STM-S3_15 Datasheet, PDF (1/6 Pages) Connor-Winfield Corporation – Stratum 3 Simplified Control Timing Modules

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NETWORK ELEMENT TIMING GENERATOR
STRATUM 3 SIMPLIFIED CONTROL
TIMING MODULES (STM-S3)
DESCRIPTION
The Connor-Winfield Stratum 3 Simplified Control
Timing Module acts as a complete system clock module for general
Stratum 3 timing applications. The STM is designed for external
control functions. Full external control input allows for selection
and monitoring of any of four possible operating states: 1)
Holdover, 2) External Reference #1, 3) External Reference #2, and
4) Free Run. The table below illustrates the control signal inputs
and corresponding operational states:
In the absence of External Control Inputs (A,B), the STM
enters the Free Run mode and signals an External Alarm. The
STM will enter other operating modes upon application of a proper
control signal. Mode 1 operation (A=1, B=0) results in an output
signal that is phase locked to the External Reference Input #1.
Mode 2 operation (A=0, B=1) results in an output signal that is
phase locked to External Reference Input #2. Holdover mode
operation (A=1, B=1) results in an output signal at or near the
frequency as determined by the latest (last) locked-signal input
values and the holdover performance of the STM.
Alarm signals are generated at the Alarm Output during
Holdover and Free Run operation. Alarm Signals are also
generated by loss-of-lock, loss of Reference, and by a Tune-Limit
indication from the PLL. A Tune-Limit alarm signal indicates
that the VCXO tuning voltage is approaching within 10% the limits
of its lock capability and that the External Reference Input may
be erroneous. A high level indicates an alarm condition. Real-
time indication of the operational mode is available at unique
operating mode outputs on pins 1-4.
Control loop filters effectively attenuate any reference
jitter and smooth out phase transients.
STM-S3 PIN ASSIGNMENT
+5Vdc
EX REF 1
GND
EX REF 2
GND
N/C
CLK_OUT
GND
N/C
SYNC_OUT
GND
PLL TVL
BOTTOM VIEW
HLDOVR
REF 1
REF 2
FRERUN
GND
N/C
N/C
N/C
N/C
ALARM OUT
CNTL A
CNTL B
CNTL A
CNTL B
EX REF 1
EX REF 2
0
1
2
2:4 3
BLOCK DIAGRAM
FRERUN
REF 1
REF 2
HOLDOVER
PLL TVL
FREE RUN
HOLDOVER
2:1
MUX
PHASE
COMPARATOR
LOCK AND
DETECTION
DAC
FILTERS
TUNING
VOLTAGE
MONITOR
PLL TVL
DAC
STRATUM3
VCXO
FIFO
STRATUM3
TCXO
STM-S3
ALARM OUT
2:1
MUX
SYNC_OUT
CLK_OUT
CONTROL
INPUT
A
B
0
0
External
1 0 Reference
#1
External
0
1 Reference
#2
1
1
OPERATIONAL MODE
Free Run (Default)
Normal
Tune Limit
LOS + LOL
Normal
Tune Limit
LOS + LOL
Holdover
REF 1
0
1
1
1
0
0
0
0
REF 2
HLDOVR
FRERUN
PLL_TVL*
ALARM
OUTPUT
0
0
1
0
1
0
0
0
0
0
0
0
0
1
1
0
0
0
0
1
1
0
0
0
0
1
0
0
1
1
1
0
0
0
1
0
1
0
0
1
INT
Specifications subject to change without notice.
DATA SHEET #: _T_M__0_0_0______ PAGE___1___ OF ___6____ REV:__0_4_____ DATE:___1_/_3_/_2_0_0_0__ © Copyright 2000 Connor-Winfield all rights reserved.