Comtech EF Data SDM-650B User Manual

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SDM-650B

Satellite Modem Installation and Operation Manual

Part Number MN/SDM650B.IOM Revision 5

EFData Corporation is an ISO 9001 Registered Company

SDM-650B

Satellite Modem Installation and Operation Manual

Part Number MN/SDM650B.IOM Revision 5 May 28, 1996

Special Instructions:

This is the sixth edition of the manual.

Change bars were not utilized.

This revision supersedes part number MN/SDM650 Rev. 4 dated May 5, 1995.

EFData Corporation, 2105 West 5th Place, Tempe, Arizona 85281 USA, (602) 968-0447, FAX: (602) 921-9012.

Warranty Policy

This EFData Corporation product is warranted against defects in material and workmanship for a period of one year from the date of shipment. During the warranty period, EFData will, at its option, repair or replace products that prove to be defective.

For equipment under warranty, the customer is responsible for freight to EFData and all related custom, taxes, tariffs, insurance, etc. EFData is responsible for the freight charges only for return of the equipment from the factory to the customer. EFData will return the equipment by the same method (i.e., Air, Express, Surface) as the equipment was sent to EFData.

Limitations of Warranty

The foregoing warranty shall not apply to defects resulting from improper installation or maintenance, abuse, unauthorized modification, or operation outside of environmental specifications for the product, or, for damages that occur due to improper repackaging of equipment for return to EFData.

No other warranty is expressed or implied. EFData Corporation specifically disclaims the implied warranties of merchantability and fitness for particular purpose.

Exclusive Remedies

The remedies provided herein are the buyer's sole and exclusive remedies. EFData Corporation shall not be liable for any direct, indirect, special, incidental, or consequential damages, whether based on contact, tort, or any other legal theory.

Disclaimer

EFData has reviewed this manual thoroughly in order that it will be an easy-to-use guide to your equipment. All statements, technical information, and recommendations in this manual and in any guides or related documents are believed reliable, but the accuracy and completeness thereof are not guaranteed or warranted, and they are not intended to be, nor should they be understood to be, representations or warranties concerning the products described. Further, EFData reserves the right to make changes in the specifications of the products described in this manual at any time without notice and without obligation to notify any person of such changes.

If you have any questions regarding your equipment or the information in this manual, please contact the EFData Customer Support Department. (For more information, refer to the preface.)

About this Manual

This manual provides installation and operation information for the EFData SDM-650B satellite modem.

This is a technical document intended for earth station engineers, technicians, and operators responsible for the operation and maintenance of the SDM-650B satellite modem.

Preface

Organization

This manual includes the following chapters and appendixes:

• Chapter 1 — describes the unit’s purpose, function, description, options, and

system specification.

• Chapter 2 — describes the unit’s installation process, external connectors, and

system requirements.

• Chapter 3 — describes the unit’s configuration.

• Chapter 4 — provides front panel operation information.

• Chapter 5 — describes the unit’s theory of operation.

• Chapter 6 — describes the maintenance of the unit, and provides troubleshooting

assistance.

• Appendix A — provides data rate change instructions and the differences for

fixed and variable rate filters.

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Preface SDM-650B Satellite Modem

• Appendix B — describes the unit’s remote control operation protocol and

command structure.

• Appendix C — provides field compatibility specifications.

• Appendix D — provides software change instructions.

• Appendix E — describes the unit’s Automatic Gain Control (AGC) interface

option.

• Appendix F — describes the asynchronous overhead channel unit option.

• Appendix G — describes the Trojan interface option.

• Glossary.

Conventions Used in this Manual

Cautions and Warnings

CAUTION indicates a hazardous situation that, if not avoided, may result in minor or moderate injury. CAUTION may also be used to indicate other

CAUTION

WARN ING

unsafe practices or risks of property damage.

WARNING indicates a potentially hazardous situation that, if not avoided, could result in death or serious injury.

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SDM-8000 Satellite Modem Preface

References Used in this Manual

Military Standards

References to “MIL-STD-188” apply to the 114A series (i.e., MIL-STD-188-114A), which provides electrical and functional characteristics of the unbalanced and balanced voltage digital interface circuits applicable to both long haul and tactical communications. Specifically, these references apply to the MIL-STD-188-114A electrical characteristics for a balanced voltage digital interface circuit, Type 1 generator, for the full range of data rates.

For more information, refer to the following document:

• Department of Defense (DOD) MIL-STD-188-114A, “Electrical Characteristics of Digital Interface Circuits.”

Trademarks

Product names mentioned in this manual may be trademarks or registered trademarks of their respective companies and are hereby acknowledged.

European EMC Directive

In order to meet the European Electro-Magnetic Compatibility (EMC) Directive (EN55022, EN50082-1), properly shielded cables for DATA I/O are required. More specifically, these cables must be double-shielded from end-to-end, ensuring a continuous ground shield.

The following information is applicable for the European Low Voltage Directive (EN60950):

<HAR> Type of power cord required for use in the European Community.

CAUTION: Double-pole/Neutral Fusing

International Symbols:

ACHTUNG: Zweipolige bzw. Neutralleiter-Sicherung

Alternating Current.

Fuse. Safety Ground.

Chassis Ground.

Note: For additional symbols, refer to “Cautions and Warnings” listed earlier in this preface.

Reporting Comments or Suggestions Concerning this Manual

Comments and suggestions regarding the content and design of this manual will be appreciated. To submit comments, please contact the EFData Customer Support Department according to the following information.

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SDM-8000 Satellite Modem Preface

Customer Support

Contact the EFData Customer Support Department for:

• Product support

• Information on returning a product

• Information on upgrading a product

• Product training

• Reporting comments or suggestions concerning manuals

An EFData Customer Support representative may be reached at:

EFData Corporation Attention: Customer Support Department 2105 West 5th Place Tempe, Arizona 85281 USA

(602) 968-0447 (Main EFData Number) (602) 517-2444 (Customer Support Desk) (602) 921-9012 FAX

or, E-Mail can be sent to the Customer Support Department at:

service@efdata.com

To return an EFData product (in-warranty and out-of-warranty) for repair or replacement:

1. Request a Return Material Authorization (RMA) number from the EFData Customer Support Department.

Be prepared to supply the Customer Support representative with the model

number, serial number, and a description of the problem.

2. To ensure that the product is not damaged during shipping, pack the product in its original shipping carton/packaging.

3. Ship the product back to EFData. (Shipping charges should be prepaid.)

For more information regarding the warranty policies, refer to the disclaimer page located behind the title page.

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This page is intentionally left blank.

vi Rev. 5

CHAPTER 1. INTRODUCTION.................................................................................. 1–1

1.1 Purpose and Function ..................................................................................................................................1–2

1.2 Description....................................................................................................................................................1–3

1.3 System Specification.....................................................................................................................................1–5

CHAPTER 2. INSTALLATION................................................................................... 2–1

2.1 Unpacking .....................................................................................................................................................2–1

2.2 External Connections................................................................................................................................... 2–2

2.2.1 DATA I/O...............................................................................................................................................2–3

2.2.2 Remote (J6).............................................................................................................................................2–3

2.2.3 Fault (J7).................................................................................................................................................2–3

2.2.4 IF Output (CP1) ......................................................................................................................................2–4

2.2.5 IF Input (CP2)......................................................................................................................................... 2–4

2.2.6 AC Power ...............................................................................................................................................2–4

2.2.7 GROUND ...............................................................................................................................................2–5

2.3 System Requirements...................................................................................................................................2–5

2.4 System Installation.......................................................................................................................................2–6

CHAPTER 3. CONFIGURATION............................................................................... 3–1

3.1 Monitor and Control.................................................................................................................................... 3–1

3.1.1 Description of Options............................................................................................................................3–2

3.1.1.1 Remote Interface .............................................................................................................................3–2

3.1.1.2 Remote Baud Rate...........................................................................................................................3–3

3.1.1.3 Remote Address ..............................................................................................................................3–4

3.1.1.4 Battery ............................................................................................................................................. 3–4

3.1.1.5 Modulator/Coder Defaults............................................................................................................... 3–5

3.1.1.6 Demodulator/Decoder Defaults....................................................................................................... 3–5

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3.1.1.7 Utility Defaults ................................................................................................................................3–5

3.1.2 Remote Interface Specification............................................................................................................... 3–6

3.1.3 M&C Theory of Operation ..................................................................................................................... 3–6

3.2 Digital Interfaces ..........................................................................................................................................3–7

3.2.1 RS-422 and MIL-STD-188-114 Interface ..............................................................................................3–7

3.2.1.1 Functional Description ....................................................................................................................3–7

3.2.1.2 Connector Pinouts .........................................................................................................................3–12

3.2.1.3 Specification..................................................................................................................................3–13

3.2.2 V.35 Interface ....................................................................................................................................... 3–14

3.2.2.1 Functional Description ..................................................................................................................3–14

3.2.2.2 Connector Pinouts .........................................................................................................................3–18

3.2.2.3 Specification..................................................................................................................................3–19

3.2.3 DS-1 Interface.......................................................................................................................................3–20

3.2.3.1 Functional Description ..................................................................................................................3–20

3.2.3.2 Connector Pinouts .........................................................................................................................3–23

3.2.3.3 Specification..................................................................................................................................3–23

3.2.4 G.703, 2048 kbit/s Interface .................................................................................................................3–24

3.2.4.1 Functional Description ..................................................................................................................3–24

3.2.4.2 Optional EXT CLK .......................................................................................................................3–26

3.2.4.3 Switch Configuration for G.703 2048 kbit/s Interface..................................................................3–27

3.2.4.4 Connector Pinouts .........................................................................................................................3–27

3.2.4.5 G.703 2048 kbit/s Connector Board Option.................................................................................. 3–28

3.2.4.6 External Reference (J3) .................................................................................................................3–30

3.2.4.7 Send Data (J4) ............................................................................................................................... 3–30

3.2.4.8 Receive Data (J5) ..........................................................................................................................3–30

3.2.4.9 Specification..................................................................................................................................3–31

3.2.5 Asynchronous Overhead Interface........................................................................................................3–31

3.2.5.1 Functional Description ..................................................................................................................3–31

3.2.5.2 Terrestrial Interface ....................................................................................................................... 3–32

3.2.5.3 Multiplexer ....................................................................................................................................3–35

3.2.5.4 Demultiplexer................................................................................................................................3–35

3.2.5.5 Plesiochronous Buffer ...................................................................................................................3–36

3.2.5.6 Remote Interface Specification .....................................................................................................3–36

3.2.5.7 Interface Connector Pinouts .......................................................................................................... 3–37

3.2.5.8 Asynchronous Interface Specifications .........................................................................................3–38

3.2.6 Asynchronous Breakout Panel.............................................................................................................. 3–39

3.3 Doppler Buffer............................................................................................................................................3–40

3.3.1 Buffer Setup.......................................................................................................................................... 3–44

3.3.1.1 Buffer Size.....................................................................................................................................3–46

3.3.1.2 Doppler..........................................................................................................................................3–46

3.3.1.3 Plesiochronous ..............................................................................................................................3–47

3.3.1.4 Frame/Multiframe Length ............................................................................................................. 3–47

3.3.1.5 Total Buffer Length.......................................................................................................................3–48

3.3.1.6 Converting.....................................................................................................................................3–48

3.4 Doppler Buffer Specification..................................................................................................................... 3–49

3.5 I/O Connectors ...........................................................................................................................................3–49

3.6 Interface Clocking Options .......................................................................................................................3–50

3.6.1 Master/Slave .........................................................................................................................................3–50

3.6.1.1 Master/Slave RS-422 or V.35 .......................................................................................................3–51

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3.6.1.1.1 Modem Settings (Master).......................................................................................................3–52

3.6.1.1.2 Modem Settings (Slave).........................................................................................................3–52

3.6.1.2 Master/Slave G.703 .......................................................................................................................3–53

3.6.1.3 Master/Slave X.21 .........................................................................................................................3–54

3.6.1.3.1 Modem Settings (Master).......................................................................................................3–54

3.6.1.3.2 Modem Settings (Slave).........................................................................................................3–54

3.6.1.4 Master/Slave External Station Clock.............................................................................................3–55

3.6.1.4.1 Modem Settings (Master).......................................................................................................3–55

3.6.1.4.2 Modem Settings (Slave).........................................................................................................3–55

3.6.2 Master/Master .......................................................................................................................................3–56

3.6.2.1 Master/Master (Customer Clock) ..................................................................................................3–56

3.6.2.1.1 Modem Settings (Master).......................................................................................................3–57

3.6.2.2 Master/Master (Station Clock) ......................................................................................................3–58

3.6.2.2.1 Modem Settings (Master).......................................................................................................3–59

CHAPTER 4. OPERATION........................................................................................ 4–1

4.1 Front Panel ...................................................................................................................................................4–2

4.1.1 LED Indicators........................................................................................................................................4–3

4.1.2 Controls ..................................................................................................................................................4–3

4.1.3 Menus and Options Overview ................................................................................................................4–4

4.1.4 Menu Explanations .................................................................................................................................4–9

4.1.4.1 Select Configuration........................................................................................................................4–9

4.1.4.2 Select Monitor ...............................................................................................................................4–15

4.1.4.3 Select Faults ..................................................................................................................................4–16

4.1.4.3.1 Modulator Faults (Mod_Flts).................................................................................................4–17

4.1.4.3.2 Demodulator/Decoder Faults (Dmd_Flts)..............................................................................4–17

4.1.4.3.3 Common Equipment Faults (CEq_Flts)................................................................................. 4–17

4.1.4.4 Select Stored Faults (StFaults) ......................................................................................................4–18

4.1.4.5 Select Utility..................................................................................................................................4–19

CHAPTER 5. THEORY OF OPERATION.................................................................. 5–1

5.1 Modulator ..................................................................................................................................................... 5–1

5.1.1 Specifications..........................................................................................................................................5–3

5.1.2 Theory of Operation ...............................................................................................................................5–5

5.2 Sequential Decoder/Demodulator Processor .............................................................................................5–7

5.2.1 Specification ...........................................................................................................................................5–8

5.2.2 Theory of Operation ...............................................................................................................................5–9

5.2.2.1 Demodulator Processor ...................................................................................................................5–9

5.2.2.2 Sequential Decoder........................................................................................................................5–10

5.2.2.2.1 Sequential Decoder BER Performance Specifications...........................................................5–12

5.3 Demodulator ...............................................................................................................................................5–16

5.3.1 Specifications........................................................................................................................................5–17

5.3.2 Theory of Operation .............................................................................................................................5–17

5.4 Reacquisition, Fast Acquisition, and Directed Sweep.............................................................................5–18

5.4.1 Reacquisition ........................................................................................................................................5–18

5.4.2 Fast Acquisition ....................................................................................................................................5–19

5.4.3 Directed Sweep.....................................................................................................................................5–20

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CHAPTER 6. MAINTENANCE................................................................................... 6–1

6.1 System Checkout ..........................................................................................................................................6–1

6.1.1 Modulator ...............................................................................................................................................6–1

6.1.2 Demodulator ........................................................................................................................................... 6–2

6.1.3 Test Points ..............................................................................................................................................6–8

6.1.3.1 Modulator ........................................................................................................................................6–8

6.1.3.2 Demodulator....................................................................................................................................6–9

6.1.3.3 Sequential Decoder/Demod Card ..................................................................................................6–10

6.2 Fault Isolation.............................................................................................................................................6–11

6.2.1 Modulator Faults (Mod_Flts Menu) ..................................................................................................... 6–11

6.2.2 Demodulator/Decoder Faults (Dmd_Flts Menu)..................................................................................6–12

6.2.3 Common Equipment Faults (CEq_Flts Menu) ..................................................................................... 6–14

6.3 Interface Fault Isolation ............................................................................................................................ 6–15

6.3.1 Transmit Faults (TX_INTF) .................................................................................................................6–15

6.3.2 Receive Faults (RX_INTF)...................................................................................................................6–16

6.4 Module Replacement .................................................................................................................................6–21

6.5 Module Identification.................................................................................................................................6–21

APPENDIX A. DATA RATES AND FILTERS............................................................A–1

A.1 Fixed Rate Filters ....................................................................................................................................... A–1

A.1.1 Data Rate Change Instructions.............................................................................................................. A–1

A.1.2 Hardware Configuration .......................................................................................................................A–5

A.2 Variable Rate Filters..................................................................................................................................A–6

A.2.1 Data Rate Change Instructions.............................................................................................................. A–6

A.2.2 Hardware Configuration .......................................................................................................................A–7

A.2.3 Utility ....................................................................................................................................................A–9

APPENDIX B. REMOTE CONTROL OPERATION ...................................................B–1

B.1 Standard Version........................................................................................................................................ B–1

