Asymptotic Waveform Evaluation (AWE) (Pillage & Rohrer, TCAD April 1990)
AWE is a qth-order extension of the Elmore delay for general, lumped linear(ized) RLC circuits.
AWE calculates a “q” time- constant model of the impulse response, 1?q ? N, where N is the number of poles (natural frequencies) in the circuit.
The q unknown time- constants, or poles, of the circuit, are obtained through a moment matching technique (called a Padé approximation)
Using this, an Nth order system (with N poles) is modeled by a (reduced) qth-order system (with the q most dominant poles)