Hi Gabriele, have you tried adding more gain on the TX side? Also, you will need to increase sampling rate. Right now, you're using 100kHz, which is 1/1000 of the master clock rate of the N200. If I'm not mistaken, the maximum decimation for the N200 is 512, and hence the minimum rate would be 100MHz/512 = 195.3125kHz. You probably just want to use 200kHz or something similarly practical.
I hope that helps! Best regards, Marcus On 06/25/2015 02:23 PM, Gabriele Galiero wrote: > Hello, I was interested to test tx_ofdm.grc and rx_ofdm.grc from > gr-digital, at the same time using USRP N200 devices. > > TX OFDM: > > The changes that I did were, removing throttle block and adding an UHD > Sink instead, with center frequency 430 MHz, which is the frequency band > for which my department has license to transmit. > > RX OFDM: > > In this case I removed all blocks before throttle (included), and placed > there an UHD Source at the same center frequency. > > Flow graphs attached in the files. > > I monitored the output signal and the received signal. I also used a > spectrum analyzer to check the actual signal that is being transmitted. > Pics are attached. > > In the tx signal measured by a spectrum analyzer, we can see that the > spectrum is not that we desire. I would like to ask if I am doing > something wrong with the configuration. Before transmission there was no > signal at that frequency and tx and rx antennas are suitable for the > carrier frequency. > > In addition I tried to transmit a file instead of just random bits. In > reception I was not receiving the file. The config was just adding a > file sink at the end of the rx block and a file source at the beginning > of the tx block. Could you please help me with some tip? > > Attachments: > http://www.ruby-forum.com/attachment/10886/tx_ofdm.jpg > http://www.ruby-forum.com/attachment/10887/rx_ofdm.png > http://www.ruby-forum.com/attachment/10888/tx_signal.jpg > http://www.ruby-forum.com/attachment/10889/rx_signal.jpg > http://www.ruby-forum.com/attachment/10890/tx_sig_spectrum.jpg > > _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