B.1.1 General.................................................................................................................................................. B–2

B.1.2 Message Structure ................................................................................................................................. B–2

B.1.2.1 Start Character ...............................................................................................................................B–2

B.1.2.2 Device Address.............................................................................................................................. B–3

B.1.2.3 Command/Response ...................................................................................................................... B–4

B.1.2.4 End Character ................................................................................................................................B–4

B.1.3 Configuration Commands/Responses ................................................................................................... B–5

B.1.3.1 Set Modulator Frequency............................................................................................................... B–5

B.1.3.2 Set RF Output ................................................................................................................................ B–5

B.1.3.3 Set Demodulator Frequency ..........................................................................................................B–5

B.1.3.4 Set Modulator Power Offset .......................................................................................................... B–6

B.1.3.5 Set Modulator Output Power Level ............................................................................................... B–6

B.1.3.6 Modulator Rate .............................................................................................................................. B–7

B.1.3.6.1 Modulator Filter Rate Assignment ......................................................................................... B–7

B.1.3.6.2 Select Modulator Rate ............................................................................................................ B–8

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SDM-650B Satellite Modem Table of Contents

B.1.3.6.3 Select Modulator Rate Variable .............................................................................................B–8

B.1.3.7 Demodulator Rate.......................................................................................................................... B–9

B.1.3.7.1 Demodulator Filter Rate Assignment..................................................................................... B–9

B.1.3.7.2 Select Demodulator Rate...................................................................................................... B–10

B.1.3.7.3 Select Demodulator Rate Variable ....................................................................................... B–10

B.1.3.8 Scrambler Enable......................................................................................................................... B–10

B.1.3.9 Descrambler Enable..................................................................................................................... B–10

B.1.3.10 Differential Encoder Enable ......................................................................................................B–11

B.1.3.11 Transmit Clock .......................................................................................................................... B–11

B.1.3.12 Receive Clock............................................................................................................................ B–11

B.1.3.13 Baseband Loopback...................................................................................................................B–11

B.1.3.14 RF Loopback ............................................................................................................................. B–12

B.1.3.15 IF Loopback............................................................................................................................... B–12

B.1.3.16 Time of Day............................................................................................................................... B–12

B.1.3.17 Date............................................................................................................................................ B–13

B.1.3.18 Remote....................................................................................................................................... B–13

B.1.3.19 Clear Stored Faults .................................................................................................................... B–13

B.1.3.20 BER Threshold .......................................................................................................................... B–13

B.1.3.21 Sweep Reacquisition.................................................................................................................. B–14

B.1.3.22 Fast Acquisition Mode............................................................................................................... B–14

B.1.3.22.1 Sweep Center Frequency.................................................................................................... B–15

B.1.3.22.2 Sweep Width Range ........................................................................................................... B–15

B.1.3.22.3 Sweep Direction ................................................................................................................. B–16

B.1.3.23 Modem Operation Mode............................................................................................................ B–16

B.1.3.24 Buffer Control Mode ................................................................................................................. B–16

B.1.3.24.1 Buffer Clock....................................................................................................................... B–17

B.1.3.24.2 Interface Buffer Center....................................................................................................... B–17

B.1.3.24.3 Interface Buffer Size .......................................................................................................... B–17

B.1.4. Status Commands/Responses............................................................................................................. B–18

B.1.4.1 Configuration............................................................................................................................... B–18

B.1.4.1.1 Modulator/Coder Status ....................................................................................................... B–18

B.1.4.1.2 Modulator/Coder Program.................................................................................................... B–18

B.1.4.1.3 Demodulator/Decoder Configuration Status ........................................................................ B–19

B.1.4.1.4 Demodulator/Decoder Configuration Program .................................................................... B–20

B.1.4.2 Modem Faults Status (Summary) ................................................................................................ B–20

B.1.4.3 Modulator Status.......................................................................................................................... B–21

B.1.4.4 Demodulator Status...................................................................................................................... B–21

B.1.4.5 Common Equipment Status ......................................................................................................... B–22

B.1.4.6 Interface Receive Side Status ...................................................................................................... B–22

B.1.4.7 BER Status................................................................................................................................... B–23

B.1.4.7.1 Raw BER..............................................................................................................................B–23

B.1.4.7.2 Corrected BER ..................................................................................................................... B–23

B.1.4.8 E

Status.................................................................................................................................. B–24

b/N0

B.1.4.9 Modulator Rate Status ................................................................................................................. B–24

B.1.4.10 Demodulator Rate Status ........................................................................................................... B–24

B.1.4.11 Receive Signal Level Status ...................................................................................................... B–25

B.1.4.12 Current Sweep Value................................................................................................................. B–25

B.1.4.13 Stored Faults .............................................................................................................................. B–26

B.1.4.13.1 Modulator Stored Faults..................................................................................................... B–26

B.1.4.13.2 Demodulator Stored Faults................................................................................................. B–26

B.1.4.13.3 Common Equipment Stored Faults..................................................................................... B–27

B.1.4.13.4 Interface Receive Side Status Stored Faults ....................................................................... B–27

B.1.4.14 Bulk Consolidated Status........................................................................................................... B–28

B.1.4.15 Bulk Consolidated Analog Status .............................................................................................. B–30

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B.1.4.16 Bulk Consolidated Status Faults ................................................................................................ B–30

B.1.4.17 Change Status ............................................................................................................................B–31

B.1.4.18 Equipment Type......................................................................................................................... B–32

B.2 Asynchronous Overhead Interface Support Option ............................................................................. B–33

B.2.1 General................................................................................................................................................ B–33

B.2.2 Message Structure ............................................................................................................................... B–33

B.2.2.1 Start Character .............................................................................................................................B–34

B.2.2.2 Device Address............................................................................................................................ B–34

B.2.2.3 Command/Response .................................................................................................................... B–35

B.2.2.4 End Character ..............................................................................................................................B–35

B.2.3 Modulator Configuration Commands ................................................................................................. B–36

B.2.3.1 Set Modulator Frequency............................................................................................................. B–36

B.2.3.2 Set RF Output .............................................................................................................................. B–36

B.2.3.3 Set Modulator Power Offset ........................................................................................................ B–36

B.2.3.4 Set Modulator Output Power Level ............................................................................................. B–37

B.2.3.5 Modulator Rate ............................................................................................................................ B–38

B.2.3.5.1 Modulator Filter Rate Assignment ....................................................................................... B–38

B.2.3.5.2 Select Modulator Rate .......................................................................................................... B–39

B.2.3.5.3 Select Modulator Rate Variable ...........................................................................................B–39

B.2.3.6 Scrambler Enable......................................................................................................................... B–39

B.2.3.7 Differential Encoder Enable ........................................................................................................B–40

B.2.4 Demodulator Configuration Commands ............................................................................................. B–40

B.2.4.1 Set Demodulator Frequency ........................................................................................................B–40

B.2.4.2 Demodulator Rate........................................................................................................................ B–40

B.2.4.2.1 Demodulator Filter Rate Assignment................................................................................... B–41

B.2.4.2.2 Select Demodulator Rate...................................................................................................... B–41

B.2.4.2.3 Select Demodulator Rate Variable ....................................................................................... B–41

B.2.4.3 Descramble Enable ...................................................................................................................... B–42

B.2.4.4 RF Loopback ............................................................................................................................... B–42

B.2.4.5 IF Loopback................................................................................................................................. B–42

B.2.4.6 BER Threshold ............................................................................................................................ B–42

B.2.4.7 Sweep Reacquisition.................................................................................................................... B–43

B.2.4.8 Fast Acquisition Mode................................................................................................................. B–43

B.2.4.8.1 Sweep Center Frequency...................................................................................................... B–44

B.2.4.8.2 Sweep Width Range ............................................................................................................. B–44

B.2.4.8.3 Sweep Direction ................................................................................................................... B–45

B.2.5 Interface Configuration Commands.................................................................................................... B–45

B.2.5.1 Transmit Clock ............................................................................................................................ B–45

B.2.5.2 Buffer Clock ................................................................................................................................B–45

B.2.5.3 Receive Clock.............................................................................................................................. B–46

B.2.5.4 External Reference Frequency..................................................................................................... B–46

B.2.5.5 Interface Loopback ...................................................................................................................... B–46

B.2.5.6 Baseband Loopback.....................................................................................................................B–46

B.2.5.7 Interface Coding Format Transmit............................................................................................... B–47

B.2.5.8 Interface Coding Format Receive ................................................................................................ B–47

B.2.5.9 Interface Buffer Center ................................................................................................................ B–47

B.2.5.10 Interface Buffer Size.................................................................................................................. B–47

B.2.5.11 Transmit Overhead Baud Rate................................................................................................... B–48

B.2.5.12 Receive Overhead Baud Rate .................................................................................................... B–48

B.2.5.13 Overhead Channels Character Length ....................................................................................... B–48

B.2.5.14 Overhead Channels Stop Bits .................................................................................................... B–48

B.2.5.15 Overhead Channels Parity ......................................................................................................... B–49

B.2.5.16 Interface Substitution Pattern (Transmit 2047 Pattern) .............................................................B–49

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B.2.6 System Commands/Responses............................................................................................................ B–49

B.2.6.1 Time of Day.................................................................................................................................B–49

B.2.6.2 Date.............................................................................................................................................. B–50

B.2.6.3 Remote......................................................................................................................................... B–50

B.2.6.4 Clear Stored Faults ...................................................................................................................... B–50

B.2.6.5 Modem Operation Mode.............................................................................................................. B–51

B.2.7 Automatic Uplink Power Control (AUPC) Configuration Commands............................................... B–51

B.2.7.1 Local Modem AUPC Commands ................................................................................................ B–51

B.2.7.1.1 Local AUPC Enable ............................................................................................................. B–51

B.2.7.1.2 Nominal AUPC Power Level ............................................................................................... B–51

B.2.7.1.3 Maximum AUPC Power Limit............................................................................................. B–52

B.2.7.1.4 Minimum AUPC Power Limit .............................................................................................B–52

B.2.7.1.5 E

Target AUPC Set Point............................................................................................... B–52

b/N0

B.2.7.1.6 Maximum AUPC Tracking Rate .......................................................................................... B–52

B.2.7.1.7 AUPC Local Carrier Loss Action......................................................................................... B–53

B.2.7.1.8 AUPC Remote Carrier Loss Action .....................................................................................B–53

B.2.7.2 Remote Modem AUPC Commands............................................................................................. B–53

B.2.7.2.1 Remote AUPC Enable.......................................................................................................... B–53

B.2.7.2.2 Remote Interface Substitution Pattern (Transmit 2047 Pattern)........................................... B–54

B.2.7.2.3 Remote Interface Baseband Loopback................................................................................. B–54

B.2.7.2.4 Remote Interface Read Error Status (Received 2047 Pattern) .............................................B–54

B.2.8 Status Commands/Responses.............................................................................................................. B–55

B.2.8.1 Configuration Status .................................................................................................................... B–55

B.2.8.1.1 Modulator/Coder Configuration Status ................................................................................ B–55

B.2.8.1.2 Modulator/Coder Configuration Program ............................................................................ B–56

B.2.8.1.3 Demodulator/Decoder Configuration Status ........................................................................ B–57

B.2.8.1.4 Demodulator/Decoder Configuration Program .................................................................... B–58

B.2.8.1.5 Interface Configuration Status.............................................................................................. B–59

B.2.8.1.6 AUPC Configuration Status ................................................................................................. B–59

B.2.8.2 Modem Faults Status (Summary) ................................................................................................ B–60

B.2.8.3 Modulator Status.......................................................................................................................... B–60

B.2.8.4 Demodulator Status...................................................................................................................... B–60

B.2.8.5 Common Equipment Status ......................................................................................................... B–61

B.2.8.6 Interface Transmit Side Status..................................................................................................... B–61

B.2.8.7 Interface Receive Side Status ...................................................................................................... B–61

B.2.8.8 Bit Error Rate Status.................................................................................................................... B–62

B.2.8.8.1 Raw BER..............................................................................................................................B–62

B.2.8.8.2 Corrected BER ..................................................................................................................... B–62

B.2.8.9 E

............................................................................................................................................ B–63

b/N0

B.2.8.10 Modulator Rate .......................................................................................................................... B–63

B.2.8.11 Demodulator Rate...................................................................................................................... B–63

B.2.8.12 Receive Signal Level ................................................................................................................. B–64

B.2.8.13 Current Sweep Value................................................................................................................. B–64

B.2.8.14 Interface Buffer Fill Status ........................................................................................................ B–64

B.2.8.15 Interface Read Error Status........................................................................................................ B–64

B.2.8.16 Stored Faults .............................................................................................................................. B–65

B.2.8.16.1 Modulator Stored Faults..................................................................................................... B–65

B.2.8.16.2 Demodulator Stored Faults................................................................................................. B–65

B.2.8.16.3 Common Equipment Stored Faults..................................................................................... B–66

B.2.8.16.4 Interface Transmit Side Stored Faults ................................................................................ B–66

B.2.8.16.5 Interface Receive Side Stored Faults.................................................................................. B–66

B.2.8.17 Bulk Consolidated Status........................................................................................................... B–67

B.2.8.18 Bulk Consolidated Analog Status .............................................................................................. B–69

B.2.8.19 Bulk Consolidated Status Faults ................................................................................................ B–70

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Table of Contents SDM-650B Satellite Modem

B.2.8.20 Change Status ............................................................................................................................B–72

B.2.8.21 Equipment Type......................................................................................................................... B–72

B.2.8.22 Bulk Consolidated Status AUPC ............................................................................................... B–72

APPENDIX C. FIELD COMPATIBILITY ....................................................................C–1

C.1 SDM-650B Standard Modem....................................................................................................................C–1

C.2 SDM-650B Fairchild-Compatible Modem...............................................................................................C–2

C.3 SDM-650B Aydin Data Rate Modem ....................................................................................................... C–2

C.4 SDM-650B Comstream Modem................................................................................................................C–2

APPENDIX D. SOFTWARE CHANGE INSTRUCTIONS...........................................D–1

APPENDIX E. AGC INTERFACE .............................................................................. E–1

E.1 Connector Pinouts ...................................................................................................................................... E–2

E.2 Installation Instructions............................................................................................................................. E–2

E.2.1 Parts Required ....................................................................................................................................... E–2

E.2.2 Installation Procedure............................................................................................................................ E–3

APPENDIX F. ASYNCHRONOUS OVERHEAD CHANNEL UNIT ............................ F–1

F.1 Functional Description of ASYNC Overhead Channel Unit .................................................................. F–2

F.1.1 Terrestrial Interface ................................................................................................................................F–4

F.1.2 Multiplexer .............................................................................................................................................F–6

F.1.3 Demultiplexer .........................................................................................................................................F–6

F.1.4 Plesiochronous Buffer ............................................................................................................................F–7

F.2 ASYNC Interface Connector Pinouts ....................................................................................................... F–8

F.3 ASYNC Interface Specifications................................................................................................................ F–9

F.4 Functional Description of ASYNC Overhead Channel Unit with AUPC............................................ F–10

F.4.1 AUPC ...................................................................................................................................................F–10

F.4.2 Modem-to-Modem Channel for Remote M&C....................................................................................F–11

F.5 Front Panel Operation ............................................................................................................................. F–12

F.5.1 Menus and Options Overview ..............................................................................................................F–13

F.5.2 Menu Explanations...............................................................................................................................F–20

F.5.2.1 Select Configuration......................................................................................................................F–20

F.5.2.1.1 Configuration Modulator .......................................................................................................F–21

F.5.2.1.2 Configuration Demodulator...................................................................................................F–23

F.5.2.1.3 Configuration Interface..........................................................................................................F–25

F.5.2.1.4 Configuration AUPC .............................................................................................................F–28

F.5.2.2 Select Monitor...............................................................................................................................F–29

F.5.2.3 Select Faults ..................................................................................................................................F–30

xiv Rev. 5

SDM-650B Satellite Modem Table of Contents

F.5.2.3.1 Modulator Faults (Mod_FLTS) .............................................................................................F–31

F.5.2.3.2 Demodulator/Decoder Faults (Dmd_Flts) .............................................................................F–31

F.5.2.3.3 Common Equipment Faults (CEq_Flts).................................................................................F–31

F.5.2.3.4 Transmit Faults (TX_INTF) ..................................................................................................F–32

F.5.2.3.5 Receive Faults (RX_INTF)....................................................................................................F–32

F.5.2.4 Select Stored Faults (StFaults) ......................................................................................................F–33

F.5.2.5 Select Remote................................................................................................................................F–34

F.5.2.5.1 Remote Configuration............................................................................................................F–34

F.5.2.5.2 Remote Monitor.....................................................................................................................F–34

F.5.2.6 Select Utility..................................................................................................................................F–35

