Patent ID: 7036097

Claim:
A method for designing a cascade of digital filters for use in controlling an electrolytic reduction cell, the cascade having a filter order corresponding to a number of digital filters in the cascade and each digital filter having a specifying parameter, the method comprising the steps of: selecting a lowest value for the parameter for each digital filter such that each of a group delay and a settling time are within predetermined performance characteristics; determining if a smoothing quality of the cascade of digital filters is within predetermined performance characteristics; increasing the filter order by one when the smoothing quality is not within predetermined performance characteristics; determining if a result of a time domain analysis is within predetermined performance characteristics; and increasing the filter order by one when the result of the time domain analysis is not within predetermined performance characteristics; wherein the filter order and the parameters for each of the digital filters is used to specify the cascade of digital filters to be used in controlling the electrolytic reduction cell.