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

[Patrick Yeon]

On 7/15/2010 1:00 PM, address@hidden wrote:
> Zitat von "Matt Ettus" <address@hidden>:
> > 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
>
>
> Hi,
>
> Thanks a lot for your help!
>
> Can I also use those 35db as the total noise at the input of the USRP to
> compute the signal to noise ratio?
>
> For that I'd also need the transmitting Power Pt. Would you by any
> chance also have an idea how i could figure out Pt?

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