DATE authors use metamorphic relations to expose a PFD bug in a SystemC-AMS PLL model

A DATE 2021 paper reports metamorphic testing of an industrial partner's SystemC-AMS PLL model. A relation between scaled reference and divided-feedback frequencies exposed a PFD dead-zone bug missed by existing tests: changing the reference from 1 MHz to 1.01 MHz produced 50 kHz feedback. The authors report restoring the relation after adding delay in the PFD reset path. This concerns a system-level model rather than a demonstrated silicon defect; the industrial partner is unnamed.