Useful tables and formulae
C.1 The deciBel
The deciBel (dB) represents a logarithmic ratio between two quantities. Of itself it is unitless. If the ratio is referred to a specific quantity (P2, V2 or l2 below) this is indicated by a suffix, e.g. dBμV is referred to 1μV, dBm is referred to 1mW.
|suffix||refers to||suffix||refers to|
|dBV||1 volt||dBA||1 amp|
|dBmV||1 millivolt||dBμA||1 microamp|
|dBμv||1 microvolt||dBμA/m||1 microamp per metre|
|dBV/m||1 volt per metre||dBW||1 watt|
|dBμV/m||1 microvolt per metre||dBm||1 milliwatt|
Originally the dB was conceived as a power ratio, hence it is given ...