[Discuss-gnuradio] regarding calculating the noise power

[shantharam balasubramanian]

Hi.
I am using USRP2 testbed. I have been recently working on plotting the
PSD of the received signal and I was able to do it. The graph plots
the signal in baseband frequency level.
Then I turned on the receiver node while keeping the sender node off.
When I plotted the PSD graph for that, I was expecting to see a PSD
which should be more or less constant over all the frequencies.
But I saw a peak in the 0 Hz which is the center frequency. I was told
that this is due to DC offset. I am not sure what is meant by that
exactly and how to control or measure the DC offset in the output I
got.
Can anyone help me out?