Problem receiving RX-A and RX-B simultaneously

GNU Radio
1

Hello,

I programmed a module into the FPGA that is able to process separately
two
independent signals at the same time with the LFRX. Using and external
oscilloscope and the LFTX I checked that it works properly.

Now, I tried to check the output on the PC side using tools like
*fft_sink_c

  • or scope_sink_c but I found several problems. My graph implements
    two
    blocks at the output of the USRP2 source: a “complex to real()” and a
    “complex_to_imag()”. I thought that I would get the ‘I’ and ‘Q’ doing
    this.
    I connected each output to a FFT Sink with float inputs but the plot I
    get
    only depends on the RX-A input.

Later, I also read that setting the “is_quadrature” value to ‘true’ in
the
file named *db_basic.c (
http://gnuradio.org/cgit/gnuradio.git/tree/usrp2/firmware/lib/db_basic.c?h=next#n123
) *could work but what I got is that I have the same plot for ‘I’ and
‘Q’.

I am using Ubuntu 10.10 and GNU Radio driver. Any help would be great!

Thanks!

Eduardo.