A-law algorithm

Template:No footnotes In telecommunication, antenna noise temperature is the temperature of a hypothetical resistor at the input of an ideal noise-free receiver that would generate the same output noise power per unit bandwidth as that at the antenna output at a specified frequency.

Antenna noise temperature has contributions from several sources:

• Galactic radiation
• Earth heating
• The sun
• Electrical devices
• The antenna itself

Galactic noise is high below 1000 MHz. At around 150 MHz, it is approximately 1000K. At 2500 MHz, it has leveled off to around 10K.

Earth has an accepted standard temperature of 290K.

The level of the sun's contribution depends on the solar flux. It is given by

$T_{A}=3.468F{{\lambda }^{2}}10^{G/10}$

where $F$ is the solar flux,

$\lambda$ is the wavelength,

and $G$ is the gain of the antenna in decibels.

The antenna noise temperature depends on antenna coupling to all noise sources in its environment as well as on noise generated within the antenna. That is, in a directional antenna, the portion of the noise source that the antenna's main and side lobes intersect contribute proportionally.

For example, a satellite antenna may not receive noise contribution from the earth in its main lobe, but sidelobes will contribute a portion of the 290K earth noise to its overall noise temperature.

See also

• Noise Temperature
• Federal Standard 1037C
• MIL-STD-188

References

43 year old Petroleum Engineer Harry from Deep River, usually spends time with hobbies and interests like renting movies, property developers in singapore new condominium and vehicle racing. Constantly enjoys going to destinations like Camino Real de Tierra Adentro. 20 year-old Real Estate Agent Rusty from Saint-Paul, has hobbies and interests which includes monopoly, property developers in singapore and poker. Will soon undertake a contiki trip that may include going to the Lower Valley of the Omo.

My blog: http://www.primaboinca.com/view_profile.php?userid=5889534