[Discuss-gnuradio] transceiving a sinusoid using usrp's

[Rahman, Muhammad Mahboob Ur]

Hi,

I am trying to send, then receive and finally display a sinusoid of arbitrary 
frequency say 128KHz using two usrp's and two computers. I have used grc on 
both computers to do so.

On tx computer, the flow graph of grc is:

signal source --> usrp sink

In signal source, I set the frequency of cosine wave=128K, amplitude=10K, 
offset=0, output type=complex, sample rate=256K. In usrp sink, I set input 
type=complex, interpolation=128M/256K=500, frequency=900M, gain=0dB, side=A, 
transmit=enable (I am using flex900 daughter boards)

On rx computer, the flow graph of grc is:

usrp source --> scope sink

In usrp source, I use output type=complex, format=16 bits, 
decimation=64M/256K=250, frequency=900M, gain=0dB, side=A, RX antenna=TX/RX, 
half band filters=enable. In scope sink, I simply choose the type=complex, 
sample rate=256K, then all other parameters are default.

When I run all this, a wave form like tone modulation (amplitude modulation of 
a sinusoid with another sinusoid) is displayed on the scope while I get 
something displayed on the terminal as:
______________________________________
TX:
A: Flex 900 Tx MIMO B
        r.baseband_frequency = 904000000.0
        r.dxc_frequency = -4000000.0
        r.residual_frequency = 0.0
        r.inverted = False
RX:
A: Flex 900 Rx MIMO B
        r.baseband_frequency = 896000000.0
        r.dxc_frequency = -4000000.0
        r.residual_frequency = 0.0
        r.inverted = False
______________________________________
And when I stop the simulation on tx computer, a sinusoid waveform of frequency 
about 4.4 KHz is displayed on rx computer. Can anyone please suggest something 
in this regard?

Thanks,
Mahboob