This tool calculates the Noise floor of a spectrum analyzer. The noise floor represents the weakest possible signal that can be detected by the instrument.
Calculator
Enter
- Displayed Average Noise Level (DANL)
- Resolution Bandwidth
- Transducer Factor (LISN)
- Correction Factor
Formula
Spectrum Analyzer Noise Floor = DANL + 10*Log10(RBW) + Correction Factor + Transducer Factor
Correction and Transducer factors are used in EMC testing and this is also called the System Noise Floor.
Example Calculation
For a DANL of -151 dBm/Hz and RBW = 1 MHz, Transducer Factor = 3 dB and Correction Factor = 3 dB, the noise floor of the spectrum analyzer is -85 dBm. The tool also provides the Watt equivalent or 3.16*10-12 W.
The picture below shows the variation of noise level with bandwidth
![](https://i0.wp.com/www.3roam.com/wp-content/uploads/2024/03/Spectrum-analyzer-noise-level-vs-bandwidth-1024x537.png?resize=770%2C404&ssl=1)
Practical Note
The lower the noise floor of the spectrum analyzer, the better it is at detecting weaker signals and consequently the more expensive it is.
A good spectrum analyzer will have a noise floor of -160 dBm/Hz or better at lower frequencies.
Related Posts
- Receiver Sensitivity (every spectrum analyzer is a radio receiver)
- dBm per Hz to dBm
- Spectrum Analyzer Scan Rate Calculator
- Resolution Bandwidth Calculator