UmTRX UHD firmware

Alexander Chemeris alexander.chemeris at gmail.com
Mon Apr 23 17:14:46 UTC 2012


JFYI:

Attached is a GMSK samples file I use for testing (1.083333MSPS, 4
smp/symb) and the spectrum I get with UmTRX.

On Sat, Apr 21, 2012 at 12:00, Alexander Chemeris
<alexander.chemeris at gmail.com> wrote:
> Hi all,
>
> Attached is an UHD-based FPGA image for UmTRX. We've just fixed one
> last bug in the Tx chain and I think it's a good time to let everyone
> know about the progress. Corresponding host software could be built
> from the 'fairwaves/umtrx-dboard' branch in our repo:
> https://github.com/chemeris/UHD-Fairwaves/tree/fairwaves/umtrx-dboard
>
> Notes:
>
>  1. UHD code doesn't touch LMS configuration at all. So all LMS
> configuration should be done before you run UHD tools with the help of
> 'umtrx_lms.py' utility. This includes turning on LMS Rx/TX modules,
> tuning, calibration, amplifiers configuration, etc:
> https://github.com/chemeris/UHD-Fairwaves/blob/fairwaves/umtrx-dboard/host/utils/umtrx_lms.py
>
>  2. So far only Tx has been tested and is known to work fine. Rx
> testing is our next target.
>
>  3. LMS works at 13 MSPS and UHD allows you to go up to this rate.
> Interpolation in Tx chain is known to work well, so you could also use
> fractions of that rate, like 0.270833 MSPS ;)
>
>  4. It's strongly recommended to tune VGA1 DC offset in a LMS before
> using - it reduces LO leakage by very nice 25 dB.
>
>  5. We still have to figure out how to tune I/Q balance in UHD.
> Without calibration LMS doesn't perform very well. I know it should be
> pretty straightforward to do, but we have to figure out how.
>
> --
> Regards,
> Alexander Chemeris.
> CEO, Fairwaves LLC / ООО УмРадио
> http://fairwaves.ru



-- 
Regards,
Alexander Chemeris.
CEO, Fairwaves LLC / ООО УмРадио
http://fairwaves.ru
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