APPENDIX G. TROJAN INTERFACE ...................................................................... G–1

G.1 Functional Description ..............................................................................................................................G–1

G.2 Connector Pinouts......................................................................................................................................G–5

G.3 Specification................................................................................................................................................G–6

G.3.1 MIL-STD-188-114 Parameters.............................................................................................................G–6

G.3.2 Clock Synthesizer/Dejitter Circuit........................................................................................................G–6

G.3.3 Doppler Buffer Parameters ................................................................................................................... G–6

G.4 Configuration Guide..................................................................................................................................G–7

G.4.1 Modulator/Coder Defaults .................................................................................................................... G–7

G.4.2 Demodulator/Decoder Defaults (Dmd_Flts)......................................................................................... G–8

G.4.3 Interface Defaults.................................................................................................................................. G–8

G.5 Front Panel Operation...............................................................................................................................G–9

G.5.1 Menus and Options Overview ..............................................................................................................G–9

G.5.2 Menu Explanations .............................................................................................................................G–14

G.5.2.1 Select Configuration....................................................................................................................G–14

G.5.2.2 Select Monitor .............................................................................................................................G–14

G.5.2.3 Select Faults.................................................................................................................................G–14

G.5.2.3.1 Modulator Faults (Mod_Flts)...............................................................................................G–14

G.5.2.3.2 Demodulator/Decoder Faults (Dmd_Flts)............................................................................ G–14

G.5.2.3.3 Common Equipment Faults (CEq_Flts)...............................................................................G–14

G.5.2.4 Select Stored Faults (StFaults) ....................................................................................................G–15

G.5.2.5 Select Utility................................................................................................................................G–15

G.6 Remote Control Operation......................................................................................................................G–16

G.6.1 General................................................................................................................................................ G–16

G.6.1.1 Message Structure........................................................................................................................G–16

G.6.1.1.1 Start Character ......................................................................................................................G–17

G.6.1.1.2 Device Address ....................................................................................................................G–17

G.6.2 Command/Response............................................................................................................................G–18

G.6.3 End Character .....................................................................................................................................G–18

G.6.4 Configuration Commands/Responses.................................................................................................G–19

G.6.4.1 Modulator .................................................................................................................................... G–19

G.6.4.1.1 Set Modulator Frequency.....................................................................................................G–19

G.6.4.1.2 Set RF Output....................................................................................................................... G–19

G.6.4.1.3 Modulator Rate.....................................................................................................................G–20

G.6.4.1.3.1 Modulator Filter Rate Assignment................................................................................G–20

G.6.4.1.3.2 Select Modulator Rate...................................................................................................G–21

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Table of Contents SDM-650B Satellite Modem

G.6.4.1.3.3 Select Modulator Rate Variable.................................................................................... G–21

G.6.4.1.3.4 Set Modulator Power Offset ......................................................................................... G–21

G.6.4.1.3.5 Set Modulator Output Power Level .............................................................................. G–22

G.6.4.1.3.6 Scrambler Enable..........................................................................................................G–22

G.6.4.1.3.7 Differential Encoder Enable .........................................................................................G–22

G.6.4.2 Demodulator................................................................................................................................G–23

G.6.4.2.1 Set Demodulator Frequency................................................................................................. G–23

G.6.4.2.2 Demodulator Rate ................................................................................................................G–23

G.6.4.2.2.1 Demodulator Filter Rate Assignment ...........................................................................G–24

G.6.4.2.2.2 Select Demodulator Rate ..............................................................................................G–24

G.6.4.2.2.3 Select Demodulator Rate Variable................................................................................G–24

G.6.4.2.3 Descramble Enable...............................................................................................................G–25

G.6.4.2.4 IF Loopback ......................................................................................................................... G–25

G.6.4.2.5 RF Loopback........................................................................................................................G–25

G.6.4.2.6 Sweep Reacquisition ............................................................................................................ G–25

G.6.4.2.7 Fast Acquisition Mode ......................................................................................................... G–26

G.6.4.2.8 Sweep Center Frequency...................................................................................................... G–26

G.6.4.2.9 Sweep Width Range.............................................................................................................G–27

G.6.4.2.10 Sweep Direction .................................................................................................................G–27

G.6.4.2.11 Bit Error Rate Threshold....................................................................................................G–27

G.6.4.3 Interface/Doppler Buffer .............................................................................................................G–28

G.6.4.3.1 Baseband Loopback ............................................................................................................. G–28

G.6.4.3.2 Transmit Clock..................................................................................................................... G–28

G.6.4.3.3 Receive Clock ......................................................................................................................G–28

G.6.4.3.4 External Reference Frequency ............................................................................................. G–28

G.6.4.3.5 Interface Reference Clock....................................................................................................G–29

G.6.4.3.6 Interface Buffer Center ........................................................................................................G–29

G.6.4.3.7 Interface Buffer Depth .........................................................................................................G–29

G.6.4.4 System Commands/Responses .................................................................................................... G–30

G.6.4.4.1 Time of Day .........................................................................................................................G–30

G.6.4.4.2 Date ...................................................................................................................................... G–30

G.6.4.4.3 Remote .................................................................................................................................G–31

G.6.4.4.4 Clear Stored Faults...............................................................................................................G–31

G.6.4.4.5 Modem Operation Mode ......................................................................................................G–31

G.6.4.5 Status Commands/Responses ...................................................................................................... G–32

G.6.4.5.1 Configuration .......................................................................................................................G–32

G.6.4.5.1.1 Modulator/Coder Configuration Status.........................................................................G–32

G.6.4.5.1.2 Modulator/Coder Configuration Program.....................................................................G–33

G.6.4.5.1.3 Demodulator/Decoder Configuration Status.................................................................G–33

G.6.4.5.1.4 Demodulator/Decoder Configuration Program.............................................................G–34

G.6.4.5.1.5 Interface Configuration Status ......................................................................................G–34

G.6.4.5.2 Modem Faults Status (Summary)......................................................................................... G–35

G.6.4.5.3 Modulator Status .................................................................................................................. G–35

G.6.4.5.4 Demodulator Status..............................................................................................................G–35

G.6.4.5.5 Common Equipment Status..................................................................................................G–36

G.6.4.5.6 Bit Error Rate Status ............................................................................................................G–36

G.6.4.5.6.1 Raw BER ...................................................................................................................... G–36

G.6.4.5.6.2 Corrected BER..............................................................................................................G–37

G.6.4.5.7 E

.....................................................................................................................................G–37

b/N0

G.6.4.5.8 Modulator Rate.....................................................................................................................G–37

G.6.4.5.9 Demodulator Rate ................................................................................................................G–38

G.6.4.5.10 Receive Signal Level.......................................................................................................... G–38

G.6.4.5.11 Current Sweep Value .........................................................................................................G–38

G.6.4.5.12 Stored Faults ......................................................................................................................G–38

xvi Rev. 5

SDM-650B Satellite Modem Table of Contents

G.6.4.5.12.1 Modulator Stored Faults .............................................................................................G–39

G.6.4.5.12.2 Demodulator Stored Faults ......................................................................................... G–39

G.6.4.5.12.3 Common Equipment Stored Faults.............................................................................G–39

G.6.4.5.13 Bulk Consolidated Status ................................................................................................... G–40

G.6.4.5.14 Bulk Consolidated Analog Status ......................................................................................G–42

G.6.4.5.15 Bulk Consolidated Status Faults ........................................................................................G–42

G.6.4.5.16 Change Status..................................................................................................................... G–43

G.6.4.5.17 Equipment Type.................................................................................................................G–44

GLOSSARY ............................................................................................................... g–1

Rev. 5 xvii

Table of Contents SDM-650B Satellite Modem

Figures

Figure 1-1. SDM-650B....................................................................................................................................1–1

Figure 1-2. Satellite Communications System with an SDM-650B ................................................................ 1–2

Figure 1-3. Modular Construction ................................................................................................................... 1–4

Figure 1-4. Sequential Decoder BER Performance Curves (1/2 Rate)............................................................1–8

Figure 1-5. Sequential Decoder BER Performance Curves (3/4 Rate)............................................................1–9

Figure 1-6. Sequential Decoder BER Performance Curves (7/8 Rate)..........................................................1–10

Figure 1-7. Viterbi Decoder BER Performance Curves (1/2 Rate) ...............................................................1–11

Figure 1-8. SDM-650B Typical Output Spectrum ........................................................................................1–12

Figure 2-1. SDM-650B Rear Panel View........................................................................................................2–2

Figure 3-1. M&C Card ....................................................................................................................................3–2

Figure 3-2. RS-422 and MIL-STD-188-114 Interface Board..........................................................................3–7

Figure 3-3. RS-422 and MIL-STD-188-114 Block Diagram ..........................................................................3–8

Figure 3-4. V.35 Interface Card..................................................................................................................... 3–14

Figure 3-5. V.35 Interface Block Diagram ....................................................................................................3–15

Figure 3-6. DS-1 Interface Card .................................................................................................................... 3–20

Figure 3-7. DS-1 Interface Block Diagram....................................................................................................3–21

Figure 3-8. G.703 2048 kbit/s Interface Card................................................................................................3–24

Figure 3-9. G.703 2048 Interface Block Diagram .........................................................................................3–25

Figure 3-10. G.703 2048 kbit/s Interface Connector Board (Optional)......................................................... 3–28

Figure 3-11. G.703 2048 kbit/s Connector Board Schematic Diagram.........................................................3–29

Figure 3-12. Asynchronous Overhead Interface Block Diagram ..................................................................3–32

Figure 3-13. Asynchronous Overhead Jumpers.............................................................................................3–33

Figure 3-14. AS/3812 Doppler Buffer Daughter Card .................................................................................. 3–43

Figure 3-15. Clock Slip Diagram...................................................................................................................3–45

Figure 3-16. RS-422 or V.35 Master Slave Configuration............................................................................3–51

Figure 3-17. G.703 Master Slave Configuration ...........................................................................................3–53

Figure 3-18. X.21 Master/Slave Configuration .............................................................................................3–54

Figure 3-19. G.703 Master Slave Configuration ...........................................................................................3–55

Figure 3-20. Master/Master Customer Clock Configuration .........................................................................3–56

Figure 3-21. Master/Master Station Clock Configuration Diagram ..............................................................3–58

Figure 4-1. SDM-650B Front Panel View.......................................................................................................4–2

Figure 5-1. Modulator Block Diagram ............................................................................................................ 5–2

Figure 5-2. Modulator Output Spectral Occupancy.........................................................................................5–4

Figure 5-3. Decoder Block Diagram................................................................................................................5–7

Figure 5-4. Sequential Decoder BER Performance Curves (1/2 Rate)..........................................................5–13

Figure 5-5. Sequential Decoder BER Performance Curves (3/4 Rate)..........................................................5–14

Figure 5-6. Sequential Decoder BER Performance Curves (7/8 Rate)..........................................................5–15

Figure 5-7. Demodulator Block Diagram ......................................................................................................5–16

Figure 6-1. Typical Output Spectrum ..............................................................................................................6–4

Figure 6-2. Typical Output Spectrum ..............................................................................................................6–4

Figure 6-3. Typical Eye Pattern with Noise (Approximately 7.5 dB E

Figure 6-4. Typical Eye Pattern without Noise ...............................................................................................6–6

Figure 6-5. Typical Eye Constellation with Noise (Approximately 7.5 dB E

Figure 6-6. Typical Eye Constellation without Noise......................................................................................6–7

Figure 6-7. Modulator Test Points...................................................................................................................6–8

Figure 6-8. Demodulator Test Points...............................................................................................................6–9

Figure 6-9. Sequential Decoder/Demod Card Test Points.............................................................................6–10

Figure 6-10. Rear View Without Cover.........................................................................................................6–20

Figure A-1. Modulator Filter Card Change ....................................................................................................A–2

Figure A-2. Demodulator Filter Card Change ................................................................................................ A–4

) ...................................................6–6

b/N0

) .........................................6–7

b/N0

xviii Rev. 5

SDM-650B Satellite Modem Table of Contents

Figure E-1. Rear Panel View .......................................................................................................................... E–2

Figure E-2. Wiring Diagram........................................................................................................................... E–4

Figure E-3. AGC Adapter Board .................................................................................................................... E–5

Figure F-1. Asynchronous Overhead Interface Block Diagram ......................................................................F–3

Figure F-2. Asynchronous Overhead Interface Board.....................................................................................F–5

Figure G-1. Trojan Interface Block Diagram .................................................................................................G–2

Rev. 5 xix

Table of Contents SDM-650B Satellite Modem

Tables

Table 1-1. Operating Specifications ................................................................................................................1–5

Table 1-2. BER Performance Specifications ...................................................................................................1–7

Table 2-1. Rear Panel Connectors ...................................................................................................................2–2

Table 3-1. AS/0627-3 Rev. E Board Jumper Selection ................................................................................. 3–11

Table 3-2. AS/0627-2 Rev. E Board Jumper Selection ................................................................................. 3–17

Table 3-3. Equalizer Control .........................................................................................................................3–22

Table 3-4. G.703, 2048 kbit/s Interface Switch Configurations ....................................................................3–26

Table 3-5. G.703 2048 kbit/s Interface Connector Jumpers ..........................................................................3–29

Table 3-6. Asynchronous Overhead Jumper Table........................................................................................3–34

Table 3-7. Data Rate Jumper Table ...............................................................................................................3–34

Table 3-8. Jumper Selections......................................................................................................................... 3–41

Table 3-9. INTELSAT Delay Variations....................................................................................................... 3–41

Table 4-1. Main Front Panel Menu (Standard)................................................................................................4–4

Table 4-2. Select Configuration Menu ............................................................................................................4–5

Table 4-3. Select Monitor Menu......................................................................................................................4–6

Table 4-4. Select Faults Menu .........................................................................................................................4–6

Table 4-5. Select Stored Faults (StFaults) Menu .............................................................................................4–7

Table 4-6. Select Utility Menu.........................................................................................................................4–8

Table 6-1. EFData Conversion of (S+N)/N to S/N and E

Table 6-2. Programmable Data Rates for the Variable Rate SDM-650B Modem.........................................6–17

Table 6-3. EFData Part Numbers for SDM-650B Modules...........................................................................6–22

Table D-1. EFData M&C Viterbi Decoder Firmware ....................................................................................D–2

Table F-1. Asynchronous Overhead Jumpers..................................................................................................F–5

Table F-2. Data Rate Jumpers..........................................................................................................................F–5

Table F-3. Main Front Panel Menu with Asynchronous Overhead (with AUPC) ........................................F–13

Table F-4. Select Configuration Modulator Menu (with AUPC) ..................................................................F–13

Table F-5. Select Configuration Demodulator Menu (with AUPC)..............................................................F–14

Table F-6. Select Configuration Interface Menu (with AUPC).....................................................................F–15

Table F-7. Select Configuration AUPC Menu (with AUPC) ........................................................................F–16

Table F-8. Select Monitor Menu (with AUPC) .............................................................................................F–16

Table F-9. Select Faults Menu (with AUPC).................................................................................................F–17

Table F-10. Select Stored Faults (StFaults) Menu (with AUPC) ..................................................................F–18

Table F-11. Select Remote Menu (with AUPC)............................................................................................F–18

Table F-12. Select Utility Menu (with AUPC)..............................................................................................F–19

Table G-1. Main Front Panel Menu (Trojan Interface) ..................................................................................G–9

Table G-2. Select Configuration Modulator Menu....................................................................................... G–10

Table G-3. Select Configuration Demodulator Menu...................................................................................G–10

Table G-4. Select Configuration Interface Menu .........................................................................................G–11

Table G-5. Select Monitor Menu..................................................................................................................G–11

Table G-6. Select Faults (StFaults) Menu.....................................................................................................G–12

Table G-7. Select StFaults Menu..................................................................................................................G–13

Table G-8. Select Utility Menu..................................................................................................................... G–13

for Various Code Rates...................................6–5

b/N0

xx Rev. 5

Chapter 1.

INTRODUCTION

This manual describes the SDM-650B satellite modem, referred to in this document as “the modem” (Figure 1-1).

Figure 1-1. SDM-650B

Rev. 5 1–1

Introduction SDM-650B Satellite Modem

1.1 Purpose and Function

The modem is a high performance, full-duplex, Bi-Phase Shift Keying/Quadrature Phase Shift Keying (BPSK/QPSK), digital modulator/demodulator (modem), for Frequency Division Multiple Access (FDMA) satellite communication systems.

The modem provides an interface between Single Channel Per Carrier (SCPC) fixed-rate terminal equipment, having a data rate of 19.2 kbit/s to 3.584 Mbit/s.

The modem also provides an interface between IF converter equipment operating in a 50 to 90 MHz band, or 100 to 180 MHz band (Figure 1-2).

