System for highly repeatable clock parameter recovery from data

Abstract

A system for recovering parameters of an underlying clock signal from data modulated signals includes a time digitizer, or time stamping device, for sampling and locating edges of the data modulated signals, thereby selectively providing time stamp readings identifying incoming edges of the data signals. The time stamp readings are used, along with a user-input nominal clock frequency, to determine an array of actual clock cycle stamps, each representing an integral number of actual clock cycles occurring between adjacent time stamps. The array is then used in conjunction with the time stamps to characterize parameters of the underlying clock data. Once the clock parameters are recovered, a wide variety of information, for example, frequency and phase information, including jitter, can be determined with a very modest rate of sampling compared to the high data bandwidth. No phase locked loops are used and no physical clock is recovered. The system is operable over a well-defined range and is highly repeatable, independent of particular circuit design detail or parametric performance of circuit components.