[hpsdr] Blackfin

[Tony Langdon]

At 04:02 PM 7/12/2007, Chris Albertson wrote:
> > I don't mean to throw cold water on the idea.  It probably makes
> > more
> > sense in India where there may not be as many surplus PCs, laptops,
> > etc. available at cheap prices.
>
>Even if the older PC is nearly free, What do you pay for the high speed
>interface?  If you place the DSP inside the SDR front end you don't
>need that interface.

I see a lot of value in a standalone DSP interface.  First, it allows 
the radio to be fully portable (just add antenna and battery, 
assuming you're using a switchmode DC-DC converter).  The radio 
interface here could be mostly knobs, switches and a small LCD.

Secondly, if you are running an older PC, you can offload the heavy 
duty DSP to the radio, and then use the PC to provide the 
enhancements, such as spectrum display, point and click tuning, etc, 
without having to do as much of the number crunching.  That would 
allow the use of an older shack PC.  A "transparent mode" could be 
included to allow the PC to take over fully for running modes that 
haven't yet been implemented in the on board DSP.  That transparent 
mode could use the hardware DSP as an IF filter/AGC with a low 
bitrate (relatively!) link to the PC, or it can simply pass the full 
raw datastream to the PC, unaltered.  Flexibility would be the key

While I don't want my SDR permanently tethered to a PC, I would like 
the option of taking advantage of the extra capabilities of a PC, 
when this option is available, and to be able to tailor that 
interface to suit the PC (e.g. the dual Xeon would be able to handle 
a high speed bitstream, while this old lappy with USB 1.1 would have 
to take a lower speed feed).  But this lappy is light enough to be 
used in the field. :)

73 de VK3JED
http://vkradio.com


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