Endace Measurement Systems
®
Ltd
http://www.endace.com
EDM05.05-01r1 TDS-2 Module TDS-6 Unit User Manual
Copyright© All rights reserved
1
Version 2. 22 September 2005.
1.0 OVERVIEW
Introduction
The Endace time distribution servers provide accurate synchronized
timing signals to DAG cards for packet timestamping through use of
global positioning system time signals.
The process involves a global positioning system [GPS] or code division
multiple access system [CDMA], time distribution server components, and
DAG cards.
In this chapter
This chapter covers the following sections of information.
•
User Manual Purpose
•
Time Distribution Server System
1.1 User Manual Purpose
Description
The purpose of this TDS 2 installation manual is to identify and explain:
•
Installing TDS-2 Time Distribution Server Module
•
Connecting TDS-6 Time Distribution Server Extension Unit
•
Appendix A – TDS-2 Module, Connector Specifications
•
Appendix B – TDS-6 Extension Unit, Connector Specifications
1.2 Time Distribution Server System
Description
The time distribution server system involves TDS-2 Time Distribution
Server modules [TDS-2 module] receiving time signals either directly
from a GPS receiver or a CDMA time receiver.
Accurate time synchronization information constantly transmitted by GPS
satellites orbiting Earth is collated on the ground by GPS receivers.
Receiver units can be mounted on building exteriors or elsewhere with an
unobstructed sky view. A GPS receiver unit is connected to a TDS-2
module by fitting a DB25 cable to a DB25-toDB9 adapter on the module.
In many situations it is not possible or economic to run cable to a GPS
receiving unit mounted externally on buildings. In this case, a CDMA
cellular telephone network is used, where available. A CDMA system
base station has a GPS receiver to collate the accurate timing transmitted
by satellites.
Timing information is retransmitted from CDMA base stations to all
CDMA receivers. Being of a lower frequency these transmissions can
often be received within buildings without an external antenna.
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