How to do a FFT ? Comment faire une FFT ?

[[email protected]]

Hello ,



I am a new user of the TMS320C6711 DSP and i would like to know how i
must do to make an fft with this device.

Actually I acquire six tensions with an analog to digital converter and
i would like to analyse the frequencies of these tension.

Thank you per advance for your help

regards

Vincent.W


The devices that i employed :

- OSR 116 acquissition board :
http://www.traquair.com/products/microline/ors116.html
- 6711 board : http://www.traquair.com/products/microline/c6x11cpu.html

[[email protected]]

I used sp_fftSPxSP.

DSPF_sp_fftSpxSP(FFTLEN,&in[0],&w[0],scratch,brev,2,0,FFTLEN);

This is a mixed radix, cache optimized routine specially made for c67x.
You can find good docs on the internet.
http://focus.ti.com/docs/apps/catalog/resources/appnoteabstract.jhtml?abstractName=spru657b

The sp means single precision. The w and brev arguments will need to
be calculated ahead of time. There is a tool for calculating w. You
have to be very careful when using TI's optimized routines. There are
many special requirements - like padding arrays and an even number of
elements. I suggest you try an example in the emulator to verify it
works.

http://www.signalsguru.net

[John Herman]

In article <[email protected]. com>, [email protected] wrote:
>I used sp_fftSPxSP.
>
>DSPF_sp_fftSpxSP(FFTLEN,&in[0],&w[0],scratch,brev,2,0,FFTLEN);
>
>This is a mixed radix, cache optimized routine specially made for c67x.
> You can find good docs on the internet.
>http://focus.ti.com/docs/apps/catalog/resources/appnoteabstract.jhtml?abstractN
>ame=spru657b

This worked better for me.

http://focus-webapps.ti.com/general/docs/sitesearch/searchsite.
tsp?selectedTopic=1653260327&searchTerm=sp_fftSPxSP&Input=New+Search