Comtech EF Data DMD50 Installation And Operation Manual

Comtech EF Data is an

DMD50

AS9100 Rev B / ISO9001:2000 Registered Company

IMPORTANT NOTE: The information contained in this document supersedes all previously
published information regarding this product. This manual is subject to change without prior notice.

Universal Satellite Modem

Installation and Operation Manual

Part Number MN-DMD50 Revision 3

Subject:

Errata A

Comtech EF Data Documentation Update

Revise “Trademarks” subsection in Preface to include CEFD Patents
and Patents Pending note

Original Manual Part
Number/Rev:

Errata Number/
PLM Document ID:

PLM CO Number:
Comments:

MN-DMD50 Rev 2

ER-DMD50.EA2
C-0022887
The updated information will be incorporated into the next formal

revision of the manual.

Update the manual Preface: Revise the ‘Trademarks’ section to
read (addition in bold):

Trademarks

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

See all of Comtech EF Data's Patents and Patents Pending at
http://patents.comtechefdata.com.

ER-DMD50.EA2 THIS DOCUMENT IS NOT SUBJECT TO REVISION/UPDATE! PLM CO C-0022887 Page 1 of 2

ErrataAforMN‐DMD50Rev2 UpdatePreface

This page is intentionally blank.

ER-DMD50.EA2 THIS DOCUMENT IS NOT SUBJECT TO REVISION/UPDATE! PLM CO C-0022887 Page 2 of 2

Comtech EF Data Documentation Update

Manual Part Number:

Errata B

DMD50 Universal Satellite Modem

MN-DMD50

Revision:

Errata Subject:

Errata Part Number:

CO Number:

Comments:

Rev 3

Updates to registered trademarks and licenses for Raytheon Applied
Signal Technology, DoubleTalk and Carrier-in-Carrier

ER-MNDMD50-EB3

C-0023089
Att ach Errata to Preface, page 1.

Note:

"Applied Signal Technology, Inc." is now "Raytheon Applied Signal Technology". All references
to "Applied Signal Technology, Inc." in this manual are changed to "Raytheon Applied Signal
Technology

".

Patents and Trademarks

See all of Comtech EF Data’s Patents and Patents Pending at http://patents.comtechefdata.com.

Comtech EF Data acknowledges that all trademarks are the property of the trademark owners.

®

• DoubleTalk

• DoubleTalk

• Carrier-in-Carrier

is licensed from "Raytheon Applied Signal Technology".

®

is a registered trademark of "Raytheon Applied Signal Technology".

®

is a registered trademark of Comtech EF Data.

Errata Page 2 of 2

This page is intentionally blank.

ER-MNDMD50-EB3 THIS DOCUMENT IS NOT SUBJECT TO REVISION/UPDATE. C-0023089

DMD50

Universal Satellite Modem

Installation and Operation Manual

Part Number MN-DMD50

Revision 3

January 13, 2011

Copyright © 2011 Comtech EF Data. A ll rights res erved. Printed in the USA .

Comtech EF Data, 21 14 Wes t 7th St re et , Tem pe, Ariz on a 85 28 1 USA, 480.333.22 00, FAX: [phone]

This page is intentionally blank.

Table of Contents

TABLE OF CONTENTS ............................................................................................................III

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

1.1 Overview ...................................................................................................................................... 1–1

1.2 8BConfigurations ............................................................................................................................. 1–2

1.2.1 Features/Options Installed at Time of Order ......................................................................... 1–2

1.2.2 Feature Upgrades .................................................................................................................. 1–2

1.2.3 Hardware Options ................................................................................................................. 1–2

1.2.4 Factory Installed Options ...................................................................................................... 1–2

1.3 Function Accessibility ................................................................................................................. 1–2

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

2.1 Unpacking and Inspection .......................................................................................................... 2–1

2.2 Installation Requirements .......................................................................................................... 2–2

2.3 Mounting Considerations ........................................................................................................... 2–3

2.4 Initial Configuration Check ....................................................................................................... 2–4

2.5 Modulator Checkout ................................................................................................................... 2–5

2.5.1 Initial Power-Up .................................................................................................................... 2–5

2.5.2 Factory Terminal Setup ......................................................................................................... 2–6

CHAPTER 3. THEORY OF OPERATION .................................................................. 3–1

3.1 Modem Hardware ....................................................................................................................... 3–1

3.1.1 L-Band/IF Printed Circuit Card ............................................................................................ 3–1

3.1.2 Baseband Processing Printed Circuit Card ........................................................................... 3–2

3.1.3 Enhanced Interface Printed Circuit Card .............................................................................. 3–3

3.2 Functional Block Diagram ......................................................................................................... 3–3

3.2.1 Front Panel ............................................................................................................................ 3–4

3.2.2 Baseband Processing ............................................................................................................. 3–4

3.2.3 Tx Baseband Processing ....................................................................................................... 3–5

3.2.4 Rx Baseband Processing ....................................................................................................... 3–5

3.3 Monitor & Control (M&C) Subsystem ..................................................................................... 3–5

3.3.1 Terminal Port ........................................................................................................................ 3–6

3.3.2 Modem Remote Communications (RLLP) ........................................................................... 3–6

3.3.3 Ethernet M&C Port ............................................................................................................... 3–6

3.3.4 103BModem Monitor Status

......................................................................................................... 3–7

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3.4 Async Port / ES-ES Communications ....................................................................................... 3–7

3.5 Internal Clock .............................................................................................................................. 3–7

3.6 22BLoopback Features (Terrestr ia l & IF) ...................................................................................... 3–8

3.7 Clocking Options ....................................................................................................................... 3–11

3.7.1 TX Clock Options ............................................................................................................... 3–11

3.7.1.1 SCTE: Serial Clock Transmit External ........................................................................... 3–12

3.7.1.2 SCT: Serial Clock Transmit ............................................................................................ 3–12

3.7.2 RX Buffer Clock Options ................................................................................................... 3–12

3.7.2.1 RX SAT Clock ................................................................................................................ 3–13

3.7.2.2 SCTE: Serial Clock Transmit External ........................................................................... 3–13

3.7.2.3 SCT: Serial Clock Transmit ............................................................................................ 3–13

3.7.2.4 EXT CLK/EXT BNC: External Clock, J16 .................................................................... 3–13

3.7.2.5 EXT IDI: Insert Data In .................................................................................................. 3–14

3.7.3 EXT REF: External Reference, Top BNC Port, J10 ........................................................... 3–14

3.8 RS530/422/V.35 Interface (Standard) ..................................................................................... 3–14

3.8.1 G.703 Interface (Optional) .................................................................................................. 3–14

3.8.2 HSSI Interface (Optional) ................................................................................................... 3–15

3.8.3 Ethernet Data Interface (Optional) ...................................................................................... 3–15

3.9 Reed-Solomon Codec ................................................................................................................ 3–15

3.9.1 Reed-Solomon Operation .................................................................................................... 3–15

3.9.2 Reed-Solomon Code Rate ................................................................................................... 3–15

3.9.3 Interleaving ......................................................................................................................... 3–16

3.10 Asynchronous Overhead Operation (Framing/Multiplexer Capability) ............................. 3–17

3.11 Standard IBS Mode .................................................................................................................. 3–18

3.12 Asynchronous Multiplexer Mode ........................................................................................... 3–19

3.13 29BESC Backward Alarms ............................................................................................................. 3–19

3.13.1 To Disable the ESC Backward Alarms ............................................................................... 3–20

3.14 DoubleTalk Carrier-in-Carrier Option .................................................................................. 3–21

3.14.1 What is DoubleTalk Carrier-in-Carrier? ............................................................................. 3–21

3.14.2 Application Requirements ................................................................................................... 3–22

3.14.3 Operational Recommendations ........................................................................................... 3–24

3.14.4 System Functionality and Operational Considerations ....................................................... 3–25

3.14.5 DoubleTalk Carrier-in-Carrier Cancellation Process .......................................................... 3–27

3.14.6 Margin Requirements .......................................................................................................... 3–29

3.14.7 Carrier-in-Carrier Latency .................................................................................................. 3–29

3.14.8 Carrier-in-Carrier and Adaptive Coding and Modulation ................................................... 3–29

3.14.9 Carrier-in-Carrier Link Design ........................................................................................... 3–29

3.14.9.1 Symmetric Data Rate Link .............................................................................................. 3–30

3.14.9.2 Asymmetric Data Rate Link ........................................................................................... 3–33

3.14.9.3 Power Limited Links ....................................................................................................... 3–34

3.14.10 Carrier-in-Carrier Commissioning and Deployment ...................................................... 3–35

3.14.11 Validating Carrier-in-Carrier Performance ..................................................................... 3–36

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3.14.12 Operational References ................................................................................................... 3–37

3.14.13 Carrier-in-Carrier Link Budget Calculation .................................................................... 3–37

3.14.14 Estimating PSD Ratio ..................................................................................................... 3–38

3.14.14.1 Estimating PSD Ratio from LST .................................................................................... 3–38

3.14.14.2 Estimating PSD Ratio from Satmaster ............................................................................ 3–39

3.14.14.3 Estimating PSD Ratio Using Spectrum Analyzer ........................................................... 3–39

3.14.15 DoubleTalk Carrier-in-Carrier Specifications ................................................................. 3–40

3.14.16 Carrier-in-Carrier Summary ............................................................................................ 3–40

3.14.17 Glossary .......................................................................................................................... 3–41

3.15 Satellite Control Channel (SCC) ............................................................................................. 3–43

3.15.1 SCC Framing Structure ....................................................................................................... 3–43

3.15.2 115BAggregate Data Rate ........................................................................................................... 3–45

3.15.3 Overhead Rate Comparison ................................................................................................ 3–45

3.15.4 Actual Overhead Rate Calculation ...................................................................................... 3–46

3.15.5 SCC Overhead Channel Setup ............................................................................................ 3–47

3.16 EDMAC Satellite Framing/Deframing Mode ......................................................................... 3–48

3.17 Locating the ID Code Operationa l Pro cedure........................................................................ 3–48

3.18 Strap Codes ................................................................................................................................ 3–48

CHAPTER 4. USER INTERFACES............................................................................ 4–1

4.1 User Interfaces ............................................................................................................................ 4–1

4.2 Front Panel User Interface ......................................................................................................... 4–1

4.2.1 LCD Front Panel Display ...................................................................................................... 4–2

4.2.2 Cursor Control Arrow Keys .................................................................................................. 4–2

4.2.3 Numeric Keypad ................................................................................................................... 4–2

4.2.4 Front Panel LED Indicators .................................................................................................. 4–3

4.3 Parameter Setup .......................................................................................................................... 4–4

4.4 Front Panel Control Screen Menus ........................................................................................... 4–4

4.4.1 Main

Menus .......................................................................................................................... 4–4

4.4.2 Modulator Menu Options and Parameters ............................................................................ 4–5

4.4.3 Demodulator Menu Options and Parameters ...................................................................... 4–11

4.4.4 Interface Menu Options and Param eters ............................................................................. 4–16

4.4.5 Monitor Menu Options and Parameters .............................................................................. 4–21

4.4.6 Alarms Menu Options and Parameters ............................................................................... 4–23

4.4.7 System Menu Options and Parameters ............................................................................... 4–32

4.4.8 Test Menu Options and Parameters .................................................................................... 4–41

4.5 Terminal Mode Control............................................................................................................ 4–42

4.5.1 Modem Terminal Mode Control ......................................................................................... 4–43

4.5.2 Modem Setup for Terminal Mode ...................................................................................... 4–43

4.6 Terminal Port User Interface ................................................................................................... 4–43

4.7 Connecting the Terminal .......................................................................................................... 4–44

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4.8 Terminal Screens ...................................................................................................................... 4–45

4.9 RS485 Remote Port Interface (RL LP Prot oco l) ..................................................................... 4–45

4.9.1 Protocol Structure ............................................................................................................... 4–45

4.10 43BEthernet Remote Port Interface (SNMP & Web Browser) ................................................... 4–46

CHAPTER 5. REAR PANEL INTERFACES .............................................................. 5–1

5.1 Connections ................................................................................................................................. 5–1

5.2 Compact Flash ............................................................................................................................. 5–2

5.3 Power Input Modules ................................................................................................................. 5–3

5.3.1 AC Power Input Module ....................................................................................................... 5–3

5.3.2 DC Power Input/Switch ........................................................................................................ 5–3

5.4 Chassis Connections (Standard) ................................................................................................ 5–3

5.4.1 EXT REF (J10) ..................................................................................................................... 5–3

5.4.2 TX IF (J11) ........................................................................................................................... 5–3

5.4.3 TX L-Band IF (J12) .............................................................................................................. 5–3

5.4.4 RX IF (J13) ........................................................................................................................... 5–4

5.4.5 RX L-Band IF (J14) .............................................................................................................. 5–4

5.4.6 ALARM (J15) ....................................................................................................................... 5–4

5.4.7 EXT CLK (J16) ..................................................................................................................... 5–4

5.4.8 143B ASYNC (J17) ....................................................................................................................... 5–5

5.4.9 J18 ......................................................................................................................................... 5–5

5.4.10 EIA-530 (J19) ....................................................................................................................... 5–5

5.4.11 REMOTE (J20) ..................................................................................................................... 5–7

5.4.12 ETHERNET (J21) ................................................................................................................. 5–7

5.5 G.703 IDR/IBS Interface (Optional) ......................................................................................... 5–7

5.6 ESC ALARM (J1) ....................................................................................................................... 5–8

5.7 64K AUDIO (J2) ......................................................................................................................... 5–9

5.8 K DATA (J3) ............................................................................................................................. 5–10

5.9 G.703 BAL (J4) .......................................................................................................................... 5–10

5.9.1 SWITCH INTERFACE (J5) ............................................................................................... 5–11

5.9.2 SD (DDI) (J6) ..................................................................................................................... 5–13

5.9.3 DDO (J7) ............................................................................................................................. 5–13

5.9.4 IDI (J8)

................................................................................................................................ 5–13

5.9.5 SD (IDO) (J9) ..................................................................................................................... 5–13

5.10 Ethernet Data Interface (Optional) ......................................................................................... 5–13

5.11 High-Speed Serial Interface (HSSI) (Optional) ...................................................................... 5–14

5.12 HSSI (J6) .................................................................................................................................... 5–14

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5.13 ASI/DVB/M2P Interface ( Opt iona l) ........................................................................................ 5–15

5.13.1 ASI IN (J1) .......................................................................................................................... 5–15

5.13.2 ASI OUT (J2) ...................................................................................................................... 5–15

5.13.3 DVB/M2P IN (J3) ............................................................................................................... 5–15

5.13.4 DVB/M2P OUT (J4) ........................................................................................................... 5–17

5.14 Ethernet Data Interface (Optional) ......................................................................................... 5–18

5.15 HSSI / G.703 .............................................................................................................................. 5–18

5.15.1 64K AUDIO (J2) ................................................................................................................. 5–19

5.15.2 8K DATA (J3) .................................................................................................................... 5–20

5.15.3 G.703 BAL (J4)................................................................................................................... 5–20

5.15.4 ESC ALARM (J5) ............................................................................................................... 5–21

5.15.5 161BSD (DDI) (J6) ..................................................................................................................... 5–22

5.15.6 162BDDO (J7) ............................................................................................................................. 5–22

5.15.7 IDI (J8) ................................................................................................................................ 5–22

5.15.8 SD (IDO) (J9) ..................................................................................................................... 5–22

5.16 HSSI / Ethernet (J1) .................................................................................................................. 5–22

5.17 Ethernet Data Interface ............................................................................................................ 5–23

5.18 GigE Interface ........................................................................................................................... 5–23

CHAPTER 6. MAINTENANCE AND TROUBLESHOOTING ..................................... 6–1

6.1 Periodic Maintenance ................................................................................................................. 6–1

6.1.1 Clock Adjustment ................................................................................................................. 6–1

6.2 Troubleshooting .......................................................................................................................... 6–2

6.2.1 Alarm Faults .......................................................................................................................... 6–2

6.2.1.1 Major Tx Alarms ............................................................................................................... 6–2

6.2.1.2 Major Rx Alarms .............................................................................................................. 6–3

6.2.1.3 Minor Tx Alarms .............................................................................................................. 6–3

6.2.1.4 Minor Rx Alarms .............................................................................................................. 6–3

6.2.1.5 Drop and Insert Alarms ..................................................................................................... 6–4

6.2.1.6 C

ommon Major Alarms .................................................................................................... 6–4

6.2.2 Alarm Masks ......................................................................................................................... 6–5

6.2.2.1 Active Alarms ................................................................................................................... 6–5

6.2.2.1.1 Major Alarms ....................................................................................................................... 6–5

6.2.2.1.2 Minor Alarms ....................................................................................................................... 6–5

6.2.2.1.3 Common Equipment Faults ................................................................................................. 6–6

6.2.2.2 Latched Alarms ................................................................................................................. 6–6

6.2.2.3 Backward Alarms .............................................................................................................. 6–6

6.3 IBS Fault Conditions and Actions ............................................................................................. 6–6

CHAPTER 7. TECHNICAL SPECIFICATIONS .......................................................... 7–1

7.1 Data Rates .................................................................................................................................... 7–1

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7.2 Modulator .................................................................................................................................... 7–1

7.3 Demodulator ................................................................................................................................ 7–2

7.4 Plesiochronous Buffer ................................................................................................................. 7–3

7.5 Monitor and Control ................................................................................................................... 7–3

7.6 DMD50 Drop and Insert (Optional) .......................................................................................... 7–3

7.7 Terrestrial Interfaces .................................................................................................................. 7–3

7.8 IDR/ESC T2/E2 Interface (Optional) ........................................................................................ 7–3

7.9 IDR/ESC T3/E3/STS1 Inter face (Optional) ............................................................................. 7–3

7.10 IBS/Synchronous Interface (Standard) ..................................................................................... 7–4

7.11 High-Speed Serial Interface (HSSI) .......................................................................................... 7–4

7.12 ASI ................................................................................................................................................ 7–4

7.13 DVB/M2P ..................................................................................................................................... 7–4

7.14 Ethernet Data Interface (Optional) ........................................................................................... 7–4

7.15 Gigi Ethernet Data Interface (Optional) ................................................................................... 7–4

7.16 HSSI / G703 T2/E2 Max ............................................................................................................. 7–4

7.17 HSSI / G703 T3/E3/STS1 Max ................................................................................................... 7–4

7.18 HSSI /ETHERNET ..................................................................................................................... 7–5

7.19 Environmental ............................................................................................................................. 7–5

7.20 Physical ........................................................................................................................................ 7–5

7.21 DMD50 Data Rate Limits ........................................................................................................... 7–6

7.21.1 Non-DVB .............................................................................................................................. 7–6

7.21.2 DVB ...................................................................................................................................... 7–8

7.22 DMD50 BER Specifications ..................................................................................................... 7–10

7.22.1 BER Performance (Viterbi) ................................................................................................ 7–10

7.22.2 BER Performance (Sequential) ........................................................................................... 7–11

7.22.3 BER Performance (Viterbi with Reed-Solomon) ............................................................... 7–12

7.22.4 BER Performance (Turbo) .................................................................................................. 7–13

7.22.5 BER Performance (8PSK Trellis)

....................................................................................... 7–14

7.22.6 BER Performance (8PSK Turbo) ........................................................................................ 7–15

