Noise floor

[1] Avoiding interference between electrical systems is the distinct subject of electromagnetic compatibility (EMC).

In a measurement system such as a seismograph, the physical noise floor may be set by the incidental noise, and may include nearby foot traffic or a nearby road.

In special circumstances, the noise floor can also be artificially lowered with digital signal processing techniques.

Signals that are below the noise floor can be detected by using different techniques of spread spectrum communications, where signal of a particular information bandwidth is deliberately spread in the frequency domain resulting in a signal with a wider occupied bandwidth.

Every additional 6.02 dB of noise floor corresponds to a 1-bit reduction of the effective number of bits of an analog-to-digital converter or digital-to-analog converter.

Image showing the screen of a spectrum analyzer to illustrate a measurement noise floor.
Measurement from a spectrum analyzer showing a noise-like measurement from an unspecified component.