measure FFT RMS from spectrum values

[tintin_99]

Hi Could you please let me know how can I calculate the RMS FFT level of the above spectrum. I know value of df and the magnitide numbers but I don't know how can I calculate the RMS value. For the following grapg my audio analyser shows value of about -91 dBV. Do we have any function in LabVIEW to do it

[NI-MarkN]

Hi,

If it's a simple RMS analysis you're after check out the Amplitude and Level Measurements Express VI. You can simply feed the waveform as an input and get lots of different analysis outputs as explained on this page: https://www.ni.com/docs/en-US/bundle/labview-api-ref/page/vi-lib/express/express-analysis/ampandleve...

Having a look at the Spectral Measurements Express VI might also be useful (https://www.ni.com/docs/en-US/bundle/labview-api-ref/page/vi-lib/express/express-analysis/spectral/x...

If you are interested in lower-level approach there are functions such as Averaged DC-RMS VI (more info: https://www.ni.com/docs/en-US/bundle/labview-api-ref/page/vi-lib/measure/madcrms-llb/averaged-dc-rms...

Hope that helps!