7.22.7 BER Performance (16QAM Viterbi) .................................................................................. 7–16

7.22.8 BER Performance (16QAM Viterbi with Reed-Solomon) ................................................. 7–17

7.22.9 BER Performance (16QAM Turbo) .................................................................................... 7–18

7.22.10 BER Performance ((O)QPSK Turbo) ............................................................................. 7–19

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7.22.11 BER Performance (8PSK Turbo) .................................................................................... 7–20

7.22.12 BER Performance (16QAM Turbo) ................................................................................ 7–21

7.22.13 1/2 Rate B/O/QPSK BER Performance (LDPC) ............................................................ 7–22

7.22.14 2/3 Rate Q/8PSK/8QAM BER Performance (LDPC) .................................................... 7–23

7.22.15 3/4 Rate Q/8PSK, 8/16QAM BER Performance (LDPC) .............................................. 7–24

7.22.16 ACG Output Voltage ...................................................................................................... 7–30

APP E NDI X A. PRODUCT OPTIONS .......................................................................... A–1

A.1 Hardware Options ..................................................................................................................... A–1

A.2 G.703/IDR ESC Interface .......................................................................................................... A–1

A.3 Internal High Stability ............................................................................................................... A–1

A.4 DC Input Prime Power .............................................................................................................. A–1

A.5 ASI/RS-422 Parallel ................................................................................................................... A–1

A.6 ASI/LVDS Parallel ..................................................................................................................... A–1

A.7 HSSI ............................................................................................................................................ A–1

A.8 Ethernet Data Interface ............................................................................................................. A–2

A.9 HSSI / G.703 ............................................................................................................................... A–2

A.10 HSSI / ETHERNET ................................................................................................................... A–2

A.11 Turbo Product Code / Variable Reed-Soloman ...................................................................... A–2

A.12 Customized Options ................................................................................................................... A–2

APPENDIX B. FRONT PANEL UPGRADE PROCEDURE ......................................... B–1

B.1 Introduction ................................................................................................................................ B–1

B.2 Required Equipment ................................................................................................................. B–1

B.3 Upgrade Procedure .................................................................................................................... B–1

B.4 Demonstration Procedure ......................................................................................................... B–3

B.4.1 Running in Demonstration Mode ......................................................................................... B–5

B.4.2 Canceling Demonstration Mode .......................................................................................... B–6

APPENDIX C. CARRIER CONTROL ......................................................................... C–1

C.1 States

........................................................................................................................................... C–1

C.2 Carrier Off .................................................................................................................................. C–1

C.3 Carrier On .................................................................................................................................. C–1

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C.4 Carrier Auto ............................................................................................................................... C–2

C.5 Carrier VSat ............................................................................................................................... C–2

C.6 Carrier RTS ................................................................................................................................ C–2

APPENDIX D. WEB BROWSER SETUP GUIDE ...................................................... D–1

D.1 Introduction ................................................................................................................................ D–1

D.2 WEB Users Configuration......................................................................................................... D–2

D.3 Change Web User Name............................................................................................................ D–3

D.4 Change Authentication Password ............................................................................................. D–3

D.5 Change Access Rights ................................................................................................................ D–4

D.6 Modem Web Site ........................................................................................................................ D–4

D.7 Web Page Appearance ............................................................................................................... D–7

APPENDIX E. STRAP CODES .................................................................................. E–1

E.1 Strap Codes ................................................................................................................................. E–1

E.2 Sample Applications .................................................................................................................. E–5

E.3 Operational Case Examples ...................................................................................................... E–6

E.3.1 Case 1: IDR 8.448 Mbps, 3/4 Rate Viterbi .......................................................................... E–6

E.3.2 Case 2: IBS 1.544 Mbps, 3/4 Rate Viterbi ........................................................................... E–7

E.3.3 Case 3: Closed Network, 3/4 Rate Viterbi, IBS Overhead .................................................. E–8

E.3.4 Case 4: Loop Timing Example ............................................................................................ E–9

APPENDIX F. TCP/IP ETHERNET SETUP ................................................................ F–1

F.1 Introduction ................................................................................................................................. F–1

F.2 TCP/IP Network Configuration ................................................................................................ F–1

F.3 Network Configuration Summary ............................................................................................. F–3

F.4 Ethernet Test ............................................................................................................................... F–3

F.5 Testing the Ethernet Connection using the Ping Program (Optional) ................................... F–6

APPENDIX G. AUPC OPERATION ............................................................................ G–1

G.1 Automatic Uplink Power Control (AUPC Operation) ........................................................... G–1

G.1.1 Radyne AUPC ...................................................................................................................... G–1

G.1.2 EF AU

PC ............................................................................................................................. G–2

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G.1.3 Near Side AUPC .................................................................................................................. G–2

APPENDIX H. DROP AND INSERT (D&I) .................................................................. H–1

H.1 Drop and Insert (D&I) ............................................................................................................... H–1

H.1.1 Drop Only ............................................................................................................................ H–3

H.1.2 Insert Only ........................................................................................................................... H–3

H.1.3 Mode Selection .................................................................................................................... H–4

H.1.3.1 PCM-30 ............................................................................................................................ H–4

H.1.3.2 PCM-30C ......................................................................................................................... H–4

H.1.3.3 PCM-31 ............................................................................................................................ H–5

H.1.3.4 PCM-31C ......................................................................................................................... H–5

H.1.3.5 T1-D4/T1-D4-S ................................................................................................................ H–5

H.1.3.6 T1-ESF/T1-ESF-S ............................................................................................................ H–5

H.1.4 Multidestinational Systems .................................................................................................. H–5

H.1.5 Drop and Insert Mapping ..................................................................................................... H–6

H.2 Configuring the Modem for Drop and Insert .......................................................................... H–8

H.2.1 Data Rate .............................................................................................................................. H–8

H.2.2 Operational Network Specification ...................................................................................... H–9

H.2.3 Terrestrial Framing - Drop Mode/Insert Mode .................................................................. H–10

H.2.3.1 Insert Terrestrial Frame Source ...................................................................................... H–10

H.2.4 D&I Sample Configurations and D&I Clock Setup Options ............................................. H–11

H.3 D&I Maps and Map Editing ................................................................................................... H–15

APPENDIX I. EFFCIENT DROP AND INSERT (D&I) ................................................. I–1

I.1 Introduction ................................................................................................................................. I–1

I.2 Prerequisite .................................................................................................................................. I–1

I.3 Efficient Drop & Insert Mode .................................................................................................... I–2

I.3.1 Calculating the Required Satellite Bandwidth ........................................................................... I–3

I.3.2 Calculating the Basic Efficient D&I Rate

.................................................................................. I–3

I.3.3 Calculating the Efficient D&I Rate with E1 Signaling .............................................................. I–3

I.3.4 Calculating the Efficient D&I Rate with Enhanced Asynchronous Overhead .......................... I–4

APPENDIX J. ETHERNET DATA INTERFACE SETUP ............................................. J–1

J.1 Configuring the modem to use the Ethernet Data Interface (Optional) ................................ J–1

J.1.1 Ethernet Flow Control ............................................................................................................... J–1

J.1.1.1 Half-Duplex Flow Control ................................................................................................ J–2

J.1.1.2 Full-Duplex Flow Control ................................................................................................. J–2

J.1.2 Ethernet Daisy Chain ................................................................................................................ J–2

J.1.3 Ethernet QOS Type ................................................................................................................... J–2

J.1.4 Ethernet QOS Queue ................................................................................................................. J–2

J.1.5 Setting Up The DMD20/DMD20 LBST Ethernet Bridge To Operate Like A FIFO............... J–3

J.1.6 Packet Statistics ........................................................................................................................ J–4

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Notes:

xii

PREFACE

About this Manual

This manual describes th e installation and operati on for the Radyne DMD50. T his is a technical
document intended for earth station engineers, technicians, and operators responsible for the
operation and maintenance of the DMD50.

Reporting Comments or Suggestions Concerning this Manual

Comments and suggestio ns regarding the c ontent an d design of this m anual will be appreciate d.
To submit comments, please contact the Comtech EF Data Technical Publications Department:

[e-mail]

Trademarks

Copyright

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

2011, Comtech EF Data This manual is proprietary to Comtech EF Data and is
intended for the exclusive use of Comtech EF Data’s customers. No part of this
document may in whole or in part, be copied, reproduced, distributed, translated or
reduced to any electronic or magnetic storage medium without the express written
consent of a duly authorized officer of Comtech EF Data

i

DMD50 Universal Satellite Modem Revision 3
Preface MN-DMD50

Conventions and References

Related Documents

The following documents are referenced in this manual:

• EN300-421 and EN301-210 ETSI

• ETSI EN302-307

• INTELSAT Earth Station Standar ds IESS-308, -309, -310, and -315

• EUTELSAT SMS

Metric Conversion

Metric conversi on inf orm atio n is loc ated o n the i nside b ac k cover of this m anu al. T his inf orm ation is
provided to assist the operator in cross-referencing non-Metric to Metric conversions.

ii

DMD50 Universal Satellite Modem Revision 3

WARNING

potentially hazardous situation that, if not avoided,

CAUTION

CAUTION indicates a hazardous situation that, if not avoided, may result in

IM P O RTA N T

IMPORTANT or NOTE indicates information critical for proper equipment

IM P O RTA N T

Preface MN-DMD50

Cautions and Warnings

WARNING indicates a
could result in death or serious injury.

minor or moderate injury. CAUTION may also be used to indicate other unsafe
practices or risks of property damage.

function.

Recommended Standard Designations

Recommended St andard (RS) Desig nations have been super seded by the new desi gnation of the
Electronic Ind ustries Association (E IA). References to the old designations are sh own only when
depicting actual text displayed on the screen of the unit (RS-232, RS-485, etc.). All other references
in the manual will be shown with the EIA designations.

The user should carefully review the following information.

iii

DMD50 Universal Satellite Modem Revision 3

The modem contains a Lithium Battery. DANGER O F EXPLOSION EXISTS i f the

with local and national regulations.

PROPER GROUNDING PROTECTION REQUIRED: The installation instructions
equipment shall be connected to the protective earth connection at all times.

"Laite on liitettävä suojamaadoituskoskettimilla varustettuun

In Sweden: “Ap p araten skall anslutas till j o rdat uttag.”

CAUTION

Preface MN-DMD50

Electrical Safety

The DMD50 has bee n shown to comply with the EN 60950-1 Safety of Information Technology
Equipment (including electrical business machines) safety standard.

The equipment is rated for a nominal operating range of 100 - 240 volts AC or an appropriately
equipped DC option, nominal operating range is 48+/-5 volts DC . The unit has a maximum power
consumption of 250 watts.

Battery

battery is incorrectly replaced. Replace only with the same or equivalent type
recommended by the manufacturer. Dispose of used batteries in accordance

Grounding

require that the integrity of the protective earth must be ensured and that the

Fuses

Therefore, it is imperative during installation, configuration, and operation that
the user ensures that the unit has been properly grounded using the ground
stud provided on the rear panel of the unit.

• In Finland:

pistorasiaan."

• In Norway: “Apparatet må tilkoples jordet stikkontakt.”

•

FOR CONTINUED OPERATOR SAFETY, ALWAYS REPLACE THE FUSES WITH
THE CORRECT TYPE AND RATING.

The DMD50 contains no Fuses.

iv

DMD50 Universal Satellite Modem Revision 3

PROPER GROUNDING PROTECTION IS REQUIRED – REFER TO THE

system that has no direct connection to ground.

International Symbols

Preface MN-DMD50

Environmental

The DMD50 must not be o perated in an environment wher e the unit is exposed to precipitation;
condensation; humid atmospheres above 95% RH; altitudes (unpressurized) greater than 2000
metres; excessive dust or vibration; flammable gases, corrosive or explosive atmospheres; or
extremes of temperature outside the ambient range 0 to +50°C. Maximum storage temperature
allowed is -20 to +70°C.

Operation in vehicles or other transportable installations that are equipped to provide a stable
environment is permitted. If such vehicles do not provide a stable environment, safety of the
equipment to EN 60950 may not be guaranteed.

Installation

GROUNDING ‘CAUTION’ NOTE PROVIDED ON THE PREVIOUS PAGE. The DMD50
is designed for connection to a power system that has separate ground, line and
neutral conductors. The equipment is not

The installation and c onn ec tion to the l in e supply must be m ade i n compliance to local or na tio na l
wiring codes and regulations.

designed for connection to a power

The DMD50 is shipped with a line inlet c able suitable for use in the countr y of operation. If it is
necessary to replace this cable, ensure the replacement has an equivalent specification.
Examples of acceptab le ratings for the c able include HAR, BASEC and HOXX X-X. Examples of
acceptable connector ra tings include VDE, NF-U SE, UL, C SA, OVE, C EBEC, N EMKO, DEMKO ,
BS1636A, BSI, SETI, IMQ, KEMA-KEUR and SEV.

Symbol Definition Symbol Definition

Alternating Current

Fuse

Telecommunications Terminal Equipment Directive

In accordance with the Telecommunications Terminal Equipment Directive 91/263/EEC, this
equipment should not be directly connected to the Public Telecommunications Network.

CE Mark

Protective Earth

Chassis Ground

Comtech EF Data dec lares that the DMD50 modem meets the nec essary requirements for the
CE Mark.

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DMD50 Universal Satellite Modem Revision 3

IM P O RTA N T

Preface MN-DMD50

RoHS Compliancy

This unit satisfies (with exemptions) the requirements specified in the European Union Directive on the
Restriction of Hazardous Substance s, Di re ctiv e 2 002 /9 5/E C (E U RoHS) .

EMC (Electromagnetic Compatibility)

In accordance with European Directive 2004/108/EEC, the DMD50 has been shown, by
independent testing, to comply with the following standards:

Emissions: EN 55022 C lass B - Limits and m ethods of measurement of radio interfer ence

characteristics of Information Technology Equipment.

(Also tested to FCC Part 15 Class B.)
Immunity: EN 55024 – Information Technology Equipment: Immunity Characteristics,
Limits, and Methods of Measurement.

Additionally, the DMD50 has been shown to comply with the following standards:

EN 61000-3-2 – Harmonic Currents Emission;
EN 61000-3-3 – voltage Fluctuations and Flicker.

To ensure that the Modem continues to comply with these standards, observe
the following instructions:

• Connections to the transmit and receive IF ports should be made using a good quality
coaxial cable. For example, RG58 or RG59 for BNC IF connectors and LMR200,
LMR240 or equivilant for the L-band SMA IF ports.

• All 'D' type connectors attached to the rear panel must have back-shells that provide
continuous metallic s hieldin g. Cable with a conti nuous outer shie ld (either f oil or b raid, or
both) must be used, and the shield must be bonded to the back-shell.

• The equipment must be operated with its c o ver on a t all times. If it becomes nec es sary to
remove the cover, the user should ensure that the cover is correctly re-fitted before
normal operation commences.

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DMD50 Universal Satellite Modem Revision 3
Preface MN-DMD50

Warranty Policy

Comtech EF Data products are warranted against defects in material and
workmanship for a specific period from the date of shipment, and this period
varies by product. In most cases, the warranty period is two years. During the
warranty period, Comtech EF Data will, at its option, repair or replace products
that prove to be defective. Repairs are warranted for the remainder of the original
warranty or a 90 day extended warranty, whichever is longer. Contact Comtech
EF Data for the warranty period specific to the product purchased.

For equipment under warranty, the owner is responsible for freight to Comtech EF
Data and all related customs, taxes, tariffs, insurance, etc. Comtech EF Data is
responsible for the freight charges only for return of the equipment from the factory
to the owner. Comtech EF Data will return the equipment by the same method
(i.e., Air, Express, Surface) as the eq ui pment was sent to Comtech EF Data.

All equipment returned for warranty repair must have a valid RMA number issued
prior to return and be marked clearly on the return packaging. Comtech EF Data
strongly recommends all equipment be returned in its original packaging.

Comtech EF Data Corporation’s obligations under this warranty are limited to
repair or replacement of failed parts, and the return shipment to the buyer of the
repaired or replaced par ts .

Limitations of Warranty

The warranty does not apply to any part of a product that has been installed,
altered, repaired, or misused in any way that, in the opinion of Comtech EF Data
Corporation, would affect the reliability or detracts from the performance of any
part of the product, or is damaged as the result of use in a way or with equipment
that had not been previously approved by Comtech EF Data Corporation.

The warranty does not apply to any product or parts ther eof where t he serial number
or the serial number of any of its parts has been altered, defaced, or removed.

The warranty does not cover damage or loss incurred in transportation of the
product.

The warranty does not cover replacement or repair necessitated by loss or
damage from any cause beyond the control of Comtech EF Data Corporation,
such as lightning or other natural and weather related events or wartime
environments.

The warranty does not cover any labor involved in the removal and or
reinstallation of warranted equipment or parts on site, or any labor required to
diagnose the necessity for repair or replacement.

vii

DMD50 Universal Satellite Modem Revision 3
Preface MN-DMD50

The warranty excludes any responsibility by Comtech EF Data Corporation for
incidental or consequential damages arising from the use of the equipment or
products, or for any inability to use them either separate from or in combination with
any other equipment or products.

A fixed charge established for each product will be imposed for all equipment
returned for warranty repair where Comtech EF Data Corporation cannot identify
the cause of the reported failure.

Exclusive Remedies

Comtech EF Data Corporation’s warranty, as stated is in lieu of all other
warranties, expressed, implied, or statutory, including those of merchantability
and fitness for a particular purpose. The buyer shall pass on to any purchaser,
lessee, or other user of Comtech EF Data Corporation’s products, the
aforementioned warranty, and shall indemnify and hold harmless Comtech EF
Data Corporation from any claims or liability of such purchaser, lessee, or user
based upon allegations that the buyer, its agents, or employees have made
additional warranties or representations as to product preference or use.

The remedies provided herein are the buyer’s sole and exclusive remedies.
Comtech EF Data shall not be liable for any direct, indirect, special, incidental, or
consequential damages, whether based on contract, tort, or any other legal
theory.

viii

DMD50 Universal Satellite Modem Revision 3

IM P O RTA N T

Preface MN-DMD50

Customer Support

Refer to p. xxiv for information regarding this product’s Warranty Policy.

Contact the Comtech EF Data Customer Support Depa rtment for:

• Product support or training

• Reporting comments or suggestions concerning manuals

• Information on upgrading or returning a product

A Customer Support representative may be reached at:

Comtech EF Data
Attention: Customer Support Department
2114 West 7th Street
Tempe, Arizona 85281 USA

480.333.2200 (Main Comtech EF Data number)

480.333.4357 (Customer Support Desk)

480.333.2161 FAX

To return a Comtech EF Data product (in-warranty and out-of-warranty) for repair or
replacement:

• Contact the Comtec h EF Data Custom er Support Departm ent. Be prepare d to suppl y
the Customer Support representative with the model number, serial number, and a
description of the problem.

• Request a Return Material Auth orization (RMA) number from the Comtech EF Data
Customer Support representative.

• Pack the product in its original sh ipp in g car ton/ pac kaging to ensure that t he pr o du c t is
not damaged during shipping.

• Ship the product back to Comtech EF Data. (Shipping charges should be prepaid.)

Online Customer Support

An RMA number request can be requested electronically by contacting the Customer Support
Department through the online support page at www.comtechefdata.com/support.asp:

• Click on “Return Material Authorization” for detailed instructions on our return
procedures.

