Thanks Josh, What I am looking for on the TX side of things is basically the same thing I have on the RX side. If I set the subdev spec on the basic RX to "A:A A:B" and then use usrp->set_rx_freq(uhd::tune_request_t(freq)) for each channel, I get two separate rx channels, both with their own IQ pairs. On the TX side I only manage to have one IQ pair, as in I through TX_A and Q through TX_B. We were trying for a 4 channel transmit on 2 USRPs, so that they could all be connected by s MIMO cable. One more question, when you say "too complicated to be worth it", generally, what kind of modification would be necessary? Thanks for your time! -Anisha
On Fri, Sep 28, 2012 at 6:36 PM, Josh Blum <j...@ettus.com> wrote: > > > On 09/28/2012 08:49 AM, Anisha Gorur wrote: > > Hello All, > > > > I am using a USRP N210. When i set the subdev spec for my basic RX > > daughterboard as "A:A A:B" I can receive two channels. However, if I try > to > > do something similar for the basic TX I get an error like "The user > > specified 2 channels, but there are only 1 tx dsps on mboard 0." I assume > > this is because there is only one DUC chain in the N210. Is there a way > to > > modify this so that I can have two DUC chains in the same way that I have > > two DDC chains? > > Thanks, > > Anisha > > I think adding two complete DUC chains into N210 would be too > complicated to be worth it. > > Is there something specific that you cant do with the single DUC chain? > As long as the cordic is set to zero, I and Q will remain completely > separate from host samples, all the way to the SMA connectors A and B. > > Otherwise, perhaps you need a different rotation for I vs Q? I think > that would be better accomplished by two different cordics. Then perhaps > a custom DSP in the FPGA is for you: > > http://code.ettus.com/redmine/ettus/projects/uhd/repository/revisions/master/entry/fpga/README.txt#L29 > > I hope that helps. > > -josh > > > > > > > > > _______________________________________________ > > Discuss-gnuradio mailing list > > Discuss-gnuradio@gnu.org > > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > -- Anisha Gorur Class of 2012 Electrical Engineering
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