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LIS3DSH - Effective resolution calculation help

FF1
Associate III
Posted on February 16, 2018 at 17:47

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

2 REPLIES 2
Miroslav BATEK
ST Employee
Posted on February 20, 2018 at 15:37

Yes, your calculation is correct.

Posted on February 20, 2018 at 15:55

Thank you Miroslav!

Best regards

Fabio