go through all of the trouble of simulating things. Bill Schintler --- In , "wygonski" <jwygonski@h...> wrote: > Can anyone give me some guidance on the dynamic range of signals that > I can process with an FFT on the 563xx? Here's my situation: > > I have a 24-bit A/D, and I am doing synchronous averaging in the time > domain, followed by the single-precision FFT. My record size and FFT > size is 4096. I'm interested in measuring the amplitude of two > sinusoids, where one of the sinusiods is as much as 90 dB below the > other sinusiod at another (remote) frequency. I'm confident my > hardware has a low-enough noise floor to handle this situation, but > I'm not so sure about the FFT. Given the round-off noise of the FFT, > and the input scaling that should be done to prevent overflows in the > algorithm, what dynamic range can I expect? > > Also knowing that FFT algorithms may differ in their dynamic range, > can anyone guide me as to a correct choice of algorithm? |