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converting Volt into dB

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soldar:

--- Quote from: NaxFM on August 07, 2019, 02:44:57 pm --- You can't have a negative gain, the gain is always positive, less than one if it's an attenuation, more if it's a gain.
--- End quote ---

I don't think that's right.  https://en.wikipedia.org/wiki/Decibel shows negative numbers. 0 dB is gain of unity. Negative gains get negative numbers in dB. WIFI ranges in the -60 dB range. Audio too.

NaxFM:

--- Quote from: soldar on August 07, 2019, 06:28:15 pm ---
--- Quote from: NaxFM on August 07, 2019, 02:44:57 pm --- You can't have a negative gain, the gain is always positive, less than one if it's an attenuation, more if it's a gain.
--- End quote ---

I don't think that's right.  https://en.wikipedia.org/wiki/Decibel shows negative numbers. 0 dB is gain of unity. Negative gains get negative numbers in dB. WIFI ranges in the -60 dB range. Audio too.

--- End quote ---
Well, yes, speaking in terms of deciBels you can have negative gain. I didn't say that, but I was talking about gain expressed as a pure number.
If the ratio is less than one, then the gain in deciBels is negative

Inviato dal mio Moto G (5S) Plus utilizzando Tapatalk

radiolistener:

--- Quote from: soldar on August 07, 2019, 06:28:15 pm ---Negative gains get negative numbers in dB.

--- End quote ---

Negative gain in dB is not a gain, this is attenuation :)

soldar:

--- Quote from: radiolistener on August 09, 2019, 03:31:50 am --- Negative gain in dB is not a gain, this is attenuation :)
--- End quote ---

Attenuation is the same as "negative gain" and both are correct. Just like a negative profit is a loss, negative growth is shrinking, etc.

A program designed to calculate gain can output the result as "Gain: -20 dB" and it is not incorrect.

mikerj:

--- Quote from: soldar on August 09, 2019, 06:39:49 am ---
--- Quote from: radiolistener on August 09, 2019, 03:31:50 am --- Negative gain in dB is not a gain, this is attenuation :)
--- End quote ---

Attenuation is the same as "negative gain" and both are correct. Just like a negative profit is a loss, negative growth is shrinking, etc.

A program designed to calculate gain can output the result as "Gain: -20 dB" and it is not incorrect.

--- End quote ---

Exactly, the sign changes depending on whether you refer to a value as a gain or an attenuation.

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