• Click on the “ RMA Request Form ” hyperlink, then fill out the form com pletely before
sending.

• Send e-mail to the Customer Supp ort Depa rtment at [e-mail].

ix

DMD50 Universal Satellite Modem Revision 3
Preface MN-DMD50

Notes:

x

This chapter provides an overview of the DMD50 Universal Satellite Modem. When describing
the equipment, it may be referred to as “the modem”, or “the unit”.

1.1 Overview

The Radyne Universal Satellite Modem (Figure 1-1) offers the best features of a sophisticated
programmable IBS/IDR and Closed Network Modem, at an affordable price.

This versatile equipment package combines unsurpassed performance with numerous user­friendly Front Panel Programmable Functions. The unit provides selectable functions for
different services: Intelsat IDR and IBS, as well as closed networks. All of the configuration and
Monitor and Control (M&C) Functions are available at the Front Panel. Operating parameters,
such as variable data rates, FEC Code Rate, modulation type, IF Frequencies, IBS/IDR Framing
and interface type can be readily set and changed at the Front Panel by earth station operations
personnel.

The modem operates at all standard IBS and IDR Data Rates up to 8.448 Mbps. Selection of any
data rate is provided over the range of 2.4 Kbps to 52 Mbps in 1 bps steps.

For applications requiring system redundancy, the Modem may be used with the Radyne RCS11
1:1 Redundancy Switch or the RCS20 M:N (N < 9) Redundancy Switch. An Internal
Engineering Service Channel Unit is available to provide voice, data, and alarms for Intelsat IDR
applications.

A full range of Industry Standard Interfaces are available. Interface types are selectable from
V.35, RS-232, RS-422/-530, ITU G.703, HSSI, ASI, DVB/M2P and Ethernet Bridge.

Chapter 1. Introduction

Figure 1-1. Universal Satellite Modem Front Panel

MN-DMD50– Revision 3 1–1

DMD50 Universal Satellite Modem Introduction

1.2 Configurations

The unit can be configured in the following ways:

 Features and options that are installed when the unit is ordered
 Feature upgrades
 Hardware options that are installed to a unit that is sent to a Comtech facility
 Hardware options that the user can install at their own location

1.2.1 Features/Options Installed at Time of Order

Features installed at the time of ordering are the options pre-installed /initialized in the factory
prior to shipment. These can be reviewed from the front panel. Refer to Chapter 4, User
Interfaces, for information on how to view these features. Factory installed options are chassis
and board configurations that are introduced during manufacture.

1.2.2 Feature Upgrades

Feature Upgrades are a simple and quick way of changing the feature set of an installed modem.
Feature upgrades are how most options are implemented. Features may be purchased at any time
by contacting a Comtech Corp. salesperson. Refer to Chapter 4 and Appendix D, for information
on how upgrade features are enabled.

1.2.3 Hardware Options

Hardware options (refer to Appendix A) are purchased parts that can be installed into the unit at
the customer’s site. A screwdriver is normally the only tool required. Please contact the
Customer Service Department for information not limited to availability and to shipping costs.

Only authorized service personnel should handle and install optional
hardware options.

1.2.4 Factory Installed Options

Units may also be sent to the factory for hardware option installation. Please contact the
Customer Service Department for information not limited to availability and to shipping costs.

1.3 Function Accessibility

All functions can be accessed with a terminal or personal computer via a serial link for complete
remote monitoring and control capability.

MN-DMD50– Revision 3 1–2

Chapter 2. Installation

CAUTION

2

Remove the cardboard/foam space covering the modem.

3

4

Save the packing material for storage or reshipment purposes.

submit a damage report.

2.1 Unpacking and Inspection

Inspect shipping containers for damage. If shipping containers are damaged, keep them until the
contents of the shipment have been carefully inspected and checked for normal operation.
The Universal Satellite Modem and its Installation and Operation Manual are packaged and shipped
in a pre-formed, reusable cardboard carton containing foam spacing for maximum shipping
protection.

Do not use any cutting tool th at w ill extend more tha n 1/2 in ch in to th e co n ta ine r.
This can cause damage to the modem.

Unpack and inspect the modem as follows:

Step Procedure

1

5

6

7

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

Remove the modem, power cord, and user’s manual from the carton.

Inspect the equipment for any poss ible dam age in curre d du ring shi pment .
Note: If damage is evident, contact the carrier and Comtech EF Data immediately and

Check the contents against the packing list to verify completenes s of the shipment.

Refer to the sections that follow for further installation instructions.

The Universal Satellite Modem was carefully packaged to avoid damage and should arrive
complete with the following items for proper installation:

1. DMD50 Universal Satellite Modem

2. Power Cord, six foot with applicable AC Connector

3. Installation and Operation Manual

MN-DMD50– Revision 3 2–1

DMD50 Universal Satellite Modem Installation

IM P O RTA NT

CAUTION

CAUTION

Should the AC power cable connector be of the wrong type for the installation, either

the cable or the power connector end should be replaced.

2.2 Installation Requirements

The modem is shipped fully assembled. It does not require removal of the covers for any purpose
in installation. . The power supply itself is designed for universal application using from 100 to
240 VAC, 50 to 60 Hz, 1.0A.

WARNING

There are no user-serviceable parts or configuration settings located inside
the Chassis. There is a potential shock hazard internally at the power supply
module. DO NOT open the Chassis under any circumstances.

Before initially applying power to the unit, it is a good idea to disconnect the
transmit output from the operating ground station equipment. This is
especially true if the current configuration settings are unknown, where
incorrect settings could disrupt existing communications traffic.

The unit contains a Lithium Battery. DANGER OF EXPLOSION exists if
the battery is incorrectly replaced. Replace only with the same or equivalent
type recommended by the manufacturer. Dispose of used batteries in
accordance with local and national regulations.

MN-DMD50– Revision 3 2–2

DMD50 Universal Satellite Modem Installation

IM P O RTA N T

The unit CANNOT have rack slides mounted to the side of the chassis. Cooling

ventilation, particularly at the sides. In rack systems where there is high heat

PROPER GROUNDING PROTECTION REQUIRED: The installation

2.3 Mounting Considerations

The can be installed within any standard 19 inch equipment cabinet or rack. The unit is a one
rack unit (RU) mounting space (1.75 inches) vertically and 19 inches of depth a nd requires a
minimum rack depth of 22 inches for cabling. The rear panel of the DMD50 is designed to have
power enter from the left and IF Cabling enter from the right when viewed from the rear of the
unit. Data and control cabling can enter from either side based on data interface option. The
unit can be placed on a table or suitable surf ace if requ ired

When mounted in an equipment rack, adequate ventilation must be provided. The ambient
temperature in the rack should be between 10° and 35° C, and held constant for best equipment
operation. The air available to the rack should be clean and relatively dry. The DMD50 units
may be stacked one on top of the other up to a maximum of 10 consecutive units before providing
one RU of space for airflow. Demodulator units should not be placed immediately above a high
heat or EMF generator to ensure the output signal integrity and proper receive operation.

Do not mount the in an unprotected outdoor location where there is direct contact with rain, snow,
wind or sun. The is designed for indoor applications only.

Shielded cables with the shield terminated to the conductive backshells are required in order to
meet EMC directives. Cables with insulation flammability ratings of 94 VO or better are required
in order to meet low voltage directives.

fans are mounted on the right-hand side of the unit.
If the unit is to be mounted in a rack, ensure that there is adequate clearance for

dissipation, forced air cooling must be provided by top or bottom mounted fans or
blowers. Under no circumstance should the highest internal rack temperature be
allowed to exceed 50°C (122°F).

instructions require that the integrity of the protective earth must be ensured
and that the equipment shall be connected to the protective earth connection
at all times. Therefore, it is imperative during installation, configuration, and
operation that the user ensures that the unit has been properly grounded
using the ground stud provided on the rear panel of the unit.

• In Finland: "Laite on liitettävä suojamaadoituskoskettimilla

varustettuun pistorasiaan."

• In Norway: “Apparatet må tilkoples jordet stikkontakt.”

• In Sweden: “Apparaten skall anslutas till jordat uttag.”

MN-DMD50– Revision 3 2–3

DMD50 Universal Satellite Modem Installation

IM P O RTA N T

customer’s order.

IM P O RTA N T

of the strap code.

2.4 Initial Configuration Check

The is shipped from the factory with preset factory defaults. Upon initial power-up, a user check
should be performed to verify the shipped modem configuration. Refer to Section 4, User
Interfaces to locate and verify that the following configuration settings are correct:

Transmit (Tx) and Receive (Rx) Interface types are dependent upon the

Implementing Strap Code 26 can set the following modem configuration.
Refer to Table D-1 for an explanation and tabular listing of available Strap
Codes. The Frequency and Modulator Output Power are set independently

Standard Factory Configuration Settings

Modulator:

Data Rate: 2.048 Mbps
Mode: Closed Network
Satellite Framing: None
Scrambler: V.35 (IESS)
Drop and Insert: Disabled
Inner FEC: 1/2 Rate Viterbi
Outer FEC: Disabled
Modulation: QPSK

Frequency: 70.000000 MHz
Modulator Output Power: -20 dBm

Demodulator:

Data Rate: 2.048 Mbps
Mode: Closed Network
Satellite Framing: None
Scrambler: V.35 (IESS)
Drop and Insert: Disabled
Inner FEC: 1/2 Rate Viterbi
Outer FEC: Disabled
Modulation: QPSK

Frequency: 70.000000 MHz

MN-DMD50– Revision 3 2–4

DMD50 Universal Satellite Modem Installation

To lock up the modem, enter ‘IF Loopback Enable’ under the Test Menu, or connect a Loopback
Cable from J11 to J13 on the rear panel of the modem.

2.5 Modulator Checkout

The following descriptions assume that the unit is installed in a suitable location with prime AC
power and supporting equipment available.

2.5.1 Initial Power-Up

CAUTION

Before initial power up of the unit, it is a good idea to disconnect the
transmit output from the operating ground station equipment. This is
especially true if the current Modulator Configuration Settings are
unknown, where incorrect settings could disrupt the existing
communications traffic. New units from the factory are normally shipped in
a default configuration which includes setting the transmit carrier off.

Turn on the unit by placing the Rear Panel Switch (located above the power entry connector) to
the On Position. Upon initial and subsequent power-ups, the Microprocessor will test itself and
several of its components before beginning its Main Monitor/Control Program. These power-up
diagnostics show no results if successful. If a failure is detected, the Fault LED will illuminate.

The initial field checkout of the modem can be accomplished from the Front Panel or in the
Terminal Mode. The Terminal Mode has the advantage of providing full screen access to all of
the modem’s parameters, but requires a separate terminal or computer running a Terminal
Program. The Terminal Mode is enabled from the front panel in the System M&C Submenus.

MN-DMD50– Revision 3 2–5

DMD50 Universal Satellite Modem Installation

2.5.2 Factory Terminal Setup

The factory terminal setup is as follows:

Emulation Type: VT-100 (can be changed)
Baud Rate: 19.2 K (Can be changed via Front Panel)
Data Bits: 8
Parity: No Parity (Fixed)
Stop Bits: 1 Stop Bit

MN-DMD50– Revision 3 2–6

Chapter 3. Theor y of Operation

3.1 Modem Hardware

The modem is based on a two printed circuit card (minimum configuration) design with
additional optioned printed circuit cards available for additional features. The minimum
configuration consists of an L-Band/IF Assembly and a Digital Baseband Assembly. The
optional printed circuit cards include a Turbo Codec printed circuit card and one of several types
of Interface printed circuit card (refer to Appendix A). A block diagram of the DMD50 is shown
in Figure 3-1.

3.1.1 L-Band/IF Printed Circuit Card

The L-Band/IF Printed Circuit Card consists of an analog modulation function, an analog
complex downconversion, and two wide-band digital synthesizers. The block diagram of the L­Band/IF Assembly is shown in Figure 3-2.

MN-DMD50– Revision 3 3–1

Figure 3-1. Block Diagram

DMD50 Universal Satellite Modem Theory of Operation

In the modulator, analog in-phase (I) and quadrature (Q) signals are generated on the Digital
Baseband Printed Circuit Card, routed to the L-Band/IF Printed Circuit Card, and modulated at
the desired frequency. The L-Band or 70/140 modulated signal is then passed through a
microprocessor controlled variable attenuator providing gain control of the output signal.
In the complex downconverter, the signal for demodulation is amplified and sent through a
variable wideband attenuator for AGC. The gain-controlled signal is then passed through a
complex downconverter to a low IF.

Figure 3-2. IF Card Block Diagram

3.1.2 Baseband Processing Printed Circuit Card

The advent of million-plus gate count FPGAs, advanced logic synthesis tools, and DSPs
providing hundreds of MIPs enabled the design of a software configurable modem. Large, fast
FPGAs now provide designers with what is essentially an on the fly programmable ASIC. High
speed, complex digital logic functions that previously could only be implemented in dedicated
integrated circuits are now downloaded from a micro-controller through a serial or peripheral
interface. When a new digital logic function is needed, a new configuration file is loaded into the
FPGA. There is no limit to the number of digital logic configurations available to the FPGA,
aside from the amount of Flash memory available to the system microprocessor for storage of
configuration files.

The Baseband Processing Printed Circuit Card provides a flexible architecture that allows many
different modes of terrestrial and satellite framing, various FEC options, digital voice processing,
and several different modulation/demodulation formats. Also included on the Baseband Printed
Circuit Card are three synchronous interfaces, an EIA-530 Interface supporting RS-422, V.35,
and RS-232. All three interfaces are provided on the same DB-25 Connector, and are selectable
from the front panel.

MN-DMD50– Revision 3 3–2

DMD50 Universal Satellite Modem Theory of Operation

The Baseband Printed Circuit Card also contains the Monitor and Control (M&C) Circuitry
responsible for:

 Programmable part setup and initialization
 Continuous control and adjustment of some functions
 Calibration
 Monitoring fault status
 Calculating and displaying measurements
 User monitor and control interface including front panel and remote
 Units configura tion and feature set

The M&C System is based on a powerful microprocessor with a large amount of Flash memory.
several bus architectures are used to inter conne ct the M& C to all com ponents of the DMD50.
Communication to the outside world is done via connections to the remote port, terminal port,
Ethernet port, and alarm ports. The M&C runs off of software programmed into its Flash
memory. the memory can be reprogrammed via the Ethernet port to facilitate changes in
software.

3.1.3 Enhanced Interface Printed Circuit Card

The normal terrestrial data for the Baseband Processing Card can be re-routed to the enhanced
interface card. The enhanced interface card adds a variety of connections to the modem for
additional applications

3.2 Functional Block Diagram

Figure 3-3 represents the Functional Blocks. The modem is shown in a typical application with
customer data, Tx/Rx RF equipment and an antenna.

MN-DMD50– Revision 3 3–3

DMD50 Universal Satellite Modem Theory of Operation

Figure 3-3. Universal Satellite Modem Functional Block Diagram

3.2.1 Front Panel

The Front Panel includes a 2 x 16 backlit LCD Display, Indicator LEDs, and a Numeric Keypad
(refer to Chapter 4).

3.2.2 Baseband Processing

The Baseband Processor performs all of the functions required for an IBS/IDR Framing Unit, a
Reed-Solomon Codec, and an E1/T1 Drop and Insert System. In addition, the Baseband
Processing Section provides for transmit clock selection and rate adaptation as well as a rate
adapter and Plesiochronous/Doppler (PD) Buffer in the receive direction. A multiplexer is also
provided for the SCT Clock Source for Loop Timing Applications. The transmit and receive
paths may be configured independently under processor control.

MN-DMD50– Revision 3 3–4

DMD50 Universal Satellite Modem Theory of Operation

3.2.3 Tx Baseband Processing

The Tx Data and Clock enters the Baseband Processor, passes through a Rate Adapting FIFO and
enters the Framer/Drop Processor. In IDR, IBS, and D&I Modes, the framer adds the appropriate
framing and ESC as defined in IESS-308 and 309. In D&I Mode, the framer acquires the
terrestrial framing structure, E1 or T1, and synchronizes the Drop Processor. The Drop Processor
extracts the desired time slots from the terrestrial data stream and feeds these channels back to the
framer. The framer then places the ‘dropped’ terrestrial time slots into the desired satellite
channel slots. The data is then sent to the Reed-Solomon Encoder.

When enabled, the Reed-Solomon Encoder, encodes the data into Reed-S olom on Blocks. The
blocks are then interleaved and synchronized to the frame pattern as defined by the selected
specification (IESS-308, IESS-309, DVB, etc.). After Reed-Solomon Encoding, the composite
data and clock are applied to the BB Loopback Circuit.

3.2.4 Rx Baseband Processing

The Receive Processor performs the inverse function of the Tx Processor. Data received from the
satellite passes through the BB Loopback Circuit to the Reed-Solomon Decoder to the Deframer.
The Deframer acquires the IBS/IDR/DVB frame, synchronizes the Reed-Solomon Decoder and
extracts the received data and overhead from the frame structure, placing the data into the PD
Buffer, sending the overhead data to the UIM. The data is extracted from the buffer and is sent to
the UIM. Backward Alarm indications are sent to the M&C Subsystem. In Drop and Insert
Mode, the Insert Processor synchroniz es to the inc om ing terrestrial T1/E1 Data Stream, extrac ts
satellite channels from the PD Buffer, and then inserts them into the desired terrestrial time slots
in the T1/E1 Data Stream.

3.3 Monitor & Control (M&C) Subsystem

The modems M&C system is connected to most of the circuitry on any board contained in the
modem. These connections provide status on the working condition of the circuitry as well as
providing the data required for the various measurements the modem provides. The M&C
processes this information and generates status indications as well as alarms when necessary.
Detailed status information is available via the modems various user interfaces including the
remote and terminal ports. An external summary fault is available on the RS422 Data interface

The M&C contains a high-performance microprocessor and is responsible for overall command
and control of modem functions. The M&C is constantly monitoring all subsystems of the
modem by performing a periodic poll routine and configures the modem by responding to
commands input to the system. During each poll cycle, the status of each of the subsy stems is
collected and reported to each of the external ports. Performance statistics such as Eb/No, buffer
fill %, etc. are compiled. If faults are detected, the M&C will take approp ri ate acti ons to
minimize the effect of such faults on the system (refer to the Fault Matrices in Chapter 6).

The modem supports the following M&C protocols:

 Terminal Interface (Section 3.2.1)
 Remote Port Interface (Section 3.2.2)
 Ethernet M&C, Web Browser & SNMP (Section 3.2.3)
 Modem Status, Alarms & Contact Closures (Section 3.2.4)

MN-DMD50– Revision 3 3–5

DMD50 Universal Satellite Modem Theory of Operation

3.3.1 Terminal Port

This port supports an asynchronous control protocol as described in Section 4. It is configured to
support RS-232 signal levels. This port is intended for use in computer-based remote M&C. All
functions of the modem may be monitored and controlled from this port via a common terminal
connected to the Terminal Port. This function is front panel selectable.

The Terminal Mode Control allows the use of an external terminal or computer to monitor and
control the modem from a full screen interactive presentation operated by the modem itself. No
external software is required other than VT-100 Terminal Emulation Software (e.g. “Procomm”
for a computer when used as a terminal. The Control Port is normally used as an RS–232
Connection to the terminal device. The RS-232 operating parameters can be set using the modem
Front Panel and stored in Non-volatile memory for future use.

