Integrated circuit chip having built-in self measurement for PLL jitter and phase error

摘要

A built-in system and method is provided that measures Phase Lock Loop (PLL) output clock error. An edge sorting circuit is utilized to measure jitter between corresponding transition edges of a measured clock and a reference clock, and then stores the value in an N bit word. A decoder circuit reads in the value and increments a corresponding counter. A state machine then reads the counters, processes the information and outputs one or more PLL clock error values.