The reference value used for magnitude in dB from FFT Spectrum (Mag-Phase).vi

[chassan]

Hello folks,

What reference magnitude does the "FFT Spectrum (Mag-Phase).vi" use when calculating the magnitude in dB?

In other words, since amplitude in dB = 20log(A1/Aref), and A1 is from my measured signal, what is Aref (noise floor, dc component, other)?

Best Regards,

Chris 

[Andy_C.]

Hey Chris,

By default, if you are doing a FFT spectrum, Aref is 1dB.

[Darin.K]

Just being anal here, Aref is 1 (no dB). 

[chassan]

Andy C.

Thanks for the information.

Best Regards,

Chris

[chassan]

Hi Darren K.,

A unitless "1".  Your point has been duly noted.

Best Regards,

Chris