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Re: New owner of nanovna-H and H4, However pondering the next step in precision


F1AMM
 

Hello
I follow your discussion with interest but my language is not English - thank you Google. If you could avoid using acronyms such as "ADC". What does it mean ?
Could you develop a little more what follows

----o----
One other thing..
The "raw measurement" that the NanoVNA makes is essentially a filtered sum of 48 samples. The raw adc samples are probably about 1 part in 10^4 (call it 1E-4 fractional uncertainty) so 48 samples will be sqrt(N) better, or 1.4E-5. (ignoring arithmetic precision).

That's voltage, not power, relative to full scale.

In reality, the input signal isn't full scale, it's more like 0.1 full scale or 0.05 full scale, so the uncertainty is about 0.1%

The reflection coefficient is calculated as the algebraic combination of two of those measurements, so the uncertainty is roughly doubled (0.2%)
----o----
- thank you
--
F1AMM (Fran?ois)

-----Message d'origine-----
De la part de Jim Lux
jeudi 4 ao?t 2022 19:50

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