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How Does a noise measuring meter work ?

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aley_i

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Hello,
Can anybody please tell me that in noise measuring equipment after the A/D conversion is there anyway besides as discrete fourier transform or an fft to measure noise levels at different frequencies? what techniques do most commercial noise measuring equipment producers use?
Thank you
 

RCinFLA

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What kind of noise measurement are you referring to. Sideband noise of an RF source, Noise figure, or equivalent noise spec for an op amp?
 

aley_i

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What kind of noise measurement are you referring to. Sideband noise of an RF source, Noise figure, or equivalent noise spec for an op amp?

i am just referring to audio noise measuring equipment or sound level meters that tell us the sound levels at different frequencies in the hearing band range.
 

RCinFLA

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It it either a conventional heterodyne conversion or FFT to an rms volt reading.
 

zorro

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Hi,

In audio, what is needed is mesaurement in bands with logarithmic spacement and width. Not in equally-spaced, constant-width like in FFT.
An usual mean is to have a bank of filters of third-of-octave width followed by power level meter.
Regards

Z
 

FvM

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An usual mean is to have a bank of filters of third-of-octave width followed by power level meter.
Yes. Classical audio spectrum analyzers have been using analog bandpass filters, looking at today's instruments, spectrum analysis is a software option achieved with digital filters.
 

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