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TMS320F280048C: 4096 pt FFT performance

Munan Xu
Expert 5720 points

Part Number: TMS320F280048C

Hello,

I have a customer looking at the TMS320F28004x to implement an FFT based diagnostic tool using the fixed point library.

The customer would like to compute a real FFT of 4069 samples and get magnitude and phase information out within a 5 ms window.

Looking at the fixed point users guide, the RFFT table stops after N=2048. Do we have data on how many cycles it takes for these FFT functions where N=4096?

Thanks in advance for your help!

Munan

  • 0
    TI__Mastermind 27855 points

    Munan,

    It appears we haven't benchmarked for sizes larger than the sizes for which we don't provide twiddle factor tables. The customer would need to make a choice about whether to compute the twiddle factors in real-time and take the performance hit, or pre-compute and store it in memory and take the memory hit.

    Thanks,

    Sira

  • 0 in reply to Sira Rao80
    TI__Expert 5720 points

    Hi Sria,

    Thanks for the reply here. Is there any way you can provide some indication of cycle time for a 4096 pt fft assuming twiddle factors are calculated? We're trying to decide if the F280048 has adequate clock speed to do this or if we need to recommend a different C2000.

    Munan

  • 0 in reply to Munan Xu
    TI__Mastermind 27855 points

    You can apply a 2.2 scaling factor on the 2048 cycle count to estimate the 4096 cycle count. For the rest of the functions mag() etc. you can apply a 2.0 scaling factor.