This is merely a historical archive of years 2008-2021, before the migration to mailman3.
A maintained and still updated list archive can be found at https://lists.osmocom.org/hyperkitty/list/UmTRX@lists.osmocom.org/.
Robin Coxe coxe at close-haul.comSomething like the attached Taiten VCTCXO @ 30.72 MHz + ADF4002 Phase Detector/PLL synthesizer might work. I have no idea how much the oscillator costs. (The Pletronics oscillator on the UmTRX and the GAPfiller GSM900 isn't available at this frequency.) http://www.analog.com/en/rfif-components/pll-synthesizersvcos/adf4002/products/product.html<http://www.analog.com/en/rfif-components/pll-synthesizersvcos/adf4002/products/product.html#product-designtools-nav> -Robin On Sat, Oct 13, 2012 at 11:54 PM, Alexander Chemeris < alexander.chemeris at gmail.com> wrote: > John, > > On Sun, Oct 14, 2012 at 12:24 AM, John Orlando <john at epiqsolutions.com> > wrote: > > On Sat, Oct 13, 2012 at 4:30 PM, Alexander Chemeris > > <alexander.chemeris at gmail.com> wrote: > >> Hi John, > >> > >> On Sat, Oct 13, 2012 at 11:11 PM, John Orlando <john at epiqsolutions.com> > wrote: > >>> On Sat, Oct 13, 2012 at 3:47 PM, Alexander Chemeris > >>> <alexander.chemeris at gmail.com> wrote: > >>>> Hi Srdjan, > >>>> > >>>> We're looking into re-purposing UmTRX for LTE and there a few things > which > >>>> we need to understand better. > >>>> > >>>> 1. Is it possible to support 15MHz and 20MHz LTE channel bandwidths? > To > >>>> achieve this we at least need to sample at 23.04Msps and 30.72Msps > >>>> respectively. LMS6002D datasheet specifies the maximum I/Q samplerate > of > >>>> 14Msps, which is not enough. But at the same time, datasheet claims > that ADC > >>>> and DAC are specified up to 50Msps. How does this fits together? > >>> > >>> Alexander, > >>> Can you provide a reference to where the datasheet calls out a max I/Q > >>> sample rate of 14 Msps? The analog low pass filters support a max > >>> bandwidth of 14 MHz (which leads to 28 MHz RF bandwidth assuming > >>> zero-IF operation)...is this what you're referencing? > >> > >> The datasheet is not very clear on this topic. I'm referring to the > >> following line at the Table 1: > >> Baseband Bandwidth 14MHz > >> > >> Originally I read this line as "digital I/Q bus has limitation of > >> 14Msps" and this is what confuses me. > > > > Yes, this refers to the analog baseband filter bandwidth. > > Ok, thanks for the clarification. > > >>> We run the A/D > >>> converters in the LMS6002d at sample rates greater than 14 Msps all > >>> the time, including 30.72 Msps. > >> > >> Just to be sure - do you mean you feed RX_CLK and TX_CLK of LMS6002D > >> with 61.44MHz clock? It's divided by 2 internally, so if you feed them > >> with 30.72MHz clock you actually get only 15.36Msps out of LMS6002D. > > > > Correct, when running the A/D at 30.72 Msps, the RX_CLK signal needs > > to run at 61.44 MHz. > > Great! > In case you know a good 61.44 MHz oscillator with a reasonable price - > I would appreciate a pointer. > > -- > Regards, > Alexander Chemeris. > CEO, Fairwaves LLC / ООО УмРадио > http://fairwaves.ru > > -- Robin Coxe | Close-Haul Communications, Inc. | Boston, MA +1-617-470-8825 -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.osmocom.org/pipermail/umtrx/attachments/20121014/5cc8d587/attachment.htm> -------------- next part -------------- A non-text attachment was scrubbed... Name: Taiten_femtocell_vctcxo.pdf Type: application/pdf Size: 717313 bytes Desc: not available URL: <http://lists.osmocom.org/pipermail/umtrx/attachments/20121014/5cc8d587/attachment.pdf>