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5.1422 Logic
Block
The 54572 logic block is clocked by the selected clock signal and frame
synchronized from the external synchronization bus. It uses 8.192 MHz PLL
(phase locked loop). The 8.192 MHz is divided by 128 to produce the 64
kHz composite clock (CC). The logic block also contains a circuit which
disables the drivers if no input clock is present.
The block also produces synchronizing pulses which synchronize the 8 kHz
BPVs in the composite clock signals. The CC drive provides bipolar signals
to the output drivers.
The power-on disable provides time delay to ensure the card is disabled until
the power supply stabilizes after power is applied.
5.1423
Controls and Indicators
The following controls and indicators appear on the front panel of the card:
a. The red FAIL LED lights if the on-card fuse blows.
b. The green CLOCK A/B LED lights when the corresponding clock, either
A or B, is selected.
c. The yellow INPUT A/B LED lights when the corresponding input, either A
or B, is selected.
d. The yellow OVERRIDE LED lights when automatic selection has been
overridden by manual remote selection.
e. The red OUTPUT LOSS LED lights when a loss of one or more outputs
occurs. If both A and B clocks and both input references
fail, leaving no valid signal for the output cards to select, the OUTPUT
LOSS LED lights and all outputs are suppressed.
f. The front panel MON jack allows for monitoring one of the output signals
with a standard monitoring test set. The Model 54572 has ten outputs
with independent drivers.
g. On-card jumper for Protected or Non-Protected operation.
5.1423
Controls and Indicators
The following controls and indicators appear on the front panel of the card:
a. The red FAIL LED lights if the on-card fuse blows.
b. The green CLOCK A/B LED lights when the corresponding clock, either
A or B, is selected.
c. The yellow INPUT A/B LED lights when the corresponding input, either A
or B, is selected.
