Page506 of 544 NTAK20clock controller
553-3011-100 Standard14.00 January 2002
Physical description
Faceplate LEDs
Each of the motherboards have 5 DTI/PRI LEDs and one clock controller
LED. The CC LED is dual-color (red and green), with states represented as
follows:
Functional description
The main functional blocks of the NTAK20 architecture include:
•phase difference detector circuit
•digital phase-lock loop
•clock detection circuit
•digital-to-analog converter
•CPU MUX bus interface
•signal conditioning drivers and buffers
•sanity timer
•microprocessor
Table 1 58
Faceplate LEDs
State Definition
On (Red) NTAK20 is equipped and disabled.
On (Green) NTAK20 is equipped, enabled, and is either locked to a reference or is in
free run mode.
Flashing (Green) NTAK20 is equipped and is attempting to lock (tracking mode) to a
reference. If the LED flashes continuously over an extended period of time,
check the CC STAT in LD60. If the CC is tracking this may be an
acceptable state. Check for slips and related clock controller error
conditions. If none exist, then this state is acceptable, and the flashing is
identifying jitter on the reference.
Off NTAK20 is not equipped.