Comtech EF Data SLM-7650 Installation And Operation Manual

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Installation and O

765

Satellite Modem

eration Manual

Part Number MN/SLM7650.IOM

Revision 4

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Page 3

Comtech EF Data is an ISO 9001 Registered Company.

SLM-7650

Satellite Modem

Installation and Operation Manual

Part Number MN/SLM7650.IOM

Revision 4

September 10, 2005

Comtech EF Data, 2114 West 7th Street, Tempe, Arizona 85281 USA, (480) 333-2200, FAX: (480) 333-2161.

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SLM-7650 Satellite Modem Revision 4 Preface MN/SLM7650.IOM

Customer Support

Contact the Comtech EF Data Customer Support Department for:

• Product support or training

• Information on upgrading or returning a product

• Reporting comments or suggestions concerning manuals

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

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

service@comtechEF Data.com

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

2. Request a Return Material Authorization (RMA) number from the Comtech EF Data Customer Support Department.

3. Be prepared to supply the Customer Support representative with the model number, serial number, and a description of the problem.

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

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

For more information regarding the warranty policies referred to the Warranty Policy at the end of this chapter.

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Table of Contents

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

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

1.2 Description ..................................................................................................................................................1–2

1.2.1 Definition of Modulator Functions ..........................................................................................................1–3

1.2.2 Definition of Demodulator Functions ......................................................................................................1–3

1.2.3 Definition of Interface/M&C Functions...................................................................................................1–4

1.2.4 Additional Features ..................................................................................................................................1–4

1.3 Operating Modes ........................................................................................................................................1–5

1.4 Options ........................................................................................................................................................1–5

1.5 System Specifications Summary................................................................................................................1–6

1.5.1

Bit Error Rate Performance with Noise ...................................................................................................1–8

1.5.2 Dimensional Envelope ...........................................................................................................................1–10

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

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

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

2.2.1 Installation Procedure...............................................................................................................................2–2

2.2.2 External Modem Connections..................................................................................................................2–2

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CHAPTER 3. OPERATION ....................................................................................... 3-1

3.1 Front Panel.................................................................................................................................................. 3-1

3.1.1 LED Indicators......................................................................................................................................... 3-2

3.1.2 Front Panel Keypad.................................................................................................................................. 3-2

3.2 Front Panel Operation ............................................................................................................................... 3-3

3.2.1 Front Panel Menu Operation.................................................................................................................... 3-3

3.2.2 Configuration ........................................................................................................................................... 3-5

Digital Data Rate and Symbol Rate .......................................................................................................... 3-6

3.3

3.4

Menus .......................................................................................................................................................... 3-8

3.4.1 Configuration Menu................................................................................................................................. 3-8

3.4.1.1 Modulator Menu .............................................................................................................................. 3-20

3.4.1.2 Demodulator Menu.......................................................................................................................... 3-21

3.4.1.3 Interface Menu................................................................................................................................. 3-25

3.4.1.4 Local AUPC Menu .......................................................................................................................... 3-26

3.4.1.5 Save Menu ....................................................................................................................................... 3-20

3.4.1.6 Recall Menu..................................................................................................................................... 3-21

3.4.2 Monitor Menu ........................................................................................................................................ 3-20

3.4.3 Faults/Alarms Menu............................................................................................................................... 3-21

3.4.3.1 Modulator Faults.............................................................................................................................. 3-22

3.4.3.2 Demodulator Faults.......................................................................................................................... 3-22

3.4.3.3 Transmit Interface Faults ................................................................................................................. 3-23

3.4.3.4 Receive Interface Faults................................................................................................................... 3-23

3.4.3.5 Common Equipment Faults ............................................................................................................. 3-24

3.4.3.6 IDR Backward Faults....................................................................................................................... 3-24

3.4.4 Stored Faults/Alarms Menu ................................................................................................................... 3-25

3.4.5 Remote AUPC Menu ............................................................................................................................. 3-26

3.4.5.1 Remote AUPC Configuration .......................................................................................................... 3-26

3.4.5.2 Remote AUPC Monitor ................................................................................................................... 3-26

3.4.6 Utility Menu........................................................................................................................................... 3-27

3.4.6.1 Utility Modulator Menu................................................................................................................... 3-28

3.4.6.2 Utility Demodulator Menu............................................................................................................... 3-29

3.4.6.3 Utility Interface Menu...................................................................................................................... 3-30

3.4.6.4 Utility System Menu ........................................................................................................................ 3-31

3.4.6.5 Utility Modem Type Menu .............................................................................................................. 3-33

3.5 Modes of Operation.................................................................................................................................. 3-34

3.5.1 7650-00 Operation ................................................................................................................................. 3-34

3.5.2 7650-02 Operation ................................................................................................................................. 3-35

3.5.3 IDR Operation........................................................................................................................................ 3-37

3.5.4 IBS Operation ........................................................................................................................................ 3-39

3.5.5 VSAT-IBS Operation............................................................................................................................. 3-41

3.5.6 IBS-309 Operation ................................................................................................................................. 3-43

3.5.7 ASYNC/AUPC Operation ..................................................................................................................... 3-45

3.5.8 EFD Operation ....................................................................................................................................... 3-47

3.5.9 Custom Operation .................................................................................................................................. 3-49

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CHAPTER 4. THEORY OF OPERATION ................................................................ 4–1

4.1 Overview......................................................................................................................................................4–1

4.2 Built in Test.................................................................................................................................................4–1

4.3 Definitions ...................................................................................................................................................4–3

4.3.1 Differential Encoding/Decoding ..............................................................................................................4–3

4.3.2 Scrambler/Descrambler............................................................................................................................4–3

4.3.2.1 Self-Synchronizing Scrambler/Descrambler...................................................................................... 4-3

4.3.2.2 Synchronous Scrambler/Descrambler................................................................................................ 4-4

4.3.3 Encoding/Decoding..................................................................................................................................4–4

4.3.3.1 Convolutional/Viterbi (CEVD).......................................................................................................... 4-4

4.3.3.2 Reed-Solomon.................................................................................................................................... 4-5

4.3.3.3 Trellis Coding .................................................................................................................................... 4-6

4.3.3.4 Turbo Products Codec (Hardware Option) ........................................................................................ 4-7

4.3.3.5 Uncoded Operation (No FEC) ........................................................................................................... 4-9

4.3.4 Modulation Types ..................................................................................................................................4–10

4.3.4.1 BPSK ............................................................................................................................................... 4-10

4.3.4.2 QPSK ............................................................................................................................................... 4-10

4.3.4.3 Offset QPSK .................................................................................................................................... 4-10

4.3.4.4 8-PSK............................................................................................................................................... 4-10

4.3.4.5 16-QAM........................................................................................................................................... 4-11

4.3.5 Bit Error Rate.........................................................................................................................................4–11

4.3.6 Symbol Rate...........................................................................................................................................4–11

4.3.7 Symbol Rate Calculations......................................................................................................................4–12

4.4 Theory of Operation.................................................................................................................................4–13

4.4.1 Modulator...............................................................................................................................................4–13

4.4.2 Demodulator...........................................................................................................................................4–14

4.4.3 Baseband Interface.................................................................................................................................4–17

4.4.3.1 Monitor and Control ........................................................................................................................ 4-17

4.4.3.2 Transmit and Receive Baseband ...................................................................................................... 4-17

4.4.3.3 Reference and Clock Distribution.................................................................................................... 4-24

CHAPTER 5. MAINTENANCE................................................................................. 5–1

5.1 Modem Firmware Upgrade .......................................................................................................................5–1

5.2 Fault Isolation .............................................................................................................................................5–4

5.2.1 Fan............................................................................................................................................................5–4

5.2.2 M & C Battery..........................................................................................................................................5–4

5.2.3 Faults/Alarms...........................................................................................................................................5–4

5.2.4 Fault/Alarm Display and Description.......................................................................................................5–8

5.2.5 Fault/Alarm Analysis ...............................................................................................................................5–9

5.2.5.1 Modulator Faults................................................................................................................................ 5-9

5.2.5.2 Demodulator Faults.......................................................................................................................... 5-10

5.2.5.3 Transmit Interface Faults ................................................................................................................. 5-10

5.2.5.4 Receive Interface Faults................................................................................................................... 5-12

5.2.5.5 Common Equipment Faults ............................................................................................................. 5-13

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5.3 Modem Performance Verification Tests.................................................................................................5–14

5.3.1 Modulator Tests .....................................................................................................................................5–15

5.3.1.1 Spectral Shape of the IF Output....................................................................................................... 5-15

5.3.1.2 Carrier Null...................................................................................................................................... 5-15

5.3.1.3 Spurious using a Spectrum Analyzer............................................................................................... 5-16

5.3.1.4 Output Frequency............................................................................................................................. 5-16

5.3.1.5 Power Level ..................................................................................................................................... 5-16

5.3.2 Demodulator Tests .................................................................................................................................5–18

5.3.2.1 Dynamic Range................................................................................................................................ 5-18

5.3.2.2 Acquisition Range............................................................................................................................ 5-18

5.3.3 System BER Test ...................................................................................................................................5–18

5.3.4

Modem Test Modes................................................................................................................................5–19

5.3.4.1 IF Loopback..................................................................................................................................... 5-19

5.3.4.2 Base Band Loopback ....................................................................................................................... 5-20

5.3.4.3 Carrier Modes .................................................................................................................................. 5-21

5.3.4.4 Reed-Solomon Correction OFF ....................................................................................................... 5-22

5.3.4.5 2047 and MIL-188 Test Patterns...................................................................................................... 5-22

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

GLOSSARY .................................................................................................................g-1

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Figures

Figure 1-1. SLM-7650 Satellite Modem...................................................................................................................1–1

Figure 1-2. Dimensional Envelope...........................................................................................................................1–8

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

Figure 3-1. SLM-7650 Front Panel........................................................................................................................... 3-1

Figure 3-2. Keypad................................................................................................................................................... 3-2

Figure 3-3. Main Menu............................................................................................................................................. 3-4

Figure 4-1. System Block Diagram ..........................................................................................................................4–2

Figure 4-2. User Provides Clock ............................................................................................................................4–25

Figure 4-3. Modem Provides Clock........................................................................................................................4–26

Figure 4-4. Modem Clocks Internally.....................................................................................................................4–27

Figure 4-5. Slave Modem-Loop Timed ..................................................................................................................4–28

Figure 4-6. EXT Master Clock as Source...............................................................................................................4–29

Figure 4-7. User Provides Data Only......................................................................................................................4–30

Figure 4-8. Internal SCT Clock Selection ..............................................................................................................4–31

Figure 4-9. Separate Links vs Asymmetrical Loop Timing....................................................................................4–32

Figure 5-1. Reflash Program Window......................................................................................................................5–2

Figure 5-2. Example of Upgrade File Location ........................................................................................................5–3

Figure 5-3. Example of Reflash Program File Location...........................................................................................5–3

Figure 5-4. Example of USB Drivers File Location .................................................................................................5–3

Figure 5-5. Modem Verification Test Setup...........................................................................................................5–14

Figure 5-6. DUAL Test Mode ................................................................................................................................5–15

Figure 5-7. OFFSET Test Mode.............................................................................................................................5–16

Figure 5-8. CENTER Test Mode............................................................................................................................5–17

Figure 5-9. IF Loopback.........................................................................................................................................5–19

Figure 5-10. Baseband Loopback...........................................................................................................................5–20

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Tables

Table 1-1 Operating Modes......................................................................................................................................1–5

Table 1-2 SLM-7650 Options...................................................................................................................................1–5

Table 1-3. System Specifications Summary..............................................................................................................1–6

Table 1-4. Viterbi Decoder BER ..............................................................................................................................1–8

Table 1-5. High Order Modulation Options .............................................................................................................1–9

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

Table 2-2. IF Interface...............................................................................................................................................2–3

