[hpsdr] Blackfin

[Philip Covington]

On 7/12/07, Chris Albertson <chrisalbertson90278 at yahoo.com> wrote:
>
> > I think that this might be adequate if doing just the DSP processing
> > (not the GUI).  Put a small Linux on the flash IDE drive and DttSP.
> > It could handle the font panel control too.  The Ethernet port can be
> > used to connect to a PC to do the GUI.   If you want to run  it stand
> > alone you don't need the GUI.
>
> If you are going to run Linux why care why care about which
> Architecture you run?  Why not ARM or PPC or Blackfin  Why Intel?

It does not matter as long as it is cost effective and capable.  If
the Blackfin can only do 16 bit fixed point DSP then I am having
trouble seeing how it is going to be a better solution than a mini-ITX
board doing the DSP - at least we can do floating point (or 32 bit
fixed point, etc...).

> What ADC chip is this talking to.  Janus with a soundcard-like
> bandwidth, or has someone bought a pair of Mercury cards each
> with a 60 megasample per second chip.

Umm, Mercury is 125 MSPS, so is QS1RT VERB.

<snip>
> Actually I like the ideas of putting a PC in the box be it a mini
> ITX or whatever. But I think it replaces the PC on your desk not
> the one that is talking directly to the RF front end.

No, that is completely turned around from what I am proposing for a
stand alone radio.  The mini-ITX does the DSP.  If you want a GUI then
the external PC does the GUI.   The FPGA does all the heavy digital
down conversion and initial FIR filtering.

> The processor that is closest to the incoming data is going to
> be doing a lot of FFT and FIR filter stuff.  After this stage the
> bandwidth requirements go down.

This is what the FPGA does in Mercury and QS1RT VERB.  In QS1RT VERB
the data ends up coming out 32 bit fixed point after the FIR filters.
The intermediate CIC stages all get trucated  to 24 bits.  I can spit
out any rate I/Q data from about 8 MSPS to <8kSPS over USB.   With PCI
Express I can DMA into memory at up to 250 MBytes/sec.

> Chris Albertson
>   Home:   310-376-1029  chrisalbertson90278 at yahoo.com
>   Office: 310-336-5189  Christopher.J.Albertson at aero.org
>   KG6OMK/AG
>

Phil N8VB

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