20 TimeSource 3100
Description
097-72020-01 Issue 9: November 2003
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Clock Extractors
A clock extractor circuit extracts a timing signal from each external reference source
(External sources, other than the GPS antenna, are optional). The extracted timing signal is
sent to the BesTime Ensemble Timing Generator.
Power Supply
A power converter filters and converts -48 volts dc power supplied to the shelf into the
voltages required by the shelf.
NTP TimeServer
The TimeServer is a Simple Network Time Protocol (SNTP) device. The SNTP TimeServer
function is provided via the TimeSource Ethernet interface and associated IP address. User
software requests UTC time of day via NTP protocol. The TimeSource SNTP server
responds with current UTC time. The TimeServer is compatible with the SNTP RFC-1769
format.
To enable the SNTP feature, a password must be entered using the ED-EQPT TL1
command. If a user makes a fourth attempt of an incorrect password entry, the TimeServer
will lock out the user for 1 hour.
Network Time Protocol Password Activation
Use of the Simple Network Time Protocol (SNTP) feature requires activation with a
password. Activation is accomplished through receipt of a Network Time Protocol
Activation Certificate from Symmetricom. This certificate contains the unit purchase order
number, unit model number, unit activation date, unit serial number, and unit activation key.
The unit activation key is the password that enables the SNTP feature. To activate the SNTP
feature, enter the TL l command printed on the activation certificate. Once activated, this
feature will be permanently enabled. To order the SNTP feature, contact the local
Symmetricom sales representative.
BesTime Ensemble Timing Generator
Clock signals from the GPS antenna (via the IF interface), the local oscillator, the optional
external sources (E1 span lines and remote oscillators) are used as sources by the BesTime
algorithms in the BesTime Ensemble Timing Generator. The signals are analyzed for MTIE,
TDEV, and other phase and frequency characteristics.
The BesTime Ensemble Timing Generator uses mathematical models to analyze each clock.
The ensemble algorithms use the comparisons and analyses to generate a highly stable
timing signal, which uses the best qualities of all inputs.
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