Table 2-3. Modem External Reference Input ...........................................................................................................2–3

Table 2-4. Terrestrial Data Interface 37-Pin D Female ............................................................................................2–3

Table 2-5. Terrestrial Data Interface 25-Pin D Female (Optional)...........................................................................2–4

Table 2-6. Remote Control Interface (M&C) ...........................................................................................................2–4

Table-2-7. Asynchronous Data Interface..................................................................................................................2–5

Table 2-8. Fault/Alarm Status Interface ...................................................................................................................2–5

Table 2-9. 50 Pin Sub-D Female Interface Connector..............................................................................................2–6

Table 2-10. 15-Pin Sub-D Female (G.703 Balanced)...............................................................................................2–7

Table 2-11. 75Ω BNC Connectors (G.703 Unbalanced)..........................................................................................2–7

Table 3-1. Front Panel Indicators ............................................................................................................................. 3-2

Table 3-2. Keypad Functions.................................................................................................................................... 3-3

Table 3-3. Data Rate Ranges .................................................................................................................................... 3-6

Table 3-4. 7650-00 Default Parameters.................................................................................................................. 3-35

Table 3-5. 7650-02 Default Parameters.................................................................................................................. 3-36

Table 3-6. IDR Default Parameters ........................................................................................................................ 3-38

Table 3-7. IBS Default Parameters......................................................................................................................... 3-40

Table 3-8. VSAT-IBS Default Parameters ............................................................................................................. 3-42

Table 3-9. IBS-309 Default Parameters.................................................................................................................. 3-44

Table 3-10. ASYNC/AUPC Default Parameters.................................................................................................... 3-46

Table 3-11. EFD Default Parameters...................................................................................................................... 3-48

Table 4-1. Viterbi Decoding Summary.....................................................................................................................4–5

Table 4-2. Concatenated RS Coding Summary........................................................................................................4–6

Table 4-3. 8PSK/TCM Coding Summary.................................................................................................................4–7

Table 4-4. Available TPC Modes ..............................................................................................................................4–8

Table 4-5. Turbo Product Coding processing delay comparison...............................................................................4–8

Table 4-6. Reed-Solomon Factor............................................................................................................................4–12

Table 4-7. Delay Variations for Inclined Orbit Satellites .......................................................................................4–34

Table 4-8. Recommended Buffer Size....................................................................................................................4–34

Table 5-1. SLM-7650 Fault Tree..............................................................................................................................5–5

Table 5-2. Modulator Fault Information...................................................................................................................5–9

Table 5-3. Demodulator Fault Information.............................................................................................................5–10

Table 5-4. Transmit Interface Fault Information ....................................................................................................5–11

Table 5-5. Receive Interface Fault Information......................................................................................................5–12

Table 5-6. Common Equipment Fault Information ................................................................................................5–13

Table 5-7. Test Equipment Required......................................................................................................................5–14

Table 5-8. Conversion to S/N and Eb/N0 Chart .....................................................................................................5–23

Table 5-9. Reed-Solomon Overhead Correction Factor .........................................................................................5–23

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SLM-7650 Satellite Modem Revision 4 Preface MN/SLM7650.IOM

About this Manual

This manual describes the installation and operation for the Comtech EF Data SLM-7650 Satellite Modem. This is a technical document intended for earth station engineers, technicians, and operators responsible for the operation and maintenance of the SLM-

7650.

Related Documents

Standards (Military)

MIL-STD-188-165

MIL-STD-810F

MIL-STD-1686C

Standards (Federal)

FED-STD-313

Standards (General)

EIA-422

EIA-485

EIA/TIA-530

IESS-308

IESS-309

IESS-310

ANSI/J-STD-001A

ANSI/VITA, 3-1995

ISO 9001

Interoperability and Performance Standards for SHF Communications PSK Modems (FDMA Operation)

Environmental Test Method and Engineering Guidelines

Electrostatic Discharge Control Program for Protection of Electrical and Electronic Parts, Assemblies and Equipment (Excluding Electrically Initiates Explosive Devices) Metric

Material Safety Data, Transportation Data and Disposal Data for Hazardous Materials Furnished to Government Activities

Electrical Characteristics of Balanced Voltage Digital Interface Circuits

Standard for Electrical Characteristics of Generators and Receivers for use in Balanced Digital Multi-point Systems

High Speed 24-Position Interface for Data Terminal Equipment and Data CircuitTerminating Equipment

Performance Characteristics for Intermediate Data Rate (IDR) Digital Carriers

QPSK/FDMA Performance Characteristics for Intelsat Business Service (IBS)

Performance Characteristics for Intermediate Data Rate using 8PSK 2/3

(Standard A, B, C, E and F Earth Stations)

Joint Industry Standard Requirements for Soldered Electrical and Electronic Assemblies

American National Standard for Board Level Live Insertion for VME.

Quality System

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SLM-7650 Satellite Modem Revision 4 Preface MN/SLM7650.IOM

Comtech EF Data Specifications

SP/9710

SP/9710-1

Comtech EF Data Specification, SLM-7650 Satellite Modem

Comtech EF Data Specification, SLM-7650 Remote Control Protocol Specification

Conventions and References

Cautions and Warnings

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

CAUTION

WARN ING

IMPORTANT

unsafe practices or risks of property damage.

WARNING indicates a potentially hazardous situation that, if not avoided,

could result in death or serious injury.

IMPORTANT indicates a statement that is associated with the task being performed.

Metric Conversion

Metric conversion information is located on the inside back cover of this manual. This information is provided to assist the operator in cross-referencing English to Metric conversions.

Recommended Standard Designations

Recommended Standard (RS) Designations are equivalent to the Electronic Industries Association (EIA). Either reference is satisfactory, except manuafacturer only will reference one of the designators thru-out the manual.

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Trademarks

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

Reporting Comments or Suggestions Concerning this Manual

Comments and suggestions regarding the content and design of this manual will be appreciated. To submit comments, please contact the Comtech EF Data Customer Support Department.

European EMC Directive

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

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

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

CAUTION: Double-pole/Neutral Fusing

ACHTUNG: Zweipolige bzw. Neutralleiter-Sicherung

International Symbols:

Alternating Current.

Fuse. Safety Ground.

Chassis Ground.

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

preface.

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SLM-7650 Satellite Modem Revision 4 Preface MN/SLM7650.IOM

Warranty Policy

This Comtech EF Data product is warranted against defects in material and workmanship for a period of one year from the date of shipment. During the warranty period, Comtech EF Data will, at its option, repair or replace products that prove to be defective. For equipment under warranty, the customer is responsible for freight to Comtech EF Data and all related custom, taxes, tariffs, insurance, etc. Comtech EF Data is responsible for the freight charges only for return of the equipment from the factory to the customer. Comtech EF Data will return the equipment by the same method (i.e., Air, Express, Surface) as the equipment was sent to Comtech EF Data.

Limitations of Warranty

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

No other warranty is expressed or implied. Comtech EF Data specifically disclaims the implied warranties of merchantability and fitness for particular purpose.

Exclusive Remedies

The remedies provided herein are the buyer's sole and exclusive remedies. 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.

Disclaimer

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

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Chapter 1. INTRODUCTION

This chapter provides an overview of the SLM-7650 satellite modem, referred to in this manual as “the modem.”

1.1 Overview

The SLM-7650 (Figure 1-1) interfaces between terrestrial fixed-rate data terminal equipment, with data rates between 9.6 kbps and 20 Mbps, and RF converter equipment that interfaces at 50 to 90 MHz and 100 to 180 MHz on the IF ports.

Figure 1-1. SLM-7650 Satellite Modem

1–1

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SLM-7650 Satellite Modem Revision 4 Introduction MN/SLM7650.IOM

1.2 Description

The modem is a high performance, full-duplex, digital-vector, modulator/demodulator that meets the requirements of most systems encountered in the commercial and government Satellite Communications industry including:

• Government/Defense

• DSCS II

• DSCS III

• NATO III

• Commercial

• INTELSAT

• EUTELSAT

• PANAMSAT

• NEW SKIES

• SES Americom

• Others

The modem is ideal for tri-band terminals requiring both commercial and government access methods. Additionally, the modem can be used for virtually any closed network satellite communication system. The modem is compliant with MIL-STD-188-165 over the data rate range specified within this specification. The modem is also compliant to the INTELSAT Earth Station Standards (IESS) -308, -309, and –310 specifications for the following:

• Intermediate Data Rate (IDR)

• INTELSAT Business Services (IBS)

The modem is compatible with the following modems within the operating parameters defined in this manual:

• OM-73(V)

• MD-1340

• MD-1352(P)/U (BEM-7650)

• SLM-8650

• SLM-3650

• SLM-6650

• SLM-4650

• LM-46/4046

• MD-945 (OM-73 interoperability mode only; orderwire not supported)

1–2

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1.2.1 Definition of Modulator Functions

The modulator section accepts data and clock from a digital signal source and after appropriate processing modulates the information on an IF carrier. The modulator provides the following functions:

1. Interface that receives digital signals, including data, clock, frequency reference, and control from a digital signal source.

2. A function that scrambles the data.

3. A differential encoder.

4. Forward Error Correction (FEC) encoding.

5. Perform BPSK, QPSK, OQPSK, 8-PSK, and 16-QAM modulation.

6. An output IF signal.

7. Setup, control, monitoring, and upgrade of the modulator.

8. Built-in Test (BIT) function that detects fault conditions and allows faults to be isolated to the modulator. This includes provision for an IF loopback and a transmit interface test data pattern.

1.2.2 Definition of Demodulator Functions

The demodulator section accepts a signal from an Intermediate Frequency (IF) carrier, demodulate the IF carrier, and after appropriate processing, outputs the data and clock to the user. The demodulator provides the following functions:

1. An input for the IF signal.

2. Acquisition functions and a function to demodulate BPSK, QPSK, OQPSK, 8-PSK, and 16-QAM carriers.

3. Forward Error Correction (FEC) decoding.

4. A differential decoder.

5. Descrambles the received data.

6. Digital interface to output digital signals, including data, and associated clock.

7. Setup, control, monitoring, and upgrade of the demodulator.

8. Built-in Test (BIT) function that detects fault conditions and allow faults to be isolated to the demodulator. This includes provision for an IF loopback and a way to measure the error using a test data pattern.

1–3

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1.2.3 Definition of Interface/M&C Functions

The interface/M&C section consists of a device having the following identifiable functions:

1. Terrestrial Interface, defined by EIA-422 (balanced circuits) [MIL-STD-188-114A Type II and III compatible].

2. Multiplex/Demultiplex an asynchronous data channel onto the primary data channel.

3. Provide Intelsat compatible Overhead Framing for Open Network interoperability.

4. Provide a buffer that can be clocked by the Tx, terrestrial source, an external reference, internal clock, or from the recovered clock from the satellite link.

5. Monitor the modem status without interrupting service

6. Provide an interface for control of the modem parameters via the front panel or serial remote control interface

1.2.4 Additional Features

The modem contains the following additional features:

• Fully Accessible System Topology (FAST)

• Built-in self test (BIST)

• Asymmetrical loop timing (ASLT)

• Selectable near or far end, baseband loopback with ASYNC overhead option enabled

• Intelsat compliant Reed-Solomon Codec

• ASYNChronous Channel Unit Overhead (ASYNC)

• Automatic Uplink Power Control (AUPC)

• Turbo Product Code (TPC) Forward Error Correction (FEC) (Hardware Option)

• G.703 Optional Interface with Overhead Card (AS/10175), 50-pin interface and

access to IESS ESC

1–4

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1.3 Operating Modes

Table 1-1 Operating Modes

Modes Description

7650-00 This is the basic OM-73 compatibility mode. 7650-02 This mode is compatible with the SLM8650-02 modem up to the 8.448

Mbps data rate limit of the SLM-8650. Operation in this mode requires the optional ASYNC option to be

activated.

