Re: [Discuss-gnuradio] USRP w/ 4-bit I&Q samples

[Nagaraj C Shivaramaiah]

Hi Paul and Tyrel,

I'm also in a similar situation to get the maximum bandwidth possible,
but just started... For me 2 bit quantization is sufficient

I've started modifying the FPGA firmware but I think it will take some
time before I implement and test it thoroughly..

Any approximate time frame that you are planning to complete this
activity?  I'm also keen to contribute if I'm fast enough..

Nagaraj,
PhD Candidate,
University of New South Wales


On Thu, Apr 10, 2008 at 6:36 AM, Paul Creekmore <address@hidden> wrote:
>
>  We'll be looking into the possibility of contributing the new FPGA
> configuration to GNU Radio once our code has been tested and refined.
>
>  --Paul
>
>
>
>
>  Tyrel Newton wrote:
> Paul,
>
>
> Would you mind sharing your implementation along with any accompanying
> documentation? We are making some modifications to the FPGA firmware
> ourselves  (mods for a much more application specific usage) and while I'm
> not sure how far we'll get with needing the 4-bit samples, we'd happily
> share any test/usage results if we get there.
>
>
> Tyrel
>
>
> On Apr 8, 2008, at 9:18 AM, Paul Creekmore wrote:
>
>
>  Tyrel,
>
>  The current FPGA configuration does not support 4-bit samples, but it is
> possible to modify the configuration (Verilog code) to convert the samples
> to 4-bit.
>
>  My research group is currently working on adding 1, 2, and 4-bit
> quantization options to the USRP, as well as accompanying data packing to
> maximize the number of samples that we can squeeze across the USB interface
> and thus also the receivable signal bandwidth.  We've not yet tested the
> modifications.
>
>  --Paul
>
>  Tyrel Newton wrote:
> <div class="moz-text-flowed" style="font-family: -moz-fixed">We have an
> application where the overall accuracy of the A/D converter is not terribly
> important but where we need as high a sampling rate as we can get. To this
> end, we found and intend to use the 8-bit option that allows for 8-bit I and
> Q signals instead of the normal 16-bit. However, is there a similar option
> that allows for 4-bit I and Q samples? Or similarly, would it be relatively
> easy to implement a 4-bits per sample scheme, possibly w/ slight
> modifications to the USRP firmware? Any feedback and/or advice is greatly
> appreciated.
>
>  Regards,
>  Tyrel
>
>
>
>  </div>
>
>
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