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*Log _{10}(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

**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