Is there optimized dsplib funciton for real-only data FFT?

Adam Yao94020

Hi,
I see the DSPlib FFT function are all designed to support complex data input and output. Is there any function can support real data input FFT for fixed point/SP/DP? I think the real only data FFT should be further optimzed from our standard complex data input FFT.

Thanks,
Adam

over 9 years ago

0 ran35366 over 9 years ago

TI__Genius 12805 points

It is device dependent. For example , if you use C55x look at SPRU422J and you see rfft (=real FFT) function.

For a device that the dsplib does not have real FFT, you already know what to do:

1. If you have multiple real FFT you can process two at the same time
2. If not, you can slightly modify the code to do N point real FFT with N/2 points FFT (and one more phase)

Ran

0 Adam Yao94020 over 9 years ago in reply to ran35366

TI__Genius 10910 points

Hi Ran,
Thanks for the reply.
I am checking C66x DSPlib and there is no dedicated function for real FFT. Could you explain more about your suggestion 1 and 2 for real FFT?

1.How to two two real FFT at the same time using a complex FFT function?

2.How to reduce the FFT length to N/2 and add one more phase?

Thanks,
Adam

0 ran35366 over 9 years ago in reply to Adam Yao94020

TI__Genius 12805 points

You can search the net. Here are some pointers -

TI application note - http://www.ti.com/lit/an/spra291/spra291.pdf

Another resource is http://www.engineeringproductivitytools.com/stuff/T0001/PT10.HTM

I hope this helps

Ran

0 Adam Yao94020 over 9 years ago in reply to ran35366

TI__Genius 10910 points

Ran,
Thanks a lot for the help. I will study it first.

Regards,
Adam

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Is there optimized dsplib funciton for real-only data FFT?