Damping

A frequently occurring cause of errors in optical bus systems is too high an optical loss during the transmission of the light waves. This loss is also called "damping". In order to evaluate the condition of an optical data bus, the optical damping must be measured. It is given in dB (decibel) . Here the decibel is not a physical unit, such as metre or second, but rather it more often describes the ratio of two values. The decibel unit is also known for other measurements (e.g. sound level).

Damping is described as the ratio of the transmitting power to the receiving power. In addition there is a logarithmic factor  so that the following formula is used for the calculation:

 

Example: