Symmetricom 1100, 1000 manual Performance Monitoring, SUB Mode, PRR Mode

Chapter 1 Overview of the TimeProvider

Performance Monitoring

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 Selecting the Input, on page 35.

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

CCinputs (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 Setting the System Mode, on page 105.

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. BesTime, on page 43 provides more information on the BesTime technology.

To configure the TimeProvider for PRR mode, see Setting the System Mode, on page 105.

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.

24 TimeProvider User’s Guide 097-58001-02 Revision G – April 2008