EFD This is the basic closed network non-OM73 operating mode compatible

with legacy-closed network Comtech EF Data modems.

ASYNC This mode allows for an asynchronous overhead channel to be

multiplexed and demultiplexed onto the primary data channel. Automatic Uplink Power Control (AUPC) is available to maintain the link

margin of a duplex link during the normal fades that occur with a satellite communication network.

IDR, IBS, IBS-309, and VSAT-IBS

Custom This mode of operation enables the programming of the modem for

These modes of operation are typical open network operating modes used within the INTELSAT and EUTELSAT satellite networks.

emulating most proprietary modems.

1.4 Options

Table 1-2 SLM-7650 Options

Option Part No. Description Remarks

System Configuration

Modulation Type

Overhead Framing

Reed-Solomon (IESS Fixed) Turbo FEC PL/9652-1 Tx and Rx Option G.703 Option

Overhead Interface

PL/9709-1 90 – 264 VAC TNC Standard Chassis Configuration PL/9709-2 90 – 264 VAC BNC Option SS/SLM7650-0009 SS/SLM7650-0010 SS/SLM7650-0010 Rx Only Option SS/SLM7650-0009 Tx Only Option PL/9685-1 37-pin EIA-449 Standard Baseband Interface PL/9685-2 25-pin EIA-530 Option BPSK, QPSK, OQPSK Standard SS/SLM7650-0004 BPSK, QPSK, OQPSK, 8-PSK Option SS/SLM7650-0004 SS/SLM7650-0005

9.6 kbps to 10 Mbps Standard Variable Data Rate SS/SLM7650-0003 9.6 kbps to 20 Mbps Option SS/SLM7650-0006 IDR/IBS Option SS/SLM7650-0007 ASYNC/AUPC Option SS/SLM7650-0006 SS/SLM7650-0007 SS/SLM7650-0008 Tx and Rx Option

PL/10175-1 PL/10175-2

Tx and Rx Standard

BPSK, QPSK, OQPSK, 8-PSK, 16-QAM

IDR/IBS/ASYNC/AUPC Option

G.703, 50 pin, access to IESS ESC

Option

1–5

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SLM-7650 Satellite Modem Revision 4 Introduction MN/SLM7650.IOM

1.5 System Specifications Summary

Table 1-3. System Specifications Summary

Characteristic Specification

System

Operating Frequency Range 50 to 90, 100 to 180 MHz, in 1 Hz steps Modulation Types Non-Turbo Modulation Types

BPSK: 1/1 and 1/2 (CEVD) QPSK: 1/1, 1/2, 3/4, and 7/8 (CEVD) OQPSK: 1/1, 1/2, 3/4, and 7/8 (CEVD) 8-PSK: 2/3 and 5/6 (TCM)

16-QAM: 3/4, 7/8 (CEVD) Digital Data Rate 9.6 kbps to 20.0 Mbps, in 1 bps steps Symbol Rate 9.6 ks/s to 10 Ms/s External Reference In 1, 5, 10, or 20 MHz, selectable Internal Reference Stability Scrambling V.35 scrambler variations to meet MIL-STD-188-165 and IESS-308, -309,

IDR/IBS Framing Compatibility Support for IDR and IBS framing. Allows basic IDR/IBS open network

Built-in Test (BIT) Fault and status reporting, BER performance monitoring, IF loopback,

Summary Faults Reported via 15-pin D sub,

Modulation

Output Power +5 to –30 dBm, adjustable in 0.1 dB steps Output Return Loss 17 dB Output Impedance Spurious 0 to 500 MHz (-5 to –30 dBm) –5 dBc

Tx Clock Source INT, Tx Terrestrial, and Data Source Sync Output Connector TNC

Demodulation

Input Power:

Desired Carrier

Maximum Composite Input Impedance Input Connector TNC Carrier Acquisition Range Input Return Loss 17 dB minimum Buffer Clock INT, EXTERNAL, Tx Terrestrial, Rx Satellite Elastic Buffer 32 to 1,048,576 bits selectable

± 2 x 10

-310.

operation.

programmable test modes, Tx/Rx 2047 pattern provides and estimated BER.

FORM C relay contacts for Tx, Rx, Common equipment faults, and Tx and Rx Alarms.

50Ω

0 to 500 MHz (+5 tp –20 dBm) –50 dBc > 64 kbps o to 500 MHz (+5 to –20 dBm) _45 dBc < 64 kbps

-15 to –55 dBm 0 dBm or +40 dBc

50Ω

± 35 kHz, selectable

-7

Turbo Modulation Types BPSK: 5/16 and 21/44 QPSK: 3/4, 7/8, 17/18, and 21/44 OQPSK: 3/4, 7/8, 17/18, and 21/44 8-PSK: 3/4, 7/8, and 17/18 16-QAM: 3/4 and 7/8

1–6

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SLM-7650 Satellite Modem Revision 4 Introduction MN/SLM7650.IOM

Table 1-3. System Specifications Summary (continued)

Characteristic Specification Coding Options

Uncoded 1/1 Viterbi K=7 Viterbi and Reed-Solomon Concatenated Trellis Per IESS-310 Trellis and Reed-Solomon Concatenated Turbo Tutbo product Code (TPC)

Open Network Option

IDR INTELSAT IESS-308 (framing only) IDR INTELSAT IESS-310 (framing only) IBS INTELSAT IESS-309 (framing only)

Environmental and Physical Speciufication

Prime Power 90 to 264 VAC, 47 to 63 Hz (DC optional) Mounting 1 RU Size 19W x 19D x 1.71H inches (1 RU)

(48W x 48D x 4.3H cm) Weight < 15 lbs. (< 6.8 kg) Temperature:

Operating Storage (Non-operational)

Humidity 0 to 95%, non-condensing

0 to 50°C (32 to 122°F)

-40 to +70°C (-40 to 158°F)

1–7

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SLM-7650 Satellite Modem Revision 4 Introduction MN/SLM7650.IOM

1.5.1 Bit Error Rate Performance With Noise

Refer to the following tables for BER performance over the specified data rate ranges. The table values reflect specified guaranteed performance of the demodulator when operating with the associated modulator and noise. Typically the performance shall be 0.5 dB better than specified for adequate production margin.

1.5.1.1 Vfiterbi Decoding BER Performance

Table 1-4. Viterbi Decoder BER

Eb/No Performance Viterbi Decoder, QPSK

Viterbi Reed-Solomon Turbo

BER 1/2 3/4 7/8 1/2 3/4 3/4 7/8

10-3 4.2 5.2 6.4

10-4 4.8 6.0 7.2

10-5 5.5 6.7 7.9

10-6 6.1 7.5 8.6 4.1 5.6 4.1 4.5

10-7 6.7 8.2 9.2 4.2 5.8 4.3 4.6

10-8 7.2 8.8 9.9 4.4 6.0 5.5 4.7

-10

5.0 6.3 5.5 4.8

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SLM-7650 Satellite Modem Revision 4 Introduction MN/SLM7650.IOM

1.5.1.2 Viterbi Decoder and Reed-Solomon BER Performance,

Table 1-5. High Order Modulation Option

Eb/No Performance, Viterbi Decoder and Reed-

Solomon

Non-Turbo Turbo

8-PSK 16-QAM 8-PSK 16-QAM

BER 2/3 5/6 3/4 7/8 3/4 7/8 3/4 7/8

10-6 6.2 8.2 8.4 9.8 6.5 7.1 7.6 8.2

10-7 6.5 8.5 8.6 10.0 6.9 7.2 7.95 8.35

10-8 6.7 8.9 8.8 10.3 7.2 7.3 8.3 8.5

10-9 6.9 9.3 9.0 10.5 7.5 7.4 8.65 8.65

-10

7.2 9.7 9.2 10.8 7.8 7.5 9.0 8.8

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SLM-7650 Satellite Modem Revision 4 Introduction MN/SLM7650.IOM

1.5.2 Dimensional Envelope

Note: Dimensions are given in both inches and millimeters.

1–10

Figure 1-2. Dimensional Envelope

Page 25

Chapter 2. INSTALLATION

This chapter provides unpacking and installation instructions, system options, and a description of external connections.

The equipment contains parts and assemblies sensitive to damage by Electrostatic Discharge (ESD). Use ESD precautionary procedures when touching, removing, or inserting PCBs.

CAUTION

2.1 Unpacking

The modem and manual are packaged in pre-formed, reusable, cardboard carton containing foam spacing for maximum shipping protection.

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

CAUTION

To remove the modem:

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

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

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

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

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

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

7. Refer to Section 2.2 for installation instructions.

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SLM-7650 Satellite Modem Rev. 3 Installation MN/SLM7650.IOM

2.2 Installation

2.2.1 Installation Procedure

Install the SLM-7650 into the equipment rack as follows:

1. Carefully lift the modem into the selected position in the equipment rack. Refer Figure 1-2 for unit dimensional envelope.

2. Connect the cables to the proper locations on the rear panel.

Notes:

1. To allow proper cooling of the unit, the modem shall be positioned in a manner to allow an uninterrupted airflow around the unit, including no blockages in front of the fan assembly.

2. If there is any problem with the installation, contact Comtech EF Data’s Customer Support Department.

2.2.2 External Modem Connections

Op ti on al G. 70 3 C ar d

Figure 2-1. Rear Panel

2.2.2.1 Power Entry

Table 2-1. Modem Rear Panel Connectors

AC Option

Input Power 60W maximum, 50W typical Input Voltage 90 to 132, or 175 to 264 VAC

Connector Type I.E.C. Fuse Protection 2A slo-blo

Unit switches range automatically

Line and neutral fusing 5 mm type fuses

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SLM-7650 Satellite Modem Rev. 3 Installation MN/SLM7650.IOM

2.2.2.2 IF Connection: Transmit and Receive

Table 2-2. IF Interface

Connector Name Connector Type

Tx IF CP1 TNC 50Ω (optional BNC 50 Ω) Rx IF CP2 TNC 50Ω (optional BNC 50 Ω)

2.2.2.3 External Reference Input

Table 2-3 Modem External Reference Input

Connector Name Designation Connector Type

REF CP3

TNC 50Ω

(optional BNC 50 Ω)

2.2.2.4 Terrestrial Data Interfaces

Table 2-4. Terrestrial Data Interface

37-Pin D Female

Pin # Signal Name Pin # Signal Name

1 GND 2 N/C 20 GND 3 MOD_FLT 21 DEMOD_FLT 4 SDA 22 SDB 5 STA 23 STB 6 RDA 24 RDB 7 RTSA 25 RTSB 8 RTA 26 RTB 9 CTSA 27 CTSB 10 N/C 28 N/C 11 DMA 29 DMB 12 N/C 30 N/C 13 RRA 31 RRB 14 N/C 32 N/C 15 N/C 33 N/C 16 EXC/MCA 34 EXC/MCB 17 TTA 35 TTB 18 N/C 36 N/C 19 GND 37 GND

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SLM-7650 Satellite Modem Rev. 3 Installation MN/SLM7650.IOM

Table 2-5. Terrestrial Data Interface

25-Pin D Female (Optional)

Pin # Signal Name Pin # Signal Name

1 GND 2 SDA 14 SDB 3 RDA 15 STA 4 RTSA 16 RDB 5 CTSA 17 RTA 6 DMA 18 N/C 7 GND 19 RTSB 8 RRA 20 EXC/MCA 9 RTB 21 DF 10 RRB 22 DMB 11 TTB 23 EXC/MCB 12 STB 24 TTA 13 CTSB 25 MF

2.2.2.5 Remote Control Interface (M&C)

Table 2-6. Remote Control Interface (M&C)

