Re: [Discuss-gnuradio] USRP Dynamic Range and 8 Bit Problem

[Firas A.]

Hi,


> I believe that Matt was referring to using max-strength I & Q inputs
> to the Basic Rx along with an Rx mux setting that routes both ADC
> outputs into the same DDC.  (The default config with the Basic Rx
> feeds a constant zero into the Q DDC input).
> 
> Eric

I believe Matt was right about his suspects. The FPGA modifications was bad
for the RFX boards. Although it was working ok for the dbsrx board for all
ranges, and although we got a SFDR enhancement by 3 dB in low level input
signal to RFX board, but when the input signal was high, the RFX board I & Q
outputs was badly distorted, while the original USRP FPGA does not shown
such distortion. 

For the RFX boards, I tested both the TX/RX input and the RX2 input. The
TX/RX input shows a high attenuation.

The input signal was 1000.25MHz.The RFX900 board was used in the tests.

The tests results can be found at :

http://rapidshare.com/files/79333552/DBSRX_Tests.tar.gz
http://rapidshare.com/files/79333746/RFX_Tests_TX_RX_Input.tar.gz
http://rapidshare.com/files/79333825/RFX_Tests_RX2_Input.tar.gz

Best Regards,

Firas

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