My research group and I have had trouble reconciling the specs given in the ADXL355 datasheet for Noise Density.
My understanding of the device so far is that "effective" bandwidth in the ADXL 355 is the ODR/4. We are using an I2C bus with an ODR of 2KHz so 2KHz/4 = 500Hz, and not the expected Nyquist frequency due to an internal LPF. The second is that there is a coefficient present in the calculation for RMS noise based on this blog post: https://www.analog.com/en/products/landing-pages/001/accelerometer-specifications-definitions.html
Using the values from the ADXL355 datasheet, I've computed:
import numpy as np import pickle def rms(x): return np.sqrt(np.mean(np.square(x))) def rmsd(x, mean): return rms(x - mean) with open('ADXLbenchtest10182022_1020.pickle', 'rb') as handle: axisdata = pickle.load(handle) xs = axisdata['X-Axis'] xout = rmsd(xs, np.mean(xs), len(xs)) print(xout)
Cleaned up presentation so issue is clearer.
[edited by: mrem21 at 8:33 PM (GMT -4) on 19 Oct 2022]