Remote Control Interface, 9 Pin D Female, DCE

EIA-485 4 Wire EIA-485 2 Wire EIA-232

Pin # Signal Name I/O Pin # Signal Name I/O Pin # Signal Name I/O

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

2–4

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SLM-7650 Satellite Modem Rev. 3 Installation MN/SLM7650.IOM

2.2.2.6 Asynchronous Data Interface

Table-2-7. Asynchronous Data Interface

Asynchronous Interface, 9-Pin D Female, DCE

EIA-485 (4-Wire) EIA-485 (2-Wire) EIA-232

Pin # Signal Name I/O Pin # Signal Name I/O Pin # Signal Name I/O

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

2.2.2.7 Faults Status

Table 2-8. Fault/Alarm Status Interface

Specifications

Connector Type = 15-pin D subminiature, female Form C Contact Ratings = 1A maximum at 24 VDC, 0.5A at 120 VAC

Pinout

Pin # Name Function Pin # Name Function

1 COM 10 COM 2 NO COMMON EQUIPMENT OK 11 NO TRANSMIT IS ALARMED 3 NC COMMON EQ IS FAULTED 12 NC TRANSMIT IS OK 4 COM 13 COM 5 NO RECEIVE IS OK 14 NO RECEIVE IS ALARMED 6 NC RECEIVE IS FAULTED 15 NC RECEIVE IS OK 7 COM 8 NO TRANSMIT IS OK 9 NC TRANSMIT IS FAULTED

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SLM-7650 Satellite Modem Rev. 3 Installation MN/SLM7650.IOM

2.2.2.8 G.703 Overhead Option Card Connections

2.2.2.8.1 50-Pin Interface Connector

Table 2-9. 50-Pin Sub-D Female Interface Connector

50-Pin Sub-D Female

Pin # IDR IBS ASYNC / Normal D&I

1, 2 GND GND GND GND 3 AGC (O) AGC (O) AGC (O) AGC (O) 33 DF (O) DF (O) DF (O) DF (O) 49 MF (O) MF (O) MF (O) MF (O) 34 SDA G.703 (I) SDA G.703 (I) SDA G.703 (I) DDI_A G.703 (I) 18 SDB G.703 (I) SDB G.703 (I) SDB G.703 (I) DDI_B G.703 (I) 36 RDA G.703 (O) RDA G.703 (O) RDA G.703 (O) IDO_A G.703 (O) 20 RDB G.703 (O) RDB G.703 (O) RDB G.703 (O) IDO_B G.703 (O) 37 TXDA EIA422 8k (I) SD-A EIA422 (I) SD-A EIA422 (I) DDO-A G.703 (O) 38 TXDB EIA422 8k (I) SD+B EIA422 (I) SD+B EIA422 (I) DDO-B G.703 (O) 12 BWAI_1 (I) TT-A EIA422 (I) TT-A EIA422 (I) 13 BWAI_2 (I) TT+B EIA422 (I) TT+B EIA422 (I) 21 TXC-A EIA422 8k (O) ST-A EIA422 (O) ST-A EIA422 (O) 22 TXC+B EIA422 8k (O) ST+B EIA422 (O) ST+B EIA422 (O) 45 Aud1-Ain / 64SDA (I) RTS-A EIA422 (I) RTS-A EIA422 (I) 29 Aud1-Bin / 64SDB (I) RTS+B EIA422 (I) RTS+B EIA422 (I) 47 Aud2-Ain / 64STA (O) CTS-A EIA422 (O) CTS-A EIA422 (O) 31 Aud2-Bin / 64STB (O) CTS+B EIA422 (O) CTS+B EIA422 (O) 39 RXDA EIA422 8k (O) RD-A EIA422 (O) RD-A EIA422 (O) IDI-A G.703 (I) 40 RXDB EIA422 8k (O) RD+B EIA422 (O) RD+B EIA422 (O) IDI-B G.703 (I) 23 RXC-A EIA422 8k (O) RT-A EIA422 (O) RT-A EIA422 (O) 24 RXC+B EIA422 8k (O) RT+B EIA422 (O) RT+B EIA422 (O) 46 Aud1-Aout / 64RTA (O) RR-A EIA422 (O) RR-A EIA422 (O) 30 Aud1-Bout / 64RTB (O) RR+B EIA422 (O) RR+B EIA422 (O) 48 Aud2-Aout / 64RDA (O) DSR-A EIA422 (O) DSR-A EIA422 (O) DSR_ESC EIA232 (O) 32 Aud2-Bout / 64RDB (O) DSR+B EIA422 (O) DSR+B EIA422 (O) 35 EXC-A EIA422 (I) EXC-A EIA422 (I) EXC-A EIA422 (I) EXC-A EIA422 (I) 19 EXC+B EIA422 (I) EXC+B EIA422 (I) EXC+B EIA422 (I) EXC+B EIA422 (I) 5 TXOctBin EIA422 (I) TXD_ESC EIA232 (I) TXDA_ESC EIA485/232 (I) TXD_ESC EIA232 (I) 4 TXOctAin EIA422 (I) TXDB_ESC EIA485 (I) 7 RXOctBout EIA422 (O) RXD_ESC EIA232 (O) RXDA_ESC EIA485/232 (O) RXD_ESC EIA232 (O) 6 RXOctAout EIA422 (O) RXDB_ESC EIA485 (O) 14 BWAI_3 (I) TXAOct EIA422 (I) 15 BWAI_4 (I) TXBOct EIA422 (I) 8 BWO1_C RXAOct EIA422 (O) 9 BWO2_C RXBOct EIA422 (O) 10 BWO3_C PROMPT_C PROMPT_C 11 BWO4_C SERVICE_C SERVICE_C 25 BWO1_NC TCLK_ESC EIA232 (O) CTS_ESC EIA232 (O) TCLK_ESC EIA232 (O) 26 BWO2_NC RCLK_ESC EIA232 (O) RCLK_ESC EIA232 (O) 27 BWO3_NC PROMPT_NC PROMPT_NC 28 BWO4_NC SERVICE_NC SERVICE_NC 41 BWO1_NO DSR_ESC EIA232 (O) DSR_ESC EIA232 (O) DSR_ESC EIA232 (O) 42 BWO2_NO 43 BWO3_NO PROMPT_NO PROMPT_NO 44 BWO4_NO SERVICE_NO SERVICE_NO 16 Demod_Fault_C 50 Demod_Fault_NO 17 Def_Maint_Alrm (O)

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SLM-7650 Satellite Modem Rev. 3 Installation MN/SLM7650.IOM

2.2.2.8.2 15-Pin Connector (G.703 Balanced)

Table 2-10. 15-Pin Sub-D Female (G.703 Balanced)

15 Pin Sub-D Female

Pin # G.703 (Non-D&I) D&I

1 SD_A G.703 (I) DDI_A G.703 (I) 9 SD_B G.703 (I) DDI_B G.703 (I) 12 DDO_A G.703 (O) 5 DDO_B G.703 (O) 13 IDI_A G.703 (I) 6 IDI_B G.703 (I) 3 RD_A G.703 (O) IDO_A G.703 (O) 11 RD_B G.703 (O) IDO_B G.703 (O) 7 EXC_A EIA-422 (I) EXC_A EIA-422 (I) 8 EXC_B EIA-422 (I) EXC_B EIA-422 (I) 2, 4 Ground Ground

2.2.2.8.3 BNC Connectors (G.703 Unbalanced)

Table 2-11. 75 Ω BNC Connectors (G.703 Unbalanced)

Connector Characteristics

Tx Data G.703 (Input) Rx Data G.703 (Output)

BNC 75 Ω, Female BNC 75 Ω, Female

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This page is intentionally blank.

2–8

Page 33

Chapter 3. OPERATION

This chapter describes the front panel operation of the modem, including the menus and their explanations, and clocking information. For information about remote control operation, refer to Appendix B.

3.1 Front Panel

The modem front panel (Figure 3-1) enables the user to control modem configuration parameters and display the modem status.

Figure 3-1. SLM-7650 Front Panel

The front panel features include:

• 24-character, 2-line LCD display

• 6-button keypad for local control

• 8 LEDs to provide overall status at a glance

Note: All functions are accessible at the front panel by scrolling through a multilevel

menu using the front panel keypad and display.

3-1

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SLM-7650 Satellite Modem Revision 4 Operation MN/SLM7650.IOM

3.1.1 LED Indicators

The 8 LEDs on the front panel indicate general modem summary fault information and status. The indicators are defined as follows in Table 3-1:

Table 3-1. Front Panel Indicators

Name LED Meaning

Faults

Transmit Red/Yellow A fault (red) or alarm (yellow) condition exists in the transmit chain. Receive Red/Yellow A fault (red) or alarm (yellow) condition exists in the receive chain. Common Red A common equipment fault condition exists. Stored Yellow

Status

Power On Green Power is applied to the modem. Transmitter On Green

Carrier Detect Green Decoder is locked. Test Mode Yellow Flashes when the modem is in a test configuration.

A fault or alarm has been logged and stored. The fault may or may not be active.

Transmitter is currently on. This indicator reflects the actual condition of the transmitter, as opposed to the programmed condition.

3.1.2 Front Panel Keypad

The front panel keypad (Figure 3-2) controls the local operation of the modem. The keypad consists of six keys. Each key provides one or more logical functions (Table 3-2). The modem responds by beeping whenever a key is pressed:

• A single-beep indicates a valid entry and the appropriate action was taken.

• A double-beep indicates an invalid entry or a parameter is not available for

operation.

Figure 3-2. Keypad

3-2

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SLM-7650 Satellite Modem Revision 4 Operation MN/SLM7650.IOM

Table 3-2. Keypad Functions

Key Function

[ENTER]

[CLEAR]

[←] and [→]

[↑] and [↓]

This key is used to select a displayed function, or to execute a modem configuration change.

This key is used to back out of a selection, or to cancel a configuration change, which has not been executed using [ENTER]. Pressing [CLEAR] generally returns the display to the previous selection.

These keys are used to move to the next selection, or to move the cursor for certain functions.

These keys are used primarily to change configuration data (numbers), but are also used at times to move from one section to another.

3.2 Front Panel Operation

3.2.1 Front Panel Menu Operation

When the modem is first powered ON, the sign-on message for the menu system displays. This sign-on message is also displayed when the [CLEAR] key is pressed repeatedly from anywhere within the menu system. The sign-on message displays the following information:

• Line 1 is the modem model number and type.

• Line 2 is the version number of the M&C firmware.

An overview of the first three layers in modem menu system is shown in Figure 3-3.

Function Select is the main level of the menu system. To access this level from the signon message, press any of the arrow keys. The modem control and monitor parameters are accessed from the following Function Select menus:

• Configuration

• Monitor

• Faults/Alarms

• Stored Faults/Alarms

• Remote Automatic Uplink Power Control (AUPC)

• Utility

Press [←] or [→] to move from one selection to another. When line 2 displays the desired function, select that level by pressing [ENTER]. After entering the appropriate functional level, press [←] or [→] to move to the desired function.

