Tracking Coverage Artefacts for Periodic Signals using Sequence-based Abstractions

Periodic signals and recurrent events are very common in Analog and Mixed-Signal (AMS) behaviours. Tracking attributes related to frequency and recurrent behaviours is an integral part of the verification coverage plan for AMS designs. It is straight-forward to validate periodic artefacts in a signal, such as frequency or duty cycle, when a reference value is provided. From a CAD perspective, the difficulty arises when a reference is not provided, and more so when a static reference does not exist. In this paper, we propose a novel methodology to compute various artefacts of a periodic signal algorithmically in absence of prior information regarding the periodic nature of the signal. We propose to encode the signal using a window-based partitioned sequence of literals and then operate over this sequence to glean out the relevant periodic artefacts. Our experiments performed on waveforms collected from industrial test cases and medical benchmarks demonstrate the efficacy of our proposal.