Decibels relative to full scale

What is Decibels relative to full scale?

Decibels relative to full scale meaning in Digital terms is The term dB FS (or dBFS) means decibels relative to full scale. It is used for amplitude levels in digital systems with a maximum available peak level, e.g., PCM encoding, where 0 dB FS is assigned to the maximum level. A signal that reaches 50 percent of the maximum level would, for example, have a value of -6 dB FS. All peak measurements will be negative numbers. Digital signals without any samples that reach the peak of 0 dB FS can still clip when converted to analog due to intersample peaks. Various official standards pertaining to signal measurement define full scale in terms of a sinewave tone of 997 Hz, thereby avoiding tones at any sub-multiple of common sampling frequencies.


reference: Federal Agencies Digital Guidelines Initiative – Glossary