Refer to the Remote Protocol Manual (TM117) for the Terminal, Remote and

SNMP screens and protocols.

3.3.2 Modem Remote Communications (RLLP)

The Remote Port located on J20 allows for control and monitoring of parameters and functions
via an RS-232 Serial Interface, or RS-485 for RLLP Protocol. ‘Equipment Remote Mode’ setup
can be entered from the front panel or the Web Browser interface under the “System” menu. This
requires the user to first set the Remote Port Control to “Remote” then set the Multidrop Address
as needed followed by setting the Remote Interface to RS232 or RS485.

Control and status messages are conveyed between the modem and all subsidiary modems and the
host computer using packetized message blocks in accordance with a proprietary communications
specification. This communication is handled by the Radyne Link Level Protocol (RLLP), which
serves as a protocol ‘wrapper’ for the RM&C data. Complete information on monitor and control
software is contained in the following sections.

3.3.3 Ethernet M&C Port

This port is dedicated for Ethernet Communications supporting SNMP, FTP and Web Browser.
The port is configured for 10 Base-T comm unicat ion s proto col s. The Ethern et M &C Interface
requires a standard RJ45 Male connector. Refer to Appendix D and F for proper setup of the
TCP-IP interface and Web Browser Setup.

MN-DMD50– Revision 3 3–6

DMD50 Universal Satellite Modem Theory of Operation

3.3.4 Modem Monitor Status

The modems M&C system is connected to most of the circuitry on any board contained in the
chassis. These connections provide status on the working condition of the circuitry as well as
providing the data required for the various measurements the modem provides. The M&C
processes this information and generates status indications as well as alarms when necessary.
Detailed status information is available via the modems various user interfaces (front panel,
remote and terminal). A summary of this information can be connected to external equipment,
switches or alarms via the open collector and/or form-C fault connections

Form-C Contacts:

The UIM provides three Form-C Relays under processor control that appear at J15.

Mod Fault: De-energized when any transmit side fault is detected.

Demod Fault: De-energized when any receive side fault is detected.

Common Fault: De-energized when any fault that is not explicitly a Tx or Rx

Fault such as an M&C or Power Supply Fault.

Open Collector Faults:

The UIM provides two Open Collector Faults that appear at Pins 18 & 21 on J19.
Mod Fault: Will sink up to 20 ma (maximum) until a transmit or common

fault is detected. Will not sink current if a fault is detected.

Demod Fault: Will sink up to 20 ma (maximum) until a receive or common

fault is detected. Will not sink current if a fault is detected.

The open collector faults are intended for use in redundancy switch applications in order to
provide quick status indications.

3.4 Async Port / ES-ES Communications

This port is dedicated for ES-ES Communications supported by either RS232 or RS485 signal
levels. The baud rate and protocol can be selected from the Front Panel. The port may be
configured for a number of communications protocols. Overhead data to/from the UIM is routed
to/from the framer/deframer. This port is also used by SCC Framing for the in-band data.

3.5 Internal Clock

The time and date is kept in order to ‘time-tag’ system events. User can change the Internal
Clock via the front panel, Web Browser or Terminal ports.

MN-DMD50– Revision 3 3–7

DMD50 Universal Satellite Modem Theory of Operation

3.6 Loopback Features (Terrestrial & IF)

The modem provides for a number of different loopbacks. The Loopback supported are:

 IF Loopback – Tx IF port is looped back to the Rx IF port
 TX Terrestrial Loopback - Tx Data port is looped back to the Rx Data port after the

interface driver/receiver. (prior to the framing unit)

 TX Baseband Loopback - Tx Data port is looped back to the Rx Data port after the

interface driver/receiver. (after the fraiming unit)

 RX Terrestrail Loopback - Receive Data from the satellite is looped back for retransmission

to the satellite, providing a far end loopback. (prior to the framing unit)

 RX Baseband Loopback - Receive Data from the satellite is looped back for retransmission

to the satellite, providing a far end loopback. (after to framing unit)

 TX/RX Terrestrial Loopback - provides both Terrestrail loopbacks simultaneously
 TX/RX Baseband Loopback - provides both Baseband loopbacks simultaneously

Usage of the modems loopback capabilities in conjunction with the Ethernet

data interface can produce undersirable network loops. In order to run any

type of data test with an Ethernet interface you must utilize two modems

connected back to back. Simply using one modem and a loopback will not

produce the desired results.

MN-DMD50– Revision 3 3–8

DMD50 Universal Satellite Modem Theory of Operation

MN-DMD50– Revision 3 3–9

Figure 3-4. Loopback Functional Block Diagram

DMD50 Universal Satellite Modem Theory of Operation

Figure 3-5. Loopback Functional Block Diagram

MN-DMD50– Revision 3 3–10

Figure 3-6. Loopback Functional Block Diagram

DMD50 Universal Satellite Modem Theory of Operation

SD

TT

Tx CLK

SRC

High Stability

Oscillator

ST

CLOCK &

DATA

EXT REF

EXTERNAL

INTERNAL

SCT CLK

SRC

REF FREQ

SRC

SCT

SCTE

TRANSMIT

RECEIVE

CLOCK & DATA

RECOVERY

EXT CLK

EXT BNC
SCT
SCTE
RX SAT

RT

RD

SCR

BUFFER CLK

SRC

CLOCK

RECOVERY

EXT IDI

IDI

MODULATION

HIGH STABILITY

DEMODULATION

J19

J19

J10

J16

J8

CLK POL

DATA POLARITY

NORMAL
INVERTED
AUTO

INV. TERR&BASE

INVERT NONE

INV. BASEBAND
INV. TERR DATA

DATA POLARITY

BUFFER CLK POL

NORMAL
INVERTED

INV. TERR&BASE

INVERT NONE

INV. BASEBAND
INV. TERR DATA

3.7 Clocking Options

The modem supports a number of different clocking options that can be recovered from the
satellite or the terrestrial links. The various clocking options allow users to determine which
clock will best fit their applications. Figure 3-7 gives an overview on how the modem processes
the various clocks for the Tx Clock source and the Rx Buffer Clock source. Tx and Rx Clocks
may be independently locked.

3.7.1 TX Clock Options

TX clock options can be recovered from the terrestrial interface, satellite interface or internally

MN-DMD50– Revision 3 3–11

generated. The allows users to select SCTE Clock (Terrestrial) or the SCT internal clock. The
modem also allows user to recover the SCT Clock from the satellite (SCR) or from the modem
internally. The modem allows users to select clock polarity. The Tx clock selections available
are:

Figure 3-7. Clocking and Polarity Diagram

DMD50 Universal Satellite Modem Theory of Operation

The following paragraphs define the types of clocking options available to the user at the Front
Panel.

 SCT (Internal Oscillator)
 SCTE (External Tx Te rr es t rial Clock)
 Rx Satellite Clock

3.7.1.1 SCTE: Serial Clock Transmit External

The SCTE clock is the Transmit Terrestrial Clock associated with the data interface. SCTE is an
external clock received from the terrestrial equipment and the modem utilizes the terrestrial clock
to lock the internal clock.

In Figure 3-9, the Transmit Terrestrial Data enters the modem and is clocked into a dejitter FIFO.
Data is clocked out of the FIFO by the Modulator Clock. The Modulator Clock and Phase­Locked Loop (PLL), in conjunction with the Dejitter FIFO, which reduces the input jitter. Jitter
reduction exceeds the jitter transfer specified in CCITT G.821.

SCTE is sometimes referred to as Tx Terrestrial Timing or Terminal Timing. Terminal Timing is
reference to the RS422 synchronous interfaces.

3.7.1.2 SCT: Serial Clock Transmit

The SCT clock can be generated internally or recovered from the satellite. The SCT clock source
can be used as the TX clock source, RX Buffer Clock source and the Terrestrial Terminal
equipment for clocking the transmit data. If the SCT clock is recovered from the satellite, then it
is referred to as SCR. SCR is also referred to as Receive Clock, Satellite Clock, or Receive
Timing (RT).

When SCT clock is configured as Internal, the frequency of the clock is set the same as the
Transmit Terrestrial Clock rate. If SCT clock is configured as SCR, the internal clock is set to the
same rate as the incoming receive satellite clock. SCT is sometimes referred to as Internal
Timing or Send Timing (ST). In the event that the satellite clock is lost, the modem will
automatically switch over to the Internal Clock and revert back to SCR when activity is detected.

If SCT is selected, then Terrestrial data that is synchronous to the SCT Clock is required to be
supplied by the modem. It is intended for the terminal equipment to use the SCT as its clock
source. The Autophase Circuit will automatically ensure that the data is clocked correctly into
the modem. Therefore, a return clock is not necessary. The Clock Polarity should be set to Auto.

3.7.2 RX Buffer Clock Options

The modem supports a number of RX Buffer clock options that can be recovered from the
satellite, terrestrial links, internally or externally. The various clocking options allow users to
determine which clock will best fit their applications. Figure 3-7 gives an overview on how the
modem processes the various clocks for the Tx Clock and the Rx Buffer Clock. The modem
allows users to select clock polarity Tx and Rx Clocks may be independently locked. The
following RX Buffer clock selections are available:

 Rx Satellite Clock (Recovered from Satellite)
 SCTE (External Tx Te rr es t rial Clock)
 SCT (Internal Oscillator)

MN-DMD50– Revision 3 3–12

DMD50 Universal Satellite Modem Theory of Operation

 EXC Clock/EXT BNC (External Clock Source)
 EXT IDI (Drop and Insert)

The modem handles RX Buffer clock selections based on source priority levels. The user assigns
priorities to the clock sources based on source selections. Source 1 has the highest priority and
Source 5 being the last resort or lowest priority. If a fallback clock is selected and activity is lost
at the highest priority source, the modem will fall back to the next highest p r ior ity clock with
activity. When activity resumes on a higher priority source, the modem resumes using the higher
priority source

Clock Source Priority

RX SAT 1 of 5
SCTE 2 of 5
SCT 3 of 5
EXC BNC 4 of 5
EXT IDI 5 of 5

Refer to Front panel setup menus or Web Browser manual MN-DMDREMOTEOP

3.7.2.1 RX SAT Clock

The RX Sat clock is recovered from the satellite that is received from the distant end. If selected
the Buffer Clock is lock to the RX sat clock.

3.7.2.2 SCTE: Serial Clock Transmit External

When SCTE is selected as the Rx Buffer clock, the modem receives the clock from the Transmit
Terrestrial interface.

3.7.2.3 SCT: Serial Clock Transmit

If SCT clock is selected as the RX Buffer clock source, then it should be configured for internal.
SCT is sometimes referred to as Internal Timing or Send Timing (ST).

3.7.2.4 EXT CLK/EXT BNC: External Clock, J16

The External Clock that can be selected as the RX Buffer clock source. This is a 75ohm
unbalanced BNC connector. This clock source is also identified as EXT BNC. The External
Clock is often used as the station master clock. The RX Clock selection can be accessed in the
INTERFACE/RX SETUP menu. The clock frequency, EXT FREQ can be selected, in the
Interface/General Menu.

Clock specification:

Frequency: 1 MHz to 20 MHz

Level: 0.3 Vp-p to 5 Vp-p (Sine or Square wave)

MN-DMD50– Revision 3 3–13

DMD50 Universal Satellite Modem Theory of Operation

3.7.2.5 EXT IDI: Insert Data In

External IDI is used only for E1/T1 Drop and Insert applications. The available T1/E1 Frame
Source selections are External, Internal, and IDI/DDO Loopback. The T1/E1 Frame Source
selections can be accessed in the INTERFACE/RX SETUP menus. If Ext IDI is selec ted as the
RX Buffer clock, then user must first specify T1/E1 Frame Source.

 External (RX Buffer Clock recovered from the data)
 Internal (RX Buffer Clock recoverd from the internal clock)
 IDI/DDO Loopback (RX Buffer Clock recoverd from the data and looped back)

3.7.3 EXT REF: External Reference, Top BNC Port, J10

This is not actually a clock, but does have some clocking implications. When the external
reference is used, the master oscillator within the modem is locked to the external reference, and
the internal accuracy and stability of the unit assumes that of the External Reference. Therefore,
not only are the transmit frequencies locked to the external reference, but the modem’s internal
SCT Oscillator is locked to the external reference as well.

External reference port input is specified at

.3Vpp to 5Vpp (Sine or Square wave)

3.8 RS530/422/V.35 Interface (Standard)

Data must be clocked into the modem by either the SCTE or SCT Source. If SCTE is selected as
the Tx Clock Source, then SCTE must be supplied to the modem on the EIA-530 port. The output
of the dejitter buffer will be clocked with this source. SCT should be used if SCTE has excessive
jitter.

3.8.1 G.703 Interface (Optional)

If the G.703 Interface is selected, then the Tx Clock Source will default to SCTE and the Clock
Polarity will default to Auto.

Loop timing with a G.703 Interface or Asymmetrical Data Rates requires external equipment at
the remote end that is capable of using the recovered RD Clock as source timing for (SCTE) SD.
The modem will not manipulate the clock frequency. Therefore, the transmit and receive clock
rates must be equal in order for the modem to perform loop timing.

MN-DMD50– Revision 3 3–14

DMD50 Universal Satellite Modem Theory of Operation

3.8.2 HSSI Interface (Optional)

If the HSSI Interface is selected, then the Tx Clock Source will default to SCTE and the Clock
Polarity will default to Auto.

3.8.3 Ethernet Data Interface (Optional)

If the Ethernet Data Interface is selected, then the Tx Clock Source will default to SCTE and the
Clock Polarity will default to Normal.

If the Ethernet Data Interface is selected, then the Buffer Clock will default to RxSat and the
Buffer Clock Polarity will default to Normal.

3.9 Reed-Solomon Codec

Refer to Figure 3-8, Figure 3-9, and Table 3-1.

Utilizing a Reed-Solomon (R-S) Outer Codec concatenated with a Convolutional Inner Codec is
an effective way to produce very low error rates even for poor signal-to-noise ratios while
requiring only a small increase in transmission bandwidth. Typically, concatenating an R-S
Codec requires an increase in transmission bandwidth of only 9 – 12% while producing a greater
than 2 dB improvement in E

b/No

encoder which adds 2t = (N – K) check bytes to produce an N byte R-S block. The R-S decoder
can then correct up to “t” erred bytes in the block.

3.9.1 Reed-Solomon Operation

When the Reed-Solomon Codec is enabled, data is fed to the R-S Encoding Section where it is
scrambled, formed into blocks, R-S encoded, and interleaved. Unique words are added so that
the blocks can be reformed in the Receiving Modem (Refer to Figure 3-8 and Figure 3-9). Data
is then sent to the modulator where it is convolutionally encoded, modulated and transmitted to
the satellite.

When the signal is received and demodulated by the Receiving Modem, it is fed to a Viterbi
Decoder for the first layer of error correction. After error correction is performed by the Viterbi
Decoder, the unique words are located and the data is deinterleaved and reformed into blocks.
The R-S Decoder then corrects the leftover errors in each block. The data is then descrambled
and output from the R-S Section.

. R-S is a block Codec where K data bytes are fed into the

MN-DMD50– Revision 3 3–15

DMD50 Universal Satellite Modem Theory of Operation

Bandwidth

1 ]

64

(126, 112, 7)

0.125

4

115

3.9.2 Reed-Solomon Code Rate

The R-S Code Rate is defined by (N, K) where N is the total R-S block size in bytes - data +
check bytes - and K is the number of data bytes input into the R-S Encoder. The transmission
rate expansion required by the R-S Codec is then defined by N/K. The modem automatically sets
the correct R-S code rate for IDR/IBS open network operation in accordance with the data shown
in Table 3-1. The modem allows the following N and K setting: (126, 112), (219, 201), (194,

178), (225, 205).

Variable Reed-Solomon rates are available on the optional AS/5167 Super Card. Refer to
Appendix A for further information.

3.9.3 Interleaving

Iinterleaving depths of 4, 8, or 12 R-S blocks are allowed. This allows burst errors to be spread
over multiple blocks in order to enhance the error correcting performance of the R-S Codec. For
Intelsat Network Modes, the interleaving depth is automatically set to 4 for QPSK or BPSK, or 8
for 8PSK. In Closed Network Mode, the interleaver depth can be manually set to 4 or 8, and in
DVB Network Mode, the interleaver depth is automatically set to 12.

Type of Service

Small IDR

(With 16/15

O/H)

Figure 3-8. Reed-Solomon Encoder Functional Block Diagram

Figure 3-9. Reed-Solomon Decoder Functional Block Diagram

Table 3-1. Reed-Solomon Codes

Data Rate

(Kbps)

128
256
384
512
768

R-S Code

(n, k, t) 1

(126, 112, 7)
(126, 112, 7)
(126, 112, 7)
(126, 112, 7)
(126, 112, 7)

Expansion [ (n/k) -

0.125

0.125

0.125

0.125

0.125

Interleaving

Depth

4
4
4
4
4

Maximum 2 R-S

Codec Delay (ms)

58
29
19
15
10

MN-DMD50– Revision 3 3–16

DMD50 Universal Satellite Modem Theory of Operation

1024
1536

(126, 112, 7)
(126, 112, 7)

0.125

0.125

4 4 8

5

(225,

(194, 178, 8)

1544

8448

(219, 201, 9)

(219, 201, 9)

0.0896

0.0896

8

8

18

3

DVB

All

(204, 188, 8)

0.0851

12

-

1. n = code length, k = information symbols and t = symbol error correcting capability.

2. Design objective.

Baud Rate Example for

Baud Rate Example for

128

64

9.6

300

256

128

19.2

600

384

192

32

600

512

256

64

1200

640

320

128

2400

768

384

192

4800

4
4
4
4

8
8

IDR (With

96 Kbps O/H)

8PSK

1544
2048
6312
8448

2048
6312

205,10)
(219, 201, 9)
(194, 178, 8)

(219, 201, 9)
(219, 201, 9)

0.0976

0.0896

0.0899

0.0899

0.0896

0.0896

3.10 Asynchronous Overhead Operation (Framing/Multiplexer Capability)

The Asynchronous Framing/Multiplexer is capable of multiplexing a relatively low-speed
overhead channel onto the terrestrial data stream resulting in a slightly higher combined or
aggregate data rate through the modem. The overhead channel is recovered at the far end. This
added channel is termed variously “An Overhead Channel”, ”Service Channel”, “Async Channel”
or in IESS terminology an “ES to ES Data Channel.” The basic frame structure used by the
multiplexer is th a t specified in the IESS-309 Standard, resulting in a 16/15 Aggregate ratio of
overhead & data to data rates.

For Regular Async: (Standard IBS), the Baud Rate is approximately 1/2000 of the

Data Rate listed in Table 3-3.

For Enhanced Async: (IBS Async.), the Baud Rate is selectable, but Data Rate is

limited.

The maximum Baud Rate is 19,200 bps for IBS Async. Two software-controlled modes are
designed into the card to best utilize the available bits; “Standard IBS” and “IBS (Async)”. The
characteristics of the Channel Interface is also determined by the standard or Async mode.

The Async Channel can be set under software-control to either RS-232 or RS-485 mode. The pin
assignments for both modes are shown in Table 5-3.

The “RS-485” Setting controls the output into tri-state when the modem is not transmitting data,
allowing multiple modem outputs to be connected together.

