Endace DAG 5.2X, User Manual

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EDM01-33v1 DAG_7.5G4_Card_User_Guide
©2008 Endace Technology Ltd. Confidential - Version 1 - November 2008 49
Single Card No Reference
When a single DAG card is used with no external reference, the DAG card can be
synchronized to the host computer clock. Most computer clocks are not very accurate by
themselves, but the DUCK drifts smoothly at the same rate as the computer clock.
The synchronization achieved with this method is not as accurate as using an external
reference source such as GPS.
The DUCK clock is synchronized to a computer clock by setting input synchronization
selector to overflow as follows:
dagclock –d0 none overin
Output
muxin overin
muxout none
status Synchronised Threshold 11921ns Failures 0 Resyncs 0
error Freq 1836ppb Phase 605ns Worst Freq 147ppb Worst Phase 324ns
crystal Actual 49999347Hz Synthesized 16777216Hz
input Total 87039 Bad 0 Singles Missed 0 Longest Sequence Missed 0
start Wed Apr 27 14:27:41 2007
host Thu Apr 28 14:38:20 2007
dag Thu Apr 28 14:38:20 2007