Re: [Discuss-gnuradio] Portable Universal Software Radio Peripheral

[Eric Blossom]

On Tue, Jun 08, 2004 at 03:50:37PM +0800, Daniel Piccoli wrote:
> Hi All,
> 
> I think that the idea of building a USRP for the PCI slot is a good one.
> Although I guess the connection of daughterboards will be different to
> the USB device.

The daughterboards should remain the same.  We've given this some thought.

> It would also be good to ultimately build something suitable for use on
> handheld computers. ie. something that can be used in a car as mobile
> phones are today. I believe that GPS, CDMA, shortwave for mobile devices
> will be an excellent application.

At least for now, power consumption is going to be a problem.  If
you're willing to limit yourself to relatively narrow band signals, it
might work.  Cf Vanu's narrow band s/w radio that piggy backs on an
iPaq (I think that even with an extra battery it lasts on the order of
30 minutes).  In general, ASIC's are always going to win out over more
flexible architectures when it comes to power consumption.  On the
other hand, the figure of merit MIPS/Watt keeps getting better on the
fully programmable hardware.  At some point I anticipate that the
MIPS/Watt will be ``good enough'' for portable use, even though the
corresponding MIPS/Watt for the ASIC will still be better.

Right now, using the USRP rev 1 proto on my desk, we're burning about
7.5W running the 4 A/D's, 4 D/A's and FPGA.  Of course we're running
the A/D's at 64 MHz, the D/A's and FPGA at 128 MHz, so that isn't
helping matters...

Eric