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Alexander Chemeris alexander.chemeris at gmail.comAndrey, 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