How do we model the frequency response of the Bartlett Window Filter in the ADIS1646x and ADIS1647x MEMS IMUs?
NOTE: This information applies to the ADIS16460, ADIS16465, ADIS16467, ADIS16470, ADIS16475 and ADIS16477 MEMS IMUs.
Let's start by breaking this filter down into two averaging filter stages, which operate in a cascade configuration, as the ADIS16475 datasheet (revision A) illustrates in Figure 16 (see page 12).
The Scientist and Engineer's Guide to Digital Signal Processing (1999, Chapter 15, page 280) offers the following transfer function for an
Since the ADIS1646x/ADIS1647x Bartlett Window Filter uses two of these stages, in a cascade configuration, its transfer function is the square of the transfer function for the averaging filter. The following three curves were generated using this formula in the MATLAB environment (using the attached m-script file, ADIS1647xFIR.m). These three curves represent the same responses, with three different scales on the vertical axis.