Acceleometer Noise and FFT

1. What causes accelerometer noise?
2. How is accelerometer noise calculated?
3. What is FFT analysis in vibration?
4. How do I get PSD from FFT?

What causes accelerometer noise?

Noise is an unwanted signal output that does not represent true vibration. Lower noise allows smaller vibration signals to be read by an analyzer. Accelerometer amplifiers, like all electronic amplifiers, have some noise. This noise is produced by the electronic components in the amplifier.

How is accelerometer noise calculated?

To determine the accelerometer RMS noise in g's, divide the RMS voltage by the sensitivity of the accelerometer. The noise density is a useful parameter because it allows you to quickly calculate the accelerometer noise (and resolution) for different filter designs.

What is FFT analysis in vibration?

The fast Fourier transform (FFT) is an efficient algorithm used to compute a discrete Fourier transform (DFT). This Fourier transform outputs vibration amplitude as a function of frequency so that the analyzer can understand what is causing the vibration.

How do I get PSD from FFT?

To get the PSD from your FFT values, square each FFT value and divide by 2 times the frequency spacing on your x axis. If you want to check the output is scaled correctly, the area under the PSD should be equal to the variance of the original signal. Save this answer.