DeciBel relative to overload (dBov) is a measure of how much below the maximum amplitude is the signal. This measure is used when, for example, there is a maximum digital representation for the signal like a fixed number of bits to encode its amplitude. Exceding that maximum amplitude can either result in clipping or overflow. If $v$ is the amplitude of the signal that we want to measure and $v_{ov}$ the overload amplitude, the amplitude ratio in decibels is: $ L_{ov} = 20 \log_{10}\left( \frac{v}{v_{ov}}\right) $ Values in dBov are always negative.