On Thu, Oct 20, 2005 at 12:03:31PM -0600, David R. Palchak wrote: > > > I'm having trouble understanding exactly how to go about > sending two independent, real-valued signals to different > SMA connectors on the same transmit daughtercard. The > signals I want to transmit are streams of type short. Do I > need to convert these to one stream of complex type and use > a usrp.sink_c(), or can I interleave them and send them to > a usrp.sink_s()? > > Thanks, > David Palchak
Hi David, As the software is currently built, you cannot send two independent, real-valued signals to different connectors on the same transmit daughterboard. The reason is that we are using the digital up-converters in the AD9862, and have the AD9862's configured in "Dual Channel Complex DAC Data" mode. See pages 20-21 of the AD9862 datasheet. Here's a more detailed explanation: http://lists.gnu.org/archive/html/discuss-gnuradio/2005-08/msg00238.html It is possible in hardware to use the two channels on a tx daughterboard independently, but that would require several changes to the usrp host library and FPGA code. For starters, if you need digital upconversion, you'd need to perform it in the FPGA, not the AD9862. [We had this working at some point in the distant past, but removed it since using the AD9862 DUC's saved us a ton of FPGA resources.] If you only need two independent Tx channels, the quick fix is to use two Basic Tx daugherboards. This is supported. Just tell the USRP that you're using two channels of data, then provide a stream with two interleaved channels of I & Q data. If you like, I can whip up an example. Let me know. Eric _______________________________________________ Discuss-gnuradio mailing list [email protected] http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
