Instruction Manual

CSM System Time – GPS & LFR/HSO Verification – continued
Apr 2001
3-33
SC4812ET BTS Optimization/ATP — CDMA LMF
DRAFT
The HSO is a high stability 10 MHz oscillator with the necessary
interface to the CSMs. The HSO is typically installed in those
geographical areas not covered by the LORAN–C system. Since the
HSO is a free–standing oscillator, system time can only be maintained
for 24 hours after 24 hours of GPS lock.
Upgrades and Expansions: LFR2/HSO2/HSOX
LFR2/HSO2 (second generation cards) both export a timing signal to the
expansion or logical BTS frames. The associated expansion or logical
frames require an HSO–expansion (HSOX) whether the starter frame has
an LFR2 or an HSO2. The HSOX accepts input from the starter frame
and interfaces with the CSM cards in the expansion frame. LFR and
LFR2 use the same source code in source selection (see Table 3-19).
HSO, HSO2, and HSOX use the same source code in source selection
(see Table 3-19).
Allow the base site and test equipment to warm up for
60 minutes after any interruption in oscillator power.
CSM board warm-up allows the oscillator oven
temperature and oscillator frequency to stabilize prior to
test. Test equipment warm-up allows the Rubidium
standard timebase to stabilize in frequency before any
measurements are made.
NOTE
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