Logarithmic scales of measurement
DBFS
Decibels relative to full scale (dBFS or dB FS) is a unit of measurement for amplitude levels in digital systems, such as pulse-code modulation (PCM), which have a defined maximum peak level. The unit is similar to the units dBov and decibels relative to overload (dBO). The level of 0 dBFS is assigned to the maximum possible digital level. For example, a signal that reaches 50% of the maximum level has a level of −6 dBFS, which is 6 dB below full scale. Conventions differ for root mean square (RMS) measurements, but all peak measurements smaller than the maximum are negative levels. A digital signal that does not contain any samples at 0 dBFS can still clip when converted to analog form due to the signal reconstruction process interpolating between samples. This can be prevented by careful digital-to-analog converter circuit design. Measurements of the true inter-sample peak levels are notated as dBTP or dB TP ("decibels true peak"). (Wikipedia).
