Hi, I am using a USRP with RFX2400 to transmit a sinc pulse using usrp_siggen.py routine and my own sinc pulse generator that is a modified version of gr_sig_source_c.cc. I am using a separate USRP with RFX2400 to receive the pulse using usrp_rx_cfile.py. The transmitter and receiver are one meter apart.
First, I tried to put the sinc pulse on the "I" branch (real) and zeros on the "Q" branch. But the amplitude of the received pulse train is time varying. In fact, the received pulse train seems to be amplitude modulated by a low frequency signal (in KHz). Second I tried to put the same sinc pulse on both I and Q and had the same problem. For curiosity, I repeated the experiment by putting few cycles of sine wave on both I and Q and encountered the same problem of amplitude variation. Finally, I tried using a truncated sine wave on I and cosine on Q and it works perfectly fine. I am having difficulty in understanding the problem. Does this mean that I can only put sine and cosine on I and Q, respectively? Is it possible to transmit only single component not quadrature using RFX 2400? I am thinking to set MUX to disable the Q branch at the transmitter and receiver. Any help will be highly appreciated. Thanks in advance, Faisal _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
