Details on filtering of Accelerometer

[DM.10]

Trying to understand the internal mechanics of the accelerometer I'm using a bit better.

Specifically, I'm using a H3LIS331DL.

I have settings that will look like this:

ODR = 1,000 Hz

BW = 500 Hz

Filter = 780 Hz

However, there's not much detail in the datasheet on the filtering. Is that the 3dB point?

If there was a 100g 1,000 Hz impulse - would I be expecting 0g as a reading?

[Eleon BORLINI]

Hi @DM.10​ ,

if you set the ODR (i.e. at 1000Hz), you will have the maximum acquired frequency up to 500Hz.

The BW is related to the sensor -3dB cutoff frequency, so if you would have set an ODR > 2*BW, you would have measured -3dB frequency at 780 Hz indeed. Setting 780Hz means having a flat sensor FR up to ODR/2.

There is an anti-alias filter, so theoretically the sensitivity above ODR/2 is negligible, but in practice you will have a residual sensitivity even at 1000Hz (you will not see 0g, but few g).

-Eleon