LIGO Document T1000477-v1
- The Advanced LIGO Timing System distributes a highly accurate timing signal to the three LIGO interferometers. By synchronizing data collection to better than 1Ás precision, the timing system (1) reduces timing jitter, (2) improves direction reconstruction, and (3) improves background rejection, all of which serve to improve LIGO's overall sensitivity. The timing system consists of a set of electronics modules which collectively distribute a GPS timing signal to LIGO subsystems. The central node of the timing system is a master clock which receives a timing signal via a GPS antenna. Slave modules, synchronized to the master clock via fiber optic cable, interface between the timing system and any given LIGO subsystem. The IRIG-B chassis is one timing system slave module. It supplies the timing signal to frame-building servers in the LHO/LLO Mass Storage Room and the interferometer end stations. The IRIG-B chassis converts the internal timing system signal encoding to the IRIG-B signaling standard, which can be interfaced with commercial servers through use of commercially available PCI modules. By ensuring that timing information is accurately stamped on all LIGO data, the IRIG-B module maintains timing synchronization, improving the likelihood of a successful detection of gravitational waves.
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