The tool calculates the thermal noise floor of a radio receiver.
- Temperature in either Kelvin or Celsius
- Noise Figure in dB
Noise FloordBm = 10*Log10(kTB/(1 mW)) + NF
- T = Temperature in Kelvin
- B = Bandwidth in Hz
- k = Boltzmann’s constant
- NF = Noise Figure
Noise Floor of a Radio Receiver
In a radio receiver, the noise floor is the level below which a signal will not be detected. In practice, a signal has to be a few dB higher before it can be detected. This level is called the Minimum Detectable Signal level.
Example Noise Floor Calculation
Let’s calculate the noise floor of a LoRa receiver system.
For a temperature of 25oC, 125 kHz Bandwidth and a noise figure of 10 dB, the noise floor is -113 dBm. Increasing the antenna cable length will directly impact the noise figure and increase the noise floor.