User Manual

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

SC4812ET BTS Optimization/ATP — CDMA LMF

Jan 2002

3-46

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 frames. The associated expansion 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 3-26). HSO, HSO2, and

HSOX use the same source code in source selection (see Table 3-26).

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