9
7
2

<2

13

4

Table 3-2. Baud Rate Examples for Standard IBS and Enhanced Mode

Kbps

Standard IBS

MN-DMD50– Revision 3 3–17

Kbps

Enhanced Mode

DMD50 Universal Satellite Modem Theory of Operation

Baud Rate Example for

Standard IBS

Baud Rate Example for

Enhanced Mode

896

448

256

4800

1024

512

320

9600

1152

576

384

9600

1280

640

448

9600

1408

704

512

9600

1536

768

576

9600

1664

832

640

19200

1792

896

704

19200

1920

960

768

19200

1920

960

768

19200

2048

1024

832

19200

896

19200

960

19200

1024

19200

1088

19200

1152

19200

1216

19200

1280

19200

1344

19200

1408

19200

1472

19200

1536

19200

1600

19200

1664

19200

1728

19200

1792

19200

1856

19200

1920

19200

1984

19200

2048

19200

This bit is routed directly to the ES to ES Data Channel.

Kbps

Kbps

3.11 Standard IBS Mode

In the first or “Normal” mode, all bit assignments are per the IBS standard. The bits of Overhead
Housekeeping byte 32 are implemented as shown in Table 3-3 below:

Table 3-3. Bits of Overhead Housekeeping

Bit 1

Bit 2
Bit 3

MN-DMD50– Revision 3 3–18

ES to ES Data
Channel

Frame Alignment Part of the Frame Alignment word.
Backward Alarm Transmit and Receive with main processor to activate

Its data rate is 1/512th of the aggregate rate (or 1/480th of
the through terrestrial data rate), and is normally used to
super-sample an asynchronous data channel.

Main Alarm/LED.

DMD50 Universal Satellite Modem Theory of Operation

Bit 4

Multiframe Message As per IBS.

Bits 5 and 6
Bits 7 and 8

Spare Not currently utilized.
Encryption

Not currently utilized.

Utilization

The ratio of the Through Terrestrial Data Channel Rate to the aggregate rate is 15/16. The
standard transmit and receive channels of the ES to ES Data Channel in Standard IBS Mode are
raw channels operating at the specific bit rate as controlled by the data channel rate, without
buffering. In addition, no clocks are provided with this channel. Since it would be rare that the
data rate provided was exactly that required for a standard rate device, the only method of
communicating using this channel is to allow it to super-sample the user data.

3.12 Asynchronous Multiplexer Mode

Since many of the frame bits in the standard IBS mode are not used, an “Enhanced” Multiplexer
Mode has been implemented that can be engaged under software control. Since this mode
changes the use of many of the framed non-data bits, this mode is only usable when the DMD50
is at both ends of a link.

In this mode, the overhead signaling bytes 16 and 48 can be used to implement a significantly
higher speed ES to ES Data Channel under software control. When implemented, this rate is 16
times that of the normal IBS standard, or 1/30
rate).

th

of the terrestrial data rate (1/32nd of the aggregate

The IBS Async mode MUST be selected for true Asynchronous channel
operation to be available.

3.13 ESC Backward Alarms

When running in IDR Mode and if the modem has the ESC Option, there will be four Backward
Alarms available for use by the earth stations at each end of the link (both ends must have the
ESC option). These alarms are accessed via the ESC ALARMS Port. The four alarms are
controlled by four relays, each having a normally open, normally closed, and a common
connection. The common connections of these relays (referred to as Backward Alarm Inputs) can
be connected to whichever system on the earth station that the user wishes to trigger the backward
alarm.

When ground is applied to the Common (Input) Connection of one of these relays, that relay and
associated backward alarm will then be in a “no fault” state. When the ground is removed, the
relay and the associated Tx Backward Alarm will toggle to the faulted state. When in the faulted

MN-DMD50– Revision 3 3–19

DMD50 Universal Satellite Modem Theory of Operation

state, the receive end of the link will receive that backward alarm that is initiated at the transmit
end of the link.

The user can connect whichever systems on the earth stations that they desire to these Backward
Alarms Relays as long as they will supply ground to the Backward Alarm Relay Input in the “no
fault” condition and the ground will be removed in the “faulted” condition.

For example: the user could connect the Demod Summary Fault of the modem to the Backward
Alarm 1 Input, so that if the demod went into Major Alarm (such as a Carrier Loss), Backward
Alarm 1 would be transmitted to the receive end of the link. At the receive end, it would show up
as Rx Backward 1 (Receive Backward Alarm 1).

3.13.1 To Disable the ESC Backward Alarms

If the ESC ALARMS Port will not be used and the Backward Alarm Indications are to be
disabled, you must connect pins 10, 11, 22 and 23 to pin 1 (gnd) on ESC Alarms port.

MN-DMD50– Revision 3 3–20

DMD50 Universal Satellite Modem Theory of Operation

ENSURE THAT THE LINK IS ROBUST ENOUGH

AND ALL

3.14 DoubleTalk Carrier-in-Carrier Option

B E FOR E ATT E MP TING TO COMMIS S ION A S ATE L L ITE L INK US ING C AR R IE R ­IN-CARRIER, THE USER

MUST

FOR NOR MAL OP E R ATION. ONL Y WHE N THIS HAS B E E N DONE –
SYSTEM ISSUES (E.G., ANTENNA-POINTING, C AB LING, TE R R E S TR IAL
INTE R FERENCE, SATELLITE INTERFERENCE, ETC.) HAVE BEEN
SHOULD THE USER ATTEMPT THE USE OF CARRIER-IN-CARRIER.

Space segment costs are typically the most significant operating expense for any satellite-based
service, having a direct impact on the viability and profitability of the service. For a satellite
transponder that has finite resources in terms of bandwidth and power, the leasing costs are
determined by bandwidth and power used. Therefore, a satellite circuit should be designed for
optimal utilization to use a similar share of transponder bandwidth and power.

The traditional approach to balancing a satellite circuit – once the satellite and earth station
parameters are fixed – involves trade-off between modulation and coding. A lower order
modulation requires less transponder power while using more bandwidth; conversely, higher order
modulation reduces required bandwidth, albeit at a significant increase in power.

RE SOLVED –

Comtech EF Data has added a new dimension to satellite communication optimization: DoubleTalk
Carrier-in-Carrier.

3.14.1 What is DoubleTalk Carrier-in-Carrier?

The Radyne DMD50 DoubleTalk Carrier-in-Carrier option utilizes a patented (US 6,859,641)
signal processing algorithm developed by Applied Signal Technology, Inc. that allows both the
forward and reverse carriers of a full duplex link to share the same segment of transponder
bandwidth, using patented “Adaptive Cancellation.” Applied Signal uses the term DoubleTalk™,
and Comtech EF Data refers to it as DoubleTalk

CnC was first introduced in Comtech EF Data products in the CDM-Qx Satellite Modem and,
more recently, in the CLO-10 Link Optimizer.

The implementation of DoubleTalk Carrier-in-Carrier in the Radyne DMD50 has been further
refined, and some of the limitations that existed in the CDM-Qx implementation have been
overcome.

This innovative technology provides a significant improvement in bandwidth and power
utilization, beyond what is possible with FEC and modulation alone, allowing users to achieve
unprecedented savings. When combined with advanced modulation and FEC, it allows for multi­dimensional optimization:

• Reduced operating expense (OPEX) – e.g., Occupied Bandwidth & Transponder Power;

Carrier-in-Carrier (CnC).

• Reduced capital expenditure (CAPEX) – e.g., Block Up Converter/High-Power Amplifier

(BUC/HPA) size and/or antenna size;

• Increased throughput without using additional transponder resources;

• Increased link av ailab ili ty (margin) without u sing additional transpond er resou rces;

• A combination of any of the above to meet different objectives.

Summary: When carriers share common bandwidth, up to 50% savings in transponder
utilization is possible.

MN-DMD50– Revision 3 3–21

DMD50 Universal Satellite Modem Theory of Operation

3.14.2 Application Requirements

The following conditions are necessary in order to operate DoubleTalk Carrier-in-Carrier:

• Link must be full duplex.

• A Radyne DMD50 must be used at the end of the link where the cancellation needs to

take place.

• The transponder is operated as Loopback. That is, each end of the link must be able to see

a copy of its own signal in the return (downlink) path from the satellite. The looped back
signal is then subtracted which leaves the signal from the distant end of the link.

DoubleTalk Carrier-in-Carrier cannot be used in spot beam systems.

• The transponder needs to be “bent-pipe” – meaning no on-board processing, demodulati on,

regeneration can be employed. Demodulation/remodulation does not preserve the linear
combination of the forward and return signals and the resulting reconstituted waveform
prevents recovery of the original constituent sig nals.

Figure 3-1 shows a simplified conceptual block diagram of CnC processing. The two ends of the
link are denoted A and B and the uplink and downlink are shown.

This performance is achieved through advanced signal processing algorithms that provide
superior cancellation while tracking and compensating for the following common link
impairments:

1) Time varying delay: In addition to the static delays of the electronics and the round-trip

delay associated with propagation to the satellite and back, there is a time-varying
component due to movement of the satellite. The CnC module tracks and compensates
for this variation.

2) Frequency offset and drift: Common sources are satellite Doppler shift, up and down

converter frequency uncertainties, and other drift associated with the electronics in the
Radyne DMD50 itself. The CnC module tracks and compensates for this frequency offset and
drift.

3) Atmospheric effects: Fading and scintillation can affect amplitude, phase, and spectral

composition of the signal and the degree to which it correlates with the original signal.
The CnC module tracks and compensates for these atmospheric re lated im pai rments.

MN-DMD50– Revision 3 3–22

DMD50 Universal Satellite Modem Theory of Operation

DMD50 Modem

DMD50 Modem Module

4) Link Asymmetries: Various asymmetries in the forward and return link can produce

differences in the relative power of the two received signal components. These can be
both deterministic (static) or random (and time varying). An example of the former would
be the differences resulting from antenna size/gain variations between the two ends of the
link. An example of the latter would be transient power differences due to different levels
of atmospheric fading in the uplinks. CnC compensates for the asymmetries, up to a
certain extent.

Figure 3-10. Conceptual Block Diagram

In a number of ways, CnC carriers behave similar to conventional carriers in satellite links. They
are both exposed to adjacent carriers, cross-polarization and rain fade, and exhibit impairments
when any of these become too great. In addition, CnC operates in an environment where:

• Carriers intentionally occupy the same spectral slot;

• Performance depends upon desired and co-located interfering carrier.

MN-DMD50– Revision 3 3–23

DMD50 Universal Satellite Modem Theory of Operation

3.14.3 Operational Recommendations

The rules for CnC operation are summarized below:

• Both earth stations share the same footprint so each sees both carriers;

• CnC carriers are operated in pairs;

• One outbound with multiple return carriers is not allowed;

• Asymmetric data rates are allowed (no rest ric tions );

• The ratio of power spectral density is normally less than 11 dB;

• CnC operates with modems – not modulators only or demodulators only.

In addition, to minimize ‘false’ acquisition, observe the following:

• Use of IESS-315 V.35 Scrambler is highly recommended;

• Keep the search delay range as narrow as possible – once the modem has reported the

search delay, narrow the search delay range to the nominal reported value +/- 5 ms – for
example, if the modem reported delay is 245 ms, narrow the search range to say 240 –
250 ms.

• Use external data source (e.g. Firebird) or internal BER tester when testing Carrier-in-

Carrier performance.

• To prevent self-locking in case the desired carrier is lost, it is recommended that the two

carriers have some configuration difference – for example, use different settings for
Spectrum Inversion.

MN-DMD50– Revision 3 3–24

DMD50 Universal Satellite Modem Theory of Operation

DMD50 Satellite Modem

DMD50 Satellite Modem

3.14.4 System Functionality and Operational Considerations

Figure 3-2 illustrates a conventional, full duplex satellite link where two carriers are placed in

non-overlapping channels.

Figure 3-11. Conventional FDMA Link

Figure 3-3 shows the same link using the Radyne DMD50 equipped with the DoubleTalk

Carrier-in-Carrier option. Note that now only 50% of the bandwidth is being used, as now both
carriers are occupying the same bandwidth.

The transponder downlinks the composite signal containing both carriers on the same band to the
Radyne DMD50 which then translates the signal to near baseband where it can be filtered
(decimated) and then processed as a complex envelope signal. The Radyne DMD50 then
suppresses the version of the near end carrier on the downlink side and then passes the desired
carrier to the demodulator for normal processing.

To further illustrate, as shown in Figure 3-4, without DoubleTalk Carrier-in-Carrier, the two
carriers in a typical full duplex satellite link are adjacent to each other. With DoubleTalk Carrier­in-Carrier, only the composite signal is visible when observed on a spectrum analyzer. Carrier 1
and Carrier 2, shown here for reference only, are overlapping, thus sharing the same spectrum.

The Radyne DMD50 CnC module operates on the near-zero sign a l before the demodul ator, a n d is
waveform agnostic. This means that no prior knowledge of the underlying modulation, FEC, or
any other waveform specific parameter is required in order to perform the signal suppression
operation. The only caveat to this is that the waveform must be sufficient ly ra ndom.

MN-DMD50– Revision 3 3–25

DMD50 Universal Satellite Modem Theory of Operation

DMD50 Satellite Modem

DMD50 Satellite Modem

Figure 3-12. Same Link Using Radyne DMD50 and DoubleTalk

Carrier-in-Carrier

Traditional Full Duplex Link Duplex Link with DoubleTalk Carrier-in-Carrier

Figure 3-13. Duplex Link Optimization

Because acquiring the delay and frequency offset of the interfering carrier is fundamentally a
correlation operation, anything deterministic in the interfering carrier (within the correlation
window of the algorithm) will potentially produce false correlation peaks and result in incorrect
delays and/or frequency. Normally, this is not a problem, since energy dispersal techniques are
utilized in the vast majority of commercial and military modems. However, it is something that
must be kept in mind when troubleshooting a system that utilizes the DoubleTalk Carrier-in­Carrier technique for signal suppression.

One possible way to mitigate false peaks is to narrow the correlation window. For example, if the
delay is known to be around 240ms, set the minimum search delay to 230ms and the maximum
search delay to 250ms.

As all advances in modem technologies – including advanced modulation and FEC techniques –
approach their theoretical limits of power and bandwidth efficiencies, DoubleTalk Carrier-in­Carrier allows satellite users to achieve spectral efficiencies (bps/Hz) that cannot be achieved

MN-DMD50– Revision 3 3–26

DMD50 Universal Satellite Modem Theory of Operation

Spectral Efficiency (bps/Hz)

Traditional

SCPC

BPSK 1/2

0.50

1.00

QPSK 1/2

1.00

2.00

QPSK 2/3

1.33

2.67

QPSK 3/4

1.50

3.00

QPSK 7/8

1.75

3.50

8-QAM 2/3

2.00

4.00

8-QAM 3/4

2.25

4.50

8-QAM 7/8

2.63

5.25

16-QAM 3/4

3.00

6.00

16-QAM 7/8

3.50

7.00

with modulation and FEC alone. Table 3-1 illustrates how DoubleTalk Carrier-in-Carrier, when
used with 16-QAM, approaches the bandwidth efficiency of 256-QAM (8bps/Hz).

Table 3-4. Spectral Efficiency using DoubleTalk Carrier-in-Carrier

Modulation

and Code Rate

Carrier-in-Carrier

As shown here, DoubleTalk Carrier-in-Carrier allows equivalent spectral efficiency using a lower
order modulation and/or FEC Code Rate; CAPEX is therefore reduced by allowing the use of a
smaller BUC/HPA and/or antenna. And, as DoubleTalk Carrier-in-Carrier can be used to save
transponder bandwidth and/or transponder power, it can be successfully deployed in bandwidth­limited as well as pow e r-limited scenarios.

3.14.5 DoubleTalk Carrier-in-Carrier Cancellation Process

The state-of-the-art signal processing technology employed via DoubleTalk Carrier-in-Carrier
continually estimates and tracks all parametric differences between the local uplink signal and its
image within the downlink. Through advanced adaptive filtering and phase locked loop
implementations, it dynamically compensates for these differences by appropriately adjusting the
delay, frequency, phase and amplitude of the sampled uplink signal, resulting in excellent
cancellation performance.

When a full duplex satellite connection is established between two sites, separate satellite
channels are allocated for each direction. If both directions transmitted on the same channel, each
side would normally find it impossible to extract the desired signal from the aggregate due to
interference originating from its local modulator. However since this interference is produced
locally, it is possible to estimate and remove its influence prior to demodulation of the data
transmitted from the remote location.

For the DoubleTalk Carrier-in-Carrier cancellation, it is necessary to provide each demodulator
with a copy of its local modulator’s output.

MN-DMD50– Revision 3 3–27

DMD50 Universal Satellite Modem Theory of Operation

Figure 3-14. DoubleTalk Carrier-in-Carrier Signals

Referri ng to Figure 3-5: Modem 1 and Modem 2 transmit signals S1 and S2 respectively. The

satellite receives, translates, and retransmits the composite signal. The downlink signals S1* and
S2*, received at Modem 1 and Modem 2 differ from the transmit signals primarily in terms of
phase, frequency, and delay offsets.

Referring to Figure 3-6: For round trip delay estimation, a search algorithm is utilized that
correlates the received satellite signal to a stored copy of the local modulator’s transmitted signal.
The interference cancellation algorithm uses the composite signal and the local copy of S1 to
estimate the necessary parameters of scaling (complex gain/phase), delay offset and frequency
offset. The algorithm continuously tracks changes in these parameters as they are generally time­varying in a satellite link.

Figure 3-15. Carrier-in-Carrier S ignal Process ing Block Dia gra m

The resulting estimate of the unwanted interfering signal is then subtracted from the composite
signal. In practical applications, the estimate of the unwanted signal can be extremely accurate.
Unwanted interfering signal suppression of 30 dB or more has been achieved in commercial
products with minimal degradation of the demodulator performance.

MN-DMD50– Revision 3 3–28

DMD50 Universal Satellite Modem Theory of Operation

Modulation

Nominal Margin*

BPSK

0.3 dB

QPSK/OQPSK

0.3 dB

8-PSK

0.5 dB

8-QAM

0.4 dB

16-QAM

0.6 dB

* Equal power and equal symbol rate
for the interfering carrier and the

Adjacent Carriers, 1.3 spacing.

3.14.6 Margin Requirements

Typical interfering signal cancellation is 28 to 35 dB (depending on the product). The residual
interfering signal appears as noise causing a slight degradation of the Eb/No. To compensate for
the residual noise, a small amount of additional link margin is required to maintain the BER.
Margin requirements depen d on the product, modulation and power ratios:

For the Radyne DMD50, the additional margin requirements are as follows:

desired carrier, i.e., 0 dB PSD ratio.
Measured at IF with AWGN, +10 dBc

3.14.7 Carrier-in-Carrier Latency

Carrier-in-Carrier has no measurable impact on circuit latency.

3.14.8 Carrier-in-Carrier and Adaptive Coding and Modulation

Carrier-in-Carrier is fully compatible with VersaFEC Adaptive Coding and Modulation (ACM)
mode of operation in the Radyne DMD50.

Carrier-in-Carrier combined with VersaFEC ACM can provide 100 – 200 % increa se in averag e
throughput.

