Reduced-Order Modeling of Time-Varying Systems

We present a theory for reduced-order modeling of linear time-varying systems, together with efficient numerical methods for application to large systems. The technique, called TVP (Time-Varying Pade), is applicable to deterministic as well as noise analysis of many types of communication subsystems, such as mixers and switched-capacitor filters, for which existing model reduction techniques cannot be used. TVP is, therefore, suitable for hierarchical verification of entire communication systems. We present practical applications in which TVP generates macromodels which are more than two orders of magnitude smaller, but still replicate the input-output behavior of the original system accurately. The size reduction results in a speedup of more than 500.