USRP DBPSK Demod/Mod Issue


We are working on our senior design project using gnuradio and USRP
N210. We are connecting two USRP’s together through a coax cable with a
30 dB attenuator and each USRP is connected to a host computer via a
gigabit ethernet connection.

Right now we are trying to modulate and demodulate a packet consisting
only of “1’s and 0’s” from a file generated with the gnuradio file sink.
We are seeing strange fluctuation at the output of our USRP receiver. We
have attached a link to pictures of our GRC blocks and our source code
as well as the gr_plot screenshots documenting the received signal.