3.14.9 Carrier-in-Carrier Link Design

Carrier-in-Carrier link design involves finding the FEC and modulation combination that
provides optimal bandwidth utilization. Just like conventional link design, it is an iterative
process that involves trying different FEC and modulation combinations with Carrier-in-Carrier
until an optimal combination is found.

For optimal Carrier-in-Carrier performance, it is recommended that the two carriers have similar
symbol rate and power. This can be achieved by selecting appropriate MODCODs as shown in
following sections.

MN-DMD50– Revision 3 3–29

DMD50 Universal Satellite Modem Theory of Operation

Satellite & Transponder

Galaxy 18 @ 123º W, 13K/13K

Earth Station 1

Phoenix, AZ – 4.6 m

Earth Station 2

Phoenix, AZ – 2.4 m

Data Rate

512 kbps / 512 kbps

3.14.9.1 Symmetric Data Rate Link

Consider the following example:

The traditional link was based on QPSK TPC 3/4 and required 0.96 MHz of leased BW. The

1

LST

summary for the traditional link is as follows:

Carrier-in-Carrier link design involved trying different Modulation & FEC Code Rates to find the
optimal combination:

• 8-QAM, LDPC 2/3 with Carrier-in-Carrier

• QPSK, LDPC 3/4 with Carrier-in-Carrier

• QPSK, LDPC 2/3 with Carrier-in-Carrier

• QPSK, LDPC 1/2 with Carrier-in-Carrier

1

LST is Intelsat’s Lease Transmission Plan Program.

MN-DMD50– Revision 3 3–30

DMD50 Universal Satellite Modem Theory of Operation

Link parameters and LST summary for QPSK, LDPC 2/3 with Carrier-in-Carrier is as follows:

MN-DMD50– Revision 3 3–31

DMD50 Universal Satellite Modem Theory of Operation

Allocated BW

(MHz)

Leased BW

(MHz)

Savings Compared

to Original

PSD Ratio

(dB)

1

8-QAM, LDPC 2/3

0.3584

1.1468

1.1468

-20%

2.1

2

QPSK, LDPC 3/4

0.47785

0.6734

0.6734

30%

2.1

3

QPSK, LDPC 2/3

0.53735

0.5777

0.5777

40%

2.1

4

QPSK, LDPC 1/2

0.7168

0.5184

0.7168

25%

2.1

Traditional Link

(QPSK, TPC 3/4)

CnC Link

(QPSK, LDPC 2/3)

HPA @ 4.6 m

0.7 W

0.5 W

40%

HPA @ 2.4 m

1.5 W

1.1 W

36%

The link budget summary for the different MODCOD combinations is as follows:

S. No. Modulation & FEC

PEB (MHz)

Based on this analysis, QPSK, LDPC 2/3 with Carrier-in-Carrier provides the maximum savings
of 40%.

In addition to 40% reduction in Leased Bandwidth, using Carrier-in-Carrier also reduced the
required HPA Power by almost 40%:

HPA Power

HPA Power Reduction

MN-DMD50– Revision 3 3–32

DMD50 Universal Satellite Modem Theory of Operation

Satellite & Transponder

IS-901 @ 342º W, 22/22 (EH/EH)

Earth Station 1

Africa – 4.5 m

Earth Station 2

Africa – 3.0 m

Data Rate

3000 Mbps / 1000 Mbps

Original Link

With Carrier-in-Carrier and LDPC

Hub to

Remote

Remote To

Hub

Hub to

Remote

Remote to

Hub

Data Rate (kbps)

3000

1000

3000

1000

Modulation

QPSK

QPSK

QPSK

QPSK

FEC

TPC 3/4

TPC 3/4

LDPC 3/4

LDPC 1/2

Occupied BW (MHZ)

2.8

0.9

3.7

2.8

1.4

2.8

Power Eq. BW (MHz)

3.3

0.6

3.9

2.5

0.3

2.8

Leased BW (MHz)

3.9

2.8

27.5%

Hub HPA (W)

26.0

20.3

22%

Remote HPA (W)

10.6

6.4

40%

Occupied BW

2.8 MHz

Power Eq. BW

3.0 MHz

7.2% increase in Power Eq. BW

Leased BW

3.0 MHz

7.2% increase in Leased BW

Hub HPA

20.3 W

Remote HPA

8.3 W

30% increase in Remote power

3.14.9.2 Asymmetric Data Rate Link

As occupied (or allocated) bandwidth of a Carrier-in-Carrier circuit is dictated by the larger of the
two carriers, it is strongly recommended that the smaller carrier be spread as much as possible
using a lower order modulation and/or FEC, while meeting the PSD ratio spec. Spreading the
smaller carrier using a lower order modulation has multiple benefits:

• Lower order modulation is always more robust;

• Lower order modulation uses less transponder power – this reduces total transponder, and

increases available link margin;

• Lower order modulation uses less transmit power on the ground – this can significantly

reduce th e BUC/ SS PA si ze b y not only reducing the transmit EIRP, but also reducing the
BUC/SSPA backoff

Consider the following example:

While the traditional link was based on QPSK, TPC 3/4 and required 3.9 MHz of leased bandwidth,
the Carrier-in-Carrier link was based on QPSK, LDPC 3/4 and QPSK, LDPC 1/2 and required 2.8
MHz of leased bandwidth.

The savings summary is as follows:

Item

Total

Total

Savings

If this link was designed using QPSK, LDPC 3/4 in both directions, it would have required:

MN-DMD50– Revision 3 3–33

DMD50 Universal Satellite Modem Theory of Operation

Satellite & Transponder

IS-901 @ 342º W, 22/22 (EH/EH)

Earth Station 1

Africa – 9.2 m

Earth Station 2

Africa – 4.5 m

Data Rate

2.048 Mbps / 2.048 Mbps

Original Link

With Carrier-in-Carrier and VersaFEC

Hub to

Remote

Remote To

Hub

Hub to

Remote

Remote to

Hub

Data Rate (kbps)

2048

2048

2048

2048

Modulation

8-PSK

8-PSK

QPSK

QPSK

FEC

TPC 3/4

TPC 3/4

0.803

0.803

Occupied BW (MHZ)

1.3

1.3

2.6

1.8

1.8

1.8

Power Eq. BW (MHz)

2.2

1.0

3.2

1.1

0.5

1.6

Leased BW (MHz)

3.2

1.8

44%

Hub HPA (W)

5.0

2.0

60%

Remote HPA (W)

11.6

4.7

60%

3.14.9.3 Power Limited Links

Carrier-in-Carrier can provide su bstantial sa vings even when t he original li nk is power limit ed.
Spreading the carrier by using a lower modulation and/or FEC along with latest FEC such as
VersaFEC can substantially reduce the total power which can then be traded with bandwidth
using Carrier-in-Carrier. The concept is illustrated with the following examples:

The conventional link is using 8-PSK, TPC 3/4:

Switching to VersaFEC and using a lower order modulation –
e.g., QPSK, VersaFEC 0.803 increases the total occupied
bandwidth, while reducing the total power equivalent bandwidth:

Now using DoubleTalk Carrier-in-Carrier, the second QPSK,
VersaFEC 0.803 carrier can be moved over the first carrier –
thereby significantly reducing the total occupied bandwidth and
total power equivalent bandwidth when compared to the original
side-by-side 8PSK, TPC 3/4 carriers:

To continue, consider this example:

Whereas the original link used 8-PSK TPC 3/4, the Carrier-in-Carrier link used QPSK VersaFEC

0.803. The savings summary is as follows:

Item

Total

Total

Savings

Note: 1 dB HPA BO for QPSK, 2 dB HPA BO for 8-PSK, 1 dB Feed Loss.
Using Carrier-in-Carrier and VersaFEC reduced the leased bandwidth by almost 44% and HPA

power by 60%

MN-DMD50– Revision 3 3–34

DMD50 Universal Satellite Modem Theory of Operation

Step

Procedure

1

Turn ON the carrier at Site A. Carrier from Site B is OFF. CnC function is OFF at

2

Turn OFF the carrier at Site A. Turn ON the carrier at Site B. CnC function is OFF at

3

Using Co+No/No readings calculate PSD ratio at Site A and Site B. If it is not within

4

5

The test can be repeated for different PSD ratio and Eb/No.

3.14.10 Carrier-in-Carrier Commissioning and Deployment

Prior to commissioning a Carrier-in-Carrier link, it is critical that the link is fully tested in non
Carrier-in-Carrier mode and all system issues including external interference, antenna pointing,
cabling, SSPA backoff are resolved. Only after the link is robust, should the user attempt turning
on Carrier-in-Carrier.

The following procedure is recommended for Carrier-in-Carrier commissioning and deployment:

both sites.

 Using a spectrum analyzer, measure Co+No/No at the input to the modem

at Site A.

 Using a spectrum analyzer, measure Co+No/No at the input to the modem

at Site B.

 Measure/record Eb/No at Site B. Make sure there is sufficient margin to

account for CnC.

 Measure/record Receive Signal Level (RSL) at Site B.

both sites.

 Using a spectrum analyzer, measure Co+No/No at the input to the modem

at Site A.

 Using a spectrum analyzer, measure Co+No/No at the input to the modem

at Site B.

 Measure/record Eb/No at Site A. Make sure there is sufficient margin to

account for CnC.

 Measure/record RSL at Site B.

specification, make necessary adjustments to bring it within specification and repeat
measurements in Step (1) and (2).

 Also verify that the RSL is within spec.

Now without changing the transmit power levels, turn ON both the carriers (on the
same frequency) and turn CnC ON.

 Measure/record Eb/No at Site A and B.
 Measure/record RSL at Site A and B.
 Now compare Eb/No in presence of 2 over lapping carriers with CnC with

Eb/No when only 1 carrier was ON. Eb/No variation should be within spec
for that modulation, FEC and PSD ratio.

MN-DMD50– Revision 3 3–35

DMD50 Universal Satellite Modem Theory of Operation

Step

Procedure

1

Setup a conventional side-by-side link of the desired Eb/No:

2

Record the Eb/No as displayed by the Modems.

3

3.14.11 Validating Carrier-in-Carrier Performance

Carrier-in-Carrier performance can be easily validated by verifying that Eb/No degradation due to
Carrier-in-Carrier is within published specification for the observed Power Spectral Density Ratio.

The following procedure is recommended for validating Carrier-in-Carrier performance:

 Carrier-in-Carrier should be OFF.
 Record the Eb/No as displayed by the Modems.
 Observe the 2 carriers on a spectrum analyzer and record the PSD ratio.

Example Link:

• Full duplex 512 kbps, QPSK, LDPC 2/3 circuit between 4.6 m and 2.4 m
antennas

• Recorded Eb/No = 2.6 dB (at both modems)

• PSD Ratio = 1.2 dB (measured at larger Antenna)

Now relocate one of the carriers on top of the other carrier:

 Enable Carrier-in-Carrier.



Calculate change in Eb/No and verif y against sp ec if ica tion.

Example Link:

• Recorded Eb/No = 2.4 dB

• Chan ge in Eb/N o = 0.2 dB

• Eb/No Degradation (Spec.) at 1.2 dB PSD = 0.3 dB

• Modem performance is within spec.

MN-DMD50– Revision 3 3–36

DMD50 Universal Satellite Modem Theory of Operation

for the link budget

3.14.12 Operational References

3.14.13 Carrier-in-Carrier Link Budget Calculation

The following steps are required for calculating the link budget for a Carrier-in-Carrier Link:

1. Calculate the link budget for both carriers in the duplex link, with required CnC margin:

• Find the Eb/No

corresponding to
the desired BER

• Add CnC Margin

• Add any other

margin

• Use this compiled

value as the
Threshold Eb/No

2. Verify that the PDS ration is within spec for the Radyne DMD50.

3. Calculate the Allocated Bandwidth (BW) and Power Equivalent Bandwidth (PEB) for the

duplex link:

• BW

• PEB

Duplex Link

Duplex Link

• Leased BW

= Greater of (BW

= PEB

Duplex Link

+ PEB

Carrier 1

= Greater of (BW

Carrier 1

Carrier 2

, BW

Duplex Link

Carrier 2

)

, PEB

Duplex Link

)

4. For an optimal link, the Leased Bandwidth and the Power Equivalent Bandwidth should be

equal / nearly equal.

5. Repeat the link budget process by selecting different Modulation and FEC, until the BW and

PEB is nearly balanced.

MN-DMD50– Revision 3 3–37

DMD50 Universal Satellite Modem Theory of Operation

Carrier

Downlink EIRP

Symbol Rate

Power Spectral Density

A to B

27 dBW

500 ksps

-29.99 dBW/Hz

B to A

24 dBW

375 ksps

-31.74 dBW/Hz

3.14.14 Estimating PSD Ratio

PSD can be estimated from a link budget using Downlink EIRP and Symbol Rate:

PSD = Downlink EIRP – 10 * Log (Symbol Rate)

PSD Ratio Example:

PSD Ratio (@ A) = -29.99 – (-31.74) = 1.75 dB
PSD Ratio (@ B) = 01.74 – (-29.99) = -1.75 dB

3.14.14.1 Estimating PSD Ratio from LST

MN-DMD50– Revision 3 3–38

DMD50 Universal Satellite Modem Theory of Operation

3.14.14.2 Estimating PSD Ratio from Satmaster

3.14.14.3 Estimating PSD Ratio Using Spectrum Analyzer

PSD Ratio or CnC Ratio can also be estimated using a Spectrum Analyzer capable of integrating
the signal power in a given bandwidth.

CnC Ratio (in dB) = PowerC1 (in dBm) – PowerC2 (in dBm)
PSD Ratio (in dB) = (PowerC1 – 10 log BW

= CnC Ratio – 10 log (BW

If the two carriers have same Symbol Rate / Bandwidth, then the CnC Ratio is same as the PSD
Ratio.

MN-DMD50– Revision 3 3–39

/ BWC2)

C1

(in Hz)) – (Power

C1

– 10 log BW

C2

(in Hz))

C2

DMD50 Universal Satellite Modem Theory of Operation

symbol rates do not have to be equal)

BSPK/QPSK/8-PSK/8-QAM:

Maximum Symbol Rat e Ratio

3:1 (TX:RX or RX:TX)

Above 389 ksymbols/ sec: ±1 to ± (0.1Rs) kHz, up to a maximum of ± 200 kHz

Delay range

inbound) add an additional 0.3 dB

CnC ratio, in dB (ratio of absolute power, outbound interferer to desired inbound)

3.14.15 DoubleTalk Carrier-in-Carrier Specifications

Operating Mode Requires the two links to share a common carrier frequency (Outbound and Inbound

Power Spectral Density Ratio
and CnC Ratio

Inbound/Outbound frequency
uncertainty

Eb/No Degradation
(equal Inbound/Outbound
power spectral density)

Monitor Functions Delay, in milliseconds

outbound interfer er to desired inbound)
16-QAM: –7 dB to +7 dB (ratio of pow er spectral dens ity, outbound interferer to desired

inbound)
Note: With asymmetric carr iers the absolute power r atio (or CnC ratio) would be

different, depen ding on the ratio of the symbol rates.

Example:

Outbound interferer = 1 Msymbols /sec
Desired Inbound = 500 ksymbols/s ec
Ratio of power spectral density = +7 dB
Absolute power ratio (CnC Ratio) = +7dB + (10 log Outbound/desired symbol rate) =

+10 dB

Within the normal acquisition range of the demod, as foll ows:

Below 32 ksymbols/ sec: ±1 to ± (Rs/2) kHz, where Rs = symbol r ate in ksymbols/sec
Between 32 and 389 ks ymbols/sec: ± 1up to a maximum of ± 32kHz

0-330 ms
BPSK = 0.3dB QPSK = 0.3dB OQPSK = 0.3dB

8-PSK = 0.5dB 8-QAM = 0.4dB 16-QAM = 0.6dB
For +10 dB power spectral density ratio (outbound interf erer 10 dB higher than d esired

Frequency offset (between outbound interferer and desired inbound). 100 H z resolution

–7 dB to +11 dB (ratio of pow er spectral density,

3.14.16 Carrier-in-Carrier Summary

Comtech EF Data’s DoubleTalk Carrier-in-Carrier can provide significant savings in operational
expenses. The following should be considered when evaluating DoubleTalk Carrier-in-Carrier:

• DoubleTalk Carrier-in-Carrier can only be used for full duplex links where the

transmitting earth station is able to receive itself.

• DoubleT alk Carrier-in-Carrier can be used in both bandwidth limited and power limited

situations.

• The maximum savings is generally achieved when the original link is symmetric in data

rate.

MN-DMD50– Revision 3 3–40

DMD50 Universal Satellite Modem Theory of Operation

3.14.17 Glossary

Allocated Bandwidth

Bandwidth or Allocated Bandwidth or Occupied Bandwidth is the frequency space required by a
carrier on a transponder.

For example, a Duplex E1 (2.048 Mbps) Circuit with 8-PSK Modulation, FEC Rate 3/4 and 1.4
Spacing requires:

2.548 MHz = 2.048 / (3 * 0.75) * 1.4 * 2
For a 36 MHz transponder, 2.548 MHz corresponds to 7.078% Bandwidth Utilization.

Power Equivalent Bandwidth

Power Equivalent Bandwidth (PEB) is the transponder power used by a carrier, represented as
bandwidth equivalent.

PEB Calculation Example:

• Transponder EIRP = 37 dBW

• Output Backoff (OBO) = 4 dB

• Available EIRP = 37 – 4 = 33 dBW = 10

• Transponder Bandwidth = 36 MHz

• Power Available / MHz = 1955.26 / 36 = 54.424 W

• If a carrier uses 24 dBW, its PEB = 10

= 4.532 MHz

3.3

= 1955.26 Watts

2.4

/ 54.424

This corresponds to 12.59% of available transponder power.

Leased bandwidth

Almost all satellite operators charge for the Leased Bandwidth (LBW). Leased Bandwidth or
Leased Resource is the greater of the Allocated Bandwidth and Power Equivalent Bandwidth.

For example, if a carrier requires 3 MHz of Allocated BW and 4.5 MHz of PEB, the Leased
Bandwidth is 4.5 MHz

Power Spectral Density (PSD)

Power Spectral Density (PSD) is the signal power per unit bandwidth: dBW / Hz or dBm / Hz
For example: Signal power = 20 dBm

Signal bandwidth = 500 kHz
PSD = 20 – 10 *log (500 * 1000)
= -36.99 dBm / Hz

PSD Ratio

PSD ratio is the ratio of power spectral density of
the interfering carrier and the desired carrier. If
looking at the 2 carriers side-by-side on a spectrum
analyzer:

MN-DMD50– Revision 3 3–41

DMD50 Universal Satellite Modem Theory of Operation

Eb/No

Ratio of Energy per bit (Eb) to Noise density (No): Unit is dB

C/N

Carrier Power (C) to Noise (N) ratio: Unit is dB

C/No

Carrier Power (C) to Noise Density (No) ratio: Unit is dBHz

Co+No/No

Carrier Density (Co) + Noise (No) to Noise Density (No)
ratio: Unit is dB

C/N = C/N

– 10 log B [whe re B is bandwidt h in H z]

o

= C/No – 10 log R [where R is data rate in bits/sec]

E

b/No

= C/N + 10 log B – 10 log R
= C/N – 10 log (Spectral Efficiency)

= 10 log (10

E

b/No

((Co+No/No)/10)

– 1) – 10 log (Spectral Efficiency)

[Spectral Efficiency is in bps / Hz]

MN-DMD50– Revision 3 3–42

DMD50 Universal Satellite Modem Theory of Operation

3.15 Satellite Control Channel (SCC)

The SCC format uses a variable overhead rate to transmit an asynchronous data channel in
addition to the normal data channel. The SCC asynchronous mode implemented on the DMD50
is "PassThru" Mode.

