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 =
q =
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 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 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/TutorialsWritePythonApplications
http://gnuradio.org/redmine/wiki/gnuradio
Hope this helps,
–
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Work phone: 450-936-2123
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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
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.