3-3

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SLM-7650 Satellite Modem Revision 4 Operation MN/SLM7650.IOM

SLM-765 0 "TYPE"

VER:2.1. 3

FUNCTION

SELECT

CONFIGURATION

MODULATOR

CONFIGURATION

DEMODULATOR

CONFIGURATION

INTERFACE

CONFIGURATION

LOCAL MODEM

AUPC

CONFIGURATION

SAVE

CONFIGURATION

RECALL

FUNCTION

SELECT

MONITOR

MONITOR RAW BER

MONITOR

CORREC TED BER

MONITOR

EB/NO

MONITOR

REC EIVE SIGNAL

MONITOR

SWEEP

FREQ UENC Y

MONITOR

BUFFER FI LL

FUNCTION

SELECT

FAULTS/ALARMS

MODULATOR

FAULTS/ALARMS

DEMODULATOR

FAULTS/ALARMS

TX INTERFACE

FAULTS/ALARMS

RX INTERFACE

FAULTS/ALARMS

COMMON

FAULTS/ALARMS

BACKWARD

ALARM S

FUNCTION SELE CT STORED FAULTS/ALARMS

STOR ED

FAULTS/ALARMS

MODULATOR

STOR ED

FAULTS/ALARMS

DEMODULATOR

STOR ED

FAULTS/ALARMS

TX INTERFACE

STOR ED

FAULTS/ALARMS

RX INTERFACE

STOR ED

FAULTS/ALARMS

COMMON

STORED

FAULTS/ALARMS

BACKWARD

ALARMS

FUNCTION

SELECT

REMOTE AUP C

CONFIGURATION

REMOTE AUP C

MONITOR

FUNCTION

SELECT UTILITY

UTILITY

MODULATOR

UTILITY

DEMODULATOR

UTILITY

INTERFACE

UTILITY

SYSTEM

UTILITY

MODEM T YPE

MONITOR

2047 ERRORS

FRAME BER

Key:

ACCESS TO

SUBMENU

STORED

FAULTS/ALARMS

CLEAR??

CONDITIO NAL OR

OPTION-

DEPEN DENT

Parameter

Information

Figure 3-3. Main Menu

3-4

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SLM-7650 Satellite Modem Revision 4 Operation MN/SLM7650.IOM

Notes:

1. Operating mode selections and hardware configuration may change the front panel menu selection.

2. Parameters that are specific to certain modem configurations are only accessible after selecting the appropriate modem configuration. This prevents incompatible parameters from accidentally being selected.

3. All of the parameters are accessible in the Custom mode. Take caution not to select incompatible parameters, as the modem does not block out incompatible command choices in the Custom mode.

3.2.2 Configuration

To view or change the modem’s configuration, enter the Configuration level from the Function Select menu. Once in the Configuration menu, press [←] or [→] to scroll through the Configuration menu selection:

• Modulator

• Demodulator

• Interface

• Local AUPC

• Save

• Recall

Press [ENTER] to select the desired Configuration menu option. To view the options for the selected configuration parameters, press [←] or [→]. To change a configuration parameter, press [ENTER] to begin the change process.

Press an arrow key to change the parameters. When the correct parameters are displayed, press [ENTER] to execute the change. This action initiates the necessary programming by the modem.

To undo a parameter change prior to execution, press [CLEAR].

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SLM-7650 Satellite Modem Revision 4 Operation MN/SLM7650.IOM

3.3 Digital Data Rate and Symbol Rate

The digital data rate is selectable in 1 bit/s increments, from 9.6 kbps to 20.0 Mbps depending on modulation type, code rate, and overhead. The symbol rate range is

9.6 kS/s to 10.0 MS/s, and is a limiting factor to data rate. See for Table 3-3 details.

Table 3-3. Data Rate Ranges

Operating Mode

7650-00, CEFD Clsd BPSK, Uncoded None 9.60 10.000 7650-00, CEFD Clsd QPSK, OQPSK Uncoded None 19.20 20.000

7650-00, CEFD Clsd BPSK 1/2 Viterbi 9.60 5.000 7650-00, CEFD Clsd QPSK, OQPSK 1/2 Viterbi 9.60 10.000 7650-00, CEFD Clsd QPSK, OQPSK 3/4 Viterbi 14.40 15.000

7650-00, CEFD Clsd QPSK, OQPSK 7/8 Viterbi 16.80 17.500 7650-00, CEFD Clsd 8-PSK 2/3 Trellis 64.00 20.000 7650-00, CEFD Clsd 8-PSK 5/6 Trellis 80.00 20.000

7650-00, CEFD Clsd BPSK 1/2 Viterbi and R-S 9.60 4.555 7650-00, CEFD Clsd QPSK, OQPSK 1/2 Viterbi and R-S 9.60 9.111 7650-00, CEFD Clsd QPSK, OQPSK 3/4 Viterbi and R-S 13.12 13.666

7650-00, CEFD Clsd QPSK, OQPSK 7/8 Viterbi and R-S 15.31 15.944 7650-00, CEFD Clsd 8-PSK 2/3 Trellis and R-S 64.00 18.222 7650-00, CEFD Clsd 8-PSK 5/6 Trellis and R-S 80.00 20.000 7650-00, CEFD Clsd 16-QAM 3/4 Viterbi and R-S 256.00 20.000

7650-00, CEFD Clsd 16-QAM 7/8 Viterbi and R-S 256.00 20.000 CEFD Clsd BPSK 21/44 TPC 9.60 4.772 CEFD Clsd BPSK 5/16 TPC 9.60 3.125

CEFD Clsd QPSK, OQPSK 21/44 TPC 9.60 9.545 CEFD Clsd QPSK, OQPSK 3/4 TPC 14.40 15.000 CEFD Clsd QPSK, OQPSK 7/8 TPC 16.80 17.500

CEFD Clsd QPSK, OQPSK 17/18 TPC 18.13 18.888 CEFD Clsd 8-PSK 3/4 TPC 72.00 20.000 CEFD Clsd 8-PSK 7/8 TPC 84.00 20.000

CEFD Clsd 8-PSK 17/18 TPC 90.60 20.000 CEFD Clsd 16-QAM 3/4 TPC 256.00 20.000 CEFD Clsd 16-QAM 7/8 TPC 256.00 20.000

7650-02, Async BPSK, Uncoded Async 9.60 8.448 7650-02, Async QPSK, OQPSK Uncoded Async 18.00 8.448 7650-02, Async BPSK 1/2 Viterbi, Async 9.60 4.687

7650-02, Async QPSK, OQPSK 1/2 Viterbi, Async 9.60 8.448 7650-02, Async QPSK, OQPSK 3/4 Viterbi, Async 13.50 8.448 7650-02, Async QPSK, OQPSK 7/8 Viterbi, Async 15.75 8.448

7650-02, Async 8-PSK 2/3 Trellis, Async 64.00 8.448 7650-02, Async 8-PSK 5/6 Trellis, Async 80.00 8.448 7650-02, Async BPSK 1/2 Viterbi and R-S, Async 9.60 8.448

Modulation/Coding

FEC/Overhead Type

Min DR (kbps)

Max DR

(Mbps)

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Operating Mode

7650-02, Async QPSK, OQPSK 1/2 Viterbi and R-S, Async 9.60 8.448 7650-02, Async QPSK, OQPSK 3/4 Viterbi and R-S, Async 12.30 8.448 7650-02, Async QPSK, OQPSK 7/8 Viterbi and R-S, Async 14.35 8.448

7650-02, Async 8-PSK 2/3 Trellis and R-S, Async 64.00 8.448 7650-02, Async 8-PSK 5/6 Trellis and R-S, Async 80.00 8.448 7650-02, Async 16-QAM 3/4 Viterbi and R-S, Async 256.00 8.448

7650-02, Async 16-QAM 7/8 Viterbi and R-S, Async 256.00 8.448 IDR QPSK 1/2 Viterbi, IDR, 1544 1544.00 1.544 IDR QPSK 3/4 Viterbi, IDR, 1544 1544.00 1.544 IDR QPSK 1/2 Viterbi, IDR, 2048 2048.00 2.048

IDR QPSK 3/4 Viterbi, IDR, 2048 2048.00 2.048 IDR QPSK 1/2 Viterbi, IDR, 6312 & 8448 6312.00 8.448 IDR QPSK 3/4 Viterbi, IDR, 6312 & 8448 6312.00 8.448

IDR QPSK 1/2 Viterbi and R-S, IDR, 1544 1544.00 1.544 IDR QPSK 3/4 Viterbi and R-S, IDR, 1544 1544.00 1.544 IDR QPSK 1/2 Viterbi and R-S, IDR, 2048 2048.00 2.048

IDR QPSK 3/4 Viterbi and R-S, IDR, 2048 2048.00 2.048 IDR QPSK 1/2

IDR QPSK 3/4

IDR/IESS310 = ON 8-PSK 2/3 Trellis and R-S, IDR 1544.00 8.448 IBS QPSK 1/2 Viterbi, IBS 64.00 8.448 IBS QPSK 3/4 Viterbi, IBS 64.00 8.448

IBS QPSK 1/2 Viterbi and R-S, IBS 64.00 8.333 IBS QPSK 3/4 Viterbi and R-S, IBS 64.00 8.448 IBS/IESS310 = ON 8-PSK 2/3 Trellis and R-S, IBS 64.00 1.536

IBS-309 QPSK 1/2 Viterbi and R-S, IBS 64.00 8.448 IBS-309 QPSK 3/4 Viterbi and R-S, IBS 64.00 8.448 VSAT-IBS BPSK 1/2 Viterbi and R-S 64.00 4.589

VSAT-IBS QPSK 1/2 Viterbi and R-S 64.00 8.448 VSAT-IBS QPSK 3/4 Viterbi and R-S 64.00 8.448 VSAT-IBS/ IESS310 = ON 8-PSK 2/3 Trellis and R-S 64.00 1.536

Modulation/Coding

FEC/Overhead Type

Viterbi and R-S, IDR, 6312 & 8448

Min DR (kbps)

6312.00 8.448

Max DR

(Mbps)

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3.4 Menus

3.4.1 Configuration Menu

3.4.1.1 Modulator Menu

Menu Item Specifications/usage

TX-DR Data Rate, Code Rate, and

Modulation Type

TX-IF FREQUENCY

TX-IF OUTPUT Programs the modulator output On or Off.

TX POWER LEVEL Programs the modulator output power level from:

SCRAMBLER TYPE Programs the scrambler IESS, OM73, or TURBO.

Filter: A, B, C, D, or V

Data rates are referenced in Paragraph 3.3

On entry, the current transmitter rate is displayed with the flashing cursor on the first character of the code rate on line 1. Line 2 displays the data rate. Press [←] or [→] to make the selection. To select the currently defined variable data rate, select TX-V, and press [ENTER] twice.

To change the rate using the variable rate selection, press [ENTER] when TX-V is displayed. A flashing cursor is displayed on the first character of the coding type on line 1. Press [←] or [→] to move the flashing cursor, and [↑] or [↓] to increment or decrement the digit at the flashing cursor. Press [ENTER] to execute the change.

Programs the modulator transmit frequency between 50 and 90 or 100 to 180 MHz, in 1.0 Hz steps.

On entry, the current transmitter frequency is displayed with the flashing cursor on the first character. Press [←] or [→] to move the flashing cursor, and [ increment or decrement the digit at the flashing cursor. Press [ENTER] to execute the change.

Note: When the transmitter frequency is changed, the transmitter is

automatically turned off to prevent the possible swamping of other channels. To turn the transmitter on, use the IF Output function.

On entry, the current status of the output is displayed. Press an arrow key to make the selection. Press [ENTER] to execute the change.

+5 to -30 dBm for no offset. An offset can be added through the Utility menu to remove losses or gains in the system.

On entry, the current transmitter power level is displayed with the flashing cursor on the first character. Press [↑] or [↓] to increase or decrease the output power level in 0.1 dBm steps. Press [ENTER] to execute the change.

On entry, the current status of the scrambler is displayed. Press an arrow key to make the selection. Press [ENTER] to execute the change.

↑] or [↓] to

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Menu Item Specifications/usage

SCRAMBLER Programs the scrambler On or Off.

On entry, the current status of the scrambler is displayed. Press an arrow key to make the selection. Press [ENTER] to execute the change.

DIFF. ENCODER Programs the differential encoder On or Off.

On entry, the current status of the differential encoder is displayed. Press an arrow key to make the selection. Press [ENTER] to execute the change.

CARRIER MODE

(Test Mode Configuration)

Programs the modem for continuous wave mode. Four modes of operation are available:

Normal (Off):

The Carrier mode is normally in the OFF position. To execute any of the Carrier continuous wave modes, enter the Carrier mode and select the test mode of choice.

