Variations from a nominal operational voltage or current value on a power or signal line. Circuits are usually designed to function within a noise tolerance band or allowable noise budget.

1. Any unwanted disturbance within a dynamic electrical system. (e.g., undesired electromagnetic radiation in a transmission channel or device). 2. Any unwanted electrical disturbance or spurious signal which modifies the transmitting, indicating, or recording or desired data.

An unwanted electrical signal that produces an undesirable effect.

See noise.

Extraneous signals caused by externally radiated signals or electrical interferences within an ultrasonic instrument. A component of background noise.