The frequency of any synthesized radio is directly related to accuracy and stability of the reference clock.
If the ref clock is accurate to 2PPM then the accuracy of the tuned carrier frequency will 2PPM. Not an expert on 5G but many mobile phone systems require high frequency accuracy and stability not just in the carrier, but also in things like TDMA slot times. Different radio systems have different requirement s in this regard which is why there are external clock inputs available on USRP and many other SDR platforms. Sent from my iPhone > On Apr 9, 2024, at 9:20 PM, Timothy J. Salo via USRP-users > <usrp-users@lists.ettus.com> wrote: > > Hi, > > I'm writing a "Getting Started" guide for our research group. When I > got to the GPSDO section, I had difficulty in figuring out the frequency > stability and the frequency accuracy of the B210. > > At least the early versions of the B210 used a CTS Electronic Components > 520L20DA40M0000 TCXO. The datasheet for this TCXO says it has a > frequency _stability_ of +/- 2.0 ppm over an operating temperature range > of -30C - +85C. > > The CTS website states that their TCXO exhibit: "Stratum 3 Performance; > ±4.6ppm overall, ±0.28ppm over -40°C to +85°C". Am I correct in > concluding that this is the frequency _accuracy_ of the TCXO used in > the B210? Does this translate directly into the frequency _accuracy_ > of the B210? > > The B210 datasheet states a frequency _accuracy_ of +/- 2.0 ppm. Is > is a typo, and should the datasheet actually say frequency _stability_? > Or, did someone conclude that over a reasonable operating temperature, > the effects of temperature outweigh any inaccuracy in the frequency > of the TCXO? > > Anecdotally, I have heard that one organization found that three of > their four B210s, when operating as a 5G base station, were unable > to connect with commercial off-the-shelf cellular handsets, unless > an external GPSDO was used with the B210. Does anyone have any idea > what frequency accuracy is expected by cellular handsets? > > So, does anyone know what the frequency _accuracy_ of the B210 is, in > the absence of a GPSDO? Or, should I just use the +/1 2.0 ppm figure? > > Thanks, > > -tjs > - - - - > > [1] > https://www.ctscorp.com/Files/DataSheets/Passives/FCP/TCXO/TCXO-520-datasheet.pdf > > > > _______________________________________________ > USRP-users mailing list -- usrp-users@lists.ettus.com > To unsubscribe send an email to usrp-users-le...@lists.ettus.com _______________________________________________ USRP-users mailing list -- usrp-users@lists.ettus.com To unsubscribe send an email to usrp-users-le...@lists.ettus.com
