How to think in dB


The dB (decibel) is one of the most common units in engineering, yet also one of the most confusing, especially when it comes to manipulating S-parameters. Here is how not to be confused.

How to think in dB

The Bel is a fundamentally new unit, which was originally established in 1928 by The Bell System to describe sound levels. This scale has since been generalized to relate to the log of the ratio of any two power levels.

The most important principle of the Bel scale to keep in mind is that it is, without exception, by definition, the ratio of powers. It originally related to sound level powers, but has since been generalized to all types of powers. [ ]

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