CUSTOMER

DATA

REMOTE

SERIAL

INTERFACE

FAULT

INDICATORS

DIGITAL

INTERFACE

SDM-650B

SATELLITE

ENCODER/

MODULATOR

MICRO- POWER

COMPUTER

DEMODULATOR/

SUPPLY

C POWER

RF EQUIPMENTDECODER

DATA MODEM

Figure 1-2. Satellite Communications System with an SDM-650B

TRANSMIT

RF EQUIPMENT

RECEIVE

ANTENNA

1–2 Rev. 5

SDM-650B Satellite Modem Introduction

The modem contains:

• Built-in scrambler/descrambler

• Differential encoder/decoder

• Transmit and receive frequency synthesizers

• Multi-rate Forward Error Correction (FEC) convolutional encoder-sequential

decoder (Viterbi K=7 is optional)

The modem provides high performance with:

• Narrow occupied bandwidth

• Automatic signal acquisition

• High flexibility

• Extensive online monitoring circuits

1.2 Description

The modem is a complete, self-contained unit in a standard 19” rack-mountable enclosure weighing approximately 25 lbs.

The modem is of modular construction (Figure 1-3).

The chassis assembly (with the front and rear panel) encloses several Printed Circuit Boards (PCBs). The backplane PCB is mounted on the chassis assembly, and contains receptacles for five plug-in PCBs.

Rev. 5 1–3

Introduction SDM-650B Satellite Modem

Figure 1-3. Modular Construction

Test points are located on the front board edge of the modulator, demodulator, and decoder PCBs. Refer to Section 6.1.4 for listings and diagrams of the test points.

All controls and indicators for operation of the modem are located on the front panel. For more information, refer to Chapter 4.

The chassis also contains the power supply; a fan is located on the rear panel.

The modem consists of the following assemblies:

Assembly Drawing #

Chassis with Power Supply AS/1099 PCB, M&C AS/0356 PCB, Modulator AS/0773-X PCB, Demodulator AS/0778-X PCB, Sequential Decoder AS/0365-X PCB, Front Panel Control Board AS/0361 PCB, Mother Board AS/0979-1 PCB, Digital Interface V.35 AS/0627-2 (Optional) PCB, Digital Interface DS1 AS/0569 (Optional) PCB, Digital Interface MIL-STD-188-114 AS/0627-3 (Optional) PCB, Doppler Buffer AS/3812 (Optional) PCB, Asynchronous Overhead Channel Unit AS/1311-X (Optional)

Note: X = various options available on the modulator, demodulator, and decoder boards.

1–4 Rev. 5

SDM-650B Satellite Modem Introduction

1.3 System Specification

Table 1-1 lists the operating specifications of the modem.

Table 1-1. Operating Specifications

System Specifications

Operating Frequency Range 50 to 90 MHz, or 100 to 180 MHz. Synthesized in

2.5 kHz steps.

Type of Modulation QPSK.

BPSK.

Operating Channel Spacing Less than 0.5 dB degradation operating with 2 adjacent

like channels each 10 dB higher at 1.3 times the

symbol rate or 75 kHz minimum. BER See Table 1-2. Digital Interface RS-422/-449.

V.35.

DS-1 STD.

G.703.

Others optional. Digital Data Rate:

Variable Rate Single Rate

Forward Error Correction Convolutional encoding with soft decision, sequential,

Data Scrambling Selectable.

Diagnostic Features RF Loopback.

Prime Power 90 to 132 VAC, or 180 to 264 VAC, 47 to 63 Hz.

Size 5.25” x 19.0” x 18.0” (3RU).

Additional Modulator Specifications

Output Power -5 to -30 dBm, adjustable in 0.5 dB steps.

Output Spurious and Harmonics -50 dBc in-band (50 to 90 MHz, or 100 to 180 MHz).

Output Impedance 75Ω. Output Return Loss 20 dB. Output Frequency Stability ± 10 PPM. Data Clock Source Internal or External. Internal Data Clock Stability ± 50 PPM.

19.2 to 3584 kbit/s configurable. Choice of up to four

pre-defined rates, or variable rate option.

19.2 to 48 kbit/s, 1/2 rate BPSK only.

19.2 to 2048 kbit/s.

19.2 to 3584 kbit/s.

2048 kbit/s maximum for 1/2 rate.

3072 kbit/s maximum for 3/4 rate.

3584 kbit/s maximum for 7/8 rate.

or K=7 Viterbi decoding.

CCITT V.35.

None.

IF Loopback.

Digital Data Loopback.

Fault Monitoring.

BER Monitoring.

Remote Control via Serial Port.

75W maximum, fused at 2A.

-48 VDC optional.

+5 to -15 dBm with high power option.

-40 dBc out-of-band.

Rev. 5 1–5

Introduction SDM-650B Satellite Modem

Additional Demodulator Specifications

Input Power:

Desired Carrier Composite

-30 to -55 dBm. +30 dB power within 20 MHz from desired carrier. +40 dB power outside of 20 MHz from desired carrier.

0 dBm maximum composite. Input Impedance 75Ω. Input Return Loss 20 dB. Carrier Acquisition Range ± 25 kHz minimum. Clock Acquisition Range ± 100 PPM.

Remote Control Specifications

Serial Interface RS-232-C, or RS-485. Baud Rate 300 to 9600 bit/s. Signals Controlled/Monitored Transmit Frequency.

Receive Frequency

Transmit Power.

Transmitter ON/OFF.

Data Rate Select.

RF Loopback.

IF Loopback.

Data Loopback.

Scrambler ON/OFF.

Descrambler ON/OFF.

Raw Error Rate.

Corrected BER.

Receive E

b/N0

TX Clock Internal/External.

RX Clock Normal/Invert.

Receive Signal Level.

Receive Carrier Detect.

Power Supply Voltages.

Stored Fault Status. Configuration Retention Will maintain current configuration for 30 days

minimum without power. Addressing Programmable to 1 of 255 possibilities. Address 0

reserved for global addressing. Local control of all remote functions included via push-button entry.

1–6 Rev. 5

SDM-650B Satellite Modem Introduction

The specifications for the Bit Energy-to-Noise Ratio (E

-7

BER for different coding configurations is listed in Table 1-2. All values are for

) required to achieve 10-5 and

b/N0

operation in QPSK mode.

Table 1-2. BER Performance Specifications

Data Rate Sequential Viterbi K=7

1/2 Rate 3/4 rate 7/8 Rate 1/2 Rate

100 kbit/s

BER 10-5 4.8 dB 5.8 dB 6.7 dB 5.5 dB BER 10-7 5.8 dB 6.6 dB 8.0 dB 6.7 dB

1544 kbit/s

BER 10-5 5.8 dB 6.3 dB 6.9 dB 5.5 dB BER 10-7 6.6 dB 7.1 dB 8.0 dB 6.7 dB

Without coding, the modem provides operation within 0.5 dB of theoretical for BPSK, and within 0.8 dB for QPSK.

Performance measurements are with transmit, and receive IF connected back-to-back through an additive white Gaussian noise channel.

BER performances of the modem are shown in Figures 1-4 through 1-7.

A typical output spectrum of the modem is shown in Figure 1-8.

Rev. 5 1–7

Introduction SDM-650B Satellite Modem

-2

-3

-4

-5

-6

BER

-7

-8

-9

-10

3.0 4.0 5.0 6.0

100 kbit/s

SPECIFICATIONS

1544 kbit/s

7.0 8.0 9.0 10.0 11.0

(dB)

b/N0

Figure 1-4. Sequential Decoder BER Performance Curves (1/2 Rate)

1–8 Rev. 5

SDM-650B Satellite Modem Introduction

-2

-3

-4

-5

-6

BER

-7

-8

-9

-10

3.0 4.0 5.0 6.0

100 kbit/s

SPECIFICATIONS

7.0 8.0 9.0 10.0 11.0

(dB)

b/N0

1544 kbit/s

Figure 1-5. Sequential Decoder BER Performance Curves (3/4 Rate)

Rev. 5 1–9

Introduction SDM-650B Satellite Modem

-2

-3

-4

-5

-6

BER

-7

-8

-9

-10

3.0 4.0 5.0 6.0

Figure 1-6. Sequential Decoder BER Performance Curves (7/8 Rate)

100 kbit/s

SPECIFICATIONS

1544 kbit/s

7.0 8.0 9.0 10.0 11.0

(dB)

b/N0

1–10 Rev. 5

SDM-650B Satellite Modem Introduction

-2

-3

-4

-5

-6

BER

-7

-8

-9

-10

3.0 4.0 5.0 6.0

Figure 1-7. Viterbi Decoder BER Performance Curves (1/2 Rate)

100 kbit/s

1544 kbit/s

SPECIFICATIONS

7.0 8.0 9.0 10.0 11.0

(dB)

b/N0

Rev. 5 1–11

Introduction SDM-650B Satellite Modem

Figure 1-8. SDM-650B Typical Output Spectrum

1–12 Rev. 5

This chapter provides the following information:

2.1 Unpacking

The modem and manual are packaged in pre-formed, reusable, cardboard cartons containing foam spacing for maximum shipping protection. The three main circuit boards are packed in separate cardboard caddypacks (included within the cardboard carton).

To remove the modem:

CAUTION

Chapter 2.

INSTALLATION

• Unpacking instructions

• External connections

• System requirements

• System installation

Do not use any cutting tool that will extend more than 1” into the container and cause damage to the modem.

Parts and assemblies may be damaged by Electrostatic Discharge (ESD). ESD safety precautions should always be observed when handling parts.

1. Cut the tape at the top of the carton (indicated by OPEN THIS END).

2. Remove the cardboard/foam space covering the modem and caddypacks.

3. Remove the modem, caddypacks, manual, and power cord from the carton.

Rev. 5 2–1

Installation SDM-650B Satellite Modem

4. Save the packing material for storage or reshipment purposes.

5. Inspect the equipment for any possible damage incurred during shipment.

6. Check the equipment against the packing list to ensure the shipment is complete.

7. Refer to Section 2.4 for further system installation instructions.

2.2 External Connections

Connections between the modem and other equipment are made through six connectors. These connectors are listed in Table 2-1 and their locations are shown in Figure 2-1.

DATA

TX/ IF

OUTPUT

REMOTE

FAULT

RX/ IF

MADE IN USA

INPUT

Figure 2-1. SDM-650B Rear Panel View

Table 2-1. Rear Panel Connectors

Name Ref. Design. Connector Type Function

DATA I/O J8 Various RS-422/MIL-STD-188 I/O

V.35 DATA I/O DS1 DATA I/O G.703 DATA I/O Asynchronous Overhead

Channel Unit REMOTE J6 9-Pin D Interface FAULT J7 9-Pin D FORM C Fault Relay Contacts IF OUTPUT CP1 BNC TX IF Output IF INPUT CP2 BNC RX IF Input AC POWER None Standard AC Power Input GROUND GROUND #10-32 Stud Chassis Ground

The use of each connector is described in the following paragraphs.

CP1

CP2

GROUND

ERDE

2–2 Rev. 5

SDM-650B Satellite Modem Installation

2.2.1 DATA I/O

For information and pinouts on the data connectors, refer to Chapter 3.

2.2.2 Remote (J6)

The remote connector on the modem is used to interface the Monitor and Control (M&C) functions to a remote location. This interface can be either RS-232-C or RS-485. For a complete discussion on the remote interface, refer to Chapter 3.

The remote interface is provided on a 9-pin female D connector. Screw locks are provided for mechanical security of the mating connector. The remote connector is a Data Circuit Terminating Equipment (DCE) interface.

RS-485 RS-232-C

Pin # Name Pin # Name

1 GND 1 2 2 RD (RX) 3 3 TD (TX) 4 +RX/TX 4 5 -RX/TX 5 GND 6 6 DSR 7 7 RTS 8 +RX/TX 8 CTS 9 -RX/TX 9

2.2.3 Fault (J7)

The fault connector on the modem is used to provide FORM C contact closures for the purpose of fault reporting.

There are three FORM C summary fault contacts:

• Modulator

• Demodulator

• Common equipment

Refer to Chapter 4 for a complete discussion on monitored faults.

To obtain a system summary alarm, connect all FORM C contacts in parallel.

Rev. 5 2–3

Installation SDM-650B Satellite Modem

The fault interface is provided on a 9-pin female D connector. Screw locks are provided for mechanical security on the mating connector.

Pin # Name Function

1 NO Common equipment is OK 2 COM 3 NC Common equipment is faulted 4 NO Modulator is OK 5 COM 6 NC Modulator is faulted 7 NO Demodulator is OK 8 COM 9 NC Demodulator is faulted

Note: A connection between the common (COM) and normally open (NO) contacts indicates no fault.

2.2.4 IF Output (CP1)

This is the transmit IF connector. The output impedance is 75Ω, and the output power level is -5 to -30 dBm.

In normal operation, the output will be a QPSK-modulated result of the DATA I/O connector, with a frequency between 50 and 90 MHz, or 100 and 180 MHz.

2.2.5 IF Input (CP2)

This is the receive IF connector. The input impedance is 75Ω.

For normal operation, the signal level needs to be between -30 dBm and -55 dBm, with a maximum composite level of 0 dBm. Signals between 50 and 90 MHz, or 100 and 180 MHz, are selected and demodulated to produce clock and data at the DATA I/O connector.

2.2.6 AC Power

The AC power is supplied to the modem by a standard detachable, non-locking, 3-prong power cord.

Normal input voltage is 90 to 132 VAC, or 180 to 264 VAC, 47 to 63 Hz. Maximum power consumption is less than 75W.

Damage may result if the incorrect input voltage is applied to this connector. If there is any question of voltage compatibility, do not connect the unit until

CAUTION

EFData has been contacted.

2–4 Rev. 5

SDM-650B Satellite Modem Installation

2.2.7 GROUND

A #10-32 stud is available on the rear panel for the purpose of connecting a common chassis ground between all of the equipment.

2.3 System Requirements

The standard modem with all cards installed (as listed in Chapter 1) is a full-duplex QPSK satellite modem.

The system can also be configured for TX-only or RX-only operation:

• For a TX-only system, the demodulator (AS/0778-X) and decoder (AS/0365-X) are removed. The Utility menu on the front panel must be entered and Operation mode selected. Enter the menu and select TX-only. This will mask the receive faults and receive stored faults in the Faults menu.

• For an RX-only system, the modulator (AS/0773-X) is removed. Enter the Utility menu on the front panel and select Operation mode. Enter the menu and select RX-only. This will mask the transmit faults and transmit stored faults in the Faults menu.

The modem interface is configured by the selection of the data interface card. Refer to Chapter 3 for discussion on the data interface cards.

The modem data/code rate is configured by the installation of a daughter card (AS/0363, AS/0715, or AS/0930-1) on the modulator, and a daughter card (AS/0362, or AS/0929-X) on the demodulator. The Utilities function must be set up to be compatible with the daughter cards. Refer to Chapter 4 for information on the Utilities function. The modem will be set up to match the daughter cards when it is shipped from the factory.

Rev. 5 2–5

Installation SDM-650B Satellite Modem

2.4 System Installation

After unpacking, install the modem as follows:

1. Mount the modem chassis in its assigned position in the equipment rack.

2. Connect the cables to the rear panel in the appropriate locations. Refer to Section 2.2 for connector pinouts, placement, and functions.

3. Open the front panel and verify the three main cards, the M&C, and data interface cards are properly seated.

Refer to Figure 1-3 for proper positioning of the cards.

When the cards are installed correctly, the color of the card guides on the chassis

will match the color of the card ejectors on the cards.

4. Before turning ON the power switch, read and become familiar with the information in Chapter 4.

5. Turn ON the power switch (located inside the front panel).

6. Check for proper TX signal level and spectrum.

7. Check for proper RX signal level and spectrum.

8. If there is any problem with the installation, refer to Chapter 6 for troubleshooting information.

2–6 Rev. 5

This chapter provides the following information:

• Monitor and control

• Digital interfaces

• Doppler buffer assembly

• Doppler buffer specification

• I/O connectors

• Interface clocking options

3.1 Monitor and Control

Chapter 3.

CONFIGURATION

The modem uses a sophisticated microcontroller module to perform the M&C functions of the modem (refer to Figure 3-1).

The M&C monitors the modem, and provides configuration updates to other modules within the modem when necessary.

Modem configuration parameters are maintained in battery-backed RAM, which provides for total recovery after a power-down situation.

Extensive fault monitoring and status gathering are provided.

All modem functions are accessible through a local front panel interface and a remote communications interface.

Rev. 5 3–1

Configuration SDM-650B Satellite Modem

Figure 3-1. M&C Card

3.1.1 Description of Options

3.1.1.1 Remote Interface

All modem functions can be remotely controlled and monitored via an RS-485 (optional RS-232-C) communications link.

