CXR Larus 80-100-400
Issue 1, July 2006
___________________________________________________________
__________________________________________________________
CXR Larus 80-100-400
Issue 1, July 2006 1-10
1.344 The GPS radio receiver internal to the CXR Larus 54591/54593 module
receives and compares signals from these satellites and processes a result, not
in terms of a precise location but in terms of a precision frequency, since it
assumes that the installation has a fixed location on earth. It tracks up to eight
satellites in the sky and can use signals from at least three satellites to
triangulate a location, with a fourth satellite to check on the first three. Using
the fourth, the receiver can calculate and compensate for clock error by solving
four simultaneous equations (one for each satellite measurement). The output
of the GPS radio receiver, a stable reference of exactly one pulse per second
(1PPS), is then used by the Precision Time Assembly. The Precision Time
Assembly compares this 1PPS with the on-board frequency reference of the
54591/54593 to develop a time correction factor for the precision oscillator.
1.345 A GPS failure can be caused by damage to the GPS antenna or cable and
excessive amounts of jitter can cause loss of GPS tracking. The 54591
includes an ovenized crystal oscillator for Stratum 3E/LNC performance in Hold
in the event of loss of GPS tracking. The 54593 includes a rubidium oscillator
for Stratum 2/TNC Hold performance in the event of loss of the GPS primary
reference. The internal oscillators allow the 54591 and 54593 to ignore
short-term GPS tracking loss.
1.35
Track and Hold Clock Card Combinations
1.351
The following combinations of track and hold cards are acceptable. Each card
must be paired with a 54511 T1 or 54512 E1/2.048 MHz Input Card.
Stratum
1/PRC
(GPS)
Two
54591-2*
cards,
with Stratum 3E/LNC Hold:
or
One 54591-2* and
one 54522-5* card
Stratum
1/PRC
(GPS)
Two
54593-2*
cards,
with Stratum 2/TNC Hold:
or
One 54593-2* and
one 54523-3* card
Stratum
3E/LNC:
Two
54522-5*
cards
Stratum
2/TNC: Two
54523-3*
cards
*
Provides AB input architecture.
Содержание 54500-16
Страница 7: ...This page is intentionally left blank...
Страница 28: ..._______________________________________________________________ CXR Larus 80 100 400 Issue 2 July 2006 2 3...
Страница 29: ...CXR Larus 80 100 400 2 4 Issue 1 July 2006 ______________________________________________________________...
Страница 30: ..._______________________________________________________________ CXR Larus 80 100 400 Issue 2 July 2006 2 5...
Страница 31: ...CXR Larus 80 100 400 2 6 Issue 1 July 2006 ______________________________________________________________...
Страница 39: ...This page is intentionally left blank...
Страница 205: ...__________________________________________________________ 5 77...
Страница 214: ...AB 2 This page is intentionally left blank...