USRP N200 + SBX - problem receiving signal

Hello!

I’ve recenty got two USRP N200 with SBX daughter boards. I have managed
to
transmit simple sine signal with one USRP but I have problems receiving
this signal. I dont see anything but noise in spectrum. I have measured
signal that I am transmiting with spectrum analyzer and I see a spike in
spectrum, so the transmiter must be working.

I am using UHD source and sink blocks as a “top layer” for USRP devices,
and WX GUI FFT block for displaying spectrum. Sine frequency is 1kHz and
I
am samping with 200kHz. I have set the center frequency on 500MHz. I
have
tried both antenna ports on receiving device.

Is there some setting that I am missing?
Thanks

On 11/11/2011 07:37 AM, Urban K. wrote:

Hello!

I’ve recenty got two USRP N200 with SBX daughter boards. I have managed to
transmit simple sine signal with one USRP but I have problems receiving

Does that mean you have confirmed transmission with a spectrum analyzer?

this signal. I dont see anything but noise in spectrum. I have measured
signal that I am transmiting with spectrum analyzer and I see a spike in
spectrum, so the transmiter must be working.

I am using UHD source and sink blocks as a “top layer” for USRP devices,
and WX GUI FFT block for displaying spectrum. Sine frequency is 1kHz and I
am samping with 200kHz. I have set the center frequency on 500MHz. I have
tried both antenna ports on receiving device.

Is there some setting that I am missing?

Can you tell more information, or send your GRC flowgraph?
What frequency, what digital amplitude, gains, etc…

If I can make some suggestions:

  • Digital amplitude should be max magnitude 1.0, start with something
    way lower like 0.3.

  • Use a larger sample rate, at least 1Msps. This can make it easier to
    debug.

  • Did you pick the correct RX antenna?

  • Have you tried increasing RX gain?

-Josh

Hello!

Sorry for a bit late response. Regarding my problem

  1. Yes I can see the signal that I am transmiting with spectrum analyzer

  2. I tried all possible combinations for RX antenna

3.I have tried increasing RX gain

I attached my GRC flowgraph.