Re: [Discuss-gnuradio] Gnuradio over Zynq
I know we have been talking over email, but I wanted to post this for everyone to see. The Zynq build wiki has gotten a little out of date and over the next few weeks I'll be updating it to fix various issues that have been brought up. As well, there has been a lot great work on the Open Embedded side that makes building images even easier, so expect a rather large update to the wiki. -- View this message in context: http://gnuradio.4.n7.nabble.com/Gnuradio-over-Zynq-tp51051p51061.html Sent from the GnuRadio mailing list archive at Nabble.com. ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] Quadrature demodulation of FM
Before I ask my question, I'd like to thank everyone that's been helping me
out. I (and my peers at Purdue) are just starting out with the USRP and
really appreciate the support.
On to my question, I wrote a demodulation block for FM that uses a method
different than the provided quadrature_demod_cf block. Here is a block
diagram of what I'm attempting:
http://pico.iis.u-tokyo.ac.jp/media/9/20060626-SQD-princ.jpg. I can record
data from the USRP and successfully demodulate FM radio in MATLAB using this
technique. However, I cannot accomplish this with my signal processing block
I wrote. To test my block, I use the example wideband FM receiver code,
usrp_wfm_rcv.py, and basically insert my demodulation block in place of the
provided demodulation block.
Here is the work code I made, note it is just a small modification of
quadrature_demod_cf.cc:
int gr_quad_demod_baseband::work (int noutput_items,
gr_vector_const_void_star &input_items,
gr_vector_void_star &output_items)
{
gr_complex *in = (gr_complex *) input_items[0];
float *out = (float *) output_items[0];
in++;// ensure that in[-1] is valid
for (int i = 0; i < noutput_items; i++){
float I_1 = real(in[i-1]);
float I_2 = real(in[i]);
float Q_1 = imag(in[i-1]);
float Q_2 = imag(in[i]);
float dI = I_1 - I_2;
float dQ = Q_1 - Q_2;
float dQxI = dQ*I_1;
float dIxQ = dI*Q_1;
out[i] = d_gain*(dIxQ - dQxI);
}
return noutput_items;
}
The demodulation is really simple and if you do not get it at first, please
check out the link to the block diagram. On a final note, my block is also
running very slowly. I continuously get overrun notifications (I believe
that is the meaning of uO). I think I am quite close to the answer, I just
need a little guidance. Anyone have any suggestions? Thanks in advance!
Jon Pendlum
Purdue University Undergraduate Student
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[Discuss-gnuradio] Signal processing block compiling problem
Hey Everyone, To whoever can help me out, I'm trying to make my own signal processing block. I've gotten to the point where I run the make file, but I keep getting the following error: "/usr/bin/ld: cannot find -lfftw3f" This even occurs if I try to compile the howto example. Another member on my team has installed FFTW3, so I'm not sure why I am getting this error. Can anyone help me out? Thanks! Jon Pendlum Purdue University Undergrad ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Reading from TVRX board
Thank you for the reply. That is the script I use for reading in the data into MATLAB. I should have made that more clear. On Thu, Feb 14, 2008 at 1:55 PM, Johnathan Corgan < [EMAIL PROTECTED]> wrote: > On 2/14/08, Jonathon Pendlum <[EMAIL PROTECTED]> wrote: > > > Then, I use a script written to convert the binary data file into a > MATLAB > > vector. > > The data format is alternating I and Q single-precision floating point > in whatever endianness your computer is. See the following for how to > read into MATLAB: > > > http://gnuradio.org/trac/browser/gnuradio/branches/releases/3.1/gnuradio-core/src/utils/read_complex_binary.m > > -- > Johnathan Corgan > Corgan Enterprises LLC > http://corganenterprises.com/ > ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] Reading from TVRX board
Hello, I'm a student trying to use the USRP with the TVRX board to do a simple FM stereo receiver. I previously wrote a MATLAB model of a FM transmitter and receiver, and I wanted to use real data in my model. I've been modifying the wideband fm example to record data from the TVRX board by basically inserting some of the l1_record.py code like this: self.dst = gr.file_sink(gr.sizeof_gr_complex, 'data.txt') self.head = gr.head(gr.sizeof_gr_complex, 80) self.connect(self.u, self.head, self.dst) Then, I use a script written to convert the binary data file into a MATLAB vector. However, the recorded data is not meaningful to me. When plotting the data, instead of seeing some kind of waveform, I see what looks similar to a NRZI waveform. If you wish to see what I am seeing, here is a screenshot of the data: http://web.ics.purdue.edu/~jpendlum/usrpdata.bmp It is also important to note that the example wideband FM code runs flawlessly. I can tune to local radio stations and listen to them. These are the questions that I've tried very hard to answer, but I can't seem to figure out: 2. Is the recorded data in some kind of encoded format, and if so, what is this format? 3. If not, then what am I doing incorrectly in my record script? If anyone could help, I would greatly appreciate it. Thanks. Jon Pendlum ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
