Symmetricom 1000 User Manual

Page of 224
Chapter 1 Overview of the TimeProvider
Performance Monitoring
24
 TimeProvider User’s Guide
097-58001-02 Revision G – April 2008
In the SSU mode, the INP1 and INP2 inputs cannot be provisioned to receive 
Composite Clock (CC) signals, including JCC or JCC4. The method of selecting the 
system reference is described in 
SUB Mode
This mode allows the TimeProvider to operate as a Remote shelf where phase is 
critical. When you select the SUB mode, INP1 and INP2 are automatically set for 
CC inputs (including JCC and JCC4). Outputs provisioned for CC are phase-aligned 
with the selected CC input reference. Other output types comply with G.703 and 
GR-1244.
To configure the TimeProvider for Subtending mode, see 
PRR Mode
In PRR mode, the GPS is automatically selected as the system reference input. 
This requires that you connect a GPS signal to the TimeProvider through either:
the standalone TPIU (used with Antenna Kits 990-58545-01 or 990-58545-02) or
the integrated IMC/TPIU card (used with Antenna Kits 990-58545-03 or 
990-58545-04)
This mode complies with ITU-T G.811 and Telcordia GR-2830 requirements for 
Primary Reference Receivers/Clocks. Valid signals on the PRS, INP1, or INP2 
connectors are used in conjunction with BesTime to extend compliance with 
GR-2830/G.811 standards.
The PRR mode uses Symmetricom’s BesTime servo control that allows the 
TimeProvider to continue providing outputs in case GPS tracking is lost, the GPS 
data loses integrity, or if the IMC is removed from the shelf. 
provides more information on the BesTime technology.
To configure the TimeProvider for PRR mode, see 
Performance Monitoring
The TimeProvider can monitor and qualify all enabled input signals based on phase 
measurements. It measures the phase differences between the inputs and the 
output of the corrected clock. From these phase measurements, the TimeProvider 
computes frequency offset and wander of the input signals. Wander is reported in 
terms of Maximum Time Interval Error (MTIE) and Time Deviation (TDEV) and 
creates phase, MTIE, TDEV, and Fractional Frequency Offset (FFOFF) reports. 
Performance data is automatically gathered on all enabled or monitored inputs.