Hi, TwinRx is Rx only card. Look at the spec here: https://www.ettus.com/product/details/TwinRX
Regarding power measurement calibration this is how it could work (so you can measure signal power entering Rx port of your USRP): Connect to the USRP port an RF signal source with known power 'Px' (let's assume it is a sine wave). Then you can record this signal (i.e. with use of GNU Radio) and compute it's uncalibrated power as Markus described it. In Octave/Matlab this can be written as (you can use 'read_complex_binary' function that is distributed with GNU Radio to read signal samples 'x'): Px_uncal = sum(x.*conj(x))/length(x) and then you can compute simple calibration factor: c=Px/Px_uncal Now you can use it to compute estimate of power 'Py' of another RF signal 'y': Py_uncal = sum(y.*conj(y))/length(y) Py = c * Py_uncal =========== The calibration factor factor 'c' will be true for some particular frequency range (how wide depends on the frequency response of the receiver) and at some range of input signal power. It depends also on temperature and many other variables. Best Regards, Piotr Krysik W dniu 15.11.2018 o 10:56, Maria Jesus Cañavate Sanchez pisze: > Hi Piotr, > > Thank you for your answer. > > One last question, if you get the twinRX daughter cards to be able to > use 4 rx at the same time, can you still have access to the 2 tx and 2 > rx when convenient? Or the 4 rx are fixed? > > Thank you very much in advance! > > Best regards, > > Maria Jesus > > > On 13/11/2018 12:34, Piotr Krysik via USRP-users wrote: >> Hi, >> >> No, it's not. Each of your UBX-160 has one Rx chain. >> >> BTW somehow it is common confusion that Tx/Rx and Rx2 ports can be used >> to receive signals simultaneously. I have to explain this even to people >> with professor degree in electronic engineering, that behind these ports >> there is one Rx chain and there are switches on UBX/SBX/WBX/etc that >> select to which of these ports this Rx chain is connected. >> >> As Fabian has written there are TwinRX daughter cards, each with two Rx >> chains, that you can use on a USRP X310 to have 4 receivers. >> >> Best Regards, >> Piotr Krysik >> >> W dniu 13.11.2018 o 13:08, Maria Jesus Cañavate Sanchez via USRP-users >> pisze: >>> Hi again, >>> >>> Thank you very much for your answer. I have bought two daughter boards >>> UBX-160, is that enough to have 4 receivers at the same time? >>> >>> Thank you! >>> >>> Best regards, >>> >>> Maria Jesus >>> >>> _______________________________________________ USRP-users mailing list USRP-users@lists.ettus.com http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