• The 2-wire, half-duplex RS-485 interface makes it possible to operate 255 modems on a common communications link.

• The RS-232-C interface is used to communicate with a single modem.

The M&C module must be hardware configured to one of the two interfaces.

Perform the following steps to configure the M&C for RS-485 operation:

1. Remove jumpers JP4, JP5, and JPX.

2. Install jumpers JP1, JP2, and JP3.

3. Connect JP7 to RS-485.

Perform the following steps to configure the M&C for RS-232-C operation:

1. Remove jumpers JP1, JP2, and JP3.

2. Install jumpers JP4, JP5, and JPX.

3. Connect JP7 to RS-232-C.

3–2 Rev. 5

SDM-650B Satellite Modem Configuration

3.1.1.2 Remote Baud Rate

The remote communications baud rate and parity are programmed by a switch pack (SP1) on the M&C module.

Programming the baud rate and parity is accomplished by setting the appropriate switches in the OFF or ON positions:

• A switch is programmed OFF by placing it in the position furthest away from the PCB (open).

• A switch is programmed ON by placing it in the position nearest the PCB.

Switch position #1 sets the parity as follows:

Even Parity SP1-1 OFF Odd Parity SP1-1 ON

Switch positions #2, #3, and #4 set the baud rate as follows:

Baud SP1-2 SP1-3 SP1-4

110 ON ON ON 150 ON ON OFF 300 ON OFF ON

600 ON OFF OFF 1200 OFF ON ON 2400 OFF ON OFF 4800 OFF OFF ON 9600 OFF OFF OFF

Note: SP1 on the M&C modules has four additional switches (SP1-5 through SP1-8). These four switch locations are not currently assigned or used.

Rev. 5 3–3

Configuration SDM-650B Satellite Modem

3.1.1.3 Remote Address

Each modem must be configured for a distinct address between 1 and 255 to communicate using the established remote communications protocol.

Addresses are programmed by a switch pack (SP2) on the M&C module.

Addresses are binary coded numbers set at SP2. Switch #1 (SP2-1) is the most significant bit, and switch #8 (SP2-8) is the least significant bit.

3.1.1.4 Battery

A rechargeable battery on the M&C module allows the modem to retain configuration information without prime power for up to 30 days. A jumper (JP6) is supplied on the M&C module to disconnect battery power from the backup RAM. During normal operation, this jumper should be in the ON position. Should the modem be powereddown, the following sequence is carried out by the M&C microcontroller:

1. When power is applied to the M&C, the microcontroller checks the batterybacked RAM to see if valid data has been retained. If valid data has been retained, the modem is reconfigured to the configuration maintained in RAM.

2. If the battery-backed RAM failed the valid data test, the modulator, demodulator, and interface modules would be tested to determine if valid configuration information was retained by them. If valid configuration information was retained by a module, that module’s configuration will be stored in the battery-backed RAM and maintained.

3. If battery-backed RAM and a module failed the valid data test, a default configuration for the module from ROM is stored in battery-backed RAM and maintained.

To erase the configuration stored in RAM, capacitor C12 must be shorted while JP6 is OFF.

3–4 Rev. 5

SDM-650B Satellite Modem Configuration

3.1.1.5 Modulator/Coder Defaults

TXA Transmit Filter A — 7/8 code rate, 56 kbit/s TXB Transmit Filter B — 3/4 code rate, 56 kbit/s TXC Transmit Filter C — 1/2 code rate, 56 kbit/s TXD Transmit Filter D — 1/2 code rate, 64 kbit/s TXR Transmit Rate Selected — A 7/8, 56 kbit/s TX-FREQ Transmitter Frequency — 70 MHz RF-OUT RF Output — OFF TX-POWER Transmit Power Level — -10 dBm RFLOOPBK RF Loopback — OFF IFLOOPBK IF Loopback — OFF BBLOOPBK Baseband Loopback — OFF SCRAMBLR Scrambler — ON DIFENCDR Differential Encoder — ON TX-CLOCK Transmit Clock — Internal SWP-RACQ Sweep Re-acquisition — 0 Sec SWP-CNTR Sweep Center — Hz (See Note Below) SWP-RNGE Sweep Range — 5000 Hz (See Note Below) SWP-DIR Sweep Direction — Forward (See Note Below) CW-MODE Continuous Wave Mode — OFF

Note: These windows will only be displayed when FAST-ACQ (Fast Acquisition) has been turned ON in the Utility menu.

3.1.1.6 Demodulator/Decoder Defaults

RXA Receive Filter A — 7/8 decode rate, 56 kbit/s RXB Receive Filter B — 3/4 decode rate, 56 kbit/s RXC Receive Filter C — 1/2 decode rate, 56 kbit/s RXD Receive Filter D — 1/2 decode rate, 64 kbit/s RXR Receive Rate Selected — A 7/8, 56 kbit/s RX-FREQ Receiver Frequency — 70 MHz RFLOOPBK RF Loopback — OFF BBLOOPBK Base Band Loopback — OFF DSCRMBLR Descrambler — ON RX-CLOCK Receive Clock — Normal BERTHSLD BER Threshold [None]

3.1.1.7 Utility Defaults

DATE 7/4/76 TIME 12:00 AM POW-ADJ -5 dB OP-MODE Duplex FAST-ACQ OFF

Rev. 5 3–5

Configuration SDM-650B Satellite Modem

3.1.2 Remote Interface Specification

Refer to Appendix B for remote control operation information.

3.1.3 M&C Theory of Operation

The M&C module is built around the Intel 80C31 microcontroller operating at

5.5295 MHz. The microsystem is designed to support:

• 64K bytes of read-only code memory

• 64K bytes of random access data memory

Of the 64K bytes data memory, only 4K is used for RAM. The remaining address is used for memory-mapped I/O. Memory-mapped I/O includes:

• Real time clock/memory

• 8-channel analog-to-digital converter

• External buffered bus structure for overall modem control and status gathering

The 80C31 microcontroller supports a serial asynchronous communications channel with a maximum baud rate of 9600 bit/s using the 5.5295 MHz reference.

A rechargeable battery is employed to maintain the system real time clock and modem configuration through power-out situations.

3–6 Rev. 5

SDM-650B Satellite Modem Configuration

3.2 Digital Interfaces

3.2.1 RS-422 and MIL-STD-188-114 Interface

3.2.1.1 Functional Description

The RS-422 and MIL-STD-188-114 digital interface (Figure 3-2) provides the level translation, buffering, and termination between the internal modem signals and the RS-422 or MIL-STD-188-114 interface connector on the rear panel. A functional block diagram of the interface is shown in Figure 3-3.

JP3

JP8

JP10

DDRESSING SELECT JUMPERS

JP1

JP2

JP12

JP16

JP13

JP15

JP14

ASSEMBLY AND

REVISION NUMBER

Figure 3-2. RS-422 and MIL-STD-188-114 Interface Board

JP9

RS-422/MIL-188

ADAPTOR CONNECTOR

RS 422

Rev. 5 3–7

Configuration SDM-650B Satellite Modem

Electrical characteristics of the RS-422 interface signals are defined in EIA-STD-RS-422.

Electrical characteristics of the MIL-STD-188-114 interface signals are defined in MIL-STD-188-114 and MIL-STD-188-100.

• EIA-STD-RS-449 provides details of the mechanical interface.

• MIL-STD-188-114 defines signal levels, offsets, termination resistors, etc.

• MIL-STD-188-100 specifies such characteristics as signal quality and clock/data

phase relationships.

M O

D E

TX CLOCK

TX DATA

RX CLOCK

RX DAT A

COMMON E QUIPME NT

MODULA TOR

DEMODUL ATOR

TO BUFFER

OPTIONS

JP12

JP1

JP2

JP8

JP3

TO BUFFER

OPTIONS

FAULT

RELAY S

LOOP TIMI NG

TO LOGI C CONTROL

AUTO CLOCK SELECT

INVERT NORM

CONTROL

LOGIC

LOOPBACK

TO CONTRO L LOGIC

EXT ERNAL BUF FER CLOCK

INT/EXT CLOCK

TO CONTRO L LOGIC

JP9

RTS TO CTS JUMP ER

SPARE (RS -232 ONLY)

T E R R E S

T R

I A L

TTL MODULATOR FAULT

DATA BUS TO M & C

TTL DE MODULATOR FA ULT

Figure 3-3. RS-422 and MIL-STD-188-114 Block Diagram

3–8 Rev. 5

SDM-650B Satellite Modem Configuration

The RS-422 and MIL-STD-188-114 interface provides a Send Timing (ST) clock signal at the modem data rate.

In the Internal Clock mode, the data to be transmitted, Send Data (SD), must be synchronized to ST. In the External Clock mode, the clock is accepted on the Terminal Timing (TT) input to clock in the data to be transmitted. In either case, the phase relationship between the clock and data is not important as long as relationship meets the jitter specifications of RS-422 or MIL-STD-188-100.

A clock phase correction circuit is provided which shifts the clock away from the data transition times. The clock phasing is jumper-selectable at JP1.

When there is no jitter on the clock source, the Auto setting is used.

The Normal setting is used when standard specifications on clock and data relationships exist. The Invert mode is used when the incoming clock is inverted from the standard clock and data relationship.

Data received by the modem is output on the Receive Data (RD) lines.

Recovered clock is output on the Receive Timing (RT) lines.

For applications that require the rising edge of the clock to occur in the middle of the data bit time, Receive Clock Normal mode should be selected.

Invert mode puts the falling edge of RT in the middle of the data bit. This selection can be made from the front panel in the Configuration menu.

The Request to Send (RTS) lines are hard-wired to the Clear to Send (CTS) lines, since the modem does not support polled operation.

Data Mode (DM) indicates that the modem is powered-up.

Receive Ready (RR) indicates that an RF carrier is being received and demodulated with a sufficiently low error rate for the decoder to remain locked.

The RS-422 and MIL-STD-188-114 interface also provides bi-directional relay loopback of both the clock and data at the DCE interface. In Loopback:

• From the DTE side, SD is connected to RD, and either ST or TT (in Internal or External mode) is looped back to RT.

• From the modem side, the received data and recovered clock are routed back to the modulator input for re-transmission.

Rev. 5 3–9

Configuration SDM-650B Satellite Modem

Loop timing is supported by the selection of jumper JP10. When in the ON position, the transmit clock (ST) is replaced by the clock recovered from the satellite (RT). Active loop timing is indicated by a yellow light on the front edge of the card. The JP10 REM setting is for future options.

Three fault outputs are provided on dry contact FORM C relays:

• Common Equipment

• Modulator

• Demodulator

The faults are available on the fault connector on the modem rear panel. Generation of these fault conditions is described in Chapter 4. Fault indicators are also provided on TTL open collector drivers on the RS-422 or MIL-STD-188-114 connector.

The TTL MOD fault indicates a Modulator fault or Common Equipment fault.

The TTL DEMOD fault indicates a Demodulator or Common Equipment fault.

The PCB for the RS-422/MIL-STD-188-114 interface is used for a number of different interface types. The differences are jumper settings on the board, and hardware configuration. Different parts will be installed for the various configurations. Changing to a different interface can be done by replacing the board.

Table 3-1 describes the jumper settings for a Rev. E board.

3–10 Rev. 5

SDM-650B Satellite Modem Configuration

Table 3-1. AS/0627-3 Rev. E Board Jumper Selection

JP1 TX Clock Select Normal

Invert Auto

JP2 Interface Select V.35 (-2)

MIL-STD-188/RS-232-C (-3)

JP3 RX Data Normal (See Note Below)

Buffer

JP8 RX Clock Normal (See Note Below)

Buffer JP4 Address Set 0 (See Note Below) JP5 Address Set 0 (See Note Below) JP6 Address Set 1 (See Note Below) JP7 Address Set 1 (See Note Below)

MIL (-3) JP9 CTS to RTS V.35 (Processor controller for

V.35 and RS-232-C)

MIL-STD-188/RS-422

(Hard loops CTS to RTS)

JP10 Loop Timing REM

OFF

JP11 ASYNC Clk Syn (-5) Cut Shorts JP12 SCT 1 to 2 Invert

2 to 3 Normal

JP13 RD 1 to 2 Invert

2 to 3 Normal

JP14 RR 1 to 2 Invert

2 to 3 Normal

JP15 DM 1 to 2 Invert

2 to 3 Normal

JP16 SD 1 to 2 Invert

2 to 3 Normal

(See Note Below)

Note: Factory jumper settings for MIL-STD-188/RS-422 interface type.

These jumpers are factory set for each given configuration, and should not be changed. This list is supplied for troubleshooting purposes only.

Rev. 5 3–11

Configuration SDM-650B Satellite Modem

3.2.1.2 Connector Pinouts

The RS-422 and MIL-STD-188-114 interface is provided on a 37-pin female D connector, accessible from the rear panel of the modem. Screw locks are provided for mechanical security of the mating connector.

Signal Function Name Pin #

SIGNAL GROUND SG 1, 19, 20, 37 SEND DATA SD-A

SEND TIMING ST-A

RECEIVE DATA RD-A

REQUEST TO SEND RS-A

RECEIVER TIMING RT-A

CLEAR TO SEND CS-A

DATA MODE DM-A

RECEIVER READY RR-A

TERMINAL TIMING TT-A

MOD FAULT DEMOD FAULT MASTER CLOCK

(INPUT)

SD-B

ST-B

RD-B

RS-B

RT-B

CS-B

DM-B

RR-B

TT-B

−

MC-A MC-B

9 27 11 29 13 31 17 35

3 21 16

3–12 Rev. 5

SDM-650B Satellite Modem Configuration

3.2.1.3 Specification

Circuit Supported SD, ST, TT, RD, RT, DM, RR, MOD, FAULT,

DEMOD FAULT, MC. Amplitude (RD, RT, ST, DM, RR) 4, ± 2V differential into 100Ω. DC Offset (RD, RT, ST, DM, RR) 0, ± 0.4V. Impedance (RD, RT, ST, DM, RR) Less than 100Ω, differential. Impedance (SD, TT, MC) 100, ± 20Ω, differential. Polarity True when B positive wrt A.

False when A positive wrt B. Phasing (RD, RT) False to True transition of RT nominally in

center of RD data bit. Symmetry (ST, TT, RT) 50%, ± 5%. Frequency Stability (ST) ± 100 PPM. Modulator Fault Open collector output.

15V max.

20 mA max. current sink.

Fault is open circuit. Demodulator Fault Open collector output.

15V max.

20 mA max. current sink.

Fault is open circuit.

Rev. 5 3–13

Configuration SDM-650B Satellite Modem

3.2.2 V.35 Interface

3.2.2.1 Functional Description

The V.35 digital interface (Figure 3-4) provides level translation, buffering, and termination between the internal modem signals and the V.35 DCE interface connector on the rear panel.

Electrical characteristics of the interface signals are defined in CCITT Recommendation V.35.

The electrical and mechanical specifications are summarized in Section 3.2.2.2 and Section 3.2.2.3, respectively.

A functional block diagram of the V.35 interface is shown in Figure 3-5.

The V.35 interface provides a Serial Clock Transmit (SCT) clock signal at the modem data rate.

In the Internal clock mode, the data to be transmitted, SD, must be synchronized to SCT.

In the External clock mode, the clock is accepted on the Serial Clock Transmit External (SCTE) input to clock in the data to be transmitted.

DDRESS SELECT JUMPERS

JP12

JP16

JP13

JP15

JP14

ASSEMBLY NUMBER

AND REVISION

V.35 ADAPTOR

CONNECTOR

JP1

JP3

JP8

JP10

JP2

Figure 3-4. V.35 Interface Card

3–14 Rev. 5

SDM-650B Satellite Modem Configuration

M O D E M

SCT

TX CLOCK

TX DATA

RX CLOCK

RX DAT A

COMMON EQUI PMENT

MODULATOR

DEMODULAT OR

TO BUFFER

OPTIONS

TO BUFFER

OPTIONS

FAULT

RELAYS

LOOP TIMING

TO LOGI C CONTROL

UTO CLOCK SELECT

INVERT NORM

CONTROL

LOGIC

LOOPBACK

TO CONTROL LOGI C

EXTERNAL BUFFER CLOCK

INT/EXT CLOCK

TO CONTROL LOGI C

RTS TO CTS JUMPER

SPARE (RS-232 ONLY)

T E R R E S

T R

I A L

TTL MODULA TOR FAULT

DATA BUS TO M & C

TTL DEMO DULATOR FAULT

Figure 3-5. V.35 Interface Block Diagram

In either case, the phase relationship between the clock and data is not important as long as the relationship meets the jitter specification. This is because a clock phase correction circuit is provided, which shifts the clock away from the data transition times.

