NETWORK ELEMENT TIMING GENERATOR
C O N N O R THE CONNOR-WINFIELD CORPꢀ
2111 COMPREHENSIVE DRIVEꢀ
AURORA, IL 60505ꢀ
FAX (630) 851-5040ꢀ
PHONE (630) 851-4722
HTTP://WWWꢀCONWINꢀCOM
W I N F I E L D
STRATUM 3 SIMPLIFIED CONTROL
TIMING MODULES (STM-S3)
DESCRIPTION
STM-S3 PIN ASSIGNMENT
The Connor-Winfield Stratum 3 Simplified Control
Timing Module acts as a complete system clock module for general
Stratum 3 timing applicationsꢀ The STM is designed for external
control functionsꢀ 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 Runꢀ The table below illustrates the control signal inputs
and corresponding operational states:
+5Vdc
HLDOVR
REF 1
EX REF 1
GND
REF 2
EX REF 2
GND
FRERUN
GND
N/C
N/C
CLK_OUT
GND
N/C
N/C
In the absence of External Control Inputs (A,B), the STM
enters the Free Run mode and signals an External Alarmꢀ The
STM will enter other operating modes upon application of a proper
control signalꢀ Mode 1 operation (A=1, B=0) results in an output
signal that is phase locked to the External Reference Input #1ꢀ
Mode 2 operation (A=0, B=1) results in an output signal that is
phase locked to External Reference Input #2ꢀ 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 STMꢀ
N/C
N/C
SYNC_OUT
ALARM OUT
GND
CNTL A
CNTL B
PLL TVL
BOTTOM VIEW
Alarm signals are generated at the Alarm Output during
Holdover and Free Run operationꢀ Alarm Signals are also
generated by loss-of-lock, loss of Reference, and by a Tune-Limit
indication from the PLLꢀ 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 erroneousꢀ A high level indicates an alarm conditionꢀ Real-
time indication of the operational mode is available at unique
operating mode outputs on pins 1-4ꢀ
BLOCK DIAGRAM
0
1
2
FRERUN
CNTL A
CNTL B
REF 1
PLL TVL
REF 2
FREE RUN
2:4
3
HOLDOVER
HOLDOVER
ALARM OUT
LOCK AND
DETECTION
EXREF1
EXREF2
PHASE
2:1
MUX
COMPARATOR
2:1
MUX
SYNC_OUT
DAC
FILTERS
STRATUM3
VCXO
DAC
Control loop filters effectively attenuate any reference
jitter and smooth out phase transientsꢀ
TUNING
VOLTAGE
MONITOR
STRATUM3
TCXO
FIFO
CLK_OUT
PLL TVL
STM-S3
FRERUN
1
CONTROL
INPUT
ALARM
OUTPUT
OPERATIONAL MODE
REF 1
REF 2
HLDOVR
PLL_TVL*
A
B
0
0
Free Run (Default)
0
0
0
0
1
External
Reference
#1
Normal
Tune Limit
LOS + LOL
1
1
1
0
0
0
0
0
0
0
0
0
0
1
0
0
1
1
1
0
External
Reference
#2
Normal
Tune Limit
LOS + LOL
0
0
0
1
1
1
0
0
0
0
0
0
0
1
0
0
1
1
0
1
1
1
Holdover
0
0
1
0
0
1
INT
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 reservedꢀ
Specifications subject to change without noticeꢀ
