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Modeling >> Behavioral Models >> CIC filter MATLAB Modelling
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Message started by Christoforos on Jun 12^th, 2014, 2:25am

Title: CIC filter MATLAB Modelling
Post by Christoforos on Jun 12^th, 2014, 2:25am

Hello!

I am modelling the decimation filter after a Sigma-Delta converter in MATLAB using the signal processing toolbox. The passband frequency is 10 Hz and the downsampling ratio is 512. As a decimation filter I am using the Hogenauer CIC filter. The filter is stable up to and including the 3rd order. From 4th order is becomes unstable. Also, when I look at teh zplane the poles of the filter are just outside or the unit circle. Can someone help me to fix this?

Thank you!