In satellite communications, carrier-to-receiver noise density (C/kT) is the ratio of the received carrier power to the receiver noise power density.

The carrier-to-receiver noise density ratio is usually expressed in dBHz

Decibel

The decibel is a logarithmic unit that indicates the ratio of a physical quantity relative to a specified or implied reference level. A ratio in decibels is ten times the logarithm to base 10 of the ratio of two power quantities...

.

The carrier-to-receiver noise density is given by


where C is the received carrier power in watts, k is Boltzmann's constant in joules per kelvin

Kelvin

The kelvin is a unit of measurement for temperature. It is one of the seven base units in the International System of Units and is assigned the unit symbol K. The Kelvin scale is an absolute, thermodynamic temperature scale using as its null point absolute zero, the temperature at which all...

, and T is the receiver system

System

System is a set of interacting or interdependent components forming an integrated whole....

 noise temperature in kelvins.

The receiver noise power density, kT, is the receiver noise power per hertz

Hertz

The hertz is the SI unit of frequency defined as the number of cycles per second of a periodic phenomenon. One of its most common uses is the description of the sine wave, particularly those used in radio and audio applications....

.