A Sub-Picosecond Digital Clock Monitoring System

TL;DR

This paper presents a low-cost, high-precision system capable of monitoring digital clock phase variations at sub-picosecond levels, useful for detecting minute phase changes in complex clock networks and optical fibers.

Contribution

The authors introduce a novel system that achieves sub-picosecond phase monitoring of digital clocks, demonstrating its effectiveness in tracking phase variations and optical signal changes.

Findings

Achieved phase monitoring precision of ≤ 1 ps.

Successfully tracked phase variations induced by temperature and other effects.

Measured phase changes in optical fiber signals.

Abstract

We describe a low-cost system designed to monitor wander in digital clocks with a precision of $\le$ 1 ps. With this system we have shown that it is possible to track phase variations at the sub-picosecond level by adding noise to a reference clock. As in many cases where a clock is part of a complex distribution network small changes in temperature and other effects can lead to small changes in the a clock's phase. As a further demonstration of the system, we have used it to measure the phase changes induced in optical signals in fibers.