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097-55501-01 Revision M – January 2009
TimeHub 5500 User’s Guide
73
Chapter 2 Engineering Ordering Information
NTP Server Card
Figure 2-14. Block Diagram of the TimeHub NTP System
NTP Server Card Interfaces
Inputs to the NTP Server card include the following:
TOD (time code signal and 1 PPS signal) from a PRS, such as TimeSource 3500
GPS PRS. This connection is on the NTP Connector Card.
1.544 MHz sync signals from the TimeHub backplane and the associated
EXTSYNC lines from the two clock cards and the IMC. The 1.544 MHz clock is
used to generate the 125 MHz NTP system clock
In the future a GPS receiver on the NTP Connector card will provide the TOD
information that the NTP Server card needs.
Outputs from the NTP Server card are:
Two Gigabit Ethernet ports for NTP traffic. Each can use either an electrical or an
optical connection. These connectors are on the front panel of the NTP Server
card.
One TOD (time code and 1PPS signals) output connector for cascading the TOD
signals to multiple NTP cards in a TimeHub system. This connector is on the
NTP Connector Card.