Center:

Generates a carrier at the current modulator frequency. This can be

used to measure the output frequency.

Dual: Generates a dual side-band suppressed carrier signal. Side bands are

at one-half of the symbol rate from the carrier. This is used to check the channel balance and carrier null.

Offset:

Generates a single upper side-band suppressed carrier signal. The

upper side band is at one-quarter of the symbol rate from the carrier. This is used to check the quadrature.

On entry, the Center mode is displayed. To activate this test mode, press [ENTER]. Press an arrow key to select the desired mode.

To return to the Configuration menu, press [CLEAR].

RS ENCODER Programs the Reed-Solomon encoder On or Off.

On entry, the current status of the Reed-Solomon encoder is displayed. Press an arrow key to make the selection. Press [ENTER] to execute the change.

Notes:

1. Programming the Reed-Solomon encoder automatically turns off the RF transmitter.

2. A double beep will occur when attempting to turn on Reed-Solomon if the data rate and overhead type are invalid.

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3.4.1.2 Demodulator Menu

Menu Item Specifications/usage

RX-DR Data Rate, Code Rate, and

Modulation Type

RX-IF FREQUENCY

DESCRAMBLER TYPE Programs the descrambler IESS, OM73, or TURBO.

DESCRAMBLER Programs the descrambler On or Off.

DIFF. DECODER Programs the differential decoder on or off.

IF LOOP BACK

(Test Mode Configuration)

BER THRESHOLD Sets the BER threshold.

Filter: A, B, C, D, or V

Data rates are referenced in paragraph 3.3.

On entry, the current receiver rate is displayed with the flashing cursor on the first character of the code rate on line 1. The data rate is displayed on line 2. Press an arrow key to select one of four pre-defined rate (A, B, C, or D). To select the currently defined variable data rate, select RX-V, and press [ENTER] twice.

To change the rate using the variable rate selection, press [ENTER] when RX-V is displayed. A flashing cursor is displayed on the first character of the coding type on line 1. Press [←] or [→] to move the flashing cursor, and [↑] or [↓] to increment or decrement the digit at the flashing cursor. Press [ENTER] to execute the change.

Programs the demodulator receive frequency between 50 and 90 MHz or 100 to 180 MHz, in 1.0 Hz steps.

On entry, the current receive frequency is displayed with the flashing cursor on the first character. Press [←] or [→] to move the flashing cursor, and [↑] or [↓] to increment or decrement the digit at the flashing cursor. Press [ENTER] to execute the change.

On entry, the current status of the synchronous descrambler is displayed. Press an arrow key to make the selection. Press [ENTER] to execute the change.

On entry, the current status of the differential decoder is displayed. Press an arrow key to make the selection. Press [ENTER] to execute the change.

Programs the modem for IF loopback operation. When IF loopback is turned on, the demodulator input is connected to the

modulator output through an internal attenuator. The demodulator is programmed to the same frequency as the modulator. An attenuator within the modem connects the IF Out to the IF In. When IF loopback is turned off, the demodulator is tuned to the previous frequency and is reconnected to the IF input. Refer to Figure 5-9 for a block diagram of IF loopback operation.

On entry, the current status of IF loopback is displayed. Press an arrow key to make the selection. Press [ENTER] to execute the change.

If the BER threshold set is exceeded, a receive fault will be indicated by the modem status indicators. BER threshold may be set from 1.0 E-3 to 1.0 E-8, or may be disabled by specifying None.

On entry, the current setting of the BER threshold is displayed. Press [↑] or [↓] to select the desired setting. Press [ENTER] to execute the change.

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Menu Item Specifications/usage

SWEEP CENTER Programs the sweep center frequency for the directed sweep function.

The sweep center frequency can be set in the range from -35000 to +35000 Hz. On entry, the current programmed setting is displayed with a flashing cursor on

the first character. Press [←] or [→] to move the flashing cursor. Press [↑] or [↓] to increment or decrement the digit at the flashing cursor. Press [ENTER] to execute the change. When in directed sweep, the value from the sweep monitor screen (when the modem was last locked) should be entered for the sweep center frequency.

SWEEP RANGE

Programs the overall travel of the sweep width range during acquisition in the directed sweep mode. The sweep width may be set from 0 to 70000 Hz. When set at 70000 Hz, the modem is in the normal acquisition mode. Keep the sweep range narrow for low data rates.

On entry, the current programmed setting is displayed. Press [←] or [→] to move the flashing cursor. Press [↑] or [↓] to increment or decrement the digit at the flashing cursor. Press [ENTER] to execute the change. The smaller the range, the faster the modem will lock, provided the receive carrier center frequency is within the RX IF frequency sweep range.

SWEEP REACQUISITION

Programs the sweep reacquisition mode time duration. This is the time that the modem will remain in a narrow sweep of the selected range (± 500 Hz) after loss of acquisition. After this timer runs out, the modem will return to the normal acquisition sweep. The reacquisition time is 0 to 999 seconds.

On entry, the current programmed setting is displayed with a flashing cursor on the first character. Press [←] or [→] to move the flashing cursor. Press [↑] or [↓] to increment or decrement the digit at the flashing cursor. Select the number of seconds desired for the reacquisition mode. Press [ENTER] to execute the change.

RS DECODER

(Correction OFF is a Test Mode Configuration)

Programs the Reed-Solomon decoder On, Correction Off, or Off.

ON:

Enables the Reed-Solomon decoder to provide data error corrections.

CORRECTION_OFF: Turns off the Reed-Solomon decoder data error

correction circuitry. Data flow is then routed through normal data paths without error corrections. Only Viterbi error correction will be On.

OFF: The RS decoder is normally disabled (Off position). To execute any of

the Reed-Solomon decoder modes, enter the desired Reed-Solomon decoder and select the desired mode.

On entry, the current status of the Reed-Solomon decoder is displayed. Use an arrow key to select the desired mode. Press [ENTER] to execute the change.

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3.4.1.3 Interface Menu

Menu Item Specifications/usage

TX CLOCK SOURCE

TX CLOCK PHASE Programs the TX clock phase to Normal or Invert.

SCT PLL REF

Programs the clock source for the modem transmitter clock to the following configurations:

TX Terrestrial:

SCT (Internal): Setting SCT as the TX clock source will clock the data to the

Data Source Sync:

On entry, the current transmit clock setting is displayed. Press an arrow key to make the selection. Press [ENTER] to execute the change.

On entry, the current setting of the TX clock phase is displayed. Press [↑] or [↓] to make the selection. Press [ENTER] to execute the change.

Programs the timing source for the Serial Clock Transmit (SCT) Phase Lock Loop (PLL).

MODEM REF Source (Uses the timing standard that is programmed in the Modem Reference menu.)

EXT MASTER CLOCK (The MC input is on the baseband data interface. The frequency must be programmed in the Ext Master Clock Frequency menu screen.)

DATA SOURCE SYNC (appears only when DATA is selected as the Tx Clock source)

RX Loop (appears only when Loop Timing is ON) De-selecting DATA or Rx Loop is accomplished at the CONFIG / INTERFACE

On entry, the current timing source is displayed. Press [ Press [ENTER] to execute the change.

Selecting TX Terrestrial will clock the data to the encoder using the

customer terrestrial clock. Another term for this clock is terminal timing.

encoder using the internal clock of the modem. This indication will change to SCT (Loop) when loop timing is turned on.

The Clock for the modem input data will be recovered from the transitions of the input data. This clock is then used to phase lock the internal SCT clock and to clock the transmit data to the encoder. The SCT PLL REF will display Data Source Sync and can only be changed by selecting either SCT (Internal) or TX Terrestrial in this menu.

↑] or [↓] to make the selection.

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Menu Item Specifications/usage

EXT MASTER CLOCK FREQUENCY

Programs the external master clock input frequency between 9.6 kHz and 20 MHz. The data rate of the external master clock input will need to be entered by the user to match the expected rate at the input to the modem at the data I/O connector.

Notes:

1. If the EXT MC is selected as the timing source for the SCT PLL the frequency of the MC must meet one of the three following:

a. The MC frequency is equal to the transmit data rate. b. The transmit data rate and the MC freq. are both integer multiples of

600 Hz.

c. The transmit data rate and the MC freq. are both integer multiples of

1 kHz.

2. If the EXT MC is selected as the timing source for the Buffer Clock the frequency of the MC must meet one of the three following:

a. The MC frequency is equal to the receive data rate. b. The receive data rate and the MC freq. are both integer multiples of

600 Hz.

c. The receive data rate and the MC freq. are both integer multiples of

1 kHz.

On entry, the current setting for the external reference is displayed. Press [←] or [→] to increment or decrement the digit at the flashing cursor. Press [ENTER] to execute the change.

BUFFER CLOCK Programs the interface buffer output clock to one of the following modes:

RX (Satellite):

Turns off the buffer. This will clock the data in and out of the buffer with the same receive satellite clock. This is the fall back when either TX Terrestrial or the External Master Clock is missing.

SCT (Internal):

Clocks the data to the user with the internal clock of the modem.

This is also the fallback clock.

External Master Clock:

Clocks the data to the user with the external master clock input. (The MC input is on the baseband data interface. The frequency must be programmed in the Ext Master Clock Frequency menu screen.)

TX Terrestrial:

Clocks the data to the user with the customers Tx Terrestrial clock

input.

Drop and Insert applications only. Overhead must be installed.

Insert:

On entry, the current setting of the plesiochronous buffer clock is displayed. Press an arrow key to make the selection. Press [ENTER] to execute the change.

BUFFER SIZE Sets the size of the buffer.

On entry, the current buffer length is displayed. Press [↑] or [↓] to select the desired buffer size. The buffer size is displayed in seconds or bits. Enter the Interface Utility menu to change the buffer units to seconds or bits. If selecting seconds, choose from 1 to 48 ms, in increments of 1 ms or 0 (Bypass). If selecting bits, choose from 32 to 1,048,576 bits, in increments of 16 bits. Press [ENTER] to execute the change. Setting the RX buffer to RX Satellite will turn off the buffer.

Note: To have the modem calculate the plesiochronous shift, set the buffer units to

ms. When a specific buffer depth is desired, set the buffer units to bits. Select bits or ms from the Utility Interface menu.

BUFFER CENTER This configuration function is used to center the buffer.

Press [ENTER] twice to center the buffer.

RX CLOCK PHASE Programs the RX clock phase to Normal or Inverted.

On entry, the current status of the RX Clock is displayed. Press an arrow key to make the selection. Press [ENTER] to execute the change.

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Menu Item Specifications/usage

B-BAND LOOPBACK

(Test Mode Configuration)

Programs the modem for baseband loopback operation. Baseband loop back will turn around the data and clock to the user at the terrestrial

interface of the modem. This is a bi-directional loop so the data and clock over the satellite is also turned around. Refer to Figure 5-10 for a block diagram of baseband loopback operation.

On entry, the current status is displayed. Press an arrow key to make the selection. Press [ENTER] to execute the change.

LOOP TIMING

Loop timing ON will phase lock the SCT internal clock to the recovered satellite clock of the decoder. This is used at the Slave end of a Satellite link to clock the data in and out of the modem using the clock from the distant end of the link. Selecting Loop timing ON will cause the SCT (INT) to change to SCT (Loop) and the SCT PLL REF to display RX Loop. Turn loop timing OFF to make another choice at the SCT PLL REF menu.

On entry, the current status is displayed. Press an arrow key to make the selection.

Press [ENTER] to execute the change. TX CODING FORMAT AMI, B6ZS, B8ZS, or

HDB3

Programs the transmitter for AMI, B6ZS, B8ZS, or HDB3 coding of the baseband data.

On entry, the current coding format is displayed. Press an arrow key to make the

selection. Press [ENTER] to execute the change.

