Hi Marcus, Thanks for the quick reply...
On Oct 20, 2010, at 5:51 PM, Marcus D. Leech wrote: > On 10/20/2010 07:13 PM, Joseph Craig wrote: >> I have managed to install gnuradio and run usrp_fft.py with success! >> >> Now for the questions... >> >> 1) I'm always seeing... "Exception RuntimeError: 'maximum recursion depth >> exceeded while calling a Python object' in <type 'exception.AttributeError'> >> ignored ". What does this mean, and how to fix it? >> > In what application are you seeing this error? python > >> 2) How do I save the I/Q stream to disk? I'm interested in the maximum bit >> resolution for the best dynamic range. I just want the raw time samples. >> > You should investigate gnuradio-companion (GRC), which allows you to put > a signal processing > graph together graphically--like LEGO building blocks. You can very > easily put together a > "baseband recorder" application in about 5 minutes this way. 5 minutes is pretty enticing seeing how this has to be working friday. How long does it take to setup GRC? Is there a guide? > >> 3) Some of the examples (like usrp_wfm_rcv.py) spit out "...aUaUaUaUaU..." >> to the console and the sound is choppy. What does this mean, and is there a >> way to turn it off? >> > It means that you're experiencing a audio underrun, likely because your > processing chain > can't "keep up". Perhaps because you haven't specified a high enough > decimation, and > the chain is trying to keep up with a unpleasantly-large torrent of data. ah, yes. should have thought of this. I will check out increasing the decimation. > >> 4) Is it possible to tweak parameters such as quadrature downconverter >> bandwidth/decimation, etc? >> >> thanks, >> Joe Craig >> >> > Yes, absolutely. Most of the example programs take a "-d" option that > controls decimation > in the USRP hardware. For example, if you only wanted 1MHz bandwidth, > you'd use a > "-d" option to the examples (like usrp_fft.py) of "-d 64", which will > give you 1Msps of > complex samples between the USRP and the host--because the A/D in the > USRP is > 64Msps. For the USRP2, the A/D operates at 100Msps, so you'd need to > adjust your > decimation appropriately. Got it! > > You should keep in mind that except for trivial algorithms at modest > bandwidths, you'll need > a fairly-decent computer to get the best results from your Gnu Radio > experiments. Although > I think you mentioned that at first you only want to record baseband > data to disk at 1Msps, > I'm guessing you'll want to go beyond that at some point. it's a year old linux box we were using for fairly high bandwidth recording from ethernet, so it should be ok. Joe > > I'd explore gnuradio-companion as well. > > Good luck! > > -- > Principal Investigator > Shirleys Bay Radio Astronomy Consortium > http://www.sbrac.org > > > > _______________________________________________ > Discuss-gnuradio mailing list > [email protected] > http://lists.gnu.org/mailman/listinfo/discuss-gnuradio _______________________________________________ Discuss-gnuradio mailing list [email protected] http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
