UmTRX July 2012

umtrx@lists.osmocom.org

12 participants
17 discussions

Pletronics OHM4
by Alexander Chemeris 03 Aug '12

03 Aug '12

Hi, I've received 10pcs of OHM4048052GG010020-26.0M today. Andrey Sviyazov - could you measure their performance and test UmTRX with them? -- Regards, Alexander Chemeris. CEO, Fairwaves LLC / ООО УмРадио http://fairwaves.ru

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UmTRX in action picture
by Alexander Chemeris 30 Jul '12

30 Jul '12

We need a picture of UmTRX in action for the Open Hardware Summit web-site. Andrey Sviyazov - could you bring your UmTRX (the one with an enclosure) to the hackerspace to make a picture of it with antennas? -- Regards, Alexander Chemeris. CEO, Fairwaves LLC / ООО УмРадио http://fairwaves.ru

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LMS TxLO noise
by Andrey Sviyazov 30 Jul '12

30 Jul '12

Sorry, that was meant to be sent to the mailing list :) Best regards, Andrey Sviyazov. ---------- Forwarded message ---------- From: Andrey Sviyazov <andreysviyaz(a)gmail.com> Date: 2012/7/18 Subject: LMS TxLO noise Hi Thomas. Here forwarded my last e-mail with noise plots when I stopped work around it at first time, please see below. Please try to play around Tx PLL charge pump current (register 0x16) for better RMS phase stability. I think we should reach 1 degree or below. Alexander gave me the second UmTRX board and after checking and fixing all known hardware issues<http://code.google.com/p/umtrx/issues/list?can=1&q=&colspec=ID+Type+Status+…>I've got roughly the same LO noise plot. Possible Robin had no time to fixing all of our issues, so check them all please. And also check please what type of TCXO installed on your board. Best regards, Andrey Sviyazov. ---------- Forwarded message ---------- From: Andrey Sviyazov <andreysviyaz(a)gmail.com> Date: 2012/4/13 Subject: Re: LMS TxLO noise Hi all. There is progress with LMS PLL :) Pictures are attached here. t was discovered that 80 kHz spurs come from Ethernet, or rather from the ET1011. I unknowingly put the choke between transistor of 1V regulator and analog power 1V. As a result, the regulator has become unstable and oscillated 80 kHz with amplitude of 200 mV, which climbed into the LMS PLL. To correct this problem L46 should be replaced by jumper on all alfa version PCB's. Also I just played with current in the PLL loop, shown on the picture for clarity. Proved to be the optimal current 1,9 mA (you should write 0x93 in the register of 0x16). But, I think, for the RxPLL will be better use of the current 2.4 mA, because the nearest noises more important for Rx (you should write 0x98 in the register 0x26). Best regards, Andrey Sviyazov.

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UmTRXv2 final project
by Andrey Sviyazov 30 Jul '12

30 Jul '12

Hi all! Here last version PCB of UmTRXv2. In the next e-mail I'll include project files and cheapest BOM for debug variant. I think it is final, because of nobody desire to say me any suggestions (except Robin). Best regards, Andrey Sviyazov.

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DC Offset vs temperature
by Alexander Chemeris 28 Jul '12

28 Jul '12

Hi all, Thomas has discovered that DC offset calibration for LMS is drifting a lot with temperature changes and this has detrimental effect on the modulation accuracy: http://code.google.com/p/umtrx/issues/detail?id=31 One solution proposed by Sylvain is to tune modulation a bit higher using digital modulation, which should be straightforward with UHD which has digital mixer in FPGA. But I wonder what is a recommended solution for this temperature compensation for LMS in general. Srdjan, could you comment on this? -- Regards, Alexander Chemeris. CEO, Fairwaves LLC / ООО УмРадио http://fairwaves.ru

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Plan for 10/100 Ethernet support for umTRX
by Robin Coxe 27 Jul '12

27 Jul '12

The Ettus UHD framework adopted for the umTRX only supports GigE (simple_gemac). A reworked, Wishbone-compliant 10/100 Ethernet MAC is included in the OpenRISC SoC project on Opencores. It has been ported to the Digilent Atlys board, which has a Spartan-6 FPGA. http://www.chokladfabriken.org/projects/orpsoc-atlys I'll begin the port of this Ethernet MAC (a cleaned-up version of the 10/100 core on OpenCores) to the UmTRX and test it on Close-Haul's SP-605 Spartan-6 eval. board. I'm not quite sure how long this task will take, but this feature falls into the "nice-to-have-but-not-urgent" category. -Robin -- Robin Coxe | Close-Haul Communications, Inc. | Boston, MA +1-617-470-8825

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Improving LMS6002 phase noise
by Srdjan Milenkovic 23 Jul '12

