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# LSM6DS3 Gyroscope anti-aliasing filter configuration

Associate II

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

6 REPLIES 6

Maybe the question is what is bandwidth.

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.

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

ST Employee

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 🙂

Associate II

Hi @RhSilicon ,

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

Associate II

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

Best,

Rob

ST Employee

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