Functional Description; Block Diagram Of The Rs-422 Selective Rate Clock Module - Symmetricom TSG-3800 Series User Manual

Output Modules
RS-422 Selective Rate Clock Module

Functional Description

Refer to Figure 7-16
reference input signals (A and B) from separate Frame Generator modules. The
module selects one of these signals (normally A) and applies it to the ten port
drivers. Each driver supplies 1 square wave output in an RS-422 format.
If reference signal A fails, the module detects its loss and switches to reference
signal B. If an output fails, the corresponding front panel PORT FAULT indicator
turns on.
Figure 7-16. Block Diagram of the RS-422 Selective Rate Clock Module
Power A and B on the main shelf provide power to the module. These redundant
sources of –48 vDC are diode-coupled and fused, allowing the module to draw
power from either source. The internal fuse, labeled F1, protects the circuitry from
excessive current. The DC-to-DC Converter changes the negative voltage into +5
vDC; the green POWER indicator on the front panel is lit when either power source
is available to the module. The POWER indicator turns off when power is lost, for
example if the fuse on the module opens, if both –48 vDC power inputs are lost, or if
the converter fails.
254 TSG-3800 User's Guide
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for the following functional discussion. The module accepts two
12778474-002-2 Revision F – March 2004