Functional Description; T1/E1 Frame Generator Module With Clock Bypass Indicators - Symmetricom TSG-3800 Series User Manual

The Clock Bypass function allows the module to continue generating normal output
signals when both Clock modules are in warm-up mode or are when the clocks
have been removed from the unit. When there is a framed signal connected to
either input port 1.1 (PRI) or input port 2.1 (SEC), the module continues to output
signals. When either Clock module begins normal operation, the Frame Generator
module uses the reference from the selected Clock module. When the Clock
Bypass function is active and SSMs are enabled, the SSM stratum unknown (STU)
is broadcast.
Table 6-18 describes the front panel status indicators (LEDs) on the T1/E1 Frame
Generator module.
Table 6-18. T1/E1 Frame Generator Module with Clock Bypass Indicators
Indicator
POWER
FAULT

Functional Description

Refer to Figure 6-10
Generator module provides two timing output signals and two clock signals, making
it possible for the TSG-3800 to simultaneously output T1/E1, T1/CC, or E1/CC
timing signals. The module also supports SSM on the DS1-FSF and E1 outputs.
The T1 output is derived from an 18.528 MHz reference signal from the
corresponding Clock module in the TSG-3800. The reference signal is divided to
1.544 MHz and sent to the DS1-D4/ESF Format Generator. This circuit produces
balanced TTL level signals that represent a framed, all ONEs DS1 signal. The
setting of a rocker switch on the board determines whether the framing format used
is D4 or ESF.
The E1 timing signals are also created from the 18.529 MHz reference. A
phase-locked loop locked to this reference produces a frequency which is divided to
2.048 MHz. This clock is then used to create the framed all ONEs timing signal
(balanced TTL level).
When two Frame Generator modules are installed, the TSG-3800 aligns the frames
of their output signals. This allows synchronization of the frame marker and output
timing signals to each other for minimal phase hits and no change of frame
alignment. Synchronization is done automatically when the second Frame
Generator module is installed.
12778474-002-2 Revision F – March 2004
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Color
Green On = Module is receiving power.
Red On = Module failure.
Blinking = Module is disabled.
for the following functional discussion. The T1/E1 Frame
CPU, Frame Generator, and Clock Modules
T1/E1 Frame Generator Module with Clock Bypass
Description
TSG-3800 User's Guide 195