LSM6DS3 Gyroscope anti-aliasing filter configuration

[RobGeografo]

Hi everyone,

I am using an LSM6DS3 IMU sensor for my current project.

In Application Note AN4650, I read that the gyroscope analog signal coming from the mechanical parts is filtered by a low-pass anti-aliasing filter (having a constant bandwidth). Do we know what is the constant bandwidth?

Regards,

Rob

[RhSilicon]

Maybe the question is what is bandwidth.

(https://www.sfu.ca/sonic-studio-webdav/handbook/Filter.html)

Bandwidth is the difference between the upper and lower frequencies in a continuous band of frequencies.

In electronic filter design, a filter specification may require that within the filter passband, the gain is nominally 0 dB with a small variation, for example within the ±1 dB interval. In the stopband(s), the required attenuation in decibels is above a certain level, for example >100 dB. In a transition band the gain is not specified. In this case, the filter bandwidth corresponds to the passband width, which in this example is the 1 dB-bandwidth. If the filter shows amplitude ripple within the passband, the x dB point refers to the point where the gain is x dB below the nominal passband gain rather than x dB below the maximum gain.

https://en.wikipedia.org/wiki/Bandwidth_(signal_processing)

An anti-aliasing filter (AAF) is a filter used before a signal sampler to restrict the bandwidth of a signal to satisfy the Nyquist–Shannon sampling theorem over the band of interest.

https://en.wikipedia.org/wiki/Anti-aliasing_filter

[Federica Bossi]

Hi @RobGeografo ,

As mentioned at page 13 of AN4650, The anti-aliasing filter bandwidth depends on the selected accelerometer ODR as shown in the table:

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

[RobGeografo]

Hi @Federica Bossi,

That's for the accelerometer, isn't it? Or is it the same for the gyroscope?

Best,

Rob

[RobGeografo]

Hi @RhSilicon ,

Thank you for your reply.

The accelerometer anti-aliasing filter bandwidth can be selected using BW_XL [1:0].

The gyroscope anti-aliasing filter bandwidth seems to be constant. Do we know the constant value? Is it just half of the configured ODR?

Thanks

Rob

[Federica Bossi]

Hi @RobGeografo ,

What I sent is for accelerometer, for the gyroscope the information about the anti-aliasing filter is reserved.

However if you give me more details about your application and why you are interested in the bandwdith of the anti-aliasing filter I may help you.

Thanks 

[RobGeografo]

Hi @Federica Bossi,

Could you please give me your e-mail address and I can give you more details offline?

Best,

Rob