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Thermal Noise Power & Voltage

Thermal Noise Power

Noise power is based on the thermal noise power at the input of the system, along with system gain and noise figure:

Thermal noise power equation (W) - RF Cafe, where Noise power equation formula constants - RF Cafe

 

Thermal noise power (dBW) - RF Cafe

 

Multiply by 1000 to obtain milliwatts and then convert to dBm units:

 

Thermal noise power equation (dBm) - RF Cafe 

or, factoring out the 1000:

Thermal noise power (dBm) equation - RF Cafe 

 

Now that we have the thermal noise at the input, add the system gain and the additional noise added by the system (the NF) to get the noise power at the output:

Total system noise equation- RF Cafe 

Thermal Noise Voltage

Thermal noise voltage equation - RF Cafe

Thermal Noise Voltage as a Function of Resistance and Bandwidth - RF Cafe

Related Pages on RF Cafe

- Noise Power and Voltage

- Cascaded Noise Figure

- Noise Figure Meters & Noise Generators

- Noise Sources

"Noise and Interference" - WebEE Tutorial

About RF Cafe

Kirt Blattenberger - RF Cafe Webmaster

Copyright: 1996 - 2025
Webmaster: Kirt Blattenberger,
   BSEE - KB3UON - AMA92498

RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The World Wide Web (Internet) was largely an unknown entity at the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps while tying up your telephone line, and a lady's voice announced "You've Got Mail" when a new message arrived...

Copyright  1996 - 2026

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