Symmetricom ET6000, User Manual

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APPENDIX C
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Time Frame : 0.01 seconds. Code Digit Weighting Options : BCD Time-of-Year.
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Code Word - 38 binary digits . Seconds, minutes, hours, and days, 0.1 seconds, and 0.01
seconds. Recycles yearly.
Code Word Structure: BCD
Word begins at INDEX COUNT 1. Binary coded elements occur between POSITION
IDENTIFIER ELEMENTS (seven for seconds, seven for minutes, six for hours, ten for days,
four for 0.01 seconds) until the CODE WORD is complete. A POSITION IDENTIFIER occurs
between decimal digits in each group to provide separation for visual resolution.
Least Significant Digit
Occurs first, except for fractional seconds information, which occurs following the Day-of-Year
information.
Element Rates Available
•
10000 per second (basic element rate).
•
1000 per second (POSITION IDENTIFIER rate).
•
100 per second (frame rate).
Element Identification
•
“On-Time” reference point for each element is its leading edge.
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INDEX MARKER duration: 0.02 milliseconds. (Binary Zero or uncoded Element.)
•
CODE DIGIT duration: 0.05 milliseconds. (Binary One.)
•
POSITION IDENTIFIER duration: 0.08 milliseconds.
•
REFERENCE MARKER: One per second. Two consecutive POSITION IDENTIFIERS.
(The “on-time” point, to which the CODE WORD refers, is the leading edge of the second
POSITION IDENTIFIER.)
Resolution
0.10 milliseconds (unmodulated): 0.01 millisecond (modulated).
Carrier Frequency
100kHz when modulated.
C-8 ET6xxx ExacTime GPS TC & FG (Rev C) Symmetricom Inc