Software for Modeling, Analysis, and Design of Filters With LC Sections and Quartz Crystals

Filters that consist of LC sections and quartz crystals can be modelled by LC equivalent sections and represented as rational functions of very high order. In this paper, we present software that can be used as the template notebook for modeling, analysis and design of the known filter structure. A method for automated generation of schematic model of crystal filter as a ladder LC structure is described. The filter transfer function can be derived as closed-form expression from schematic model so that other analyses can be performed, such as sensitivity analysis and parameter optimization in order to satisfy desired filter specifications.