Some spectrum analyzers, like the noise spectral density, can display the spectrum amplitude in nV/rt-Hz. However, without this capability, we can calculate the spectral density by dividing the spectral magnitude by the square root of the resolution noise bandwidth. It should be noted that usually we need a conversion factor to convert the resolution bandwidth into resolution noise bandwidth. Figure 6 shows the equation for converting the decibel milliwatt spectrum into spectral density. Figure 6 also shows the conversion factor table needed to convert the resolution bandwidth into noise bandwidth. Figure 7 shows an example of converting the spectrum in an example spectrum analyzer to spectral density.
