TM022

THE CONNOR-WINFIELD CORP.

2111 COMPREHENSIVE DRIVE.

AURORA, IL 60505.

FAX (630) 851-5040.

PHONE (630) 851-4722

HTTP://WWW.CONWIN.COM

CONNOR

WINFIELD

NETWORK ELEMENT TIMING GENERATOR

STRATUM 3 SIMPLIFIED CONTROL

TIMING MODULES (MSTM-S3-R)

DATA SHEET #: ____________ PAGE______ OF _______ REV:________ DATE:____________

Specifications subject to change without notice.

PRELIMINARY

P02

3/21/01

7

1

The Connor-Winfield Stratum 3 Simplified Control

Timing Module acts as a complete system clock module for general

Stratum 3 timing applications. The MSTM 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

MSTM enters the Free Run mode and signals an External Alarm.

The MSTM 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 MSTM. In Free Run

mode, operation (A=0, B=0) is a guaranteed output of 4.6 ppm of

the nominal frequency.

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.

DESCRIPTION

MSTM-S3-R PIN ASSIGNMENT

BOTTOM VIEW

TRI-STATE

AB

REF 1

REF2

HOLD

OVER

FREE RUN PLL_TVL

ALARM

OUTPUT

0

0

0

FREE RUN MODE (DEFAULT)

0

0

0

1

0

1

01

0

EXTERNAL

REFERENCE

#1

MODE

NORMAL

PLL TUNING VOLTAGE LIMIT

LOR + LOL

1

1

1

0

0

0

0

0

0

0

0

0

0

1

0

0

1

1

00

1

EXTERNAL

REFERENCE

#2

MODE

NORMAL

PLL TUNING VOLTAGE LIMIT

LOR + LOL

0

0

0

1

1

1

0

0

0

0

0

0

0

1

0

0

1

1

0

1

1

HOLD OVER MODE

0

0

1

0

0 or 1

1

1

X

X

TRI-STATE MODE

HIGH IMPEDANCE

INDICATOR PIN

OUTPUTS

CONTROL

INPUTS

OPERATIONAL MODE

Fig. 1

Fig. 2

BLOCK DIAGRAM

MSTM-S3-R

CNTL A

CNTL B

2:4

0

1

2

3

HOLD OVER

REF 1

REF 2

FREE RUN

EX REF 1

EX REF 2

2:1

MUX

STRATUM3

TCXO

DAC

FILTERS

PHASE

COMPARATOR

CLK_OUT

SYNC_OUT

PLL_TVL

ALARM OUT

TUNING

VOLTAGE

MONITOR

STRATUM3

TCXO

DAC

FIFO

2:1

MUX

PLL TVL

FREE RUN

HOLD OVER

LOCK AND

DETECTION

TABLE 1.0

CLK_OUT

GND

TRI-STATE

GND

EX FEF 2

GND

12

10

11

14

13

16

15

PLL TVL

ALARM OUT

FREERUN

7

9

8

5

6

4

3

CNTL A

CNTL B

GND

REF 2

EX REF 1

+5Vdc

18

17

2

1

REF 1

HOLDOVER

SYNC_OUT