Development of a Multiple Time Source Comparison System for Disseminative Services in Taiwan

摘要

A multiple time source comparison system (MTCS) has been implemented that is enhancing the reliability of the time source of our time disseminative service, including the Network Time Protocol (NTP) server, Taiwan's Computer Time Service (TCTS), and the Speaking Clocks Service. The time sources of MTCS are two HP407ZA cesium-beam clocks with a micro-phase-stepper and an IRIG-B time-code generator in two shielded rooms; the other source is GPS. We designed an algorithm to make sure that at least two time sources agree. If any time source is different from the others, a switch will block its output and issue an alarm. The time difference among all three sources will stay within 20 microseconds.