Two X310 plus 4 UBX delivers 4x4 MIMO with an external 1PPS and 10Mhz clock—octoclock or something else.
The X310 does have a ref clock output, but I think it is not recommended for use in coherent applications just because of unknown clock skew. Sent from my iPhone > On Feb 27, 2021, at 2:50 PM, Marcus Müller via USRP-users > <[email protected]> wrote: > > You're right. The whole point of the TwinRX boards is to give you coherent > channels, and > you can build a coherent 4-channel *receiver*. > > However, TwinRX can't transmit, so for 4×4 MIMO, you'll need something else. > Since there's > no dual-transmit-channel daughterboards, you'll need to coordinate the phases > of four > different TX-capable daughterboards. Therefore, you'll need a clock > distributor like the > octoclock. > > Haven't tried it in a while, but the clk and pps out of the X3x0 series > should solve that > issue, however: you could link two USRP X3x0 that are equipped with e.g. two > UBX-160 each > through that to get 4 coherent TX channels, and use a single USRP X3x0 with > two TwinRX as > receiver with 4 coherent RX channels. > > Best regards, > Marcus > > >> On 27.02.21 15:50, Ali G. Dezfuli via USRP-users wrote: >> Hi all, >> When USRP X3x0 is used with TwinRX daughterboards, we can have up to 4 rx >> channels. >> (ref:AN-244, Direction Finding with the USRP™ X-Series and TwinRX™) >> But in AN-881 (Selecting a USRP Device) in Table 4, it says that USRP X3x0 >> needs >> OctoClock for 4x4 MIMO !!! >> I wonder when X3x0 can receive 4 channels with TwinRX, why it can NOT be >> used in 4x4 >> MIMO w/o OctoClock. >> >> regards, >> AGD >> >> _______________________________________________ >> USRP-users mailing list >> [email protected] >> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com > > _______________________________________________ > USRP-users mailing list > [email protected] > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com _______________________________________________ USRP-users mailing list [email protected] http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
