1/20/97
N
N
T
T
S
S
-
-
2
2
0
0
1
1
.
.
M
M
A
A
N
N
A
A
-
-
2
2
R
R
e
e
v
v
A
A
Mode
A-1.5
The mode is a three bit integer that determines the functions the NTS-100 module will
perform. TrueTime’s NTS-100 module operates in mode four or server mode. Mode
four operation allows the module to synchronize hosts but will not allow the module to be
synchronized by another host.
Stratum
A-1.6
The stratum is an eight bit integer providing the stratum level of the local time source.
TrueTime’s NTS-100 module operates in stratum 1, denoting a primary reference.
Poll Interval
A-1.7
The poll interval is a signed eight bit integer used as the exponent of two to yield in
seconds the minimum interval between consecutive messages. For example, a poll
interval value of six implies a minimum interval of 64 seconds. The NTS-100 does not
alter the setting of this field.
Precision
A-1.8
The precision is a signed eight bit integer used as the exponent of two to yield in
seconds the precision of the local time source and any other hardware affecting the base
level “jitter” of the time server. This field is set to approximate the time stamping
resolution of the NTS-100 which is 10 µs. So the precision byte is set to -16 which is
equivalent to a precision of 15.26 µs.
Synchronizing Distance (Root Delay Version 3)
A-1.9
The root delay is a signed 32 bit fixed point number representing the predicted roundtrip
delay in seconds to the primary synchronizing source. The fraction point is between bits
15 and 16. This value is set to 0 seconds in TrueTime’s NTS-100 module.
Synchronizing Dispersion (Root Dispersion Version 3)
A-1.10
The root dispersion is a signed 32 bit fixed point number representing the maximum error
in seconds relative to the primary synchronizing source. This value is a function of the
precision and the quality of the synchronization input option. The user must provide an
accuracy input via Serial I/O Function 36 when the synchronization input option is IRIG-B,
ACTS or External 1PPS, since the root primary synchronizing source is not known by the
NTS-100 in those cases. When the synchronization input option is GPS, then the NTS-
100 will self determine the accuracy. Once the accuracy has been determined, then the
NTS-100 sets the root dispersion equal to ten times the square root of the sum of the
squares of the precision and the accuracy, except for the ACTS synchronization option,
where the root dispersion is set equal to the accuracy.
Содержание IRIG NTS-100
Страница 1: ...Network Time Server IRIG NTS 100 600 201 SERIAL NUMBER_______________ Revision A January 20 1997...
Страница 42: ...1 20 97 N NT TS S 2 20 01 1 M MA AN N 4 4 1 1 R Re ev v A A 4 SECTION IV NOT USED...
Страница 75: ...1 20 97 N NT TS S 2 20 01 1 M MA AN N C C 1 1 R Re ev v A A APPENDIX D DETAILED DRAWINGS BILL OF MATERIALS...
