Hello, I am trying to transmit and receive a signal that the user defines. I am following the directions written by Eric B. on independently generating signals and then transmitting them. " u = usrp.sink_c(...) i = <generate I somehow> q = <generate Q somehow> f2c = gr.float_to_complex() fg.connect(i, (f2c, 0)) fg.connect(q, (f2c, 1)) fg.connect(f2c, u) " i = [1000, .... , 923] // 16 values in this array, one period of cosine q = [0, ....., -383] // calculated using hilbert transform, 16 values isrc = gr.vector_source_f(i, 1) qsrc = gr.vector_source_f(q, 1) fg.connect(isrc .... ....) The signal "i" is supposed to be a cosine wave. When I connect f2c to gr.filesink, I see a cosine wave. However, the received signal looks like noise centered around 51. Also: why is the waveform of gr.sig_source_c(SIN_WAVE, offset = 0) a cosine wave? I got this by using gr.file_sink, and looking at the odd=real values. file_sink output = "REAL IMAG REAL IMAG .... " Any help would be appreciated. Jonathan Shan
on 2007-04-07 08:17
on 2007-04-09 08:55
On Sat, 7 Apr 2007, Jonathan Shan wrote: > fg.connect(q, (f2c, 1)) > fg.connect(f2c, u) > " > > i = [1000, .... , 923] // 16 values in this array, one period of cosine > q = [0, ....., -383] // calculated using hilbert transform, 16 values > > When I connect f2c to gr.filesink, I see a cosine wave. However, the received > signal looks like noise centered around 51. > I tried changing the number of samples in i, q to larger values. Same result. I also tried setting the transmit gain to max. I think the problem is modulation / de-modulation. But what is usrp.tune(carrier_freq) for? I can transmit and receive correctly gr.sig_source_c just using usrp.tune on both ends. Jonathan Shan
on 2011-03-29 09:05
Hello, I am a senior student that also studying GNU Radio. I have found your post about generating signal and transmit on gnuradio mailing list (though it is written in 2007). I am wondering if you could give me some hints on generating signal and transmit using USRP? I am new to gnu radio and have not figured out where to start. I have already looked through gr_sig_source_c.cc but find no luck. My goal is to generate a sine, 2 sinc and 1 16QAM signal and transmit to another USRP device. (I am using USRP2) I will really appreciate your help. Thank you.
on 2011-03-29 15:21
On 29/03/11 01:04 AM, Yulong Y. wrote: > I have already looked through gr_sig_source_c.cc but find no luck. My > i found the tutorials on the wiki quite instructive and well-written: http://gnuradio.org/redmine/wiki/gnuradio/Tutorial... http://gnuradio.org/redmine/wiki/gnuradio Hope this helps, -- Etienne Robillard Company: Green Tea Hackers Club Occupation: Software Developer (and CEO) E-mail: email@example.com Work phone: 450-936-2123 Website (Company): https://gthc.org/ Website (Blog): https://gthc.org/blog/ PGP public key fingerprint: F2A9 32EA 8E7C 460F 1728 A1A7 649C 7F17 A086 DDEC During times of universal deceit, telling the truth becomes a revolutionary act. -- George Orwell If a free society cannot help the many who are poor, it cannot save the few who are rich. -- John F. Kennedy