How is the anti aliasing filter of ISM330DLC working: 1. Does the cutoff frequency adapt to different samplerate settings 2. What analog attenuation can be expected on vibration frequencies exceeding 50% of samplerate.

[GSvoe.1]

Do we risk folding of out of band high frequency vibration components down to the band of interest.

Appreciate any level of information you can share here.

[Eleon BORLINI]

Hi @GSvoe.1​ ,

the anti-alias filter is an analog filter just after the preamplifier, that cannot be configured in bandwidth.Instead, the downstream filters can be set according to, and the cutoff rate in this case is directly related to the ODR, according to the following table of the datasheet p.55:

The MEMS bandwidth (only for accelerometer ODR ≥ 1.67 kHz) is about 1.5kHz, see CTRL1_XL reg configurations.

If my reply answered your question, please click on Select as Best at the bottom of this post. This will help other users with the same issue to find the answer faster. 

-Eleon

[GSvoe.1]

Hello Eleon
And thank you for quick response!
You say below that the bandwidth is 1.5kHz. Our concern is the following:
If running with max samplerate, 6.6kHz, and sensor ISM330DLC is exposed for heavy vibrations in the range above 3.3kHZ, for example 4kHz, the only mitigation against data corruption from aliasing is the analog filter before the ADC.
How much will the 4kHz vibration be attenuated before entering the ADC?
Is it a first order (type RC) filter, or a multi order sharper filter?
Best regards
Geir

[Seenu]

Hello @Eleon BORLINI​  and @GSvoe.1​ ,

I am working on sensor ISM330DLC to capture vibration data to perform FFT. and able to run application on ST MCU.

If sensor ISM330DLC is exposed for heavy vibrations in the range above 3.3kHZ, for example 4kHz.

Is there a way that sensor provides any information or register update to indicate to the user that vibration is over limited?

Please assist to solve the issue.

Regards,

Seenu