3.15.1 SCC Framing Structure

Each SCC frame consists of the following:

 A 10-bit synchronization pattern called the Synchronizing Word.
 Multiple variable length slots filled with user data.
 Multiple 10-bit control words that contains eight bits of in-band data (the extra two bits are

for the async start/stop).

The number of user data slots and control words per frame is selected by the SCC Control Ratio
Parameter. This can be any value from 1 to 1 through 1 to 7. A higher ratio allows a lower
overhead rate but since there are less Sync Words, there is a higher acquisition time.

The following examples show a control ratio of 1 to 3 and 1 to 1. Example 1 shows three Control
Words for every Synchronizing Word, and Example 2 shows one Control Word for every
Synchronizing Word.

MN-DMD50– Revision 3 3–43

1 to 3 Control Ratio

DMD50 Universal Satellite Modem Theory of Operation

1 to 1 Control Ratio

The Control Ratio of the receiving units must match the Control Ratio of the transmitting unit.

MN-DMD50– Revision 3 3–44

DMD50 Universal Satellite Modem Theory of Operation

User Data

Rate

In-Band

Rate

Control

Ratio

Aggregate Data

Rate

Overhead

Ratio

512,000

19,200

1/7

533,974

1.043

1,024,000

19,200

1/7

1,045,974

1.021

2,048,000

19,200

1/7

2,069,951

1.011

3.15.2 Aggregate Data Rate

The aggregate data rate equals the following :

User Data Rate + In-Band Rate + Synchronizing Overhead Rate

Because SCC must adjust the overhead so that there are an equal number of user data bits in each
slot, the synchronizing overhead cannot be easily calculated. However, dividing the In-Band Rate
by the Control Ratio can approximate it. The following equation shows the basic calculation of
this rate:

Aggregate Date Rate = User Data Rate + In-Band Rate + (In-Band Rate/Control Ratio)

User Data

Rate

In-Band

Rate

Synchronizing

Overhead

Aggregate Data Rate

As an example, given the following parameters:

User Data Rate: 1,024,000 bps
In-Band Rate: 19,200 bps
Control Ratio: 1 to 7

Aggregate data rate = 1,024,000 + 19,200 + (19,200/7) or approximately 1,045,942 (actually

1045974).

This gives an overhead ratio of 1,045,974/1,024,000 = 1.021

In addition, another constraint changes the actual Aggregate Data Rate. The user data slot size is
limited to 2,500 bits. Because of this, the modem increases the in-band rate to reduce the user
data slot size. This only happens at higher user data rates.

3.15.3 Overhead Rate Comparison

The SCC Overhead Ratio varies depending on the User Data Rate, the In-Band Rate, and the
Control Ratio. This gives SCC the advantage of lower overhead rates when compared to IBS,
which has a fixed overhead ratio of 16/15 or 1.067. Table 3-4 shows example overhead rates for
different user data and control ratios.

MN-DMD50– Revision 3 3–45

Table 3-5. Overhead Rates Examples

DMD50 Universal Satellite Modem Theory of Operation

3,072,000

19,200

1/7

3,093,943

1.007

4,096,000

19,200

1/7

4,117,951

1.005

6,312,000

19,200

1/7

6,337,248

1.004

6,312,000

19,200

1/3

6,337,606

1.004

6,312,000

19,200

1/1

6,350,418

1.006

3.15.4 Actual Overhead Rate Calculation

The following is the actual calculation the modem does to calculate the overhead ratio:

1. The modem calculates the minimum in-band rate to limit the size of the user data slots to
2,500 bits (the result is truncated to an integer).

Minimum In-Band = (User Data Rate * Control Ratio)/((Control Ratio + 1) * 250)

2. Using the bigger of Minimum In-Band or the selected In-Band, the modem calculates the
number of bits for each user data slot (result is truncated to an integer).

Slot Bits = (User Data Rate * (Control Ratio * 10))/(In-band Rate * (Control Ratio + 1))

The actual ratio the modem uses is:

Actual Ratio = (Slot Bits + 10)/Slot Bits

Example 1:
User Data Rate: 1,024,000

bps
In-Band Rate: 19,200

bps
Control Ratio: 1 to 7

Mini mum In-Band = (1,024,000 * 7)/((7 +

1) * 250) = 3,584

(less than In-Band Rate)

Slot Bits = (1,024,000 * (7 * 10))/(19,200
* (7 + 1)) = 466

Actual Ratio = (466 + 10)/466 = 1.021

Example 2:
User Data Rate: 6,312,000

bps
In-Band Rate: 19,200 bps
Control Ratio: 1 to 7

Mini mum In-Band = (6,312,000 * 7)/((7 +

1) * 250) = 22,092 (

more than In-Band Rate)

Slot Bits = (6,312,000 * (7 * 10))/(22,092 *
(7 + 1)) = 2,500

Actual Ratio = (2,500+ 10)/2,500= 1.004

MN-DMD50– Revision 3 3–46

DMD50 Universal Satellite Modem Theory of Operation

3.15.5 SCC Overhead Channel Setup

1. Set the Framing Mode (located under Mod and Demod Data Menus) to SCC. After doing
this, two new menus will appear to the right of the Framing Menu, for both the Mod and
Demod. The new menus will be:

SCC CTL RATIO
SCC INBAND RATE

2. Set the desired SCC control ratio:

SCC CTL RATIO {1/1, 1/2, 1/3, 1/4, 1/5, 1/6, 1/7}

This allows the user to simulate the framing used by the Satellite Control Channel
Option (Pass-Thru Mode only). The SCC CTL RATIO is the ratio of overhead in-band
data to synchronizing words.

3. Set the desired SCC in-band rate:

SCC INBAND RATE {300 to 200000}

This allows the user to request the rate of in-band data for the overhead channel. This
sets the overhead amount only. The actual amount of data that can be passed through the
overhead channel will be set under “ES Baud Rate” (see Step 6 below).

4. Under the Interface > General menus, locate the TX ASYNC MODE (menu).

5. Under the TX ASYNC MODE Menu, set the desired ES Interface type:

ES INTERFACE {RS-232, RS-485}

This allows the user to select the interface type.

6. Under TX ASYNC MODE Menu, set the desired baud rate for the ASYNC Port (J17).
This will be the baud rate that will pass through the overhead channel:

ES BAUD RATE {150 - 19200}

This allows the user to select the baud rate of the ASYNC port (J17) in SCC Mode.

7. Under TX ASYNC MODE Menu, set the desired ES BITS/CHAR:

ES BITS/CHAR {7,8}

This allows the user to choose between 7 or 8 bits of data.

8. Repeat Steps 4 through 7 under the RX ASYNC MODE (menu)

9. The physical connection to the overhead channel will be the DB-9 Female Port labeled
ASYNC (J17).

MN-DMD50– Revision 3 3–47

DMD50 Universal Satellite Modem Theory of Operation

3.16 EDMAC Satellite Framing/Deframing Mode

The modem supports EDMAC satellite framing. EDMAC can be enables for both modulator and
demodulator satellite framing when modem is configured in CLOSED NET applications.
EDMAC satellite framing DOES NOT allow control or monitoring of the remote slave modem.
On the demodulator, terrestrial date is framed with NULL EDMAC commands, having no effect
at the remote demodulator. On the demodulator, EDMAC commands are stripped from the
satellite data stream and discarded, leaving the terrestrial data steam intact. EDMAC
Framing/Deframing is provided for compatibility purposes only.

3.17 Locating the ID Code Operational Procedure

The modem has unique ID codes that allow the user to add feature upgrades to the modem
without the unit having to be returned to the factory. Users are required to identify these ID codes
when they want additional features added to their unit. Comtech will supply a new ID code that is
required to be entered in the ID code field. Once the new ID code is entered, the modem will
activate the new features.

Refer to Appendix B for upgrade procedures.

3.18 Strap Codes

The Strap Code is a quick set key that sets many of the modem parameters. For quick setup of
the modem, Strap Codes are very helpful. When a Strap Code is entered, the modem is
automatically configured for the code’s corresponding data rate, overhead, code rate, framing,
scrambler type and modulation. An example of how to set a strap code follows:

Example: In the Ethernet interface <Modulator> Menu, depress the Transmit Gel-tab, then move
the cursor down and depress “General”. Now move the cursor over to ‘Strap Code’. Click inside
the box and enter the new strap code submenu and enter #16. The DMD50 will be automatically
configured to the parameters shown below in the highlighted row ‘Strap Code 16’.

Refer to Appendix D or the various strap code options.

MN-DMD50– Revision 3 3–48

Chapter 4. User Interfaces

4.1 User Interfaces

This section contains information pertaining to the user interfaces for the modem. There are four
user intefaces available for the modem. These are:

• Front Panel Interface – Refer to Section 4.2.

• Terminal Interface - :Refer to Section 4.6.

• RS485 Remote Port Interface (RLLP) – Refer to the Sect ion 4.9.

• Ethernet Remote Port Interface (SNMP) – R efer to Section 4.10.

• Ethernet Remote Port Interface (Web Browser) - Refer to Section 4.10.

4.2 Front Panel User Interface

The Front Panel allows for complete control and monitor of all parameters and functions via a
keypad, LCD display and status LEDs.

The front panel layout is shown in Figure 4-1, showing the location and labeling of the front
panel. The front panel is divided into four functional areas: the LCD Front Panel Display, the
Cursor Control Arrow Keys, the Numeric Keypad, and the Front Panel LED Indicators, each
described in Table 4-1.

MN-DMD50– Revision 3 4–1

Figure 4-1. Front Panel

DMD50 Universal Satellite Modem User Interfaces

Number

Description

Function

LCD Front Panel
Display

Cursor Control Arrow
Keys

Controls the up, down, right and left motion of the cursor in the

LCD Display window

3

Numeric Keypad

Allows entry of numeric data and Clear and Enter function keys

Front Panel LED

See Paragraph 4.1.4 below for an itemized description of these

Edit Mode Key Fun ct io ns (Front Panel On ly )

Parameter

‘Clear’ &

‘Clear’ &

Moves

Moves

Moves

Moves

Previous

List

Table 4-1. Front Panel Description

1

Displays operating parameters and Configuration data

2

4

Indicators

LEDs

4.2.1 LCD Front Panel Display

The front panel display is a 2 line by 16-character LCD display. The display is lighted and the
brightness can be set to increase when the front panel is currently in use.
The LCD display automatically dims after a period of inactivity. The display has two distinct
areas showing current information. The upper area shows the current parameter being monitored,
such as ‘Frequency’ or ‘Data Rate’. The lower line shows the current value of that parameter.
The LCD display is a single entry window into the large matrix of parameters that can be
monitored and set from the Front Panel.

4.2.2 Cursor Control Arrow Keys

A set of ‘Arrow’ or ‘Cursor’ keys (↑), (↓), (→), (←), is used to navigate the parameter currently
being monitored or controlled. Table 4-2 describes the functions available at the Front Panel.

4.2.3 Numeric Keypad

A 10-Key Numeric Keypad with two additional keys for the ‘Enter’ and ‘Clear’ function allows
the entry of data into the system. Table 4-2 describes the functions available at the Front Panel.

Type

Fixed Point

Decimal

Unsigned

Hexadecimal

Enumerated N/A

0 – 9

Changes

Digit

Changes

Digit

Table 4-2. Edit Mode Key Functions

↑ ↓ ← →

Toggles ±

(If Signed)

Toggles ±

(If Signed)

Cursor 1

Position

Left

Increments

Digit Value

Decrements
Digit Value

Cursor 1

Position

Left

Value in

Next Value

in List

N/A N/A N/A N/A

Cursor 1

Position

Right

Cursor 1

Position

Right

←

→

N/A N/A

N/A N/A

MN-DMD50– Revision 3 4–2

DMD50 Universal Satellite Modem User Interfaces

Moves

Left

Moves

Right

Moves

Left

Moves

Right

Moves

Left

Moves

Right

Clears to

Inclusive

Clears to

Inclusive

Date/ Time

IP Address

Text Strings

Changes

Digit

Changes

Digit

Changes

Character

N/A N/A

Increments

Digit Value

Increments

Character

Value

4.2.4 Front Panel LED Indicators

Eight LEDs on the Front Panel (Refer to Table 4-3) indicate the status of operation. The LED
colors maintain a consistent meaning. Green signifies that the indication is appropriate for
normal operation, Yellow means that there is a condition not proper for normal operation, and
Red indicates a fault condition that will result in lost communications.

Table 4-3. LED Color Reference

LED Color Function

Decrements
Digit Value

Decrements

Character

Value

Cursor 1

Position

Cursor 1

Position

Cursor 1

Position

Cursor 1

Position

Cursor 1

Position

Cursor 1

Position

N/A N/A

N/A N/A

Left of
Cursor

Right of

Cursor

Modem LED Indicators

Power Green Indicates that the unit is turned on.

Fault Red Indicates a hardware fault for the unit.

Event Yellow Indicates that a condition or event has occurred that the

modem has stored in memory. The events may be viewed
from the Front Panel or in the Terminal Mode.

Remote Green Indicates that the unit is in the process of updating firmware

with FTP or flashing indicates some features are demo
enabled.

Modulator LED Indicators

Transmit On Green Indicates that the transmitter is on.

Major Alarm Red Indicates that the Transmit Direction has failed, losing

traffic.

Minor Alarm Yellow Indicates that a Transmit Warning Condition exists.

Test Mode Yellow Indicates that the transmitter is involved in a current Test

Mode activity.

Demodulator LED Indicators

Signal Lock Green Indicates that the receiver locked to an incoming carrier and

MN-DMD50– Revision 3 4–3

data, including FEC Sync.

DMD50 Universal Satellite Modem User Interfaces

Major Alarm Red Indicates that the Receive Direction has failed, losing traffic.

Minor Alarm Yellow Indicates that a Receive Warning Condition exists.

Test Mode Yellow Indicates that the receiver is involved in a current Test Mode

activity.

4.3 Parameter Setup

The four Cursor Control Arrow Keys are used to navigate the menu tree and select the parameter
to be set. After arriving at a parameter that needs to be modified, depress <ENTER>. The first
space of the modifiable parameter highlights (blinks) and is ready for a new parameter to be
entered. After entering the new parameter using the keypad (Refer to Figure 4-2), depress
<ENTER> to lock in the new parameter. If a change needs to be made prior to pressing
<ENTER>, depress <CLEAR> and the display defaults back to the original parameter. Depress
<ENTER> again and re-enter the new parameters followed by <ENTER>.

Figure 4-2. Entering New Parameters

Following a valid input, the unit will place the new setting into the nonvolatile EEPROM making
it available immediately and available the next time the unit is powered-up.

4.4 Front Panel Control Screen Menus

The Front Panel Control Screens are broken down into sections under several Main Menus.

4.4.1 Main Menus

• MODULATOR

• DEMODULATOR

• INTERFACE

• MONITOR

• ALARMS

• SYSTEM

• TEST

MN-DMD50– Revision 3 4–4

DMD50 Universal Satellite Modem User Interfaces

4.4.2 Modulator Menu Options and Parameters

NETWORK SPEC {IDR, IBS, DROP & INSERT, CLOSED NET, DVB SAT}

The Network Spec Command sets a number of parameters

within the modem to meet a specification. The purpose is to
eliminate keystrokes and potential compatibility problems.

Data rates not covered by a given network specification will not

be allowed. If the mode of operation is selected after the data
rate has been entered, then the data rate must be compatible with
the desired mode of operation or the network spec will not be
allowed. The following parameters cannot be changed while the
unit is in the given mode of operation:

IDR:

(IESS-308)

For Data rates 1.544, 2.048, 6.312, 8.448 Mbps

Framing Type: 96 Kbps (IDR)
Scrambler Type: V.35
Spectrum Mask: Intelsat

For Data Rates < 1.544
Framing Type: 1/15 (IBS)
Scrambler Type: IESS-309
Spectrum Mask: Intelsat

IBS:

(IESS-309)

For Data Rates < 2048
Framing Type: 1/15 (IBS)

Scrambler Type: IESS-309

Spectrum Mask: Intelsat

Drop & Insert:

Data Rates: n x 64 n = 1, 2, 3, 4, 5, 6, 8, 10,12, 15,

16, 20, 24, 30

Framing Type: 1/15 (I BS)

Scrambler Type: IESS-309
Spectrum Mask: Intelsat

Efficient D&I Closed Network,

Data Rates: n x 64, N = 1-31 Any combination
Descrambler Type: IESS-309
Spectrum Mask: Intelsat

MN-DMD50– Revision 3 4–5

DMD50 Universal Satellite Modem User Interfaces

DVB: Per EN301-421 & En301-210

Data Rates: All Rates

Framing Type: DVB
Scrambler Type: DVB
Spectrum Mask: DVB 0.25, 0.35

Closed Net:

All possible combinations allowed, however, DVB settings

requires the DVB network spec. Activates the AUPC Menu.

STRAP CODE {Refer to Strap Code Guide, Appendix D}
The Strap Code is a quick set key that sets many modem

parameters. Consult the strap code guide for available strap
codes. Parameters set by strap code:

Data Rate

Inner Code Rate
Satellite Framing
Scrambler
Drop and Insert
Outer Code Rate (Reed-Solomon)
Modulation
Network Spec

IF (menu)

FREQUENCY (MHz) {50 – 90 MHz, 100 – 180 MHz, or 950 - 2050 MHz}
Allows the user to enter the Modulator IF Output Frequency of

the modem in 1 Hz increments.

POWER (dBm) {0 to -25 dBm}

Allows the user to enter the Transmitter Power Level.

CARRIER {ON, OFF, AUTO, VSAT, RTS}

Allows the user to select the carrier type. Refer to Appendix E

for further information.

SPECTRUM {NORMAL, INVERTED}

Allows the user to invert the direction of rotation for PSK

Modulation. Normal meets the IESS Specification..

MODULATION {QPSK, BPSK, OQPSK, 8PSK, 16QAM}
Allows the user to select the modulation type.

SPECTRAL MASK {Intelsat 0.35, DVB SAT 0.35, DVB SAT 0.25, DVB SAT

0.20}

Allows the user to set the spectral shape of Tx Data Filter.

MN-DMD50– Revision 3 4–6

DMD50 Universal Satellite Modem User Interfaces

COMPENSATION {0.0 – 1.0}

Allows you to offset output power by up to 1 dbm. This is
intended as a correction for user cabinet connectors.

DATA (menu)
DATA RATE (bps) {Refer to Technical Specs for Data Rates}

Allows the user to set the Data Rate in bps steps via the Front

Panel Arrows or Keypad.

SYMB RATE (sps) Allows the user to view the Symbol Rate.

