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ADXL355 - Frequency spectrum and Noise

Question asked by NeonGod on Jan 23, 2018
Latest reply on Feb 1, 2018 by NevadaMark

Hi,

 

I have two questions:

1) Regarding the internal low-pass filter of the ADXL355 (eval. board): If I understood the data sheet correctly, the filter cutoff frequency is at 1/4 of the output data rate (e.g. 62.5 Hz ODR -> 15.625Hz Filter corner frequency). However the frequency spectrum of my measured data shows features even at higher frequencies, where i would assume the filter response to be close to zero. It would be awesome if you could help me understand the cause of this.

 

2) Noise: The noise level along the z-axis of the accelerometer seems to agree with the theoretical value obtained from the noise density from the data sheet, however for the other two axis, the noise seems to be about a factor of 2 lower. Is this expected?

 

Thank you in advance

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