Hi, I'm really hoping someone can help me with this, as it's causing serious problems with my research. I have four USRP2s and I'm making use of the MATLAB/SIMULINK Communications Blockset. I've been trying to run the transmission demo using each of the USRP2s. Unfortunately I'm consistently picking up intermodulation distortion on all four radios. At the bottom of the e-mail, I've placed links to the spectrum analyzer graphs I've captured from each of the radios. In addition I thought it prudent to provide all other potentially relevant information: - USRP2 version 4 - XCVR2450 Daughterboard - Firmware is as specified on the Mathworks website for the XCVR2450 (http://www.mathworks.com/support/solutions/en/data/1-CUN7JZ/index.html?product=CB&solution=1-CUN7JZ) - Antennae used are the VERT2450 from Ettus (I've placed antennae on RF1 and RF2 - not sure if this is correct?) - The waveform transmitted should be a 30kHz Real Sinusoid at 2.45GHz - Simulation Gain was set at 10 - Interpolation was set at 512 While I do realize that I could use a bandpass filter to isolate the 30kHz waveform, I believe this would then prevent me from using frequency-based channel access schemes such as OFDMA. I am also aware that I seem to have a frequency shift from my desired central frequency of 2.45GHz - which is something that I am also unsure of how to fix. Lastly, I need to be able to detect when a signal is received by one of the USRP2s. I have read about various synchronization methods making use of auto-correlation with known signals - does anyone know of a simple, reliable method that can be easily implemented? Any thought would be appreciated!! http://i1215.photobucket.com/albums/cc518/RYANVANDENBERGH/USRP2%20Debugging/USRP2_40Subnet_10Gain.jpg http://i1215.photobucket.com/albums/cc518/RYANVANDENBERGH/USRP2%20Debugging/USRP2_30Subnet_10Gain.jpg http://i1215.photobucket.com/albums/cc518/RYANVANDENBERGH/USRP2%20Debugging/USRP2_20Subnet_10Gain.jpe http://i1215.photobucket.com/albums/cc518/RYANVANDENBERGH/USRP2%20Debugging/USRP2_10Subnet_10Gain.jpg Kind regards, Ryan van den Bergh