A method for designing a cascade of digital filters for use in the control of
an
electrolytic reduction cell by specifying the frequency and time response characteristics
of the transfer function of the cascade of digital filters. The digital filters
are exponential filters. The number of smoothing functions (i.e filters), each
having different filter parameter values, is determined according to desired performance
characteristics in the frequency and the time domains. These characteristics include:
smoothing quality (specifiable in terms of passband, stopband and transition band
of the filter frequency response profiles), group delay, and stabilization time.
The use of the cascade of digital filters to control a reduction cell. A system
for controlling a reduction cell comprising the cascade of digital filters. A process
for electrolytic reduction of alumina comprising a step of filtering measurements
of an electrical parameter using the cascade of digital filters.