[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
RE: [Discuss-gnuradio] USRP Update
From: |
Weber, Michael J. \(US SSA\) |
Subject: |
RE: [Discuss-gnuradio] USRP Update |
Date: |
Thu, 8 Dec 2005 08:07:27 -0500 |
Ah, that makes sense! Thanks for the clue-in.
BTW, I didn't see your response come though the list... does the list
engine not send one emails already cc'd to one?
Thanks,
Mike
> -----Original Message-----
> From: Matt Ettus [mailto:address@hidden
> Sent: Tuesday, December 06, 2005 4:51 PM
> To: Weber, Michael J. (US SSA)
> Cc: discuss gnuradio
> Subject: Re: [Discuss-gnuradio] USRP Update
>
>
> Weber, Michael J. (US SSA) wrote:
> > Matt, can you elaborate on the 20MHz bandwidth figure for
> the Flex400
> > and give some USRP application guidance? I have this "8MHz maximum
> > supportable bandwidth" figure in my head which I think came
> from the
> > sampling/decimation rates + USB2 throughput limitation discussed in
> > the USRP documentation..? Some folks have seen the release
> below and
> > are asking me if we can do XYZ in terms of bandwidth and
> I'm not sure
> > what to say at this point.
> >
> > Is there a way to move 20MHz-wide signals between the host
> machine and
> > the Flex400?
>
> 20 MHz bandwidth indicates the width of the baseband filters.
> Thus, you can tune digitally anywhere +/- 10 MHz from the
> LO. If you use 16 bit samples, you can't get that much over
> the USB bus at once.
>
> So why is 20 MHz useful? Here are 3 example scenarios:
>
> - You could simultaneously receive or transmit 2 separate
> signals which are 4 MHz wide each, which are separated by 12 MHz.
>
> - You can use 8 bit samples, and get 16 MHz of bandwidth. If
> you were a radio astronomer, you could use 4-bit samples and
> get 32 MHz of bandwidth.
>
> - You could do a wideband mod and demod in the FPGA. You
> would be able to deal with much wider signals, and send a
> lower bit rate over the bus.
>
> Matt
>