Computing H∞-norm of discrete-time periodic systems — A quadratically convergent algorithm

We study the l 2 -induced norm, or H ∞ -norm, of discrete-time periodically time varying (PTV) systems and propose a quadratically convergent algorithm to compute it. Our method involves numerically stable computations (periodic Schur decomposition) and works even for the descriptor case. This work has connections to stability radii problems. Among other things, we clarify the relationship between various TI representations of a PTV system.