The clock selection is jumper-selectable at JP1 on the front edge of the board.

• When there is no jitter on the clock source, the Auto setting is used.

• The Normal setting is used when standard specifications on clock and data

relationships exist.

• The Invert mode is used when the incoming clock is inverted from the standard clock and data relationship.

Rev. 5 3–15

Configuration SDM-650B Satellite Modem

Data received by the modem is output on the RD lines, while the recovered clock is output on the Serial Clock Receive (SCR) lines. For applications that require the rising edge of the clock to occur in the middle of the data bit time, Receive Clock Normal mode should be selected.

Invert mode puts the falling edge of SCR in the middle of the data bit. This selection can be made from the front panel in the Configuration menu.

The RTS lines are jumpered to the CTS lines, since the modem does not support polled operation. Data Set Ready (DSR) indicates that the modem is powered up. Receive Line Signal Detect (RLSD) indicates that an RF carrier is being received and demodulated with a sufficiently low error rate for the decoder to remain locked.

The V.35 interface also provides bi-directional relay loopback of both the clock and data at the DCE interface.

In loopback from the DTE side, SD is connected to RD, and either SCT or SCTE (in Internal or External mode) is looped back to SCR.

In loopback from the modem side, the received data and recovered clock are routed back to the modulator input for re-transmission.

Loop timing is supported by the selection of jumper JP10 on the front edge of the card.

When in the ON position, the internal clock (SCT) is replaced by the clock recovered from the receive (IF) data (RD). Active loop timing is indicated by a yellow light on the front edge of the card.

The JP10 REM setting is used when loop timing is supported by software on the M&C, and will be included in the front panel menu.

Three fault outputs are provided on dry contact FORM C relays:

• Common Equipment

• Modulator

• Demodulator

The faults are available on the Fault connector on the modem rear panel. Generation of these fault conditions is described in Chapter 4. Fault indicators are also provided on TTL open collector drivers on the V.35 connector.

• The TTL MOD fault indicates a Modulator fault or Common Equipment fault.

• The TTL DEMOD fault indicates a Demodulator or Common Equipment fault.

3–16 Rev. 5

SDM-650B Satellite Modem Configuration

Table 3-2 lists the jumper settings for the V.35 interface. These jumpers are factory set for a specific configuration. Clock selections, signal selections, and loop timing can be changed upon individual needs.

Table 3-2. AS/0627-2 Rev. E Board Jumper Selection

JP1 TX Clock Select Normal

Invert

Auto JP2 Interface Select V.35 (-2) (See Note Below) JP3 RX Data Normal (See Note Below)

Buffer JP8 RX Clock Normal (See Note Below)

Buffer JP4 Address Set 1 (See Note Below) JP5 Address Set 0 (See Note Below) JP6 Address Set 1 (See Note Below) JP7 Address Set 1 (See Note Below)

V.35 (-2) JP9 CTS to RTS V.35 (See Note Below)

(Processor controller for V.35 and RS-232-C)

JP10 Loop Timing Auto

OFF

JP11 ASYNC Clk Syn (-5) Cut Shorts JP12 SCT 1 to 2 Invert

2 to 3 Normal

JP13 RD 1 to 2 Invert

2 to 3 Normal

JP14 RR 1 to 2 Invert

2 to 3 Normal

JP15 DM 1 to 2 Invert

2 to 3 Normal

JP16 SD 1 to 2 Invert

2 to 3 Normal

(See Note Below)

Note: Factory jumper settings for V.35 interface type.

Rev. 5 3–17

Configuration SDM-650B Satellite Modem

3.2.2.2 Connector Pinouts

The V.35 interface is provided on the industry standard 34-pin block connector accessible from the rear panel of the modem. Screw locks are provided for mechanical security of the mating connector.

Signal Function Name Pin #

SIGNAL GROUND SG A, B SEND DATA SD-A

SD-B

SERIAL CLOCK TRANSMIT SCT-A

SCT-B

RECEIVE DATA RD-A

RD-B REQUEST TO SEND RTS C SERIAL CLOCK RECEIVE SCR-A

SCR-B V X CLEAR TO SEND CTS D DATA SET READY DSR E RECEIVE LINE SIGNAL DETECT RLSD F SERIAL CLOCK TRANSMIT EXT SCTE-A

SCTE-B U W MODULATOR FAULT DEMODULATOR FAULT MASTER CLOCK (INPUT)

−

MC-A

MC-B

P S Y (AA) R T

(MM) m (NN) n (CC) c

(DD) d

3–18 Rev. 5

SDM-650B Satellite Modem Configuration

3.2.2.3 Specification

Circuit Supported SD, SCT, SCTE, RD, SCR, DSR, RLSD, MOD,

FAULT, DEMOD FAULT, MC. Amplitude (RD, SCR, SCT, SD, SCTE) 0.55V pk, ± 20% differential, into 100Ω. Amplitude (CTS, DSR, RLSD) Impedance (RD, SCR, SCT) 100, ± 20Ω, differential. Impedance (SD, SCTE) 100, ± 10Ω, differential. Impedance (RTS) 5000, ± 2000Ω, < 2500 pF. DC Offset (RD, SCR, SCT) Polarity (SD, SCT, SCTE, RD, SCR) True when B positive wrt A.

Polarity (RTS, CTS, DSR, RLSD) True when < -3V wrt ground.

Phasing (SCTE, SCR) False to True transition nominally in center of data

Symmetry (SCT, SCTE, SCR) 50%, ± 5%. Frequency Stability (SCT) Modulator Fault Open collector output.

Demodulator Fault Open collector output.

10,

± 5V into 5000, ± 2000Ω.

± 0.6V max., 1000Ω termination to ground.

False when A positive wrt B.

False when > +3V wrt ground.

bit.

± 100 PPM.

15V max.

20 mA current sink max.

Fault is open circuit.

15V max.

20 mA current sink max.

Fault is open circuit.

Rev. 5 3–19

Configuration SDM-650B Satellite Modem

3.2.3 DS-1 Interface

3.2.3.1 Functional Description

The DS-1 digital interface (Figure 3-6) provides level translation, buffering, and termination between the internal modem signals and the DS-1 DTE interface on the rear panel.

SWITCH 1

Figure 3-6. DS-1 Interface Card

The DS-1 standard is defined in Bell System Publication 62411.

Refer to Figure 3-7 for a functional block diagram of the DS-1 interface.

The DS-1 is a single data rate interface. The interface operates at 1.544 Mbit/s, normally referred to as the “T1” rate. This interface is also unique in that no clock signals are provided.

The clock information is provided in the data signal through the data encoding method used, Alternate Mark Invert (AMI). In this method, a mark is transmitted as a positive or negative pulse, one-half the width of the data-bit time. Each consecutive mark has the opposite sign of its predecessor. Spaces are transmitted as an all-zero voltage.

In order to provide a clear channel (i.e., a channel in which an indefinite number of 0s can be transmitted), B8ZS encoding and decoding are provided. This allows the modem to interface with DTE utilizing B8ZS coding. B8ZS coding is enabled by an on-board jumper (SW1-1). SW1-1 in the open position enables the B8ZS encoder and decoder. SW-1 in the closed position disables the B8ZS encoder and decoder, and the DS1 interface will operate in AMI.

3–20 Rev. 5

SDM-650B Satellite Modem Configuration

TO BUFFER

OPTIONS

DS-1 LINE

RECEIVER/DRIVER

M O D E M

TX CLOCK

DS-1

DEJITTER

TX DATA

T E

RX CLOCK

LOOPBACK CONTROL

R R

RX DATA

E S

EXTERNAL BUFFER CLOCK

TO BUFFER

OPTIONS

COMMON EQUIPMENT

MODULATOR

DEMODULATOR

DATA BUS TO M & C

FAULT

RELAYS

CONTROL

LOGIC

TTL MODULATOR FAULT

TTL DEMODULATOR FAULT

Figure 3-7. DS-1 Interface Block Diagram

The data to be transmitted by the modem is input on the SD lines. Jitter on the SD is removed by a FIFO and clock recovery phase-locked loop. Data received and demodulated by the modem is output on the RD lines.

The RD is driven from a pulse-shaper circuit which pre-equalizes the RD output to drive up to 655 feet of ABAM cable. Refer to Table 3-3.

The DS-1 interface provides bi-directional loopback of the data at the DCE interface.

In loopback from the DTE side, SD is connected to RD.

In loopback from the modem side, the received demodulated data is routed back to the modulator input for re-transmission.

T R I A L

Rev. 5 3–21

Configuration SDM-650B Satellite Modem

Table 3-3. Equalizer Control

Distance to DSX (Ft)

(See Note 1)

(applies only to 22–GA. PIC [ABAM] Cable) (dB at 772 kHz) EC1 EC2 EC3

0 to 133 0.6 C C C 133 to 267 1.2 C C O 167 to 400 1.8 C O C 400 to 533 2.4 C O O 533 to 655 3.0 O C C

Test Clear --- O C O

Maximum Cable

SW1 (See Note 2)

4 3 2

Loss

Notes:

1. Other bit combinations represent test modes and are not used for normal operation.

2. Use maximum loss figures for other cable types.

Three fault outputs are provided on dry contact FORM C relays:

• Common Equipment

• Modulator

• Demodulator

The faults are available on the fault connector on the modem rear panel. Generation of these fault conditions is described in Chapter 4.

Fault indicators are also provided on TTL open collector drivers on the DS-1 connector.

• The TTL MOD fault indicates a Modulator fault or Common Equipment fault.

• The TTL DEMOD fault indicates a Demodulator or Common Equipment fault.

In order to facilitate testing of the modem when a DS-1 signal is not available, the output of the clock recovery circuitry is replaced by a 1.544 MHz clock whenever loss of the SD signal is detected. This allows the modem to generate its test signals at the proper data rate.

A TXC-LOSS fault will occur in the Common Equipment fault menu whenever the incoming data is missing.

3–22 Rev. 5

SDM-650B Satellite Modem Configuration

3.2.3.2 Connector Pinouts

The DS-1 interface is provided on a 15-pin female D connector accessible from the modem rear panel. Screw locks are provided for mechanical security of the mating connector.

Signal Function Name Pin #

SEND DATA SD-A

SD-B

RECEIVE DATA RD-A

RD-B

MASTER CLOCK MC-A

MC-B MODULATOR FAULT ---- 14 DEMODULATOR FAULT ---- 15 GROUND GND 2, 4

1 9 3

7 8

3.2.3.3 Specification

Circuits Supported SD, RD, MOD FAULT, DEMOD FAULT Data Rate 1.544 Mbit/s ± 100 bit/s Pulse Width (RD) 324, ± 50 ns Line Code AMI or B8ZS (selectable) RD Amplitude SD Amplitude 3, ± 1.5V pk into a 100Ω termination Jitter Attenuation (SD) Meets AT&T Publication 62411 specification Modulator Fault Open collector output

Demodulator Fault Open collector output

2.75,

± 0.25V pk into a 100Ω termination

15V max 20 mA current sink Fault is open circuit

Rev. 5 3–23

Configuration SDM-650B Satellite Modem

3.2.4 G.703, 2048 kbit/s Interface

3.2.4.1 Functional Description

The G.703 2048 kbit/s digital interface (Figure 3-8) provides level translation, buffering, and termination between the internal modem signals and the G.703 DTE interface on the rear panel.

SWITCH 1

G.703 N X 64KBITS SATELLITE MODEM INTERFACE ASSY/0679 REV-4 FSCN 4J515

Figure 3-8. G.703 2048 kbit/s Interface Card

The G.703 standard is defined in CCITT Volume III (red book).

Refer to Figure 3-9 for a functional block diagram of the G.703 2048 interface.

This interface meets G.703 specifications at 2.048 Mbit/s, normally referred to as the “E1” rate. This interface is also unique in that no clock signals are provided.

The clock information is provided in the data signal through the data encoding method used, AMI. In this method, a mark is transmitted as a positive or negative pulse, one-half the width of the data-bit time. Each consecutive mark has the opposite sign of its predecessor. Spaces are transmitted as an all-zero voltage.

Refer to Table 3-4 for line code selection and switch settings for the G.703 2048 kbit/s interface.

In order to provide a clear channel (i.e., a channel in which an indefinite number of 0s can be transmitted), HDB3 encoding and decoding is provided. This allows the modem to interface with DTE utilizing HDB3 coding. HDB3 coding is enabled by an on-board jumper (SW1-7).

3–24 Rev. 5

SDM-650B Satellite Modem Configuration

M O D E M

TX CLOCK

TX DATA

RX CLOCK

RX DATA

COMMON EQUIPMENT

MODULATOR

DEMODULATOR

DATA BUS TO M & C

TO BUFFER

OPTIONS

TO BUFFER

OPTIONS

FAULT

RELAYS

DS-1

DEJITTER

CONTROL

LOGIC

N X 64 KB

CLOCK

SYNTHESIZER

DS-1 LINE

RECEIVER/

DRIVER

EXTERNAL BUFFER CLOCK

LOOPBACK CONTROL

TTL MODULATOR FAULT

TTL DEMODULATOR FAULT

T E R R E S

T R I A L

Figure 3-9. G.703 2048 Interface Block Diagram

The G.703 2048 kbit/s interface will operate in AMI, enabled by SW1-8.

The G.703 2048 kbit/s interface provides bi-directional loopback of the data at the DCE interface. In loopback from the DTE side, SD is connected to RD. From the modem side, the received demodulated data is routed back to the modulator input for re-transmission.

Three fault outputs are provided on dry contact FORM C relays:

• Common Equipment

• Modulator

• Demodulator

Rev. 5 3–25

Configuration SDM-650B Satellite Modem

They are available on the FAULT connector on the modem rear panel. Generation of these fault conditions is described in Chapter 4.

Table 3-4. G.703, 2048 kbit/s Interface Switch Configurations

SW1 Positions Function

1 2 3 4 5 6 7 8 Selected

X X X X X X 0 0 AMI CODE X X X X X X 1 0 HDB3

0 0 0 0 0 1 X X 2048 kbit/s

Switch Positions

0 CLOSED 1 OPEN

X DON’T CARE

Fault indicators are also provided on TTL open-collector drivers on the G.703 2048 kbit/s connector.

• The TTL MOD fault indicates a Modulator fault or Common Equipment fault.

• The TTL DEMOD fault indicates a Demod or Common Equipment fault.

In order to facilitate testing of the modem when a G.703 signal is not available, the output of the clock recovery circuitry is replaced by a 2.048 MHz clock whenever loss of the SD signal is detected. This allows the modem to generate test signals at the proper data rate.

3.2.4.2 Optional EXT CLK

This option is used with the Doppler buffer.

The external clock can be used as an optional source of output clock for the optional Doppler buffer. The two inputs, EXT CLK and /EXT CLK, are capacitively coupled to a RS−422 receiver and 470Ω resistors to ground. The EXT CLK is normally grounded by jumper JP17, but may be removed to use RS-422.

In the normal mode, an unbalanced signal should be fed to EXT CLK. The signal may be sine wave, square wave, or TTL. The signal should be at least 2 Vp-p and have a 40 to 60% duty cycle. Jumpers on the Doppler buffer should be set to select external clock when this feature is used.

3–26 Rev. 5

SDM-650B Satellite Modem Configuration

3.2.4.3 Switch Configuration for G.703 2048 kbit/s Interface

Switch 1 is an 8-position dip switch located at the end of the G.703 interface board.

Table 3-4 lists the switch settings for data rates and available coding for the G.703 2048 kbit/s interface.

3.2.4.4 Connector Pinouts

The G.703 2048 kbit/s interface is provided on a 15-pin female D connector accessible from the rear panel of the modem. Screw locks are provided for mechanical security of the mating connector.

Signal Function Name Pin #

SEND DATA SD-A

SD-B

RECEIVE DATA RD-A

RD-B

MASTER CLOCK MC-A

MC-B MODULATOR FAULT ---- 14 DEMODULATOR FAULT ---- 15 GROUND GND 2, 4

1 9 3

7 8

Rev. 5 3–27

Configuration SDM-650B Satellite Modem

3.2.4.5 G.703 2048 kbit/s Connector Board Option

The G.703 2048 kbit/s interface has a connector board option that is configured with a 15-pin D and three BNCs for unbalanced signals for SD, RD, and MC (Figure 3-10). Refer to Table 3-5 for jumper connections.

