Decibels, or dB units, provide a convenient way to express relative levels between powers that differ by many orders of magnitude. The mathematical manipulation of dB units can also make it easier to consider devices which attenuate or filter power, as operations involving multiplication or division in linear units involve addition and subtraction in dB units.
The relative power in dB units is ten times the logarithm (in base 10) of the ratio of the powers (expressed in the same units). dBm units are common, where the power in milli-Watts is compared to a 1mW power level, so 0dBm is one milliwatt.
Related Terms: Power