What is DANL?

DANL or displayed average noise level is a measure used to define the sensitivity of a spectrum analyzer. The DANL specifies all the internal noise of the spectrum analyzer referenced to 1 Hz and represented in dBm/Hz. The DANL is frequency dependent and it increases with frequency. Spectrum analyzers use preamplifiers to reduce DANL. The instrument is unable to measure any input signal that is below this level.

Displayed Average Noise Level (DANL) is the noise generated internally by a test instrument. It can be thought of as the amplitude of the spectrum analyzer’s noise floor over a given frequency range with the input terminated in 50 ohms. The instrument/analyzer cannot measure any input signals below this value.

The DANL value is specified in dBm, and is measured at the narrowest resolution bandwidth (RBW) setting to attain the best sensitivity. The DANL value in datasheets is either given with a specific resolution bandwidth (Ex. -135 dBm @1 kHz RBW) or in dBm/Hz (Ex. -160 dBm (Hz)).