20 TimeSource 3500
Description
097-72050-01 Issue 7: August 2003
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Overview
The TimeSource 3500 is a Primary Reference Source (PRS) that
receives and processes signals from GPS satellites, and outputs
Stratum 1 synchronization signals traceable to UTC. TimeSource
3500 applications include synchronization for central offices,
wireless base stations, transmission nodes, and other cases where
a primary reference source can improve the performance of a
telecommunications network infrastructure.
The TimeSource 3500 is also ideal for installation in environments
where receiving GPS signals is difficult. Examples of environments
hostile to GPS signals include urban canyons which have a very
limited view of the sky because of blockage from nearby buildings,
and high interference zones where GPS signals are jammed by
competing over-the-air signals.
The TimeSource 3500 creates timing outputs by ensembling
signals from several sources. The sources include GPS signals, an
onboard rubidium local oscillator, and optional T1 signals. Timing
outputs created from the ensemble are composed of the most
stable and least noisy parts of each input. The performance of the
T1 sources can be monitored and classified using standard
measures. Synchronization outputs are delivered in a framed, all-
ones, T1 format, a 10 MHz signal, a 1 pps signal, a composite
clock format (optional), and a choice of time of day (TOD) formats.
The TimeSource 3500 minimizes timing impairments, such as
jitter and wander, that are created by network and transmission
systems. The synchronization timing is traceable to the GPS,
which provides the highest level of synchronization for telephony
networks. The TimeSource 3500 with its GPS input is a stand-
alone office PRS. With the optional inputs ensembled, holdover is
extended if GPS signals are disrupted.