User Manual

Chapter 4 - Operation and Administration Using the CLI NPU Configuration
4Motion 434 System Manual
 “Configuring the Clock Mode” on page 441
 “Configuring the Required Number of Satellites” on page 442
 “Displaying GPS Clocks Parameters” on page 443
 “Displaying GPS General Configuration Parameters” on page 444
 “Displaying the Date and Time Parameters” on page 445
 “Displaying the Position Parameters” on page 446
 “Displaying the Clock Mode Parameter” on page 446
 “Displaying the Number of Satellite Parameters” on page 447
4.3.14.2.1 Configuring the GPS Clocks
The GPS clock parameters determines the source for the main clocks in the
system. To configure the GPS clock, you are required to enable/disable:
 External 1PPS: Determines the air-frame start time. Assuming that all systems
use the same air-frame size and DL/UL Ratio, then, when the 1PPS clock is
received from a GPS system, this mechanism ensures inter-site and intra-site
synchronization among all sectors, preventing cross interference and
saturation problems. When using the internal 1PPS clock (derived from the
selected 16 MHz clock source), only intra-site synchronization among sectors
can be achieved. You can either enable the external 1PPS clock source or use
the internal 1PPS clock source derived from the selected 16 MHz clock. By
default, the External IPPS clock is enabled. When using a GPS for
synchronization, the 1PPS clock is received from the GPS receiver and must be
enabled for proper operation.
IMPORTANT
Reset the system for changes in the GPS clock configuration to be applied to the entire system.