# insertion loss - Computer Definition

- The attenuation, or loss in signal power, resulting from the insertion of a component, such as a connector or splice, in a circuit. Insertion loss is measured as a comparison of signal power at the point the incident energy strikes the component and the signal power at the point it exits the component. Insertion loss typically is measured in decibels (dB), although it also may be expressed as a coefficient or a fraction. A negative loss is a gain. See also attenuation, dB, and insertion gain.
- In a fiber optic transmission system (FOTS), insertion loss is a measure of loss across a circuit due to all factors, including absorption, bending loss from both macrobends and microbends, diffusion, dispersion, Fresnel reflection, and leaky modes. See absorption, bending loss, macrobend, microbend, diffusion, dispersion, Fresnel reflection, insertion gain, and leaky mode.

The amount of loss attributed to a particular device being used in (inserted into) the system. For example, a circuit added to filter out unwanted frequencies may reduce the output current by some amount. See injection loss.