Re: Help.....DSP on ARM9 or ARM7!!!!

"Wilco Dijkstra" <Wilco_dot_Dijkstra@xxxxxxxxxxxx> wrote in message
news:omwDf.18838$mf2.1624@xxxxxxxxxxxxxxxxxxxxxxx
>
> "jagdish.dsp" <jagdish.dsp@xxxxxxxxx> wrote in message
> news:uuSdnROkSq5X0UPeRVn-uQ@xxxxxxxxxxxxxxx
> > Dear Friends,
> >
> > In my design I need to develope a DSP algorithm on one DSP processor and
> > then to interface same with ARM which is handling all the peripherals.
> >
> > I am thinking if my DSP algorithm can be implemented on ARM or not...so
> > need you help. Right now I am using evaluation board of Texas DSK, so
> > taking the input from microphone is given to CODEC(A to D conversion)
> > whose sampling freq is 32KHz.
> >
> > I have to implement 8192 point FFT on real time sound data....
>
> An ARM7 takes 2Mhz to perform a 8192 complex Q15 FFT. ARM9E is twice as
> fast.
>
> > And also want to implement Low pass FIR filter on Real time sound data
> > before doing FFT. So can this be implemented on ARM 9 platform??????
>
> Your requirements add up to around 10Mhz on an ARM7. Unless power
> consumption is key, no need for a DSP.
>
> Wilco

In support of Wilco Dijkstra argument:

The FFT is O( n log2(n) ).

As a quick estimate, at fs = 32KHz that's around 400.000 butterflies
per second if no overlap is needed (please corect me if I'm wrong).
That would not be a big problem to do on the ARM then.

The OP does not detail the FIR requirements, but with some luck
the system may allow the FIR to simply be a scaling of the FFT bins
- in which case the FIR comes almost for free.

DJ
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