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Andrey Sviyazov andreysviyaz at gmail.comHi Alexander. As I understand, you ask about output signal difference when TXVGA2=25, isn't it? Actually I missed it before. I am sure that difference much less then 2-3dB as you mentioned, I think it there was temperature effect. Best regards, Andrey Sviyazov. 2012/11/2 Alexander Chemeris <alexander.chemeris at gmail.com> > Andrey, > > A stupid question. Why does "LDO" measurements have signal level 2-3dB > higher then "FPGA" measurements? Is it due to measurement inaccuracy > or it's an effect from the power supply change? > > On Fri, Nov 2, 2012 at 5:41 AM, Andrey Sviyazov <andreysviyaz at gmail.com> > wrote: > > Hi Jean-Samuel. > > > > I spent a lot of time yesterday and this morning because I trying to fix > > DC-DC issue which I mentioned few days ago (see pics). > > Unfortunatelly, result seems close to zero so far. > > I never saw so strange problems with dc-dc converters before. > > I am sure that there are no problems in v1 and also that this problems > > because of syncro mode. > > Now I am trying to describe this issue, may be anybody have experience > with > > this kind problem. > > Let me know if you can help me here too. > > > > Regarding +3.3V LDO regulators for LMS. > > Here attached pics of noise plots with LDO's and when supplied from > > +3.3VFPGA through TI1608U601. > > I can't find any significant difference there. > > I think we can replace LDO's by RF chokes without derating performances. > > In this case, power consumption decreased to 11..12W in dependance of > values > > TXVGA. > > > > Regarding GSM spectrum requirements you mentioned. > > As you can see, yesterday I've measured it again when made experiments > > around +3.3V. > > I found that we didn't meet requirements only when deep saturation occur. > > I mean when TXVGA2 higher then 23 (i.e. 24 and 25). > > > > Best regards, > > Andrey Sviyazov. > > > > > > > > 2012/11/2 Jean-Samuel Najnudel - BJT PARTNERS SARL <jsn at bjtpartners.com> > >> > >> Hi Andrey, > >> > >> > >> Thank you very muchf or your reply. > >> > >> Regarding the requirement at f +/- 400 KHz, the spec mentions our signal > >> must be -60 dBc bellow the signal at f. > >> You can get more details on the GSM 05.05 spec (part 4.2), from page 15. > >> http://p3e.rats.fi/oh2mqk/GSM/GSM-05.05.pdf > >> > >> To pass this spec, we need to get our phase noise bellow -113 dBc/Hz at > >> 400 KHz. > >> On last measurements, we either fail or just pass this spec. > >> If possible, this would be great to try to tune the charge pump and the > >> loop filter passives to get our phase noise as low as possible. > >> I know you already worked on this and already improved this but, if you > >> have some ideas to decrease a bit more the phase noise, this would be > very > >> interesting. > >> > >> Best regards. > >> > >> Jean-Samuel. > >> :-) > >> > >> > >> > >> On Wed, Oct 31, 2012 at 10:19 PM, Andrey Sviyazov < > andreysviyaz at gmail.com> > >> wrote: > >>> > >>> Hi Jean-Samuel. > >>> > >>> About power consumption and performancea I can say that spurs at 500 > kHz > >>> offset around 6dB above TX LO noise plot. > >>> It wad measured when 3.3V come from dogs through TI2012U601. > >>> Tomorrow I'll measure all again and share pics in this topic. > >>> As I mentioned, I'll try to find better filter to suppress 500kHz. > >>> Please let me know any partnumbers or suppliers you known. > >>> Also unoccupied place under 3.3V LDO's near LMS seems a good place for > >>> thermal sensors. > >>> About rf connectors, now I am sure that MCX much better then U_FL and > we > >>> should return them. > >>> To connect UmSEL to UmTRX v2.1 required U_FL-MCX cable assemblies till > >>> new UmSEL version. > >>> Also possible to use direct cable soldering to UmSEL board. > >>> Of course, last