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Signal to noise ratio semantics
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Circlotron:
When two quantities are compared, AFAICT if their values differ greatly then there is a high ratio between them. If their values are closer to each other then there is a low ratio. If that is the case (and maybe it isn't?) then why if a signal is very weak in a noisy environment so that the relative strengths of each differ greatly, is that considered to be a LOW s/n ratio? Why not a high ratio? Or for that matter, with a car gearbox when the input shaft rotates several times for the output shaft to rotate once we say it has a LOW ratio, but the numeric ratio is relatively great compared to top gear. I know it's just semantics but there must be some history in this.
Brumby:
It's in the terminology: Signal to Noise.  We're interested in the amount of signal and if that's down compared to the noise, we call it low.

If you want it the other way around, then use Noise to Signal.


JMO
Circlotron:

--- Quote from: Brumby on August 30, 2022, 04:19:22 am ---It's in the terminology: Signal to Noise.

--- End quote ---
If the terminology was "signal to noise" then yes, I agree.
But if the terminology is "signal to noise ratio" that's when the confusion starts.
SiliconWizard:
I don't understand where the confusion comes from. Possibly we are missing something.

Signal-to-noise ratio = ratio of signal over noise = amplitude of signal / amplitude of noise.

Brumby:
I don't see the confusion either.  By definition, the order of the two components is clear.  It's the ratio of signal to noise.  Simple.

There's nothing mysterious about the term ratio.  It is exactly what it says.  Whether gears are 10:1 or 1:10 is clarified by the descriptor.  The descriptor here is specified every time you use such a reference: Signal to Noise.

Say you have a signal that +5dBm and noise of -5dBm, the SNR is +10dB
If you have a signal that -5dBm and noise of +5dBm, the SNR is -10dB

If you want the inverse of Noise to Signal, then example 1 is -10dB and example 2 is +10dB.  That would be confusing.
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