LMS TxLO noise

Andrey Sviyazov andrey.sviyazov at fairwaves.ru
Sun Jul 22 20:48:26 UTC 2012


Hi Thomas.

Could you please make an file from the OpenBTS stream as an cycled sequence
to use with tx_samples_from_file.exe.
I would like to test my UmTRX under windows with good instrument in Moscow
(I hope to find it soon).

Best regards,
Andrey Sviyazov.



2012/7/23 Thomas Tsou <thomastsou at gmail.com>

> On Sun, Jul 22, 2012 at 3:27 PM, Alexander Chemeris
> <alexander.chemeris at gmail.com> wrote:
> > On Sun, Jul 22, 2012 at 11:11 PM, Thomas Tsou <thomastsou at gmail.com>
> wrote:
> >> On Sun, Jul 22, 2012 at 10:12 AM, Andrey Sviyazov
> >> <andrey.sviyazov at fairwaves.ru> wrote:
> >>> Hi Thomas.
> >>>
> >>> It is very good new.
> >>> Please let us know more information how you wins!
> >>> I mean which PLL filter, ICP and other LMS paremeters do you use or
> its done
> >>> by just only IQ balance correction and Laurent C1 pulse and all other
> by
> >>> default?
> >>
> >> Register dump and startup sequence are attached.
> >
> > Uhm, this is a register dump at what time? Originally I asked for the
> > dump before and after every line in the umtrx_tx_init.sh.
>
> That was for Andrey. That dump was taken during the previous 945 MHz
> measurement.
>
> These dumps are for the calibration failure, which are taken at the
> following points.
>
> 0
>   ./umtrx_lms.py --lms 1 --lms-init
> 1
>   ./umtrx_lms.py --lms 1 --lms-tx-enable 1
> 2
>   ./umtrx_lms.py --lms 1 --pll-ref-clock 26e6 --lpf-bandwidth-code
> 0x0f --lms-auto-calibration
> 3
>
> >> LO leakage was also recalibrated for different frequencies.
> >
> > How different are calibration values? I've never checked how is it
> > related to the PLL frequency.
>
> A single value within 900 MHz. At 1900 MHz it's maybe up to 3 or 4. LO
> leakage is easy to calibrate though. IQ calibration is rather tedious
> - calibration values at 900 MHz are useless at 1900 MHz.
>
> >> For comparison, after C1 pulse is added USRP1 is 1.3/3.5 and USRP2 is
> >> 1.2/3.0 when measured at 925 MHz.
> >
> > tip: Would be great if you push this to github just as you send e-mail :)
>
> I'm posting the measurement captures and the Matlab for the pulse
> sequence generation. The transceiver code is pretty ugly right now.
> There are many stuffing bits and zero padding added to minimize the
> start / end error on the E4406. It may not even work with real phones
> now.
>
> > PS Sylvain is waiting for a howto to run OpenBTS with UmTRX to test his
> setup.
>
> I'll hack something together later tonight. Can he receive a tone? If
> yes, then everything else is straightforward.
>
>   Thomas
>
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