User's Manual
CSM System Time – GPS and HSO Verification – continued
3-50 1X SC 4812T Lite BTS Optimization/ATP FEB 2005
PRELIMINARY
High Stability Oscillator (HSO)
The CSM and the HSO
The CSM performs the overall Configuration and Status Monitoring
Functions for the HSO. In the event of GPS failure, the HSO is capable
of maintaining Synchronization initially established by the GPS
Reference Signal..
HSO
The HSO is a High Stability 10 MHz oscillator with the necessary
interface to the CSM Cards. Since the HSO is a free–standing oscillator,
System Time can only be maintained for 24 hours..
Upgrades and Expansions: HSO2/HSOX
The HSO2 (second generation card) exports a Timing Signal to other
BTS Frames located at a site. These Expansion Frames require an HSO
Expansion (HSOX) Card.
The HSOX accepts input from the Starter Frame and interfaces with the
CSM Cards in the Expansion Frames. HSO, HSO2, and HSOX use the
same Source Code in Source Selection (Table 3-24).
Allow the BTS and Test Equipment to warm–up for 60
minutes after any interruption in Oscillator Power.
– CSM Warm-up allows the Oscillator Oven
Temperature and Oscillator Frequency to stabilize
prior to test.
– Test Equipment Warm-up allows the Rubidium
Standard Time Base to stabilize in frequency before
any measurements are made.
NOTE
CSM Frequency Verification
The objective of this procedure is the initial verification of the Clock
Synchronization Module (CSM) Cards before performing the RF Path
Verification Tests.
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