A knowledge-based system for the evaluation and redesign of digital circuit networks

A methodology is presented for evaluating and redesigning digital circuit networks with signal integrity problems and a tool which implements this methodology. Evaluation consists of simulating the behavior of the circuit, analyzing the simulation results to reveal signal integrity problems, and diagnosing the causes of each problem. Redesign consists of finding an appropriate method to modify the structure of a faulty circuit based on the evaluation results, forming a plan out of the operators which are included in the method and applying the plan. Evaluation and redesign of the circuit are performed in two abstraction levels. Part of the work has gone into identifying and implementing the types of circuit knowledge that are necessary for the realization of the methodology. The tool which implements the methodology is called the transmission-line troubleshooting system (TLTS). TLTS executes the evaluation-redesign loop until a problem-free circuit is obtained. TLTS is implemented in the expert-system language ORBS