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

[Matt Ettus]

On 07/15/2010 10:20 AM, Patrick Yeon wrote:
> Not quite. Noise figure is a measure of the degradation of SNR, so if
> you know your input SNR, you would know that the measurements from the
> USRP will have a 35 dB worse (lower) SNR. Alternativley, you know your
> input SNR is 35 dB better (higher) than what you measure "coming out of"
> the USRP.
>
> --
> Patrick Yeon
> ThinkRF
> 613-369-5104 x418


No, that's not how it works either.  The SNR is only degraded by an 
amount equal to the noise figure if the input signal has a noise floor 
of the thermal minimum (i.e. straight from an antenna).  For anything 
coming through a device with gain or noise would not fit that criteria.

Matt