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Comment by lifthrasiir | Hacker News Reader

As I've said in the other comment, I believe this should be ultimately addressed by the SI.

I would agree.

Right now what we've got is basically "millis", and you just have to know whether the speaker is talking about length or mass. I like your proposal.

I actually want those suffixes mandatory, because there may be multiple plausible suffixes for each use. For example the loudness might be dB(A), dB(B), dB(C), dB(D) depending on the exact curve or even dB(SPL) if the sound pressure level is used as a proxy. So it is much more confusable than, say, "millis" when suffixes are implied.

There is a legitimate use of dB without a reference point. An attenuator attenuates by -20dB, not by -20dBm.

This is right and all... But this usage still leads to confusion about what you are measuring your filter by.

There are filters we measure on power, there are filters we measure on signal amplitude, and "signal amplitude" can be ambiguous on some contexts too. There should be a way to specify this one better.

Well, dB is fully specified in that regard. It's always power. You can calculate the voltage gain from it under certain assumptions, and under normal assumptions you get that factor 2. But a -20dB attenuator will always reduce the power by a factor of 100.

There is also antenna gain in decibels.

dBi

It's SI that caused some of this weirdness in the first place by discouraging "same unit" ratio units like m/m or kg/kg and then intentionally disallowing those derived units to be individually named. On the one hand, there is a sort of "clean sense" that km/km cancels out and disappears, but on the other hand there are too many "unitless quantities" in SI that are very formula-specific that a ratio unit would better explain and help save the wrong thing from being plugged into the formula. It's enough of a need that scientists found themselves using worse tools like deciBels for some of these "same unit" ratio formulas just to have "some unit at all" to avoid accidental unit-less mistakes.

Some Scientists and Mathematicians would rather use random log_10(x) functions than allow units like km/km in their formulas. It's wild, and SI has been a part of those decisions all along.

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