[Discuss-gnuradio] usrp_fft.py questions

[Anastasopoulos Achilleas]

Now that I understand how the basic Tx and usrp_siggen works,
I am trying to get a handle on the basic Rx and the usrp_fft.py script.

Here are a couple of observations/questions:

1) If nothing is connected to the basic Rx I get a strong DC term
on the fft display. Where is this coming from? Also, this does not change
no matter what I put as the value of the multiplexer (-m option)

2) When I connect an 1MHz carrier to both Rx-A and Rx-B, then
I get the two spikes at +-1 MHz together with the DC term
and this picture does not change no matter what I put
as the value of the multiplexer (-m option)

At this point I do not have an explanation for this behavior.

Thanks
Achilleas