G.703 2048 KB S

CONNECT OR BOARD

SDM 650

AS/ 1644 REV___

S/N_________

J1 J2

Notes:

1. Balanced signals are on the 15-pin D connector.

2. Unbalanced signals are on the BNC connectors.

Figure 3-10. G.703 2048 kbit/s Interface Connector Board (Optional)

3–28 Rev. 5

SDM-650B Satellite Modem Configuration

Table 3-5. G.703 2048 kbit/s Interface Connector Jumpers

Switch J3 (EXT REF) J4 (SEND DATA) J5 (RECEIVE DATA)

BAL UNBAL BAL UNBAL BAL UNBAL

SW1-1 ON ON X X X X SW1-2 OFF OFF X X X X SW1-3 X X ON ON X X SW1-4 X X OFF OFF X X SW1-5 X X X X ON ON SW1-6 X X X X OFF OFF

Switch Positions

0 CLOSED 1 OPEN

X DON’T CARE

The interface connects to the rear of the modem, directly onto the G.703 interface connector. Refer to Figure 3-11 for a schematic diagram of the optional G.703 2048 kbit/s connector board.

EXTERNAL

REFERENCE

RECEIVE

DATA

CONNECTOR DB15S

Figure 3-11. G.703 2048 kbit/s Connector Board Schematic Diagram

Rev. 5 3–29

Configuration SDM-650B Satellite Modem

The G.703 2048 kbit/s optional connector board provides the balanced signals on a 15-pin female D connector. These signals are the same as the G.703 interface connector. Refer to Section 3.2.4.4 for the connector pinouts.

The unbalanced signals are accessible from J3, J4, and J5. A description of available unbalanced signals and directions is described in the following paragraphs.

3.2.4.6 External Reference (J3)

The external reference input signal has two inputs. The BNC connector, J3, has the unbalanced input signal, and the DB15 connector has the balanced input signal.

To use the unbalanced input on the BNC connector, SW1 positions 1 and 2 must be closed (close to PCB).

To use the balanced input on the DB15 connector, SW1 positions 1 and 2 must be open (away from PCB).

The switch pack is located on the optional G.703 2048 kbit/s connector board.

3.2.4.7 Send Data (J4)

The send data output signal has two outputs. The BNC connector, J4, has the unbalanced output signal, and the DB15 connector has the balanced output signal.

To use the unbalanced output on the BNC connector, SW1 positions 3 and 4 must be closed (close to PCB).

To use the balanced output on the DB15 connector, SW1 positions 3 and 4 must be open (away from PCB).

The switch pack is located on the optional G.703 2048 kbit/s connector board.

3.2.4.8 Receive Data (J5)

The receive data input signal has two inputs. The BNC connector, J5, has the unbalanced input signal, and the DB15 connector has the balanced input signal.

To use the unbalanced input on the BNC connector, SW1 positions 5 and 6 must be closed (close to PCB).

To use the balanced input on the DB15 connector, SW1 positions 5 and 6 must be open (away from PCB).

The switch pack is located on the optional G.703 2048 kbit/s connector board.

3–30 Rev. 5

SDM-650B Satellite Modem Configuration

3.2.4.9 Specification

Pairs Symmetrical pair, coaxial pair optional. Circuits Supported SD, RD, MOD FAULT, DEMOD FAULT. Data Rate 2.048 Mbit/s, ± 50 PPM. Pulse Width (RD) 244, ± 25 ns. Line Code AMI or HDB3 (selectable). RD Amplitude SD Amplitude Jitter Attenuation (SD) Exceeds CCITT G.823, specification for 2048 kbit/s. Modulator Fault Open collector output.

Demodulator Fault Open collector output.

3.00,

± 0.3V pk into a 120Ω termination.

± 1.5V pk into a 100Ω termination.

15V max. 20 mA current sink. Fault is open circuit.

3.2.5 Asynchronous Overhead Interface

3.2.5.1 Functional Description

The asynchronous overhead interface module consists of three subassemblies:

• Connector board is AS/1328.

• Data processor board is AS/1289.

• Terrestrial interface is AS/1311.

Dash # Interface With AUPC

1311-1 RS-422 1311-4 1311-2 V.35 1311-5 1311-3 G.703 1311-6

The connector board provides the physical interface using a 50-pin D connector.

The terrestrial interface contains all circuitry required for G.703, RS-422, MIL-STD-188, and V.35 type interfaces for synchronous data, and RS-232-C and RS-485 type interfaces for asynchronous data.

The data processor contains all circuitry required for multiplexing the synchronous and asynchronous data streams, as well as data rate synthesizers and the optional plesiochronous buffer.

Refer to Figure 3-12 for a block diagram of the asynchronous overhead interface.

Rev. 5 3–31

Configuration SDM-650B Satellite Modem

TRANSMIT SECTION

ES TO ES ASYNC

G.703

CLK

DATA

CLK

DATA

EXTERNAL REFERENCE CLOCK

(TRANSMIT TERR CLOCK)

INTERFACE

T1/E1 INTERFACE

T2/E2

RS-422 INTERFACE

MIL-STD- 188-114

V.35 INTERFACE

INTERNAL CLOCK

RECEIVE SECTION

P/O BASE BAND LPBK

FRAMING /

LOGIC (MU X)

TX DEJITTER

CLOCK

SYNTHESIS

RS-232 TIMING

P/O

INT

LPBK

MODEM

P/O

INT

LPBK

DEFRAME/TIMING

LOGIC (DEMUX)

PLESIOCHRONOUS

BUFFER

SATELLITE CLOCK

INTERNAL CLOCK

TRANSMIT TERR CLOCK

EXTERNAL REFERENCE CLOCK

P/O BASE BAND LPBK

Figure 3-12. Asynchronous Overhead Interface Block Diagram

RS-232

INTERFACE

CLOCK SYNTHESIS

ES TO ES

T1/E1 T2/E2 INTERFACE

RS-422 INTERFACE MIL-STD 188-114

V.35

INTERFACE

ASYNC

G.703

CLK

DATA

CLK

DATA

3.2.5.2 Terrestrial Interface

The terrestrial interface, AS/1311, forms the top (when mated with the connector board) of the 2-board module. The interface contains all balanced pair drivers and receivers for RS-422, MIL-STD-188, and V.35.

Data inputs are SD and transmit clock (TT or SCTE).

Data outputs are:

• Modem reference clock (SCT or ST)

• Receive data (RD)

• Receive clock (RT or SCR)

3–32 Rev. 5

SDM-650B Satellite Modem Configuration

The “handshake” asynchronous signals are:

• RTS

• CTS

• DM

• DSR

• RR

• RLSD

This board may otherwise contain the circuitry for transformer balanced data interfaces supporting CCITT G.703 parameters. Data inputs are SD, and outputs are RD. Data rates of 1.544, 2.048, 6.312, and 8.448 Mbit/s are supported.

Note: 6 and 8 Mbit/s are not supported by the modem.

Line codes for zero substitution are B6ZS, B8ZS, and HDB3. AMI is also supported. The configuration of this section is determined during production and is not user selectable in the field.

The asynchronous data channel has three interface options. The RS-232-C electrical interface allows full-duplex operation. The RS-485 4-wire option also allows full-duplex, and RS-485 2-wire allows half-duplex operation. These options are jumper selectable.

Tables 3-6 and 3-7 describe the configuration of the jumpers for the various options and data rates. Figure 3-13 shows the jumper locations.

JP11

AS/1311 REV___ ASYNC OVERHEAD TERRESTRIAL INTERFACE BOARD

JP1 JP2

JP3

Figure 3-13. Asynchronous Overhead Jumpers

JP11

JP5

JP81JP13

JP12

JP6

JP9

JP4

JP10 1

JP7

Rev. 5 3–33

Configuration SDM-650B Satellite Modem

Table 3-6. Asynchronous Overhead Jumper Table

JP # Pin # Function

JP1 1 to 3, and 2 to 4

3 to 5, and 4 to 6

JP2 1 to 2

3 to 4 5 to 6

JP3 1 to 2

2 to 3

JP10 1 to 2

2 to 3

JP11 1 to 2

3 to 4

JP12 1 to 2

2 to 3

Asynchronous

JP8, JP9, JP13 1 to 2

2 to 3

V.35, RS-422, MIL-STD-188 G.703 Auto TX CLK Phase Select Fixed Phase, Normal Fixed Phase, Inverted G.703 data activity detect TX Terr CLK activity detect V.35 operation RS-422, MIL-STD-188 operation Normal SCT output TX CLK chained to SCT output 2-wire operation 4-wire operation

RS-485 RS-232-C

Table 3-7. Data Rate Jumper Table

Data Rate Impedance JP4 JP5 JP6 JP7 Voltage

1.544 Mbit/s

2.048 Mbit/s

6.312 Mbit/s

8.448 Mbit/s

BAL−100 BAL−120 UNBAL−75 BAL−110 UNBAL−75 UNBAL−75

OFF ON ON OFF 5.8 Vp-p OFF ON ON OFF 5.8 Vp-p OFF ON ON OFF 4.6 Vp-p

1 to 2 OFF OFF OFF 1.8 Vp-p

OFF OFF OFF OFF 3.3 Vp-p OFF ON ON OFF 4.8 Vp-p

3–34 Rev. 5

SDM-650B Satellite Modem Configuration

3.2.5.3 Multiplexer

The data processor, AS/1289, forms the bottom of the 2-board module. This board contains the data multiplexer and demultiplexer.

The synchronous data stream is multiplexed with a 1/15 overhead channel, and the resultant information is interfaced to the modulator/coder section of the modem.

The input clock is normally the recovered clock from the terrestrial interface board (SCTE), but the modem reference clock can be used by selecting INT Clock.

The 1/15 overhead channel is composed of:

• Framing signals

• Flags

• Spare bit positions

• Asynchronous data stream

The maximum asynchronous data rate is limited to 1.875% of the synchronous data rate.

3.2.5.4 Demultiplexer

Receive data and clock from the demodulator/decoder is input to the demultiplexer. The demultiplexer synchronizes to the frame pattern and separates the synchronous and asynchronous data. Synchronization is indicated by the DEMUX lock LED on the front edge of the board.

The synchronous data is dejittered and interfaced either to the optional plesiochronous buffer or to the terrestrial interface board.

Rev. 5 3–35

Configuration SDM-650B Satellite Modem

3.2.5.5 Plesiochronous Buffer

User data from the DEMUX section is fed into a plesiochronous buffer. The buffer size is user selectable in 16-bit increments, from 384 to 262144 bits. The buffer is automatically centered on resumption of service after an outage, or may be commanded to center in the interface configuration section (from the front panel or remotely). For obvious reasons, manual centering will generally not be plesiochronous.

The fill status is available as a monitor function and is accurate to 1%. Overflow or underflow incidents will be momentarily indicated by red LEDs on the module. They are stored in the Stored Faults (StFaults) section of the M&C status registers, along with the date and time of the incident, provided by the modem internal clock. They are stored in battery-backed RAM.

The user may select to have the data clocked out of the buffer from four clock sources:

• Recovered EXT clock from user terrestrial input data

• User-supplied EXT-REF reference clock

• Satellite clock which is phase-locked to the demultiplexer

• Internal clock source

Satellite clock selection is similar to buffer bypass. Problems on either the TX terrestrial clock or the external clock (if selected) will substitute satellite clock, and a fault will be signaled.

3.2.5.6 Remote Interface Specification

Refer to Appendix B, Section B.2, for the remote interface specifications for the asynchronous overhead channel unit.

3–36 Rev. 5

SDM-650B Satellite Modem Configuration

3.2.5.7 Interface Connector Pinouts

The asynchronous interface is provided on a 50-pin female D connector accessible from the rear panel of the modem. Screw locks are provided for mechanical security of the mating connector.

Signal Function Name Pin #

GROUND GND 1, 2 T1E1 SEND DATA A T1E1-SDA 34 T1E1 SEND DATA B T1E1-SDB 18 EXTERNAL CLOCK A EXCA 35 EXTERNAL CLOCK B EXCB 19 T1E1 RECEIVE DATA A T1E1-RDA 36 T1E1 RECEIVE DATA B T1E1-RDB 20 TX DATA B (ASYNC) TXD-B 4 SEND DATA A SDA 37 SCT SIGNAL A SCT/STA 21 TX DATA A (ASYNC) TXD-A 5 SEND DATA B SDB 38 SCT SIGNAL B SCT/STB 22 RX DATA B (ASYNC) RXD-B 6 RECEIVE DATA A RDA 39 RECEIVE CLOCK A SCR/RTA 23 RX DATA A (ASYNC) RXD-A 7 RECEIVE DATA B RD-B 40 RECEIVE CLOCK B SCR/RTB 24 TRANSMIT TIMING A SCTE/TTA 12 REQUEST TO SEND A RTSA 45 REQUEST TO SEND B RTSB 29 TRANSMIT TIMING B SCTE/TTB 13 RECEIVER READY A RLSD/RRA 46 RECEIVER READY B RRB 30 RS-422 TX DATA A R422TXDA 14 CLEAR TO SEND B CTSB 31 DATA SET READY A DSR/DMA 48 DATA SET READY B DMB 32 CTS A CTSA 47

Rev. 5 3–37

Configuration SDM-650B Satellite Modem

3.2.5.8 Asynchronous Interface Specifications

Main Channel

Physical Interface MIL-STD-188-114. (Factory Option) RS-422/-449.

V.35.

G.703. Data Rates 9.6K, 19.2K, 32 kbit/s to 8.448 Mbit/s. G.703 Data Rates 1.544 Mbit/s. (Jumper Selectable) 2.048 Mbit/s.

6.312 Mbit/s.

8.448 Mbit/s. G.703 Line Code AMI, B8ZS, B6ZS, HDB3. Transmit Clock Reference Internal modem reference or external transmit clock

(SCT or TT). Jitter Attenuation Per G.703. Pulse Mask Per G.703.

Overhead Channel

Overhead Rate 16/15 of main channel. ASYNC Channel Rate (max.) < 1.875% of main channel. ASYNC Channel Interface RS-232-C.

2-wire RS-485 half-duplex.

4-wire RS-485 full-duplex. Connector 25-pin D on breakout panel. Baud Rates, Asynchronous 110, 150, 300, 600, 1200, 2400, 4800, 9600, 19200, 38400

bit/s. Asynchronous Format 5, 6, 7, or 8 data bits.

Even, Odd, or No Parity.

1 or 2 stop bits (1 or 1.5 for 5 bit).

Buffer Specifications (Pleisiochronous/Buffer Operation)

Buffer Size 384 to 262144 bits, in 16-bit steps. Buffer Fill Status Buffer Centering Automatic or Manual. Buffer Clock Reference Transmit.

External Clock Amplitude Differential 0.5 to 5 Vp-p.

External Clock Frequency 256 to 2048 kHz, in 64 kHz steps. External Clock Impedance External Clock Input Type Sine or Square wave.

Monitored accurate to ± 1%.

Internal (10

External.

Receive (Buffer Bypass).

Unbalanced Mode 0 to 5 VDC.

100Ω.

50%, ± 10%.

-5

Stability).

3–38 Rev. 5

SDM-650B Satellite Modem Configuration

3.2.6 Asynchronous Breakout Panel

The asynchronous breakout panel supports the use of the asynchronous interface in the modem.

For more information, refer to the ASYNC Breakout Panel Installation and Operation Manual.

Rev. 5 3–39

Configuration SDM-650B Satellite Modem

3.3 Doppler Buffer

The Doppler buffer assembly is an option that plugs on to the modem interfaces, that provides elastic buffering to the receive data channel. The Doppler buffer compensates for the effect of satellite movement or disparity between transmit and receive clocks, and can be used at data rates of 9.6 kbit/s to 2.5 Mbit/s.

Note: 120 AS/0679 PCBs.

The Doppler buffer attaches into the receive data path on the interface assembly at TTL signal levels. The buffer should be attached before the signals are configured to the specific interface type.

The buffer assembly is compatible with many different interface types.

The clock source for the buffer output can be selected from one of three sources:

If the transmit clock source is selected, the buffer output is used after being recovered and dejittered (if necessary). Any signal with which the transmit side is designed to work can supply a valid buffer output clock.

Jumpers on the buffer determine local clock source control, or the M&C system control.

The modem software must be configured for buffer support in order to use M&C functions from the front panel.

To select the required buffer depth for the system, the maximum peak-to-peak transmission delay variation has to be known.

Refer to Table 3-8 for jumper settings.

Refer to Table 3-9 for the delay variation of an INTELSAT satellite.

