Electronics World articles Popular Electronics articles QST articles Radio & TV News articles Radio-Craft articles Radio-Electronics articles Short Wave Craft articles Wireless World articles Google Search of RF Cafe website Sitemap Electronics Equations Mathematics Equations Equations physics Manufacturers & distributors LinkedIn Crosswords Engineering Humor Kirt's Cogitations RF Engineering Quizzes Notable Quotes Calculators Education Engineering Magazine Articles Engineering software RF Cafe Archives Magazine Sponsor RF Cafe Sponsor Links Saturday Evening Post NEETS EW Radar Handbook Microwave Museum About RF Cafe Aegis Power Systems Alliance Test Equipment Centric RF Empower RF ISOTEC Reactel RF Connector Technology San Francisco Circuits Anritsu Amplifier Solutions Anatech Electronics Axiom Test Equipment Conduct RF Copper Mountain Technologies Exodus Advanced Communications Innovative Power Products KR Filters LadyBug Technologies Rigol TotalTemp Technologies Werbel Microwave Windfreak Technologies Wireless Telecom Group Withwave RF Cafe Software Resources Vintage Magazines RF Cafe Software WhoIs entry for RF Cafe.com Thank you for visiting RF Cafe!
Temwell Filters

everythingRF RF & Microwave Parts Database (h1)

Copper Mountain Technologies (VNA) - RF Cafe

Please Support RF Cafe by purchasing my  ridiculously low-priced products, all of which I created.

RF Cascade Workbook for Excel

RF & Electronics Symbols for Visio

RF & Electronics Symbols for Office

RF & Electronics Stencils for Visio

RF Workbench

T-Shirts, Mugs, Cups, Ball Caps, Mouse Pads

These Are Available for Free

Espresso Engineering Workbook™

Smith Chart™ for Excel

Innovative Power Products Resistors Terminations

Noise Figure  <-->  Noise Temperature Calculator

Noise figure equation graph - RF Cafe

NF(dB) TN (°K) NF(dB) TN (°K)
0.1 7 2.1 180
0.2 14 2.2 191
0.3 21 2.3 202
0.4 28 2.4 214
0.5 35 2.5 226
0.6 43 2.6 238
0.7 51 2.7 250
0.8 59 2.8 263
0.9 67 2.9 275
1.0 75 3.0 289
1.1 84 3.1 302
1.2 92 3.2 316
1.3 101 3.3 330
1.4 110 3.4 344
1.5 120 3.5 359
1.6 129 3.6 374
1.7 139 3.7 390
1.8 149 3.8 406
1.9 159 3.9 422
2.0 170 4.0 438

This JavaScript calculator converts between noise figure and the equivalent noise temperature.

Conversion Between Noise Figure
and Noise Temperature

Noise Temperature (K) = TREF *

Noise Figure (dB) = 10 * log10 RF Cafe - Noise temperature to noise figure conversion equation

Note that unless otherwise specified TRef = 290 K

Calculated values do not change until the "Calculate" button is clicked.
Reference Temperature: K    
Noise Figure: dB =
Noise Temperature: K =

Numerical inputs are not error trapped but are converted to absolute values (no negatives).

Just what is noise temperature and why is it used? Simply put, noise temperature is the temperature at which a resistor at the component / system input would generate the same amount of noise measured at the output. It goes back to the familiar kTB calculation for thermal noise power. Noise temperature is often used in calculating the overall noise figure of a system that includes an antenna at the input. That is because strictly speaking, a 1-port device like an antenna cannot be defined in terms of noise figure. If you begin with a system at room temperature (290 K) and add a component at the input that itself has a noise temperature of 290 K, the doubling of noise power increases the overall noise figure by 3 dB (2*290-290=290). A 6 dB increase is a 4x increase in noise power (4*290-290=870). Cascaded noise temperature is done just like with noise figure.

   

Related Pages on RF Cafe

- Noise Figure <--> Noise Temperature Calculator

- Noise Power and Voltage

- Cascaded Noise Figure

- Noise Figure Meters & Noise Generators

- Noise Sources

Innovative Power Products Resistors Terminations
Rigol DHO1000 Oscilloscope - RF Cafe

withwave microwave devices - RF Cafe

Crane Aerospace Electronics Microwave Solutions: Space Qualified Passive Products