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Noise Power & Voltage

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

PThermalNoise  = k * T * B [Watts], where RF Cafe - Noise power equation formula

 
Multiply by 1000 to obtain milliwatts and then convert to dBm units or convert to dBW units and add 30 dB:

PThermalNoise [dBm] = 10 * log10 (1000 * k * T * B)

or

PThermalNoise [dBm] = 10 * log10 (k * T * B) + 30


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:

 PNoise@Output [dBm] = PNoise@Input + GainSystem + NFSystem




VThermalNoise  = Sqrt (4 * k * T * B)  [Volts]


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




"Noise and Interference" - WebEE Tutorial

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