Endace DAG 3.8S, Руководство пользователя

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EDM01-09v7 DAG 3.8S Card User Guide
©2005 33 Version 9: May 2006
Chapter 6: Synchronizing Clock Time
Description The Endace DAG range of products come with sophisticated time
synchronization capabilities, in order to provide high quality timestamps,
optionally synchronized to an external time standard.
The system that provides the DAG synchronization capability is known as
the DAG Universal Clock Kit (DUCK).
An independent clock in each DAG card runs from the PC clock. A
card’s clock is initialised using the PC clock, and then free-runs using a
crystal oscillator.
Each card's clock can vary relative to a PC clock, or other DAG cards.
DUCK
configuration
The DUCK is configured to avoid time variance between sets of DAG
cards or between DAG cards and coordinated universal time [UTC].
Accurate time reference can be obtained from an external clock by
connecting to the DAG card using the synchronization connector, or the
host PCs clock can be used in software as a reference source without
additional hardware.
Each DAG card can also output a clock signal for use by other cards.
Common
synchronization
The DAG card synchronization connector supports a Pulse-Per-Second
(PPS) input signal, using RS-422 signalling levels.
Common synchronization sources include GPS or CDMA (Cellular
telephone) time receivers.
Endace produces the TDS 2 Time Distribution Server modules and the
TDS 6 units that enable multiple DAG cards to be connected to a single
GPS or CDMA unit.
More information is on the Endace website,
http://www.endace.com/accessories.htm , or the TDS 2/TDS 6 Units
Installation Manual.
In this chapter This chapter covers the following sections of information.
•
Configuration Tool Usage
•
Time Synchronization Configurations
•
Synchronization Connector Pin-outs