Can I set LIS2DW12 ODR to 1600Hz in High Performance mode with a BW of ODR/2?

MMart.11 · ‎2020-10-26

Currently I am using LIS2DW12 in my project with ODR set to 1600Hz in High performance mode. Reading the datasheet I found that the maximum bandwidth for this ODR ir 400Hz. I want to understand why tye maximum bandwidth for this setting is 400Hz and not 800Hz. I also want to know if it is possible to set the bandwidth to 800Hz with ODR set to 1600Hz.

Eleon BORLINI · ‎2020-10-27

Hi @Marco Aurélio Martins Mijam ,

you are basically right, in the sense that also when you select ODR = 1600Hz, you are limited to a bandwidth of 400Hz (so ODR/4). This is generally due to the fact that the MEMS sensor mechanical cutoff is around the same frequency of 400Hz, meaning that even if you could acquire data at 1.6kHz, you would anyway face a drop in the signal acquired after 400Hz (in frequency domain). If you want to go up in the detected signal frequency, you should use accelerometers as vibration sensors such as the IIS3DBW.

You can find more details in app note AN5038 at p.10.

Of course, running the acquisition with ODR 1600Hz instead of with ODR = 400Hz, you will get more points per second and you'll be able to reconstruct the actual mechanical "analog" signal / stimulus with higher accuracy.

-Eleon

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Eleon BORLINI · ‎2020-10-27

Hi @Marco Aurélio Martins Mijam ,

you are basically right, in the sense that also when you select ODR = 1600Hz, you are limited to a bandwidth of 400Hz (so ODR/4). This is generally due to the fact that the MEMS sensor mechanical cutoff is around the same frequency of 400Hz, meaning that even if you could acquire data at 1.6kHz, you would anyway face a drop in the signal acquired after 400Hz (in frequency domain). If you want to go up in the detected signal frequency, you should use accelerometers as vibration sensors such as the IIS3DBW.

You can find more details in app note AN5038 at p.10.

Of course, running the acquisition with ODR 1600Hz instead of with ODR = 400Hz, you will get more points per second and you'll be able to reconstruct the actual mechanical "analog" signal / stimulus with higher accuracy.

-Eleon