Would it be possible using the PCSU1000 spectrum analyser to measure the (A-weighted) noise level of an amplifier ?
e.g. set analyser to 30KHz range, then using the markers, measure the noise level average?
What would be the best FFT window / FFT options / markers to use?
You may measure the noise voltage density by using the Spectral Density dBV/sqrt(Hz) marker. To smooth the variations of the noise select RMS Average mode. There is no big difference what FFT window you select. You may use as well rectangular window in this case.
To get the A-weighting to the spectrum you have to use a separate filter circuit or save the FFT data and import to spreadsheet (e.g. Excel) and do the weighting calculations there.
A schematic diagram for an A-Weighting Filter you’ll find by this link: sound.westhost.com/project17.htm