Spectracom 8183A GTP, Инструкция по эксплуатации

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NetClock/GTP Instruction Manual Page A-1
FAA IRIG CODE DESCRIPTION
A.0 INTRODUCTION
This Appendix contains a detailed description of the FAA modified IRIG B code.
The FAA modifies the IRIG B code by including satellite lock status and time
error flags in the Control Function Field. The error flags provide an inaccuracy
estimate based on the time elapsed since loss of GPS lock. In addition, the
Straight Binary Seconds (SBS) data was removed from the data stream. The
SBS time is the number of seconds elapsed since midnight.
The Netclock/GTP can be configured to provide IRIG timing reflecting Universal
Coordinated Time (UTC) or local time, with or without daylight saving time
corrections. The IRIG command configures the IRIG time structure and is
described in Section 4, Software Commands .
A.1 FAA IRIG B OUTPUT
The FAA IRIG B code contains the Binary Coded Decimal (BCD) time of year
and a Control Function (CF) field containing satellite lock status and time error
flags. With the exception of the position identifiers, all remaining code elements
are set to a binary 0. Figure A-1 illustrates the FAA IRIG B data structure. The
BCD time of year provides the day of the year, 001-366, and the time of day
including seconds. The hour of the day is expressed in 24-hour format.
A.1.1 FAA IRIG B General Description
1. Time frame: 1.0 seconds.
2. Pulse rates:
A. Element rate: 100 per second.
B. Position identifier rate: 10 per second.
C. Reference marker rate: 1 per second.
3. Element identification: The "on time" reference point for all
elements is the pulse leading edge.
A. Index marker (Binary 0 or uncoded element): 2 millisecond
duration.
B. Code digit (Binary 1): 5 millisecond duration.