Ω impedance-matching resistors are required on the AS/0627, AS/0569, and

• Receive channel (effective bypass mode)

• Modem transmit clock

• External customer supplied reference clock

3–40 Rev. 5

SDM-650B Satellite Modem Configuration

Table 3-8. Jumper Selections

Function Install Remove

Clock Source Control By M&C JP8, JP9 JP10, JP11 Clock Source Receive (Bypass) JP11 JP8, JP8, JP10 Clock Source Transmit CLK JP10, JP11 JP8, JP9 Clock Source External JP10 JP8, JP9, JP11 Center Control By M&C JP1 Center Control Local JP1 Clear Flags Control By M&C JP2 Clear Flags Local JP2 Buffer Depth Control By M&C JP3, JP4, JP5, JP14 SW3-1, 2, 3, and 4 — Open Buffer Depth 512 Bits SW1-Closed

SW2-Closed SW3-Closed SW4-Closed

Buffer Depth 1024 Bits SW1-Open

SW2-Closed SW3-Closed SW4-Closed

Buffer Depth 2048 Bits SW1-Closed

SW2-Open SW3-Closed SW4-Closed

Buffer Depth 4096 Bits SW1-Open

SW2-Open SW3-Closed SW4-Closed

Buffer Depth 8192 Bits SW1-Closed

SW2-Closed SW3-Open SW4-Closed

Buffer Depth 16384 Bits SW1-Open

SW2-Closed SW3-Open SW4-Closed

Buffer Depth 32768 Bits SW1-Closed

SW2-Open SW3-Open SW4-Closed

Buffer Depth 65536 Bits SW1-Open

SW2-Open SW3-Open SW4-Closed

JP3, JP4, JP5, JP14

Table 3-9. INTELSAT Delay Variations

Parameter Inclination (Degrees)

0.5 1.0 1.5 2.0 2.5 3.0 Units

Maximum Variations 1.1 1.8 2.6 3.3 4.1 4.8 ms Maximum Rate of Variations 40 67 94 121 148 175 ns/sec

Rev. 5 3–41

Configuration SDM-650B Satellite Modem

The formula for calculating the buffer depth is:

Buffer Depth (bits) = Bit Rate (bit/s) x Max. Delay Variation

Contact the satellite company to determine the delay variation of a particular domestic satellite.

The buffer depth capacity can be set either through the M&C or manually with a DIP switch on the buffer. Jumpers and optional modem software determine if the control is local or through the M&C.

When an overflow or underflow occurs, the buffer will automatically reset itself to the center, and set the respective indicator.

The buffer is not plesiochronous.

Data framing is not required for proper operation.

The buffer is centered at power-up, and may be re-centered manually or through the M&C, depending on jumper settings on the assembly.

Refer to Figure 3-14 for the Doppler buffer daughter card and jumper selections.

Refer to Table 3-8 to determine settings.

A problem can result in the switch system when using the buffer with the source clock set to TX CLK. When the TX section switches over to the

CAUTION

back-up modem, the source clock is no longer present at the prime mode. The internal oscillator in the prime modem will free-run at the frequency

± 50 PPM from the center. The prime modem running free will eventually

cause the Doppler buffer in the prime modem to overflow or underflow. Two lines are provided on the connector called the Master Clock (MC-A and MCB) that prevent the modem from overflowing or underflowing.

The pinouts on the 15-pin connector are:

• Pin 7 for MC-A

• Pin 8 for MC-B

3–42 Rev. 5

SDM-650B Satellite Modem Configuration

Figure 3-14. AS/3812 Doppler Buffer Daughter Card

Pinouts on the 34-pin V.35 are:

• “c” for MC-A

• “d” for MC-B

The pinouts on the 37-pin connector are:

• Pin 16 for MC-A

• Pin 34 for MC-B

The electrical configuration of these lines is the RS-422.

The jumper selection must be set to external clock in order to use the external reference.

The asynchronous channel unit has a plesiochronous buffer and is selectable in 16-bit increments, from 384 to 262144 bits.

Notes:

1. Maximum variations = peak-to-peak uplink plus downlink.

2. Maximum rate of variations = uplink plus downlink.

Rev. 5 3–43

Configuration SDM-650B Satellite Modem

3.3.1 Buffer Setup

The receive buffer allows for:

• Plesiochronous buffering of two dissimilar clock frequencies: the far end transmit clock and the local network clock frequency. The clocks may be very close in frequency to each other and will normally slip at a constant rate. Figure 3-15 shows plesiochronous operation of dissimilar clocks. If incoming traffic is too fast, an occasional bit will be lost. If incoming traffic is too slow, an occasional bit will be repeated.

• Doppler buffering of the signal from the satellite. A Doppler shift results from the satellite’s figure 8 shaped orbit over a period of one day. A Doppler shift should not result in a clock slip; the buffer constantly fills and empties.

If two earth stations are configured as a master/slave unit, then the buffer need only be configured for Doppler operation. The buffer has sufficient capacity for the Doppler shift on the outward and return paths.

A buffer setup for the Doppler operation will typically require less depth than one intended for both Doppler and plesiochronous operations.

3–44 Rev. 5

SDM-650B Satellite Modem Configuration

F1 is not EXACTLY equal to f2.

Plesiochronous Operation

Too Fast

Bit 1

Bit 2

Error

Bit 3

Bit 4

Bit 5

Bit 1

Bit 2

Bit 3

Bit 4

Bit 5

Bit 6

Bit 7

Too Slow

Bit 1

Bit 2

Error

Bit 3

Bit 5

Bit 6

Bit 7

Interface Interface

Bit 1

Bit 2

Bit 3

Bit 4

Bit 5

Figure 3-15. Clock Slip Diagram

Rev. 5 3–45

Configuration SDM-650B Satellite Modem

3.3.1.1 Buffer Size

The depth of the receive buffer will depend upon four parameters:

• Doppler shift caused by satellite

• Stability of each clock (plesiochronous/Doppler operation only)

• Frame/multiframe length of multiplexed data format

• Allowable time between clock slips

3.3.1.2 Doppler

A geostationary satellite with a 24-hour orbit should be positioned directly over the equator. The exact inclination of the satellite (relative to the equator) is influenced by the gravity of the earth, moon, and sun. Solar wind and station keeping motors are required to maintain the satellite’s orbital position.

When viewed from the earth, the satellite’s orbit appears to be an ellipse around the planet. However, the orbit changes to a figure 8 shape as the angle of inclination increases.

The satellite’s orbit can result in a peak-to-peak altitude variation of 0.2% (85 km). A newly launched satellite’s orbit will be typically 172 km relative to the nominal 42,164 km radius.

The variation in propagation delay will typically be 1.15 ms (up to the satellite and back down), depending upon the location of the earth station to the satellite. The 2 ms delay is used for most commercial satellites.

Since station keeping involves using fuel in the motors, the lifetime of the satellite can be extended. The satellite’s age can be prolonged by allowing the satellite to drift into a wider figure 8 orbit and using the motors less.

The older satellites will be found to be in a more inclined orbit with the station keeping varying in latitude by as much as

± 4.0°. The total effect of the inclined orbit may result

in a typical variation in path delay of 35 ms.

± 0.1° (150 km). The total effect will be

3–46 Rev. 5

SDM-650B Satellite Modem Configuration

3.3.1.3 Plesiochronous

The stability of station reference clocks is normally 10

-11

that is derived from a cesium standard. When the stability is exceptionally high, the two clocks are not in sync with each other. Eventually, the two reference clocks will pass by each other.

The clock used for the transmit signal passes over the satellite, but will not be used at the receive earth station where a national network derives its timing locally. A buffer will fill up with data using the clock from the satellite, and will empty using the local clock. The buffer ensures that the buffer overflows or underflows at regular determinable intervals. The intervals typically occur every 40 days.

The buffer depth required, from center to end, will be calculated as follows:

Buffer Depth = Minimum Slip Period (sec) x Stability of Far End (Transmit) Clock + Stability of Local Clock

The following is an example on how to calculate a buffer depth:

Far end (transmit) clock stability 1 E-9 Local (buffer) clock stability 1E-11 Minimum clock slip 40 days

Buffer Depth = (40 x 24 x 60 x 60) x (1E-9 + 1E-11) = 3.49 ms

The buffer will either be filled or empty, depending upon the frequency relationship of the two clocks. The total buffer depth will be 2 x 3.49 ms = 6.98 ms.

3.3.1.4 Frame/Multiframe Length

The depth of the receive buffer required has been discussed above and is applicable to all unframed data.

Framed data (i.e., 2048 kbit/s G732 or 1544 kbit/s G733) is desirable to provide slips in pre-defined locations. There are two advantages of organized slip locations:

• In relation to the frame, multiplexing equipment does not lose sync.

• Outages on any channel are kept to a minimum.

A 2048 kbit/s frame structure commonly used is G732. The frame structure has a length of 256 bits, with 16 frames per multiframe (4096 bits total or 2 ms).

Rev. 5 3–47

Configuration SDM-650B Satellite Modem

3.3.1.5 Total Buffer Length

The size of the buffer will be determined by the Doppler, plesiochronous, and the frame and multiframe length (the last three sections). Using the three examples given in the last three sections, the total buffer depth (end to end) will be:

Doppler + Plesiochronous ms (rounded up to the nearest multiframe) (e.g., 1.15 + 6.98 = 8.13 ms)

If the multiframe length is 2 ms, then the nearest multiframe will be 10 ms, or 20480 bits.

3.3.1.6 Converting

To convert bits to seconds:

1/Data Rate times Bits = Seconds

To convert seconds to bits:

Data Rate times Seconds = Bits

3–48 Rev. 5

SDM-650B Satellite Modem Configuration

3.4 Doppler Buffer Specification

Buffer Size (bits) Clock Source Data Rate Indicators

Controls

Miscellaneous

3.5 I/O Connectors

J1 25-pin, 0.1” spaced, dual-row header.

Pin # Description

1 /BUFBDS 2 GND 3 TCLK 4 NC (/TCLK) 5 DB0 6 DB1 7 DB2 8 DB3

9 DB4 10 DB5 11 DB6 12 DB7 13 RCLK-SND 14 RDATA-SND 15 RCLK-RTN 16 RDATA-RTN 17 /BUFALE 18 BUFWR 19 BUFRD 20 EXTCLK 21 VCC 22 VCC 23 SPARE 24 GND

512, 1024, 2048, 4096, 8192, 16384, 32768, 65536 Receive, transmit, and external clock

9.6 kbit/s to 2.4 Mbit/s Buffer overflow (latched)

Buffer underflow (latched) Reset buffer to center Reset underflow and overflow indicators Buffer depth Output clock source Control functions jumper Selectable local or M&C system (optional) Buffer automatically recenters on underflow and overflow

Rev. 5 3–49

Configuration SDM-650B Satellite Modem

3.6 Interface Clocking Options

Clocking of the data from the terrestrial circuits to the satellite, and vice versa, will depend upon the application. The most common options and recommended configurations are described in the following sections.

3.6.1 Master/Slave

This application is used where the far end earth station does not have local access to a high stability reference clock, or when it is not required to synchronize with a local clock.

The disadvantage of the master/slave application is that the signal received at the slave station is subject to Doppler shift.

Note: The length of the buffer at the master end will need to be twice the length that is normally required (since it will be compensating for the Doppler shift on the outward and return paths).

3–50 Rev. 5

SDM-650B Satellite Modem Configuration

3.6.1.1 Master/Slave RS-422 or V.35

Refer to Figure 3-16 for the RS-422 or V.35 master/slave configuration.

Figure 3-16. RS-422 or V.35 Master Slave Configuration

Notes:

1. The clock may be looped back by using JP10 on the interface board.

2. Refer to Tables 3-1 or 3-2 for more information.

RS-422 Clock Loopback V.35 Clock Loopback

Join RT-A to TT-A Join SCR-A to SCTE-A Join pin 8 to pin 17 Join pin V to pin U Join RT-B to TT-B Join SCR-B to SCTE-B Join pin 26 to pin 35 Join pin X to pin Y

Note: By wiring the interface for clock turnaround, the impedance will be reduced. This generally will cause no problem, providing the cable length to the final terminal equipment is not excessive. Selecting “no loading” at the terminal equipment will ensure correct line matching.

Rev. 5 3–51

Configuration SDM-650B Satellite Modem

3.6.1.1.1 Modem Settings (Master)

1. TX-CLOCK: EXT.

2. Install JP10 and JP11 on buffer card (AS/3812).

3. Set S3 as required. Refer to Table 3-9.

3.6.1.1.2 Modem Settings (Slave)

1. TX-CLOCK: EXT.

2. Set S3 to minimum size, and install JP11 on buffer card (AS/3812). Refer to Table 3-9.

3–52 Rev. 5

SDM-650B Satellite Modem Configuration

3.6.1.2 Master/Slave G.703

Refer to Figure 3-17 for the G.703 master/slave configuration.

Note: There is no loop timing selection on board for G.703. It is assumed that any G.703 termination equipment will extract the clock from the satellite signal, and turn it around for re-transmitting. The settings for the master and slave modems are the same as listed in previous sections.

Figure 3-17. G.703 Master Slave Configuration

Rev. 5 3–53

Configuration SDM-650B Satellite Modem

3.6.1.3 Master/Slave X.21

Refer to Figure 3-18 for the X.21 master/slave configuration.

Figure 3-18. X.21 Master/Slave Configuration

Note: On Rev. E boards, there are on-board jumpers to loop back the clock. Refer to

Table 3-1 (see the note in the previous example).

3.6.1.3.1 Modem Settings (Master)

• TX-CLOCK: INT.

• Install JP10 and JP11 on buffer card (AS/3812).

• Set S3 as required. Refer to Table 3-9.

3.6.1.3.2 Modem Settings (Slave)

• TX-CLOCK: EXT.

• Install JP11 on buffer card (AS/3812).

• Set S3 as required. Refer to Table 3-9.

3–54 Rev. 5

SDM-650B Satellite Modem Configuration

3.6.1.4 Master/Slave External Station Clock

Figure 3-19 shows the master/slave external station clock configuration diagram.

Note: Clock must be looped externally at slave end. (For RS-422 and V.35, see the note in the previous example.)

Figure 3-19. G.703 Master Slave Configuration

3.6.1.4.1 Modem Settings (Master)

• TX-CLOCK: EXT.

• Install JP10 on buffer card (AS/3812), and set S3 as required.

• Refer to Table 3-9.

3.6.1.4.2 Modem Settings (Slave)

• TX-CLOCK: EXT.

• Set S3, and install JP11 on buffer card (AS/3812).

Rev. 5 3–55

Configuration SDM-650B Satellite Modem

3.6.2 Master/Master

This application is used where both earth stations have high stability clocks available, and the received data is to be clocked onto the local network.

The disadvantage of the master/master application is that the receive data will slip, as the clocks will not be synchronized. By using very high stability clocks, the expected time between slips can be many days.

The buffer clock will normally automatically revert to the low stability internal reference.

3.6.2.1 Master/Master (Customer Clock)

Refer to Figure 3-20 for the master/master customer clock configuration.

Figure 3-20. Master/Master Customer Clock Configuration

3–56 Rev. 5

SDM-650B Satellite Modem Configuration

3.6.2.1.1 Modem Settings (Master)

• TX-CLOCK: EXT.

• Install JP10 and JP11 on buffer card (AS/3812).

• Set S3 as required. Refer to Table 3-9.

Rev. 5 3–57

Configuration SDM-650B Satellite Modem

3.6.2.2 Master/Master (Station Clock)

Care should be taken when using this mode. Make sure that the station clock is also used to synchronize the transmit data. Phasing problems may also occur between the transmit data and the station clock input. For this reason, it is better to use the TERR clock on transmit.

Refer to Figure 3-21 for a diagram of the master/master station clock configuration.

Figure 3-21. Master/Master Station Clock Configuration Diagram

3–58 Rev. 5

Comtech EF Data SDM-650B User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

About this Manual

Preface

Organization

Conventions Used in this Manual

Cautions and Warnings

References Used in this Manual

Military Standards

Trademarks

Related Documents

European EMC Directive

Reporting Comments or Suggestions Concerning this Manual

Customer Support

Table of Contents

INTRODUCTION

1.1 Purpose and Function

1.2 Description

1.3 System Specification

2.1 Unpacking

INSTALLATION

2.2 External Connections

2.2.1 DATA I/O

2.2.2 Remote (J6)

2.2.3 Fault (J7)

2.2.4 IF Output (CP1)

2.2.5 IF Input (CP2)

2.2.6 AC Power

2.2.7 GROUND

2.3 System Requirements

2.4 System Installation

3.1 Monitor and Control

CONFIGURATION

3.1.1 Description of Options

3.1.2 Remote Interface Specification

3.1.3 M&C Theory of Operation

3.2 Digital Interfaces

3.2.1 RS-422 and MIL-STD-188-114 Interface

3.2.2 V.35 Interface

3.2.3 DS-1 Interface

3.2.4 G.703, 2048 kbit/s Interface

3.2.5 Asynchronous Overhead Interface

3.2.6 Asynchronous Breakout Panel

3.3 Doppler Buffer

3.3.1 Buffer Setup

3.4 Doppler Buffer Specification

3.5 I/O Connectors

3.6 Interface Clocking Options

3.6.1 Master/Slave

3.6.2 Master/Master