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pierrejaquier9
Visitor II
September 14, 2012
Question

LIS3DH noise characteristics

  • September 14, 2012
  • 1 reply
  • 753 views
Posted on September 14, 2012 at 16:03

Dear all,

I am using the LIS3DH configured with 1.25 kHz bandwith (ODR) and high resolution (12bits), full scale range of +/- 2g. I have a question regarding the noise I should expect at this frequency :

The datasheet gives an Acceleration noise density of 220 ug/sqrt(Hz). I found in a Freescale pdf the following note :

'' When this value (noise density) is multiplied by the square root of the measurement bandwidth, this result is the RMS acceleration noise of the

sensor at nominal VDD and temperature. Accelerations below this value will not be resolvable.  ''

In my case this calculation gives a peak to peak noise of 22 mg (about 5 bits). Is this reasoning correct ?

Thanks for your help.
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    1 reply

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    pierrejaquier9Author
    Visitor II
    September 20, 2012
    Posted on September 20, 2012 at 09:32

    Hello,

    Did somebody already characterize the noise of the LIS3DH accelerometer ? The only information available in datasheet isthe noise density of 220 ug/sqrt(Hz). Is this a white noise characteristics ?

    The results obtained with a BW of 625 Hz is as shown in the

    attached figure

    :

    Pratical results of RMS noise are close to 220 ug/sqrt(625), however the peak obseved in the FFT graph have higer amplitude.

    Let me know your opinion. Is this the intrinsic noise characteristics of the LIS3DH ?

    ________________

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