Note: This menu is only available when G.703 interface is installed. RX CODING FORMAT AMI, B6ZS, B8ZS, or

HDB3

Programs the receiver for AMI, B6ZS, B8ZS, or HDB3 coding.

On entry, the current coding format is displayed. Press an arrow key to make the

selection. Press [ENTER] to execute the change.

Note: This menu is only available when G.703 interface is installed. TX DATA Alarm Transmit data fault. Press an arrow key to select one of the following modes:

None:

The transmit interface fault Data/AIS is not activated.

Alarm Indication Signal (AIS): This is also commonly referred to as All Ones. The

M&C will produce an alarm if the customer is inputting data that is all ones.

Data:

The M&C will produce an alarm if the Customer input data is missing (all

zeros or all ones).

On entry, the current TX data fault that is being monitored is displayed. Press an arrow

key to make the selection. Press [ENTER] to execute the change. RX DATA ALARM Receive data Alarm. Selects a receive interface alarm monitor of None, AIS, or Data.

The data monitored for RX data is coming from the satellite. Refer to TX DATA

ALARM for a description of function choices.

On entry, the current RX DATA ALARM that is being monitored is displayed. Press an

arrow key to make the selection. Press [ENTER] to execute the change. TX 2047 PATTERN

(Test Mode Configuration)

Programs the modem to transmit a test pattern instead of the incoming data stream.

Selections are as follows:

NONE 2047

(compatible with a Fireberd BERT)

MIL-188

This is a modified 2047 pattern that is used to test the Data Source Sync

function of the modem. It has the maximum number of consecutive zeros that the modem can handle when recovering the clock from the data transitions.

On entry, the current status is displayed. Press an arrow key to make the selection.

Press [ENTER] to execute the change.

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Menu Item Specifications/usage

RX 2047 PATTERN

(Test Mode Configuration)

SERVICE CHANNEL ADJUST

DROP FORMAT

Programs the modem to monitor a test pattern. Selections are as follows:

See the options for TX 2047 Pattern.

The 2047 Errors menu choice under the Monitor menu will report Bit Error Rate if a

2047 pattern is being received by the demod and this option is set to 2047.

On entry, the current status is displayed. Press an arrow key to select on or off. Press

[ENTER] to execute the change.

This configuration function is used to set service channel audio gain at TX-1, TX-2,

RX-1, or RX-2.

On entry, press [

channel gain (+8.0 to -6.0 dBm), press [ENTER]. Press [

channel. Press [ENTER] to execute the change.

Note: This window is only available when IDR has been selected for modem type in

This configuration is used to select the desired drop data channel signaling. The choices

are:

←] or [→] to select the desired service channel. To adjust the service

↑] or [↓] to adjust the service

the Utility menu and option card (PL/10175-2) is installed.

• E1_CCS (E1 Common Channel Signaling)

• E1_CAS (E1 Channel Associated Signaling)

• T1 (T1 Data, D4 framing)

• T1_ESF (T1 Extended Super Frame)

Note: This menu is only available for the D&I option.

On entry, the current drop data channel signal is displayed. Press an arrow key to make

the selection. Press [ENTER] to execute the change. INSERT FORMAT Selects the desired insert data channel signaling. The choices are:

• E1_CCS (E1 Common Channel Signaling)

• E1_CAS (E1 Channel Associated Signaling)

• T1 (T1 Data, D4 framing)

• T1_ESF (T1 Extended Super Frame)

Note: This menu is only available for the D&I option.

On entry, the current insert data channel signal is displayed. Press an arrow key to make

the selection. Press [ENTER] to execute the change.

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Menu Item Specifications/usage

DROP CHANNEL ASSIGNMENTS

Drop Channel Assignments: Maps terrestrial time slots to transmit satellite channels.

Terrestrial time slots:

T1 = 1 to 24

E1 (CCS) = 1 to 31

E1 (CAS) = 1 to 15 and 17 to 31

Channels: 1 to N (N = Satellite Data Rate ÷ 64 kbps)

N = 30 (1920.0 kbps) is a transparent mode which

disables time slot to channel mapping.

On entry, drop channel 1 and the current time slot are displayed. Press [↑] or [↓] to

select the drop channel to be programmed.

Press [ENTER] to begin programming. Press [↑] or [↓] to select the time slot for each

available drop channel by incrementing or decrementing the digit at the flashing cursor.

Press [ENTER] to execute the change.

Note: This menu is only available for the D&I option. INSERT CHANNEL

ASSIGNMENTS

Insert Channel Assignments: Maps received satellite channels to terrestrial time slots.

Terrestrial time slots:

T1 = 1 to 24

E1 (CCS) = 1 to 31

E1 (CAS) = 1 to 15 and 17 to 31

Channels: 1 to N (N = Satellite Data Rate ÷ 64 kbps)

N = 30 (1920.0 kbps) is a transparent mode which

disables time slot to channel mapping.

On entry, satellite channel 1 and the current terrestrial time slot are displayed. Press [↑]

or [↓] to select the satellite channel to be programmed. Press [ENTER] to choose the

satellite channel to be programmed. Press [↑] or [↓] to select the terrestrial time slot for

each available satellite channel by incrementing or decrementing the digit at the flashing

cursor. If a time slot is unused, select NI (Not Inserted). Press [ENTER] to execute the

change.

Note: This menu is only available for the D&I option. DDO/INI LOOP

Selects Drop Data Output to Insert Data Input Loop. This provides an internal path so an

external cable connection does not have to be connected. Selection is ON or OFF.

Note: This menu is only available for the D&I option.

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Menu Item Specifications/usage

ASYNC TX

Programs the baud rate settings and interface format of ASYNC overhead in the

modem.

To change the ASYNC overhead baud rate (110 to 38400 bps), press [ENTER]. Press

←] or [→] to position the cursor over the baud rate parameter. Press [↑] or [↓] to select

[

one of the following baud rates (bps): 110, 150, 300, 600, 1200, 2400, 4800, 9600,

19200, 38400. Once the desired baud rate is displayed, press [ENTER] to set the

baud rate.

To change the ASYNC overhead interface format of the modem is displayed press

[ENTER]. Press [

↑] or [↓] to scroll through the available interface formats. Once the desired

Press [

←] or [→] to position the cursor over the interface format parameter.

format is displayed, press [ENTER] to set the baud rate.

The number of data bits, parity, and stop bits is selectable. Available formats are: 7

data bits, Even parity, and 1 stop bits (7E1); 7 data bits, Odd parity, and 1 stop bits

(7O1), 7 data bits, No parity, and 1 stop bit (7N1), 7 data bits, Even parity, and 2 stop

bits (7E2); 7 data bits, Odd parity, and 2 stop bits (7O2); 7 data bits, No parity, and 2

stop bit (7N2), 8 data bits, Even parity, and 1 stop bits (8E1); 8 data bits, Odd parity,

and 1 stop bits (8O1); 8 data bits, No parity, and 1 stop bit (8N1), 8 data bits, Even

parity, and 2 stop bits (8E2); 8 data bits, Odd parity, and 2 stop bits (8O2);8 data bits,

or No parity, and 2 stop bit (8N2) ASYNC RX

Programs the baud rate settings and interface format of RX ASYNC overhead in the

modem.

To change the RX ASYNC overhead baud rate (110 to 38400 bps), press [ENTER].

←] or [→] to position the cursor over the baud rate parameter. Press [↑] or [↓] to

Press [

select one of the following baud rates (bps): 110, 150, 300, 600, 1200, 2400, 4800,

9600, 19200, 38400. Once the desired baud rate is displayed, press [ENTER] to set

the baud rate.

To change the RX ASYNC overhead interface format of the modem is displayed press

[ENTER]. Press [

↑] or [↓] to scroll through the available interface formats. Once the desired

Press [

←] or [→] to position the cursor over the interface format parameter.

format is displayed, press [ENTER] to set the baud rate.

The number of data bits, parity, and stop bits is selectable. Available formats are: 7

data bits, Even parity, and 1 stop bits (7E1); 7 data bits, Odd parity, and 1 stop bits

(7O1), 7 data bits, No parity, and 1 stop bit (7N1), 7 data bits, Even parity, and 2 stop

bits (7E2); 7 data bits, Odd parity, and 2 stop bits (7O2); 7 data bits, No parity, and 2

stop bit (7N2), 8 data bits, Even parity, and 1 stop bits (8E1); 8 data bits, Odd parity,

and 1 stop bits (8O1); 8 data bits, No parity, and 1 stop bit (8N1), 8 data bits, Even

parity, and 2 stop bits (8E2); 8 data bits, Odd parity, and 2 stop bits (8O2);8 data bits,

or No parity, and 2 stop bit (8N2). ASYNC COMM TYPE

Programs the ASYNC COMM type as EIA-232, EIA-485 (2-Wire),

or EIA-485 (4-wire).

On entry, press an arrow key to make the selection. Press [ENTER] to execute the

change. ASYNC CONNECTOR Selects interface connector to use for ASYNC Channel, J2 (9 pin) or J6 (50 pin).

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3.4.1.4 Local AUPC Menu

The Local AUPC menu is used to configure the Automatic Uplink Power Control parameters for a Duplex or Simplex (Broadcast) link. This menu will only be displayed if the modem is programmed to a mode that requires AUPC functionality. Within the Utility: Modem Type menu, selection of Modem Types 7650-02 or ASYNC or programming the Local Modem AUPC to ON will activate this display.

Menu Item Specifications/usage

AUPC ENABLE Programs the Automatic Uplink Power Control On or Off.

On entry, the current status is displayed. Press an arrow key to make the selection.

Press [ENTER] to execute the change. NOMINAL POWER

MINIMUM POWER

MAXIMUM POWER

TARGET Eb/N0 Programs the Eb/N0 target set point. The Eb/N0 target set point ranges from 3.2 to 16.0

TRACKING RATE Programs the maximum tracking rate of the AUPC.

LOCAL CL ACTION Choices are: HOLD, NOMINAL, MAXIMUM

REMOTE CL ACTION Choices are HOLD, NOMINAL, MAXIMUM

Programs the nominal power value of the AUPC. The nominal power value can range

from +5 to -30 dBm, in 0.1 dBm steps.

On entry, the current nominal power value is displayed. Press an arrow key to

increment or decrement the digit at the flashing cursor. Press [ENTER] to execute the

change.

Programs the minimum power level of the AUPC. The minimum power level can range

from +5 to -30 dBm, in 0.1 dBm steps.

On entry, the current minimum power level is displayed. Press an arrow key to

increment or decrement the digit at the flashing cursor. Press [ENTER] to execute the

change.

Programs the maximum power level to the AUPC. The maximum power level can

range from +5 to -30 dBm, in 0.1 dBm steps.

On entry, the current maximum power level is displayed. Press an arrow key to

increment or decrement the digit at the flashing cursor. Press [ENTER] to execute the

change.

dB, in 0.1 dB steps.

On entry, the current E

increment or decrement the digit at the flashing cursor. Press [ENTER] to execute the

change.

Maximum tracking rate can range from 0.5 to 6.0 dBm per minute, in 0.5 dB steps.

On entry, the current maximum tracking rate is displayed. Press an arrow key to

increment or decrement the digit at the flashing cursor. Press [ENTER] to execute the

change.

If the local demodulator loses lock then the modulator output level will change

depending on the selected choice. The choices are:

HOLD to the current level

Return to the selected NOMINAL level

To shoot to the selected MAXIMUM power level

On entry, the current status of the local carrier loss is displayed. Press an arrow key to

make the selection. Press [ENTER] to execute the change.

This will cause the local modulator output level to change depending on the distant

ends loss of demodulator lock.

On entry, the current status of the remote carrier loss is displayed. Press an arrow key

to make the selection. Press [ENTER] to execute the change.

b/N0 target set point is displayed. Press an arrow key to

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3.4.1.5 Save Menu

The Configuration Save menu allows the user to program configuration parameters into memory on the M&C. There are five memory locations that may be used to store specific configuration setups that are used frequently. This feature speeds up the configuration process by allowing faster configuration changes.

