I have been attempting to use the FFT Routines as found in AN142 (Rev 1.1 12/03). So far my results do not appear correct, and do not agree with other FFT calculators.
A search of this forum suggests there were corrections make to AN142 after Rev1.1.
Is there a more recent (corrected) version available?
Hello Delu, thanks for your reply.
I thought it best to verify that I had the most recent version of the application with any corrections before getting too much into details.
The actual processor used is a C8051F020.
I am using IntFFT_BRIN.C. I have set the sample size to 8 and 'No window' (WINDOW_TYPE = 0)
Input data is assumed to be differential, (SE_data = 0).
Inputting 8 sample points from one period of a 60 Hz sine wave into real array to test. I am expecting to see a single spike in the output representing the 60 Hz signal, but so far does not look correct.
I have very limited internal Ram available to use so I did change the variable allocation to use xdata. Not sure if this may be the problem. I may try freeing up some internal RAM and trying again without this modification.
The link to the post that I mentioned is:
There are some suggested corrections in the thread.
Final post in the thread is from Silicon Labs employee advising that an updated revision with corrections will be made available (2007):
Re: an142 - adapting fft example code for using complex inputs
I was able to get the FFT routines working now. So the current Rev of AN142 does work.
Thanks for the status update.