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LIS3DSH - Effective resolution calculation help

Question asked by Fabio Filippa on Feb 16, 2018
Latest reply on Feb 20, 2018 by Fabio Filippa

Hi all,

I'm try to understand what can be the real usable resolution of the LIS3DSH accelerometer because I need to evaluate it for inclometric measurements.

From the datasheet I can read a PSD=150ug/sqrt(Hz) @ ODR=100 Hz then BW=50 Hz

For a analog output with one single pole filter the overall noise can be calculated as PSD*SQRT(1.57*BW),supposing to use same calculation we have 150ug*SQRT(78.5)=1.33mg, having a sensitivity equal to 0.06 mg/digit @ ±2g we have:

1.33mg/0.06 mg/digit = 22.16 digit of error then instead the theoretical 16 bit we should have 65536/22.16=2957.4 digit which is approx equivalent to 11-12 bit of final resolution.

I kindly ask if this is a correct mode to estimate the real final resolution by taking in account the effect of the noise or if I missing some point and then what can be the correct way to perform this calculation.

 

Hope someone can point me in the correct direction.

 

Thanks in advance and

best regards

Fabio

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