[hpsdr] Teamspeak items (softcore/FFT)

[Charles Brain]

Hi Phil,

Yes having a parametrized FFT in ones toolbox is pretty important.
For my DVB-T implementation I used one from a Intel application note
which uses MMX instructions to implement a 16 bit fixed point FFT
(it actually only has a resolution of 14 bits because of bit growth 
inside the FFT).
That implementation is pipelined so it might make a suitable example
to start from when trying to do a pipelined FPGA FFT as the priciples 
are similar.
It uses 2x2 butterflies (I recall) but they say it can be extended to 
larger butterflies.

I was just hoping there was a free one I could blag :-)

- Charles G4GUO

On 24/11/2010 08:48, Phil Harman wrote:
> Hi Charles,
>
> I'm interested in adding an FFT to Metis. One of our members has modified
> the Mercury code to be a complete receiver i.e. filtering, demodulation
> and AGC done in the FPGA. This way Mercury can be used as a remote
> receiver and the data rate is OK to send over a VHF/UHF link.
>
> I am intending the add an FFT to this project so you can have a remote
> bandscope as well.
>
> Part of the project is to implement the FFT, the other is to find an
> elegant way of compressing the bandscope data.
>
> I've tried the Altera Megafunction FFT and that compiles in the project
> OK.  However, I need to write my own version since the purchase price is
> too high.
>
> I'm presently reading an ebook "An Introduction to Signal Processing and
> Fast Fourier Transform" by Kevin McGee. It's the best detailed explanation
> of the FFT that I've come across and highly recommended.
>
> 73 Phil....VK6APH
>


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