INNER FEC Viterbi {1/2, 3/4, 7/8, None}

Optional FEC Rates:
Sequential {1/2, 3/4, 7/8}
Trellis {8PSK}
Turbo ≤ 20Mbps {.793, .495, 3/4, 7/8}
Turbo >20Mbps {.750, .875}
CSC {3/4}
DVB VIT {2/3, 5/6}
DVB Trellis {3/4, 5/6, 7/8, 8/9}
LDPC (B/O/QPSK) {1/2, 2/3, 3/4}
LDPC (8PSK) {2/3, 3/4}
LDPC (8QAM) {2/3, 3/4}
LDPC (QPSK/OQPSK) {1/2, 2/3, 3/4}
LDPC (16QAM) {3/4}
Allows the user to select the Rx Code Rate and Type

TPC INTERLEAVER {DISABLE, ENABLE}
Allows user to disable or enable the TPC Interleaver. Valid only

for Radyne turbo codes TPC.495 and TPC.793

DIFF CODING {ENABLED, DISABLE}
Allows the user to enable or disable the Differential Encoder.

Having the encoder enabled ensures proper phase lock. May not
be adjustable in some modes.

SCRAMBLER SEL {NONE, V.35-IESS, V.35 CITT, V.35 EF, IBS w/Optional

Framing and optional Reed-Solomon, Reed-Solomon
Scrambler w/Optional Framing, CCITT, V.35FC, OM-73,
V.35EF_RS, TPC SCRAMBLER (Turbo Codec), DVB,
EDMAC}

Allows the user to select the descrambler type.

SCRAMBLER CTRL {ENABLED, DISABLE}
Allows the user to enable or disable scrambler operation.

SAT FRAMING {1/15 (IBS), 1/15 (Async), 96 Kbps (IDR), DVB, EDMAC,

EFAUPC, SCC, EFFICIENT D&I, None}

Used with IDR, IBS, or Asynchronous Interface Only.
Allows the user to select the framing type.

MN-DMD50– Revision 3 4–7

DMD50 Universal Satellite Modem User Interfaces

IN-BAND RATE {150, 300, 600, 1200, 2400, 4800, 9600, 19200}
Allows the user to select the rate of in-band data for the ES to

ES, Async overhead channel.

Only displayed when Effiecient D&I with Enhanced Async

are selected.

SCC CTL RATIO {1/1, 1/2, 1/3, 1/4, 1/5, 1/6, 1/7},

Allows th e u se r to simulate the framing used by the Satellite

Control Channel Option (Pass Thru Mode only). The SCC CTL
RATIO is the ratio of overhead in-band data to synchronizing
words.

Only displayed when SCC Framing is selected
SCC INBAND RATE {300 to 200000}, when using SCC Framing

Allows the user to request the rate of in-band data for the

overhead channel.

Only displayed when SCC Framing is selected
TERR FRAMING {NONE, 188, 204}, when using DVB Network Specifications

DATA POLARITY {INV. TERR & BASE, INV. BASEBAND, INV.TERR

DATA, NONE}

Allows the user to invert the Tx Data polarity.

SYMBOL PAIR {NONE, SWAPPED}
Allows the user to swap the I & Q Channels, when using BPSK

modulation.

ESC OVERHEAD {VOICE X2, DATA 64KBPS}
IDR ESC Channel used for Voice or 64 K data channel. Only

available when IDR Network is selected.

AUPC (menu)

LOCAL AUPC (menu) The 'LOCAL AUPC CONFIGURATION' Menu contains the

local configuration parameters for the AUPC Function.

AUPC MODE {DISABLED, NEARSIDE, RADYNE, EFDATA}

DISABLED: Allows the user to enable or disable the Local

AUPC Function of the local modem.

EFDATA: Enables EFDATA Local AUPC Function. In the
event that the remote or local demodulator losses lock, the output
power level will adjust itself to the lev e l se tt in gs indicated in the
'REMOTE CL ACTION' Menu or the 'LOCAL CL ACTION'.

MN-DMD50– Revision 3 4–8

DMD50 Universal Satellite Modem User Interfaces

RADYNE: Enables Radyne Local AUPC Function. In the
event the remote demodulator losses lock, the local output power
level will adjust itself to the nominal level. This nominal power
should be set to a level high enough to re-establish
communications regard less of rain fad e.

NEARSIDE: Enables NEARSIDE Local AUPC function. In
the event the local demodulator losses lock due to signal loss, the
output power level will adjust itself to the nominal level. This
nominal power should be set to a level high enough to re­establish communications r eg ardle ss of rain fad e.

NOMINAL TX POWER {0 TO -25 dB}
This allows the user to set the nominal Transmit Power. The

nominal transmit power is the default output power level.

MINIMUM TX POWER {0 to -25 dB}
This allows the user to set the minimum Transmit Power.

EFDATA AUPC: When configured for EFDATA AUPC the

minimum Transmit Power is the lowest power setting that will
be used when the local modem commands a decrease of the
Transmit Power from the Remote modem.

RADYNE: When configured for Radyne AUPC, the minimum

Transmit Power is the lowest power setting that will be used
when the remote modem commands a decrease of the Transmit
Power from the Local modem.

NEARSIDE: When configured for NEARSIDE AUPC the

minimum Transmit Power is the lowest power setting that will
be used by the local modem when the Eb/No increases above the
Eb/No target.

MAXIMUM TX POWER {0 to -25 dB}
This allows the user to set the maximum Transmit Power.

EF AUPC: When configured for EF AUPC, the maximum

Transmit Power is the highest power setting that the local
modem will use when the local modem commands an increase in
Transmit power from the Remote modem.

RADYNE: When configured for Radyne AUPC, the maximum

Transmit Power is the highest power setting that will be used
when the remote modem commands an increase of the Transmit
Power from the Local modem

NEARSIDE: When configured for NEARSIDE AUPC the

maximum Transmit Power is the highest power setting that will
be used by the local modem when the Eb/No decreases below
the Eb/No target.

TARGET Eb/No {4.0 to 16 dB}

MN-DMD50– Revision 3 4–9

DMD50 Universal Satellite Modem User Interfaces

This allows the user to set the desired Eb/No for the local

receiver.

RADYNE AUPC: When configured for Radyne AUPC, this

setting is compared against the rem ote E

and commands to

b/No

the local modem to increase or decrease the local transmit
power.

EF AUPC: When configured for EF AUPC, this setting is

compared against the local received E

and commands to the

b/No

remote modem to increase or decrease transmit power.

NEARSIDE: When configured for NEARSIDE AUPC, this

setting is compared against the receiv ed E

of the local

b/No

modem and commands to the local modem to increase or
decrease transmit power.

TRACKING RATE {0.5 to 6.0}
Allows the user to set the rate at which the commands to increase

or decrease Transmit Power are sent. Each command will result
in a 0.5 dB increase or decrease in Transmit Power from the
remote transmitter. The tracking rate is adjustable from 0.5 dB
per minute to 6.0 dB per minute in 0.5 dB steps. (Only

available when EFAUPC is selected as the framing )

LOCAL CL ACTION {HOLD, NOMINAL, MAXIMUM}
This allows the user to set the Remote Transmit Power Setting to

be used when the local modem receiver loses lock. The setting
can be 'HOLD' (no action taken), 'NOMINAL' (the nominal
Transmit Power Setting is used), and 'MAXIMUM' (the
maximum Transmit Power Setting is used). (Only available

when EFAUPC is selected as the framing)

REMOTE CL ACTION {HOLD, NOMINAL, MAXIMUM}
This allows the user to set the Local Transmit Power Setting to

be used when the remote modem receiver loses lock. The setting
can be 'HOLD' (no action taken), 'NOMINAL' (the nominal
Transmit Power Setting is used), and 'MAXIMUM' (the
maximum Transmit Power Setting is used).

REMOTE AUPC (menu) The 'REMOTE AUPC CONFIGURATION' Menu contains the

remote configuration parameters for the AUPC Function.
Remote AUPC menus are only available when modem is
configured for EF AUPC

AUPC MODE {DISABLE, EFDATA}

Allows the user to enable or disable the AUPC Function of the
remote modem. The remote AUPC Function is the response of
the local modem to commands for an increase or decrease of the
Transmit Power in 0.5 dB steps and the command to change to
the setting indicated in the 'REMOTE CL ACTION' Menu of the
remote modem upon receiver loss of lock.

LOOPBACK {DISABLE, ENABLE}

MN-DMD50– Revision 3 4–10

DMD50 Universal Satellite Modem User Interfaces

Allows the user to enable or disable the Baseband Loopback Test

Mode of the remote modem.

TX 2047 TEST {DISABLE, ENABLE}
Allows the user to enable or disable the Transmit 2047 Pattern

Test Mode of the remote modem.

RX 2047 BER: Reports the BER measurement of the receiver 2047 Pattern Test

Mode of the remote modem. BER is reported from the 1x10

-7

1x10

in tenth decade steps.

-5

to

if the pattern does not synchronize or is out of range, ‘NO

DATA’ will be displayed.

When modems are configured for Radyne AUPC, the remote Eb/No will be
displayed in the Monitor Menus.

REED-SOLOMON (menu) These selections are visible only when the Reed-Solomon Option

is installed.

ENABLE/DISABLE {ENABLED, DISABLE}
Allows the user to Enable/Disable the Reed-Solomon Encoder.

RS RATE {Refer to Table 3-1 for standard n/k values}
Displays the currently used n, k Reed-Solomon Codes. In

Closed Net Mode and using the appropriate hardware, the user
may select custom R-S Codes.

INTERLVR DEPTH {4, 8, 12}
Allows the user to select the Reed-Solomon interleaver depth. In

Closed Net Mode, a depth of 4 or 8 may be selected.

4.4.3 Demodulator Menu Options and Parameters

NETWORK SPEC {IDR, IBS, DROP & INSERT, CLOSED NET, DVB SAT}
The Network Spec Command sets a number of parameters

within the modem to meet a specification. The purpose is to
eliminate keystrokes and potential compatibility problems.

MN-DMD50– Revision 3 4–11

DMD50 Universal Satellite Modem User Interfaces

Data rates not covered by a given mode will not be allowed. If

the mode of operation is selected after the da ta rate has been
entered, then the data rate must be compatible with the desired
mode of operation or the Network Spec will not be allowed. The
following parameters cannot be changed while the unit is in the
given mode of operation:

IDR:

(IESS-308)
For Data rates 1.544, 2.048, 6.312, 8.448 Mbps
Framing Type: 96 Kbps (IDR)
Descrambler type: V.35
Spectrum Mask: Intelsat

For Data Rates < 1.544 Mbps
Framing Type: 1/15 (IBS)
Descrambler Type: IESS-309
Spectrum Mask: Intelsat

IBS:

(IESS-309)
For Data Rates < 2.048 Mbps
Framing Type: 1/15 (IBS)
Descrambler Type: IESS-309
Spectrum Mask: Intelsat

Drop & Insert:
Data Rates: n x 64, n = 1, 2, 3, 4, 5, 6, 8, 10, 12, 15,

16, 20, 24, 30
Framing Type: 1/15 (IBS)
Descrambler Type: IESS-309
Spectrum Mask: Intelsat

Efficient D&I Closed Network,

Data Rates: n x 64, 1-31 Any combination
Descrambler Type: IESS-309
Spectrum Mask: Intelsat

DVB: Per EN301-421 & En301-210
Data Rates: All Rates

Framing Type: DVB

Scrambler Type: DVB
Spectrum Mask: DVB 0.25, 0.35

Closed Net:

All possible combinations allowed, however, DVB settings
requires the DVB network spec.

STRAP CODE {Refer to Strap Code Guide, Appendix D}

MN-DMD50– Revision 3 4–12

DMD50 Universal Satellite Modem User Interfaces

The Strap Code is a quick set key that sets many modem

parameters. Consult the strap code guide for available strap
codes. Parameters set by strap code:

Data Rate

Inner Code Rate
Satellite Framing
Scrambler
Drop and Insert
Outer Code Rate (Reed-Solomon)
Modulation

Network Spec

IF (menu)

FREQUENCY (MHz) {50 – 90 MHz, 100 – 180 MHz, or 950 - 2050 MHz}

Allows the user to enter the Modulator IF Frequency in 1 Hz

increments.

SPECTRUM {NORMAL INVERTED}

Allows the user to invert th e di rec tion of rotation for PSK

Modulation. Normal meets the IESS Specification.

MODULATION {QPSK, BPSK, OQPSK, 8PSK, 16QAM}

Allows the user to select the demodulation type.

SPECTRAL MASK {Intelsat 0.35, DVB 0.35, DVB 0.25, DVB 0.20}
Allows the user to set the spectral shape of Tx Data Filter.

SWEEP RANGE (kHz) {±0 to 255 kHz}
Allows the user to set the acquisition range for the demodulator

SWEEP DELAY (Sec) {0.0 – 6553.5 sec}

Allows the user to set the reacquisition delay time in 1/10

th

second increments.

REACQ RANGE (Hz) {0 – 65535 Hz}

Allows the user to set the reacquisition sweep in 1 Hz

increments.

ADJ CARRIER PWR {Normal, Supressed}
Allows the user to indicate adjacent carrier as Normal or

Supressed (High Power). Unit will increase or decrease post
decimination gain appropriately.

FAST ACQUISITION {DISABLED, ENABLED}
Allows the user to disable or enable the Rx fast acquisition

capability.

MN-DMD50– Revision 3 4–13

DMD50 Universal Satellite Modem User Interfaces

Does not support spectral inversion applications.

Limitations of Fast Acquistion:
The maximum symbol rate for Fast Acquistion is 1028Ksps.
Fast Acquistion must be disable for rates greater than 1028Ksps.
Only supports QPSK and 8PSK in a NON-DVB MODE.

INPUT THRESHOLD (dBm) {-30 to 90 dbm}
Allows the user to adjust the low level threshold limit for input

power. Input power level below the threshold limit will trigger a
major alarm on the demodulator.

EB/NO ALARM {0.0 to 9.90 db}
Allows the user to set the desired E

This setting is compared against the receive E

for the local receiver.

b/No

and

b/No

commands to the remote modem to increase or decrease
Transmit Power accordingly are sent.

DATA (menu)

DATA RATE (bps) {Refer to Technical Specs for Data Rates}
Allows the user to set the Data Rate in bps steps via the Front

Panel Arrows or Keypad.

SYMB RATE (sps) Allows the user to view the Symbol Rate.
INNER FEC Viterbi {1/2, 3/4, 7/8, None}

Optional FEC Rates:
Sequential {1/2, 3/4, 7/8}
Trellis {8PSK}
Turbo ≤ 20Mbps {.793, .495, 3/4, 7/8}
Turbo >20Mbps {.750, .875}
CSC {3/4}
DVB VIT {2/3, 5/6}
DVB Trellis {3/4, 5/6, 7/8, 8/9}
LDPC (B/O/QPSK) {1/2, 2/3, 3/4}
LDPC (8PSK) {2/3, 3/4}
LDPC (8QAM) {2/3, 3/4}
LDPC (QPSK/OQPSK) {1/2, 2/3, 3/4}
LDPC (16QAM) {3/4}

Allows the user to select the Rx Code Rate and Type

TPC INTERLEAVER {DISABLED, ENABLED}

MN-DMD50– Revision 3 4–14

DMD50 Universal Satellite Modem User Interfaces

Allows the user to disable or enable TPC Interleaver. Valid only

for Radyne turbo codes TPC.495 and TPC.793.

DIFF CODING {ENABLED, DISABLE}
Allows the user to enable or disable the Differential Decoder.

Having the decoder enabled ensures proper phase lock. May not
be adjustable in some modes.

SCRAMBLER SEL {NONE, V.35-IESS, V.35 CITT, V.35 EF, IBS w/Optional

Framing and optional Reed-Solomon, Reed-Solomon
Scrambler w/Optional Framing, CCITT, V.35FC, OM-73,
V.35EF_RS, TPC SCRAMBLER (Turbo Codec), DVB,
EDMAC}

Allows th e u se r to select the descrambler type.

SCRAMBLER CTRL {ON, OFF}
Allows the user to enable or disable the descrambler operation.

SAT FRAMING {1/15 (IBS), 1/15 (Async), 96 Kbps (IDR), EDMAC,

EFAUPC, SCC, EFFICIENT D&I, None}

Used with IDR, IBS, or Asynchronous Interface Only.
Allows the user to select the Framing Type.
IN-BAND RATE {150, 300, 600, 1200, 2400, 4800, 9600, 19200}
Allows the user to select the rate of in-band data for the ES to

ES, Async overhead channel. Only displayed when Effiecient

D&I with Esc Enhanced are selected.

SCC CTL RATIO {1/1, 1/2, 1/3, 1/4, 1/5, 1/6, 1/7}
Allows the user to simulate the framing used by the Satellite

Control Channel Option (Pass Thru Mode only). The SCC CTL
RATIO is the ratio of overhead in-band data to synchronizing
words.

Only displayed when SCC Framing is selected.
SCC INBAND RATE {300 to 200000},

Allows the user to request the rate of in-band data for the

overhead channel.

Only displayed when SCC Framing is selected.
TERR FRAMING {NONE, 188, 204}, when using DVB Network Spec

DATA POLARITY {INV. TERR & BASE, INV. BASEBAND, INV.TERR

DATA, NONE}

Allows the user to invert the Rx Data polarity.

SYMBOL PAIR {NONE, SWAPPED}
Allows the user to swap the I & Q Channels, when using BPSK

Modulation.

ESC OVERHEAD {VOICE X2, DATA 64KBPS}
IDR ESC Channel used for Voice or 64 K data channel.
Only available when IDR Network is selected.

MN-DMD50– Revision 3 4–15

DMD50 Universal Satellite Modem User Interfaces

REED-SOLOMON (menu) These selections are visible only when the Reed-Solomon Option

is installed.

ENABLE/DISABLE {ENABLED, DISABLED}
Allows the user to Enable/Disable the Reed-Solomon Encoder.

RS RATE {Refer to Table 3-1 for standard n/k values}
Displays the currently used n, k Reed-Solomon Codes. In

Closed Net Mode and using the appropriate hardware, the user
may select custom R-S Codes.

INTERLVR DEPTH {4, 8, 12}

Allows the user to select the Reed-Solomon interleaver depth.

CNC (menu) These selections are visible only when the Carrier in Carrier card

is installed.

ENABLE/DISABLE {ENABLED, DISABLED}
Allows the user to Enable/Disable the Carrier in Carrier.

MIN SRCH DELAY {Minimum Search Delay (ms), 0 to Max}

MAX SRCH DELAY {Maximum Search Delay (ms), Min to 330ms}

FREQ OFFST RNG {Range of Frequency Offset (KHz) between the Interferer

and the desired received signal. (+/- 1Khz to +/- 32Khz)}

4.4.4 Interface Menu Options and Parameters

TX SETUP (menu)

CIRCUIT ID Allows the user entry of a Tx Circuit Identifier. Circuits can be

given up to an 11 Character alphanumeric identity such as
LINK1.

TERR INTERFACE STANDARD INTERFACE

{RS422 SERIAL,RS232 SERIAL, V.35}

OPTIONAL HARDWARE INTERFACES
{M2P PARALLEL, DVB PARALLEL, ASI}
{HSSI}
{ETHERNET 10/100 BASE-T}
{G.703: T1 AMI, T1 B8ZS, , E1 BAL, E1 UNBAL, T2 BAL,

T2 UNBAL, E2}

{G.703: T1 AMI, T1 B8ZS, , E1 BAL, E1 UNBAL, T2 BAL,

T2 UNBAL, E2, E3, T3, STS1}

Allows the user to select the Transmit Interface Type.

MN-DMD50– Revision 3 4–16