Hi, Mike, Thanks very much for your reply. I also searched online about the usrp calibration. I found a post and some information:
"During cal, the TX is switched away from the TX antenna into the "closed" switch port, where it leaks into the RX which is listening to the TX/RX antenna. So termination on RX2 should have no effect as that port is already unused in calibration." Here is the link: http://lists.ettus.com/pipermail/usrp-users_lists.ettus.com/2012-April/004028.html. I am a little confused. Since calibration uses full duplex, why is there no direct connection between RX2 and TX/RX? I thought they are connected inside the usrp during calibration. Best, Gang On Mon, Jan 28, 2013 at 4:08 PM, Mike Jameson <mikej...@gmail.com> wrote: > Hi, > > Calibration uses full duplex and should only be done without anything > plugged into the 'tx/rx' or 'rx2' ports. There is no direct connection, just > measurement of the residual rf escaping. > > Mike > M0MIK > > On 28 Jan 2013 20:17, "gang li" <blant....@gmail.com> wrote: >> >> Hi, guys, >> >> I am reading the codes for uhd_cal_rx_iq_balance.cpp. >> When doing calibration by setting the RX and TX antenna as "CAL", is >> the signal from TX directly switched to RX? >> And I noticed that in the function set_optimum_defaults(), the tx_gain >> is 0 but the rx_gain is 25! Is that too high? I heard that when >> directly connecting TX and RX, we should use attenuators. So why does >> it set 25 rx_gain? Thanks. >> >> Best, >> Gang >> >> _______________________________________________ >> USRP-users mailing list >> usrp-us...@lists.ettus.com >> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