variant look not perfect. > >>> About requirements at 400kHz we can't meet, I actually can't understand > >>> what do you mean. > >>> > >>> > >>> > >>> Best regards, > >>> Andrey Sviyazov. > >>> (Sent from my mobile client) > >>> > >>> 31.10.2012 22:47 пользователь "Jean-Samuel Najnudel - BJT PARTNERS > SARL" > >>> <jsn at bjtpartners.com> написал: > >>> > >>>> Hi Andrey, > >>>> > >>>> Do you think it will be possible to decrease the power consumption and > >>>> to keep the best possible performances for industrial applications ? > >>>> I know you cannot be sure about this but I would like to know how > >>>> confident you feel about this ? > >>>> > >>>> Best regards. > >>>> > >>>> Jean-Samuel. > >>>> :-) > >>>> > >>>> > >>>> On Wed, Oct 31, 2012 at 7:40 PM, Andrey Sviyazov > >>>> <andreysviyaz at gmail.com> wrote: > >>>>> > >>>>> Hi Jean-Samuel, Alexander. > >>>>> > >>>>> Tomorrow I'll let you know what possible to make on time. > >>>>> And we should set time limit for this. > >>>>> For example, next morning. > >>>>> > >>>>> Best regards, > >>>>> Andrey Sviyazov. > >>>>> (Sent from my mobile client) > >>>>> > >>>>> 31.10.2012 22:24 пользователь "Jean-Samuel Najnudel - BJT PARTNERS > >>>>> SARL" <jsn at bjtpartners.com> написал: > >>>>> > >>>>>> Hi Alexander, > >>>>>> > >>>>>> Thank you very much for your reply. > >>>>>> > >>>>>> Why skip/populate LMS power supply block ? > >>>>>> As I understand we always need the LMS power supply block. I > probably > >>>>>> missed something. Could you explain this in more details to let me > better > >>>>>> understand ? > >>>>>> > >>>>>> Thanks a lot for your help. > >>>>>> > >>>>>> Best regards. > >>>>>> > >>>>>> Jean-Samuel. > >>>>>> :-) > >>>>>> > >>>>>> > >>>>>> On Wed, Oct 31, 2012 at 7:14 PM, Alexander Chemeris > >>>>>> <alexander.chemeris at gmail.com> wrote: > >>>>>>> > >>>>>>> Yes, lesser input voltage range makes sense only if it saves >$10 > >>>>>>> and/or considerably increases power efficiency. I think this not > the > >>>>>>> case, and then only these changes will be needed: > >>>>>>> > >>>>>>> * traditional power connector > >>>>>>> * MCX RF connector, because they sustain much more > connect-disconnect > >>>>>>> cycles > >>>>>>> * lower power consumption mod > >>>>>>> > >>>>>>> I would appreciate if we could keep the same PCB for both versions > >>>>>>> and > >>>>>>> populate the proper version of power connector/RF connector and > >>>>>>> skip/populate LMS power supply block. > >>>>>>> > >>>>>>> On Wed, Oct 31, 2012 at 9:56 PM, Jean-Samuel Najnudel - BJT > PARTNERS > >>>>>>> SARL <jsn at bjtpartners.com> wrote: > >>>>>>> > Hi Alexander, > >>>>>>> > > >>>>>>> > This would be much easier to have the same board for both lab and > >>>>>>> > deployment. Only the UmSEL would make the difference. > >>>>>>> > For deployment, I really need wide input voltage range as I plan > to > >>>>>>> > power > >>>>>>> > the whole system (UmTRX + PA) with a single 28V supply. > >>>>>>> > Even if this can save a few euros, I would really prefer we do > not > >>>>>>> > make the > >>>>>>> > input voltage range smaller. > >>>>>>> > By the way, even for lab, it might be convenient and it can avoid > >>>>>>> > damages in > >>>>>>> > case of wrong voltage supply. > >>>>>>> > > >>>>>>> > Best regards. > >>>>>>> > > >>>>>>> > Jean-Samuel. > >>>>>>> > :-) > >>>>>>> > > >>>>>>> > > >>>>>>> > > >>>>>>> > On Wed, Oct 31, 2012 at 6:50 PM, Alexander Chemeris > >>>>>>> > <alexander.chemeris at gmail.com> wrote: > >>>>>>> >> > >>>>>>> >> Andrey, how much time do you need to create 2.1? If it's mire > than > >>>>>>> >> a day, > >>>>>>> >> we should postpone this. I believe that enclosure is a much more > >>>>>>> >> important > >>>>>>> >> issue at this moment. > >>>>>>> >> > >>>>>>> >> I think we need following changes for the lab version: > >>>>>>> >> * traditional power