Provisioning The Clock Modules; Clock Operating Modes - Symmetricom TSG-3800 Series User Manual

Operating the TSG-3800

Provisioning the Clock Modules

Provisioning the Clock Modules
This section describes the operating modes of the Clock module, and then
describes how the operator can provision the following parameters on the Clock
modules:
Operating mode
Automatic return to a higher-stratum clock
Loop Time Constant
Control Value
You can also enable and disable Clock and Frame Generator modules. Use the
command syntax described in

Clock Operating Modes

After start-up, each Clock module automatically sequences through three operating
modes: Warm-Up, Acquire and Locked. A fourth operating mode, Holdover, is not
part of the cycle unless a valid input signal is not available. All modes may be
entered at user request. The following sections describe the operating modes.
Warm-Up Mode
Warm-up Mode starts when power is applied to the shelf. The warm-up period
varies from 15 minutes to one hour, depending on the type of Clock module
installed. The warmup period is 15 minutes for ST2 Rb modules, 30 minutes for
ST3E modules and 60 minutes for ST2 modules.
Acquire Mode
After the oscillator warms up, the TSG-3800 phase-locks the Clock module to the
most acceptable valid input reference signal. The system uses the following three
criteria to determine this signal:
Frequency stability
Clock noise
Phase offset
The TSG-3800 starts with a fast time constant (tau) and gradually increases it
toward an operator-selected or default value once the phase error has stabilized
near zero. Once the frequency stability is less than 1E
locked mode.
96 TSG-3800 User's Guide
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Clock Command, on page 342.
12778474-002-2 Revision F – March 2004
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, the oscillator enters the