Symmetricom ET6000, Руководство пользователя

Страница: 128 / 206

OPTION DESCRIPTIONS
Code Word Structure: SB
Word begins at INDEX COUNT 80. Seventeen binary-coded elements occur, with a POSITION
IDENTIFIER between the 9
th
and 10
th
binary-coded elements.
Least Significant Digit
Occurs first.
Element Rates Available
•
100 per second (basic element rate).
•
10 per second (POSITION IDENTIFIER rate).
•
One per second (frame rate).
Element Identification
•
“On-Time” reference point for each element is its leading edge.
•
INDEX MARKER duration: 2 milliseconds. (Binary Zero or uncoded Element.)
•
CODE DIGIT duration: 5 milliseconds. (Binary One.)
•
POSITION IDENTIFIER duration: 8 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
10 milliseconds (unmodulated): One millisecond (modulated).
Carrier Frequency
1kHz when modulated.
1.3.3 IRIG FORMAT G
Time Frame = 0.01 Second
50 60 70
P5 P6 P7 1 2 4 8
0.01 Sec
100µS (Element Rate = 10 KPPS)
80
90
P8
P9
Control Functions
0
P0 PR
Binary One = 50 µS
Binary Zero = 20 µS
Reference = 80 µS
Reference Marker = 80 µS
Time = 091 Days : 14 Hours : 08 Minutes : 32.86 Seconds
Seconds Minutes Hours
BCD Time of Year
Days
0.1 Sec
Time Frame = 0.01 Second
P0 PR 1 2 4
8
10 20 40 P1
P2
0 10 20
P3 P4
30 40 50
P5 1 2 4 8 10 20 40 1 2 4 8 10 20 40 80 100 200 1 2 4 8 10 20 1 2 4 8
Symmetricom Inc ET6 ExacTime GPS TC & FG (Rev C) C-7