connector > >>>>>>> >> * MCX RF connector, because they sustain much more > >>>>>>> >> connect-disconnect > >>>>>>> >> cycles > >>>>>>> >> * lower power consumption mod > >>>>>>> >> * smaller input voltage range (only if this makes things > cheaper) > >>>>>>> >> > >>>>>>> >> Sent from my Android device. > >>>>>>> >> > >>>>>>> >> -- > >>>>>>> >> Regards, > >>>>>>> >> Alexander Chemeris > >>>>>>> >> CEO, Fairwaves LLC > >>>>>>> >> http://fairwaves.ru > >>>>>>> >> > >>>>>>> >> 31.10.2012 14:05 пользователь "Andrey Sviyazov" > >>>>>>> >> <andreysviyaz at gmail.com> > >>>>>>> >> написал: > >>>>>>> >> > >>>>>>> >>> Hi Jean-Samuel. > >>>>>>> >>> > >>>>>>> >>> First of all, you didn't said about delay duration :) > >>>>>>> >>> I can't delay this batch just due to my wishes that each next > >>>>>>> >>> batch > >>>>>>> >>> should work more and more ideally. > >>>>>>> >>> > >>>>>>> >>>> These modifications looks interesting. I think it is a good > >>>>>>> >>>> idea. > >>>>>>> >>> > >>>>>>> >>> Hope so. > >>>>>>> >>> > >>>>>>> >>>> > >>>>>>> >>>> I just have a few question. > >>>>>>> >>>> > >>>>>>> >>>> Why do you call this board revision 2.1 "a special batch for > >>>>>>> >>>> labs" ? > >>>>>>> >>>> Would these modifications make this revision 2.1 also more > >>>>>>> >>>> suitable for > >>>>>>> >>>> field deployment, at least as much as the revision 2.0 ? > >>>>>>> >>> > >>>>>>> >>> Because of I can fix only known issues. > >>>>>>> >>> Also not all really required improvements are known yet. > >>>>>>> >>> > >>>>>>> >>>> Decreasing power consumption to 10..11 W would be great. Is > >>>>>>> >>>> there any > >>>>>>> >>>> drawbacks of this modification ? Would it decrease some > >>>>>>> >>>> performances ? If > >>>>>>> >>>> not, this modifiction to decrease power consumption is a > >>>>>>> >>>> significant very > >>>>>>> >>>> good modification. > >>>>>>> >>> > >>>>>>> >>> Decreasing of performances it is only spurs with DC/DC > conversion > >>>>>>> >>> freq > >>>>>>> >>> ~500kHz. > >>>>>>> >>> Now I searching more good LC filter to suppress it better than > >>>>>>> >>> TI2012U601 > >>>>>>> >>> can. > >>>>>>> >>> > >>>>>>> >>>> Do you have enough space on the board to replace some U_FL > >>>>>>> >>>> connectors > >>>>>>> >>>> with MCX connectors as you suggest ? > >>>>>>> >>> > >>>>>>> >>> Yes, but may be not all should be MCX. > >>>>>>> >>> Of course I did not insist, but just asking whether there is a > >>>>>>> >>> reason to > >>>>>>> >>> do it or not. > >>>>>>> >>> > >>>>>>> >>>> An external LNA would probably need around 5 Volts instead of > >>>>>>> >>>> 6V. A > >>>>>>> >>>> small PA would probably need a little bit higher voltage. Do > you > >>>>>>> >>>> think it > >>>>>>> >>>> would be possible to have a variable voltage low power > connector > >>>>>>> >>>> ? > >>>>>>> >>> > >>>>>>> >>> On my opinion, variable voltage is not good idea. > >>>>>>> >>> For example for LNA's better to place low noise LDO 6V to 5V > near > >>>>>>> >>> to IC's > >>>>>>> >>> to get Vcc clean too. > >>>>>>> >>> > >>>>>>> >>>> By the way, could you pelase also add the 2 LMS output > matching > >>>>>>> >>>> capacitors we need to improve output power figures in the 1800 > >>>>>>> >>>> band ? > >>>>>>> >>> > >>>>>>> >>> Of course, because it is issue which should be fixed, but not > >>>>>>> >>> improvement. > >>>>>>> >>> > >>>>>>> >>> Best regards, > >>>>>>> >>> Andrey Sviyazov. > >>>>>>> > > >>>>>>> > > >>>>>>> > >>>>>>> > >>>>>>> > >>>>>>> -- > >>>>>>> Regards, > >>>>>>> Alexander Chemeris. > >>>>>>> CEO, Fairwaves LLC / ООО УмРадио > >>>>>>> http://fairwaves.ru > >>>>>> > >>>>>> > >>>> > >> > > > > > > -- > Regards, > Alexander Chemeris. > CEO, Fairwaves LLC / ООО УмРадио > http://fairwaves.ru > -------------- next part -------------- An HTML attachment was scrubbed... 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