Symmetricom ET6000, Руководство пользователя

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OPTION DESCRIPTIONS
•
CODE DIGIT duration: 24 milliseconds. (Binary One.)
•
REFERENCE MARKER: One per second. Duration is 36 milliseconds. (The “on-time”
point, to which the CODE WORD refers, is the leading edge of the second POSITION
IDENTIFIER.)
Resolution
One second (frame rate, unmodulated). 40 millisecond during code word only. Four
milliseconds (modulated).
Carrier Frequency
1 kHz.
1.3.8 NASA 36-BIT TIME CODE
Time Frame = 1 Second
Tens of
Hours
Units of
Days
50 60 70
10 20
40 1
2 4 8
10 mS (Element Rate = 100 PPS)
Tens of
Days
10 20 40 80
80 90
0
100 200
100 mS
Control
Functions
Reference
Marker
Time = 191 Days : 14 Hours : 08 Minutes : 32 Seconds
Hundreds of
Days
50 40 30
10 20 40 1 2 4 8
Tens of
Minutes Units of
Hours
Time Frame = 1 Second
10 20
Tens of
Seconds
Units of
Minutes
1 2 4 8
0
Units of
Seconds
8 4 2 1 10 20 40
Binary One = 6 mS
Binary Zero = 2 mS
Reference = 6 mS
•
Time Frame : One second. Code Digit Weighting Options : BCD.
•
Binary Coded Decimal Time-of-Year CODE WORD - 30 binary digits. Seconds, minutes,
hours, and days. Recycles yearly.
Code Word Structure: BCD
Word begins at INDEX COUNT 1. Binary coded elements occur between POSITION
IDENTIFIER ELEMENTS in four digit groups until the CODE WORD is complete. A CODE
DIGIT occurs between decimal digits in each group to provide separation for visual resolution.
Least Significant Digit
Occurs first.
Element Rates Available
•
100 per second (basic element rate).
•
One per second (frame rate).
Symmetricom Inc ET6 ExacTime GPS TC & FG (Rev C) C-13