Incremental Design for Linear Circuits

In this paper, we present a framework for performing incremental design in the domain of linear circuits (Kerr 1977 ; Lancaster 1974 ; Walton 1987) . By incremental design, we mean the modification of an existing design to meet additional design goals while not denying certain design constraints . We start with a given circuit and want to modify aspects of its behavior while not changing others . Through means-ends search, we add components to the circuit to achieve the desired behavior without violating given constraints . The means-ends solution is based on a constraint-based model derived from circuit theory . A given design problem is first solved in terms of a qualitative model of the circuit . The framework we present is also capable of determining numerical values of parameters associated with the components added by the design process . This is accomplished by using the operating conditions of the circuit as input and the values of the parameters as output and running our constraint propagation system to determine the output values . This feature allows us to complete the design process, combining qualitative and quantitative reasoning .