User's Manual

CSM System Time – GPS & LFR/HSO Verification – continued

PRELIMINARY

1X SCt4812ET Lite BTS Optimization/ATP

08/01/2001

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synchronized to Universal Time Coordinates (UTC) and GPS time. The

LFR can maintain system time indefinately after initial GPS lock.

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 (Table 3-20). HSO,

HSO2, and HSOX use the same source code in source selection

(Table 3-20).

Allow the base site and test equipment to warm up for

60 minutes after any interruption in oscillator power. CSM

card 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