The White Rabbit (WR) protocol aims at providing time and frequency dissemination over GbE optical fiber networks. Our focus, beyond qualifying WR in a practical environment, is to consider the user perspective of distributed synchronous data acquisition and radiofrequency signal generation. Considering the lack of training on this topic, a dedicated network has been setup between the École Nationale Supérieure de Mécanique et des Microtechniques (ENSMM) [French] hosting 3 hydrogen masers, the Besançon Observatory hosting Cs clocks, and the teaching department at the University for training purposes.

White Rabbit 1-PPS (top) v.s GPS 1-PPS (bottom), the offset being due to different cable lengths.

Current deployment has allowed to assess the round trip (4-km) delay correction jitter in the 10 ps range with peak-to-peak values in the 100 ps range. Such a performance is sufficient for distributed data acquisition of radiofrequency signals, e.g. for Direction of Arrival (DoA) measurements, up to the GHz range.

White Rabbit network between ENSMM, Observatory and teaching rooms at university.

Auteur : | Date : 18/02/2019