Hi Holger, On Mon, Jan 27, 2014 at 4:49 PM, Holger Hans Peter Freyther <[email protected]> wrote: > On Sun, Jan 26, 2014 at 06:29:00PM -0500, Tom Tsou wrote: >> On Fri, Jan 24, 2014 at 7:29 AM, Holger Hans Peter Freyther >> <[email protected]> wrote: >> > SDRs provide the greatest flexibility but unless you have specific >> > RF filters in your frontend you will not pass the harmonized norms >> > of the European Union for GSM. >> >> I think this statement is quite dated. > > Ah cool. Can you point me to papers/text showing how the n-th harmonic > is being removed from the spectrum?
Do you mean carrier harmonics? >From what we know, to follow general regulation, no noise (including those harmonics) must be above: -30 dBm @ 30 kHz span above 1 GHz -36 dBm @ 30 kHz span below 1 GHz In case of UmTRX without an amplifier it's enough to use a ceramic or SAW duplexer to bring harmonics below those levels. For those buying UmTRX's as a lab package of universal UmDESKs, we offer to buy an external ceramic duplexers. These improves coverage and solves the out of band noise issues. For those buying band-specific UmDESK's, we use SAW duplexers, which are even more efficient in reducing out of band noise. >> A calibrated USRP N200 running osmo-trx passes RF spectrum and >> modulation accuracy requirements of 3GPP 05.05 by very large margins >> and is competitive with commercial GSM equipment in this regard. Other >> SDR devices are also capable to varying degrees. > > The policy of FCC vs. European Union is quite different. There are more > norms that apply in Europe. You're obviously more proficient in European norms. Could you point me to a link where we could find these differences between the ETSI published GSM Standard and European harmonized norms? It would be a very good addition to the OpenBSC wiki's "Standards" page. -- Regards, Alexander Chemeris. CEO, Fairwaves LLC / ООО УмРадио http://fairwaves.ru
