EDM01-36v10 DAG_9.2X2_Card_User_Guide - Synchronizing clock time
©2010 - 2012 Endace Technology Ltd. Confidential - Version 10 - May 2012
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Synchronizing clock time
Overview
The core of the DAG synchronization capability is known as the DAG Universal Clock Kit (DUCK).
DAG cards have sophisticated time synchronization capabilities. This allows for high quality timestamps
and optional synchronization to an external time standard.
A clock in each DAG card runs independently from the computer clock. The DAG card’s clock is initialized
using the computer clock, and then free-runs using a crystal oscillator.
Each DAG card's clock can vary relative to a computer clock, or other DAG cards.
DUCK configuration
The DUCK (DAG Universal Clock Kit) is designed to reduce time variance between sets of DAG cards or
between DAG cards and coordinated universal time [UTC].
You can obtain an accurate time reference by connecting an external clock to the DAG card using the
time synchronization connector. Alternatively you can use the host computer's clock in software as a
reference source without any additional hardware.
Each DAG card can also output a clock signal for use by other DAG cards.
Common synchronization
The DAG card time synchronization connector supports a Pulse-Per-Second (PPS) input signal, using RS-
422 signaling levels.
Common synchronization sources include GPS or CDMA (cellular telephone) or a single DAG card as a
Time Reference Source.
Endace also provides several Time Distribution Servers that provide timing synchronization over multiple
DAG cards. Currently the available Time Distribution Servers include:
•
TDS 2 - for further information, refer to
EDM05-01 Time Distribution Server User Guide
.
•
TDS 6 - for further information, refer to
EDM05-01 Time Distribution Server User Guide
.
•
TDS 24 - for further information, refer to
EDM05-02 TDS 24 Installation Guide
.
For more information on the Time Distribution Server, refer to the
Accessories
section at
http://www.endace.com
.
IRIG-B
For information on synchronizing the DAG 9.2X2 with an IRIG-B device, please refer to
EDM04-33
dag_irigb Software Guide
.