The unit of measure used to indicate relative changes insignal intensity or sound volume.

A logarithmic unit that expresses ratios of powers, voltages and currents. The scale is logarithmic. It is commonly used for signal-to-noise ratios and for the evaluation of sound volume. Written as dB

Units of measurement expressing ratios using logarithmic scales to give results related to human aural or visual perception.

Many different attributes are given to a reference point termed 0 dB – for example a standard level of sound or power – subsequent measurements then being relative to that reference.

Many performance levels are quoted in dB – for example signal to noise ratio (S/N). Decibel ratios are given by the expression: 20log 10 (Level 1/Level 2) where level 1 and 2 could be audio,video or any other appropriate voltage levels.