Hello! As to introduct me, im very new to GnuRadio and the general topic of SDR. However, i have a project in which i should implement a very basic way of sending packets. This given packet format has a constant preamble and a constant length of appended databits. For detecting those out of a stream etc. ive already written a working matlab script, now im stuck at the GnuRadio side. As a simple Presentation it would be enough to save a captured bitstream from GnuRadio to harddrive which i later load in Matlab and send it through my script. So my question is, how can setup the most easily a one way tx/rx connection between 2 SDR's, without any packet format or, which simply gives me the received bits? My basic idea is like that: TX: <http://gnuradio.4.n7.nabble.com/file/n38924/tx.png> RX: <http://gnuradio.4.n7.nabble.com/file/n38924/rx.png> I simply cant get it working at all. It would be too kind if somebody could give me some kind of introduction how to handle that. Regards -- View this message in context: http://gnuradio.4.n7.nabble.com/Help-on-easy-digit... Sent from the GnuRadio mailing list archive at Nabble.com.
on 2013-01-10 21:34
on 2013-01-10 21:39
Hanz, You have a few options. You can build a digital tx/rx in GRC, run an example like tunnel.py, etc. I've also created a set of examples with a libraby called pre-cog, which you can see here: http://www.youtube.com/watch?v=f8emQ-TvD90 An updated url to the pre-cog github pages: https://github.com/jmalsbury/pre-cog/wiki If you do use pre-cog, feel free to send any questions. It's a work-in-progress and the documentation may not explain everything... -John
on 2013-01-11 14:53
Thank you for the advising! That looks like something what i could use. I just came up with another question: I simply tried to simulate a DPBSK Path with noise, loaded from a file and sinked to a file. Between Demod and Sink i placed a "Pack K Bits" with K=8. <http://gnuradio.4.n7.nabble.com/file/n38935/08.png> But my received data just contains 0's! It has the right length, but just zeros... Any ideas anyone? -- View this message in context: http://gnuradio.4.n7.nabble.com/Help-on-easy-digit... Sent from the GnuRadio mailing list archive at Nabble.com.
on 2013-01-14 21:57
I now have 2 new problems :( 1. I have a random source hooked to a Modulator and then to USRP. From the same device i listen at the same Frequency. But since the antennas are just a few cm's away, the constellation graph is completely diffuse and the points are anywhere, there arent any fixed points noticeable. Do I have to change something at the gain or add something? <http://gnuradio.4.n7.nabble.com/file/n38994/const.png> 2. How can i differentiate if there is a signal receiving or just some background noise. I mean if i put the Demodulator directly after the USRP and stream it to file, then of course ill mostly get just random amplified noise... -- View this message in context: http://gnuradio.4.n7.nabble.com/Help-on-easy-digit... Sent from the GnuRadio mailing list archive at Nabble.com.
on 2013-01-14 23:59
On 01/14/2013 02:56 PM, Hanz wrote: > noise... > Few tips, the modulator tags packed bytes, so the random source should be [0, 256) The modulator produces amplitude 1.0 samples. You will want to scale these down as fullscale can clip. Either multiply constant block or fullscale stream arg in UHD block: http://files.ettus.com/uhd_docs/doxygen/html/struc... Put the output of the modulator on a the FFT plotter. You should see the response of the matched filter. -josh