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Re: [Discuss-gnuradio] transmitting two independent Signals
From: |
Eric Blossom |
Subject: |
Re: [Discuss-gnuradio] transmitting two independent Signals |
Date: |
Tue, 20 Feb 2007 07:45:29 -0800 |
User-agent: |
Mutt/1.5.9i |
On Tue, Feb 20, 2007 at 03:41:31PM +0100, anmar wrote:
> hi all,
>
> we have been searching for a way to transmit two independent signals one
> on TxA and the other on TxB.
Using two daughterboards, you can send different complex baseband
signals out the A side d'board and the B side d'board. You must set
nchan=2 in the usrp.sink_c constructor, and provide an interleaved
stream of complexes. (Yes, the interface is a bit strange and ought
to be revisited/fixed.) You can create the interleaved output stream
using
u = usrp.sink_c(nchan=2, interp_rate=<interp>)
src0 = <first complex source>
src1 = <second complex source>
interleaver = gr.interleave(gr.sizeof_gr_complex)
fg.connect(src0, (interleaver, 0))
fg.connect(src1, (interleaver, 1))
fg.connect(interleaver, u)
r0 = u.tune(0, u.db[0][0], freq_0) # set center freq on side A d'board
r1 = u.tune(1, u.db[1][0], freq_1) # set center freq on side B d'board
> we have read the Tx_MUX documentation and tried some settings but we
> only could send two different frequencies two only 80khz!!! and we
> always have had two signals!
> what we like to do is is to chose the "two independent real signal" mode
> on the AD9862, how can we do that, just change the AD9862.h, or some
> different approach? if yes how to load it to the USRP.
> reading some of the forum questions, we understand that the gnuradio
> have the "Dual channel complex" mode and changing it would give
> conflicts with the FPGA and the software.
That's right. If you're using a single Basic Tx daughterboard, and
you want independent real output out the I and Q, that'll take a fair
amount of hacking. Using two daughterboards is going to be much, much
easier ;)
> is there some thing that we're missing or just not understanding.
>
> thanks,
>
> Wim & anmar
Eric