A DC stabilized log‐domain n th‐order multifunction filter based on the decomposition of n th‐order HP filter function to FLF topology

• Published in: International journal of circuit theory and applications 2009-12, Vol.37 (10), p.1075-1091
• Main Authors: Shah, N. A., Khanday, F. A.
• Format: Article
• Language: English
• ISSN: 0098-9886; 1097-007X
• DOI: 10.1002/cta.533

The design of high‐order log‐domain filters can be easily accomplished by transposing already known linear‐domain G m ‐C filter topologies to their counterparts in the log‐domain through the employment of a set of complementary operators. To achieve the G m ‐C filter topologies, the multiple feedback approach is widely used due to its accrued advantages. In this paper a synthesis approach for the development of an n th‐order multifunction log‐domain filter comprising lowpass (LP), highpass (HP) and bandpass (BP) filter functions is proposed. The approach is based on the decomposition of n th‐order HP filter function to follow‐the‐leader‐feedback (FLF) topology. The design is simple and simultaneously achieves nearly all of the chief advantages. The design offers superior performance factors vis‐à‐vis the ones recently reported. To verify the high‐order behavior of the topology, a 5th‐order multifunction filter was designed and the achieved simulated results verify the theory. Copyright © 2008 John Wiley & Sons, Ltd.