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Frequency Measurement

Digital Eye
Intellectual 350 points

Hi,

I am needing a DSP (or any other option) running FFT detecting signals in the frequency range of 20khz to 200KHz.

Frequency bursts are about 500uS maximum but every 1ms.
Can anyone please help for my solution ?
Thanks.
Jitendra

  • 0
    TI__Expert 8560 points
    Hi Jitendra,

    My name is John Walker, and I am part of TI's Online Support Systems team. I'll be helping you with this question.

    FFT is a pretty generic function that most DSP's and microcontrollers can handle. To help narrow down which devices we should be looking at, can you tell me more about the rest of your system and any other functions or peripherals you need for the processor? Is this just running FFTs or are there other things that you need as well? Are you using an external ADC or will the DSP need to have this onboard? Any communication peripherals needed?

    My initial suggestion is to take a look at our C55x family of DSPs: www.ti.com/.../overview.page

    There are several EVMs available for this family, such as the C5517 EVM: www.ti.com/.../tmdsevm5517

    Please look this over and let me know how else we can help.

    Thanks,
    John
  • 0 in reply to John Walker
    Intellectual 350 points
    Hi John,

    Thanks for your reply.

    I need only FFT function, it doesn't have any other peripherals. And DSP need to have this onboard.
    So can you please suggest me the best dsp which can fulfill my application ?


    Thanks.
    Jitendra
  • 0 in reply to Digital Eye
    TI__Expert 8560 points

    Hi Jitendra –

     

    I’ll do my best to make a recommendation, but if you have more details on your application that would help me narrow it down to the best choice. Knowing what kind of FFT and how many points would help.

     

    For a basic DSP that has built in FFT acceleration in HW, I’d suggest the C5535: http://www.ti.com/product/tms320c5535

     

    Here’s the brief description of the FFT accelerator that is on these parts from the TRM for the device: (http://www.ti.com/lit/ug/spruh16b/spruh16b.pdf)

     

    1.1.3 FFT Hardware Accelerator The C55x CPU includes a tightly-coupled FFT hardware accelerator that communicates with the C55x CPU through the use coprocessor instructions. For ease of use, the ROM has a set of C-callable routines that use these coprocessor instructions to perform 8, 16, 32, 64, 128, or 256-point FFTs. The main features of the FFT hardware accelerator are: • Support for 8 to 1024-point (in powers of 2) real and complex-valued FFTs and IFFTs.

    • An internal twiddle factor generator for optimal use of memory bandwidth and more efficient programming.

    • Basic and software-driven auto-scaling feature provides good precision vs cycle count trade-off.

    • Single-stage and double-stage modes enabling computation of one or two stages in one pass, thus handling odd power of two FFT widths.

     

    Let me know if you have any additional questions.

     

    John

  • 0 in reply to John Walker
    TI__Expert 8560 points

    Hi Jitendra –

    Just wanted to check in with you and see if this answered your question. If you're good, we can go ahead and close this thread.

    Thanks,
    John