[hpsdr] DDC Noise Figure

[Edson Pereira]

Ulrich,

Thanks for the clarification.

Let me rephrase my question: Given a signal already digitalized by a
16-bit at 80MSPS ADC with a known noise figure (let's say 20dB). Can processing
gain improve the noise figure?

73,

-- Edson

On Sun, Mar 27, 2011 at 7:58 PM, <KA2WEU at aol.com> wrote:

>  The formula is confusing because it calculations from the s/(n+d)
> backwards the noise figure. Not well written.
>
> Vr= SQRT ( 4kTo times R (50 ohms) times "integrated" bandwidth )
>
> find something better in the literature. The typical NF of a A/DC converter
> is close to 20 dB and Zin=800 Ohm.
> So you have tranform the 50 Ohm to 800 and you need a pr-amp, slightly more
> then 15 dB.
>
> Look at
>
> http://www.adat.ch/pub/Parameter_Verifikation_090305.pdf
>
> In the non-professional area this is the absolute best design, the
> explaination is in German, sorry.
>
> In the professional area this is the best radio
>
>
>
> http://www.marcoisland.org/eb500.htm
>
>
> 73 de Ulrich
>
>
>
>
>  In a message dated 3/27/2011 6:36:37 P.M. Eastern Daylight Time,
> ewpereira at gmail.com writes:
>
>
> Hello Ulrich,
>
> Thanks for letting me know that my understanding is totally incorrect. The
> source of my misunderstanding is Equation 8 on this paper.
>
> http://www.analog.com/static/imported-files/tutorials/MT-006.pdf
>
>  <http://www.analog.com/static/imported-files/tutorials/MT-006.pdf>73,
>
> -- Edson
>
> On Sun, Mar 27, 2011 at 6:07 PM, <KA2WEU at aol.com> wrote:
>
>>  I am sorry, that is totally incorrect. The noise figure ( expressed in
>> dB) from the noise factor is a dimensionless value totally independent of
>> the bandwidth. That is the beauty of it. The Signal /(Noise + Distortion )
>> value is bandwidth dependent.
>>
>> 73 de Ulrich , N1UL
>>
>>  In a message dated 3/27/2011 3:30:37 P.M. Eastern Daylight Time,
>> ewpereira at gmail.com writes:
>>
>> . Since the noise figure takes into account the bandwidth,
>>
>>
>
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