Re: [Discuss-gnuradio] USRP and XCVR2450 Noise Figure

[Matt Ettus]

On 07/15/2010 08:51 AM, Jeffrey Lambert wrote:
> Hello,
>
> The noise figure will in large part depend upon the receiver front-end
> that is attached the USRP or in the daughter board that is used. In that
> case that you would like to know the noise figure of the USRP without
> any RF front-end then the results may vary whether you are using a
> BasicRX board or one of the LFRX boards. For a 50 Ohm system, either of
> these should yield accurate results. Mainly, the noise figure of the
> USRP will be derived from the AD9862 digitizer. Since this IC contains
> an amplifier, the noise figure will vary with the gain of the PGA.
>
> I too am interested in measuring the noise figure of the USRP. If you
> are unable to find anything, I will be able to supply measurement data
> within the next few weeks for a USRP device and BasicRX daughterboard.

The USRP + BasicRX will have a noise figure of around 35dB, since it has 
no amplification.  If designing a daughterboard, you can use that number 
as the noise figure of the ADC for your calculations of the overall 
noise figure.

Matt