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Andrey Sviyazov andreysviyaz at gmail.com2012/8/8 Jean-Samuel Najnudel - BJT PARTNERS SARL <jsn at bjtpartners.com> > Hi Andrey, > > Thank you very much for your reply. > > I understand your point of view regarding the ADF4350. I agree with you, > the ADF4350 still have quite good performances. I also agree that easier > software support is also important. It would just be a great news if we > could pass the GSM spec, at least as micro BTS. > > Regarding the GSM 1800 version of the selectivity board, it will not be a > problem to change the mixer and the filters. However, are you sure we will > be able to get the correct matching if we only change the passives ? Are > you sure we would not need to modify the PCB traces to get a good matching > for a 1800 MHz version of the board ? What do you think ? > Most of cooper would be 50 Ohm, so only FR-4 losses a bit higher. Also RF cables losses and so on, therefore 1800 parameters will be a bit worse, but it typical. About components, I've checked again and found that RF SAW filter for 1800 UL require coil at input (added). Best regards, Andrey Sviyazov. > > Best regards. > > Jean-Samuel. > :-) > > > > On Tue, Aug 7, 2012 at 7:27 PM, Andrey Sviyazov <andreysviyaz at gmail.com>wrote: > >> Hi Jean-Samuel. >> >> 1/ A few weeks ago, we discussed together about phase noise issues to be >>> able to pass the GSM spec. You explained HMC830LP6GE has much better >>> performances than the ADF4350. I know the HMC830LP6GE is a bit more >>> expensive but, as discussed together before, I really believe this worth >>> the extra cost. This would allow us to pass the macro or at least micro BTS >>> specs without the need for designing another slectivity board. This would >>> save a lot of work. Moreover, we espcially need this preselectivity board >>> for a micro or even macro BTS. In this use case, I really believe price >>> difference (like 40 or 50 USD) will be very low, especially compared to all >>> other costs of a mid-long range micro/macro BTS installation. Unless you >>> really disagree, I would really suggest to use the best performance >>> components as we reasonably can. >>> >> >> First of all, Robin said that ADF4350 already supported by UHD therefore >> it could save time to implement it for UmTRX. >> 2nd, I think that parameters differences isn't really as significant (few >> dB) as price and soft changing time cost. >> 3rd, it isn't last design and I am sure that we will change it for more >> functions, performances and for housing adaptations. >> Also I'm planing to buy HP4352 to design and measure PLL's, so of course >> I'll test HMC830 too, but now we just have to be sure that it will work >> properly and without risks. >> >> >>> 2/ In my deployment in Mayotte, I will also deploy GSM 1800 band base >>> stations because most of the spectrum I have is in this frequency band. To >>> avoid making another PCB for GSM 1800, could you design the board to allow >>> to populate either GSM 900 or GSM 1800 filters and matching passives with >>> the same PCB copper ? A single PCB would be easier to test and to maintain. >>> Moreover, this would save some costs as we will be able to order lager PCB >>> volumes. This could make a quite significant saving. Please let me know >>> what you think about this. >>> >> As I mentioned before, there are band specific components with same >> footprint. >> So, there are no changes required in PCB design for 1800 band, only BOM. >> For example, HMC485 instead of HMC483 and FAR-F6KA-1G7475 instead of >> FAR-F5KA-897. >> >> Best regards, >> Andrey Sviyazov. >> >> >> >>> >>> Anyway, thank you very much for this design. With UmTRX, this would >>> really make a cost effective and great performances base station. Thanks a >>> lot. >>> >>> By the way, as I am abroad, I may take a bit more time than usual to >>> reply to your e-mails. I really appologize for this and I will do my best >>> to reply as soon as I can. >>> >>> Best regards. >>> >>> Jean-Samuel. >>> :-) >>> >>> >>> >>> On Mon, Aug 6, 2012 at 5:07 PM, Andrey Sviyazov <andreysviyaz at gmail.com>wrote: >>> >>>> I've found first error: >>>> Missed AC block required for Vref pin of ADF4350. >>>> Also translated some components descriptions to English to avoid >>>> misunderstanding of Russian. >>>> All newest files here in zip. >>>> >>>> Best regards, >>>> Andrey Sviyazov. >>>> >>>> >>>> >>>> 2012/8/6 Andrey Sviyazov <andreysviyaz at gmail.com> >>>> >>>>> Sorry. >>>>> Zip file here :) >>>>> >>>>> Best regards, >>>>> Andrey Sviyazov. >>>>> >>>>> >>>>> >>>>> 2012/8/6 Andrey Sviyazov <andreysviyaz at gmail.com> >>>>> >>>>>> Hi all. >>>>>> >>>>>> Here first release of preselector project, schema and BOM. >>>>>> Any questions and suggestions welcomed. >>>>>> >>>>>> Best regards, >>>>>> Andrey Sviyazov. >>>>>> >>>>>> >>>>> >>>> >>> >> > -------------- next part -------------- An HTML attachment was scrubbed... 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