# Carrier-to-noise-density ratio

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In satellite communications, **carrier-to-noise-density ratio** (* C/N_{0}*) is the ratio of the carrier power

*C*to the noise power density

*N*, expressed in dB-Hz. When considering only the receiver as a source of noise, it is called

_{0}**carrier-to-receiver-noise-density ratio**.

It determines whether a receiver can lock on to the carrier and if the information encoded in the signal can be retrieved, given the amount of noise present in the received signal. The carrier-to-receiver noise density ratio is usually expressed in dBHz.

The noise power density, *N _{0}*=

*kT*, is the receiver noise power per hertz, which can be written in terms of the Boltzmann constant

*k*(in joules per kelvin) and the noise temperature

*T*(in kelvins).

## See also[edit]

- C/N: carrier-to-noise ratio
- C/I: carrier-to-interference ratio
- E
_{b}/N_{0}: bit energy to noise density ratio

## References[edit]

This article incorporates public domain material from the General Services Administration document "Federal Standard 1037C" (in support of MIL-STD-188).