Functional Description; Analog Output Module Indicators - Symmetricom TSG-3800 Series User Manual

Table 7-18 describes the Analog Output Module front panel status indicators.
Table 7-18. Analog Output Module Indicators
Indicator
POWER
INPUT
FAULT A
INPUT
FAULT B
OUTPUT
FAULT
PLL FAULT

Functional Description

Refer to Figure 7-8
reference input signals (A and B) from separate Frame Generator modules. The
module selects one of these signals (normally A) and applies it to a 20 MHz PLL
circuit.
The PLL circuit has a 1 MHz, 5 MHz, and 10 MHz output which feeds sine filter
circuits for each frequency. The sine filter outputs are jumper-selectable to six
output buffer circuits.
If reference signal A fails, the module detects its loss and switches to reference
signal B. The processor can also switch references.
The phase lock loop (PLL) circuit has a lock detect circuit which creates four PLL
faults and turns on the PLL fault indicator on the front panel.
The module checks the outputs to confirm signal presence. Should an output fail,
the front panel OUTPUT FAULT indicator lights.
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.
12778474-002-2 Revision F – March 2004
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Color
Green On = The module is receiving power.
Amber On = No reference signal applied to input A.
Amber On = No reference signal applied to input B.
Red On = PLL unlocked
Amber On = Output failure on one or more channels.
for the following functional discussion. The module accepts two
Analog Output Module
Description
TSG-3800 User's Guide 231
Output Modules