Provisioning Automatic Return To A Higher-Stratum Clock; Setting The Clock Module Loop Time Constant (Tau) - Symmetricom TSG-3800 Series User Manual

Operating the TSG-3800
Provisioning the Clock Modules
Manually Setting the Operating Mode of the Clock Module
You can manually place the Clock Module into any operating mode. Holdover is the
only mode that reports whether it was entered into automatically or manually. The
terminal displays a message, depending upon the operating state.
To set the clock operating mode manually, type:
CLOCK A|B MODE WARMUP|ACQUIRE|LOCKED|HOLDOVER
Example
Purpose: Change Clock B from Locked to Holdover operating mode.
Command:
CLK B MODE HOLDOVER
Display:
->CLK B MODE HOLDOVER
«date» «time» «oper» put Clk B into Man HO, was Locked
+>

Provisioning Automatic Return to a Higher-Stratum Clock

When Auto Return is ON, the TSG-3800 returns to Clock A for output generation
when it is of equal or higher operating mode than Clock B. When OFF, the
TSG-3800 will stay on Clock B, once selected, until it has been disabled or faulted.
To set the AutoReturn Mode for the Clock module, type:
CLOCK AR ON|OFF

Setting the Clock Module Loop Time Constant (Tau)

The time constant for the clock control loop sets the averaging time used to filter the
short-term variations in frequency between the input reference signal and the clock
oscillator. The time constant is also known as the Tau of the control loop. It is set to
a default value that is best for typical operation, but it can be changed to optimize
control in special cases. Increasing the Tau provides more filtering of short-term
variations on the reference input, but it delays the response to environmental effects
on the oscillator. Decreasing the Tau provides quicker response to changes in either
the input or oscillator frequency, but reduces the smoothing effect of the filtering of
unwanted changes. The default values are optimized for typical operation of each
type of clock oscillator (quartz or Rubidium).
To change the clock control loop time constant, type:
CLOCK A|B TC {number}
98 TSG-3800 User's Guide
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12778474-002-2 Revision F – March 2004