State space representation for log domain filtering synthesis

摘要

New method for the state space representation of filters based on the companion form technique has been proposed. Itis useful for synthesis of log domain filters. For state space representation of a log domain filter, it is very important to havealmost equal coefficients of the state space equations since these coefficients are proportional to currents or voltages of thedesigned device. The method allows selection of two arbitrary parameters (α, β) to adjust these coefficients. By using thistechnique, more balanced state space equations can be obtained. This method offers an option to obtain desired adjustablecoefficients. It is particularly useful for synthesizing high order log domain circuits using state space methods. The proposedmethod is applied to second and fifth order log domain filter designs to show the application. Simulation resultsdemonstrated that different system equations which are determined by the proposed method affect the performance of thefilter.