23 Jul '12

Hi all, As far as I am aware, you are currently discussing how to improve LMS6002 PLL phase noise. Below are some inputs from my side which may help. Apart from playing with PLL registers we have two additional options. 1. Use clean TCXCO which provides 4 times higher reference followed by divide by 4 to generate PLL reference clock. Recently, we experimented with 30.72*4 MHz TCXCO. Dividing its output by 4 before going into LMS chip we have got improvement of 6dB in phase noise plateau region. 2. Current PLL loop filter has been designed to cover the whole LMS frequency range hence using kind of mid value for Kvco. We can customize the loop filter for a particular band. To do that we need to know frequency range China Mobile is looking for and reference clock you want to use (26MHz, 26*4/4MHz, ...). Please note that PLL reference clock does not need to be the same as system clock i.e. we can also use 30.72MHz, 30.72*4/4MHz etc. Best regards, Srdjan

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OpenBTS with UmTRX
by Thomas Tsou 23 Jul '12

23 Jul '12

Google project hosting is currently read only for network maintenance. Here are general OpenBTS / UmTRX setup instructions. I'll post them when write access is restored. Download ======= UHD git://github.com/chemeris/UHD-Fairwaves.git fairwaves/umtrx-dboard OpenBTS git://github.com/ttsou/openbts-p2.8 umtrx Follow standard build instructions. http://files.ettus.com/uhd_docs/manual/html/build.html http://wush.net/trac/rangepublic/wiki/BuildInstallRun UmTRX Setup =========== Configuration of the LMS6003D is through the control script 'umtrx_lms.py', which is installed in '/usr/local/share/uhd/utils'. Calibration prior to operation is strongly recommended. Example setup for ARFCN 925: Initialization and auto-calibration: ./umtrx_lms.py --lms 1 --lms-init ./umtrx_lms.py --lms 1 --lms-tx-enable 1 ./umtrx_lms.py --lms 1 --lms-rx-enable 1 ./umtrx_lms.py --lms 1 --pll-ref-clock 26e6 --lpf-bandwidth-code 0x0f --lms-auto-calibration RX LNA and RXVGA2 selection and gain control ./umtrx_lms.py --lms 1 --reg 0x75 --data 0xf0 ./umtrx_lms.py --lms 1 --reg 0x65 --data 10 TX LPF control ./umtrx_lms.py --lms 1 --reg 0x34 --data 0x3e LO leakage cancellation (calibration data values may vary) ./umtrx_lms.py --lms 1 --reg 0x42 --data 0x67 ./umtrx_lms.py --lms 1 --reg 0x43 --data 0x89 TX/RX PLL charge pump current ./umtrx_lms.py --lms 1 --reg 0x16 --data 0x93 Tuning ./umtrx_lms.py --lms 1 --lms-rx-pll-tune 925.2e6 ./umtrx_lms.py --lms 1 --lms-tx-pll-tune 880.2e6 TXVGA2 gain to max and enable PA ./umtrx_lms.py --lms 1 --reg 0x45 --data 0xc8 ./umtrx_lms.py --lms 1 --lms-pa-on 2 Running OpenBTS ============== Follow standard instructions. http://wush.net/trac/rangepublic/wiki/BuildInstallRun Thomas

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Running OpenBTS with UmTRX
by Alexander Chemeris 21 Jul '12

21 Jul '12

Hi Thomas, Could you hack together a quick guide how to run OpenBTS with UmTRX at the wiki? http://code.google.com/p/umtrx/wiki/RunningOpenBTS This should basically include which branch to use, what patches to apply (if any), and a script for umtrx_lms.py to tune LMS to the correct frequency. I was meaning to write this for about a week, but turns out it's very hard to allocate enough time to do that accurately. -- Regards, Alexander Chemeris. CEO, Fairwaves LLC / ООО УмРадио http://fairwaves.ru

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Testing reception
by Alexander Chemeris 21 Jul '12

21 Jul '12

Andrey Sviyazov, You wanted to know how to plot received signal under Windows without installing Matlab or something as big and as expensive. Dmitri Stolnikov recommended to use a free version of Signals Analyzer software which should be very powerful. You could download it as "SA free" here: http://signals.radioscanner.ru/info/item1/ Dmitri says that the free version of SA could only import .wav files, so you will need to convert raw files into .wav files. My preferred way to do this is to use 'sox' command line utility like that: sox -r 270833 -e signed -b 16 -c 2 record.cfile record.wav Windows binaries of 'sox' is available from the official web-site: http://sox.sourceforge.net/ -- Regards, Alexander Chemeris. CEO, Fairwaves LLC / ООО УмРадио http://fairwaves.ru

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UmTRX July 2012