Continuous frequency measurement for predictive periodic synchronization

摘要

Embodiments are described for a method of continuously measuring the ratio of frequencies between the transmit and receive clock domains of a heterochronous system using an array of digital frequency measurement circuits that provide overlapping frequency and detection interval measurements within single counter periods required for a single frequency measurement circuit to complete a frequency measurement. Embodiments may be used in a predictive synchronizer to provide low latency, continuous frequency measurements for system-on-chip (SOC) devices that employ frequency drift or ramping to reduce power consumption and overheating conditions.

主权项

1. A method for continuously monitoring frequencies between transmit and receive clock domains, comprising:
taking a series of frequency measurements generated by a first measurement loop that restarts itself whenever a previous frequency measurement is complete; taking a series of detection interval measurements generated by a second measurement loop that restarts itself whenever a previous detection interval measurement is complete; and providing the series of frequency measurements and the series of detection interval measurements to a phase estimator that provides an estimate of the transmit clock phase to a synchronizer arranged between the transmit and receive clock domains during a condition in which at least one of the transmit and receive clocks is actively ramped between two frequencies.