State-Space Synthesis of Current-Mode First-Order Log-Domain Filters

Authors: ALİ KIRÇAY, UĞUR ÇAM

Abstract: This paper proposes current-mode first-order log-domain filters, which are systematically derived using the state-space synthesis procedure. First-order low-pass, high-pass, and all-pass responses are obtained with different circuit types. The filter circuits have very simple structures, since they use only bipolar junction transistors (BJTs) and a grounded capacitor. They can be electronically tuned by changing an external current. The filters have a greater bandwidth due to inherently current-mode and log-domain operation. PSPICE simulations are given to confirm the theoretical analysis.

Keywords: Log-domain filters, current-mode circuits, state-space synthesis

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