[USRP-users] Simulink+USRP2+RFX900: Daughterboard broken?

Robert Morelos-Zaragoza morelos_zaragoza at yahoo.com
Sat Nov 13 18:49:07 EST 2010


We started using the USRP2 with Simulink. The daughterboard used is the 
RFX900.

Yesterday, a test model at 901 MHz was running successfully (see 
attached tone_901MHz_before.jpg). However, upon running the model again 
hours later, the same result was not observed (see attached 
tone_901MHz_after.jpg).

A strong interference is present that first was thought to be due to an 
ISM band signal. However, when zooming out (see attached 
zoom6MHz_915MHz.jpg) a strong waveform is observed of fundamental 
frequency approximately 400 kHz.

Has anyone experience the same problem? Is it due to Tx-Rx leakage? Upon 
a little "googling", I discovered that an amplifier may burn if 
excessive signal levels are used, or if the transmit antenna impedance 
is not properly matched. It appears that U5 (near the RX2 edge) of the 
RFX900 gets too hot. It was also observed that blowing air to the IC 
causes the frequency of the waveform to change (!?) ...

Thanks in advance for your help,

Robert
-------------- next part --------------
A non-text attachment was scrubbed...
Name: tone_901MHz_before.jpg
Type: image/jpeg
Size: 294708 bytes
Desc: not available
URL: <http://lists.ettus.com/pipermail/usrp-users_lists.ettus.com/attachments/20101113/4d41ad15/attachment.jpg>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: tone_901MHz_after.jpg
Type: image/jpeg
Size: 293914 bytes
Desc: not available
URL: <http://lists.ettus.com/pipermail/usrp-users_lists.ettus.com/attachments/20101113/4d41ad15/attachment-0001.jpg>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: zoom6MHz_915MHz.jpg
Type: image/jpeg
Size: 257015 bytes
Desc: not available
URL: <http://lists.ettus.com/pipermail/usrp-users_lists.ettus.com/attachments/20101113/4d41ad15/attachment-0002.jpg>


More information about the USRP-users mailing list