Re: [Discuss-gnuradio] transmitting two independent Signals

[Robert Miller]

Hi -
Just wanted to say that I found out what was wrong.  In the code below,
self.dst.db[0][0] was the issue when using the new GNU Radio version.  I had
to change the code to:   self.dst.db(0)[0] in order for it to run
properly.... perhaps this was a python issue?
Thanks!
Rob


Robert Miller wrote:
> 
> Hi -
> I have been using the code snippet below as a reference to transmit two
> signals with my USRP.  However, when trying to run the code under a peer's
> newer Ubuntu installation (w/ the latest GNU Radio code), I get an error
> stating that an object is unsubscriptable.  It is referring to the
> following line in my code:
> 
> ...
> self.dst =  usrp.sink_c(nchan=2)
> ...
> self.subdev = (self.dst.db[0][0], self.dst.db[1][0])            <----
> Error here
> ...
> 
> From reading online (http://www.daniweb.com/forums/thread192533.html), I
> see that this error occurs when the object that is being indexed into is
> 'NoneType'.   My question is why would this work on my installation and
> not my peers?  Is there something silly I am not changing due to the usage
> of the newer GNU Radio code (I've already made the changes from
> http://www.mail-archive.com/address@hidden/msg14463.html). 
> Also, receiving and transmitting from a single daughterboard work just
> fine on my peer's installation.
> 
> Thanks!
> Rob
> 
> 
> 
> Eric Blossom wrote:
>> 
>> 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
>> 
>> 
>> _______________________________________________
>> Discuss-gnuradio mailing list
>> address@hidden
>> http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>> 
>> 
> 
> 

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