After changing the configuration parameters to the desired settings, enter the Configuration Save menu and select memory location 1 through 5. Press [ENTER] to execute the save. A hard reset of the modem will clear out the saved parameters.

3.4.1.6 Recall Menu

The Configuration Recall menu allows the user to recall a previously saved configuration setup. On entry, select memory location 1 through 5 by pressing an arrow key. Press [ENTER] to execute the recall.

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3.4.2 Monitor Menu

The Monitor level is accessible from the Function Select menu. The Monitor menu provides information on the link performance of the demodulator. When the Monitor level is entered, press [←] or [→] to select the desired monitor function. Each monitor function is displayed in real time as long as it is selected.

Menu Item Specifications/usage

RAW BER Displays the current BER or “No Data” (if carrier is not locked).

Range: <m.m E-e to >m.m E-e. Note: Low limit is based on performance. High limit is based on data/code rate.

CORRECTED BER Displays the current corrected BER or “No Data” (if carrier is not locked).

Range: <m.m E-e to >m.m E-e. Note: Low limit is based on performance. High limit is 1.0 E-12.

Eb/No Displays the current Eb/N0 or “No Data” (if carrier is not locked).

Range: <mm.m to >mm.m. Note: Low limit is based on the data rate. High limit is 16.0 dB.

RECEIVE SIGNAL Displays the current receive signal level.

Range: -15.0 to -55.0 dBm.

SWEEP FREQUENCY

BUFFER FILL Displays the current plesiochronous buffer fill status percent.

2047 ERRORS

FRAME BER Displays the IDS/IBR frame error rate in the same format as 2047 errors.

Displays the current sweep frequency offset from the configured demodulator center frequency.

Range: -35,000 to +35,000 Hz.

Range: nn% (1% to 99%). Note: Press [ENTER] twice to reenter the buffer. Displays the 2047 data pattern error rate or “No Data” if the 2047 data pattern is not

detected. Range: <nun E-e to >nun E-e. Note: Low limit is based on performance. High limit is based on the data/code rate.

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3.4.3 Faults/Alarms Menu

The Faults/Alarms level is accessible from the Function Select menu. The Faults/Alarms are similar to monitor functions, as they display the current fault status of the group being displayed. Press [←] or [→] to move between the following Fault/Alarm groups:

• Modulator

• Demodulator

• Transmit Interface

• Receive Interface

• Common Equipment

• Backward Alarms (IDR ESC only)

The current Faults/Alarms status is displayed on line 2 of the display in real time. For each parameter monitored, fault status is displayed as one of the following:

“–” Indicates that no fault or alarm exists. “+” Indicates that a fault exists, and will cause switching in a redundant system. Reversed contrast “+” indicates an active alarm. Alarms do not cause switching to occur.

To display labels for individual faults or alarms, press [ENTER]. Press [←] or [→] to move the flashing cursor to make the selection. The label for that Fault/Alarm is then displayed on line 1 of the display. Press [CLEAR] to exit this level of operation and return to the previous level.

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3.4.3.1 Modulator Faults

Menu Item Specifications/usage

MODULE

IF SYNTHESIZER Modulator IF synthesizer fault. DATA CLOCK SYNTH Transmit symbol clock lock detect. Indicates that the symbol clock is not locked. I CHANNEL I channel data activity fault. Q CHANNEL Q channel data activity fault. AGC LEVEL TX IF AGC level fault.

Modulator section fault. Typically indicates that the modulator section will not program.

3.4.3.2 Demodulator Faults

Menu Item Specifications/usage

MODULE

CARRIER DETECT Carrier detect fault. Indicates the demodulator/decoder is not locked. IF SYNTHESIZER Demodulator IF synthesizer fault. Indicates the IF synthesizer is not locked. I CHANNEL

Q CHANNEL

BER THRESHOLD

Demodulator/decoder section fault. Typically indicates that the Demod/decoder section will not program.

I channel activity fault. Indicates a loss of activity in the I channel of the quadrature demodulator.

Q channel activity fault. Indicates a loss of activity in the Q channel of the quadrature demodulator.

Secondary alarm result of the BER threshold set in the DEMOD Configuration menu.

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3.4.3.3 Transmit Interface Faults

Menu Item Specifications/usage

MODULE

TX DATA/AIS

TX CLK ACTIVITY

TX CLK PLL Indicates TX input clock is out of range. SCT PLL

SCT REFERENCE ACT

TX DROP

TX Interface section fault. Typically indicates that the TX Interface section will not program.

Data or AIS. When DATA fault is selected in the Configuration Interface menu, the fault indicates a data stable condition. This indicates the data is all 1s or 0s (i.e., data is not transitioning). When AIS is selected, the alarm indicates the data is all 1s from customer data input to the modem. When NONE is selected, the TX Data/AIS Fault/Alarm is not activated. Note: AIS is an alarm, not a switching fault.

Activity detector alarm of the selected interface transmit clock. The interface will fall back to the internal clock (SCT) when this alarm is active.

SCT phase-locked loop (PLL) fault. Indicates the internal transmit clock oscillator PLL is not locked to the selected reference.

Activity detector alarm at the input of the selected source for SCT Reference. Indicates the selected clock is not being detected.

Drop interface fault. Typically indicates that terrestrial data stream is not synchronized (D&I only)

3.4.3.4 Receive Interface Faults

Menu Item Specifications

MODULE

BUFFER CLK PLL Buffer clock phase-locked loop fault. Indicates the buffer clock PLL is not locked. BUFFER CLK ACT

RX DATA/AIS

DEMUX LOCK DEMUX lock fault. Indicates that the Demux is not locked. RX 2047 LOCK

BUFFER OVERFLOW Buffer overflow alarm. Indicates that a buffer overflow has occurred. BUFFER UNDERFLOW Buffer underflow alarm. Indicates that a buffer underflow has occurred. BUFFER FULL Buffer full alarm. Indicates the buffer is less than 10%, or greater than 90% full. BACKWARD ALARM Indicate reception of IBS backward alarms. RX INSERT

FRAME BER Fault if Frame BER exceeds 1E-3 (option card PL/10175-2 only).

RX Interface section fault. Typically indicates that the RX Interface section will not program.

Activity detector alarm of the selected interface receive clock. The interface will fall back to the satellite clock when this fault is active.

Data or AIS. When DATA fault is selected in the Configuration Interface menu, the fault indicates a data stable condition. This indicates the data coming from the satellite is all 1s or 0s (i.e., data is not transitioning). When AIS is selected, the alarm indicates the data is all 1s from the satellite. When NONE is selected the RX Data/AIS Fault/Alarm is not activated. Note: AIS is an alarm, not a switching fault.

RX 2047 lock alarm. Indicates the RX 2047 data pattern is not locked. Note: This alarm is only active when receive 2047 is on.

D&I Insert fault. Typically indicates that terrestrial data stream is not synchronized (D&I only)

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3.4.3.5 Common Equipment Faults

Fault Cause

MODULE

BATTERY/CLOCK Battery or clock fault.

-12V SUPPLY -12V power supply fault. +12V SUPPLY +12V power supply fault. +5V SUPPLY +5V power supply fault. +3.3V SUPPLY +3.3 V power supply fault. +2.5V SUPPLY +2.5V power supply fault. +1.8V SUPPLY +1.8V power supply fault. TEMPERATURE

MODEM REF ACT

MODEM REF PLL Reference Phase Lock loop is Not Locked.

Interface/M&C section summary fault. Typically indicates that the interface section will

not program or the M&C has failed

Over/Under Temperature Fault. Indicates that the internal temperature of the modem

has exceeded +75°C or is below -10°C.

Activity detector alarm at the input of the selected source for the Modem Reference.

Indicates that a signal is not being detected at the Modem Reference connector (CP3).

The Modem Reference will fall back to the internal reference if this fault is active.

3.4.3.6 IDR Backward Alarms

BW Alarm RX #4 Receive backward alarm #4 indicator. BW Alarm RX #3 Receive backward alarm #3 indicator.

BW Alarm RX #2 Receive backward alarm #2 indicator. BW Alarm RX #1 Receive backward alarm #1 indicator. BW Alarm TX #4 Transmit backward alarm #4 indicator.

BW Alarm TX #3 Transmit backward alarm #3 indicator. BW Alarm TX #2 Transmit backward alarm #2 indicator. BW Alarm TX #1 Transmit backward alarm #1 indicator.

Note: Only available with IDR selected and with IDR ESC.

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3.4.4 Stored Faults/Alarms Menu

The Stored Faults/Alarms level is accessible from the Function Select menu. The modem stores the first 10 (Flt0 through Flt9) occurrences of fault status changes in each of the following major fault categories:

• Modulator

• Demodulator

• Transmit Interface

• Receive Interface

• Common Equipment

Each fault status change is stored with the time and date of the occurrence (i.e., when a fault occurs). Stored faults may be viewed by entering the stored faults level from the Select menu.

Stored faults are not maintained through controller power-on reset cycle. However, the last known time is maintained in nonvolatile Random Access Memory (RAM). On power-up, a common equipment fault is logged (Flt0) with that time and date. Also on power-up, an additional common equipment fault is logged (Flt1) to indicate the powerup time and date. The power-down and power-up times are logged as common equipment fault 0 and common equipment fault 1, respectively.

On entering the stored faults level, press [←] or [→] to move between the fault groups and the “Clear Stored Faults?” selections. The time and date of the first stored fault status (Flt0) for the selected group will be displayed alternately on line 2 of the display. Press [↑] or [↓] to cycle through the selected group’s stored fault status (Flt0 through Flt9). To display the fault status associated with the displayed time and date, press [ENTER]. To identify the fault, press [←] or [→] to move the flashing cursor. To clear the stored faults currently logged, press [ENTER] when the “Clear Stored Faults/Yes?” selection is displayed.

Note: Faults are stored in time sequence, with the oldest fault status change stored in

Flt0, and the most recent in Flt9. Only the first 10 fault status changes are stored. All stored faults, which have not been used, indicate “No Fault” on the display.

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3.4.5 Remote AUPC Menu

This menu will only be displayed if the modem is programmed to a mode that allows AUPC functionality. Within the Utility Modem Type menu, selection of Modem Types 7650-02 or ASYNC will activate this display.

Note: These are extra configuration commands that can modify the distant end

modem. These configuration or monitor functions can only be accomplished if the modems are locked under the configuration of 7650-02 or ASYNC as a modem type.

The remote functions may be viewed or changed by entering the Remote AUPC level from the Function select menu on the front panel After entering the Remote AUPC menu, press [←] or [→] to select the Configuration or Monitor menu. Enter the selected menu by pressing [ENTER]. Press [←] or [→] to view the selected configuration parameters.

3.4.5.1 Remote AUPC Configuration

Menu Item Specifications/usage

AUPC ENABLE Programs the AUPC enable On or Off.

On entry, the current status of the remote AUPC is displayed. Press an arrow key to make the selection. Press [ENTER] to execute the change.

Note: This program is for control or last known status.

B-BAND LOOP BACK Programs the remote baseband loopback On or Off.

On entry, the current status of the remote baseband loopback is displayed. Press an arrow key to make the selection. Press [ENTER] to execute the change.

Note: This program is for control or last known status.

TX 2047 PATTERN Programs the remote TX 2047 pattern On or Off.

On entry, the current status of the remote TX 2047 is displayed. Press an arrow key to make the selection. Press [ENTER] to execute the change.

Note: This program is for control or last known status.

3.4.5.2 Remote AUPC Monitor

Menu Item Specifications/usage

2047 ERRORS

Receive 2047 BER. This is a monitor point that displays the current distant end RX 2047 BER. If no data is available, “No Data” is displayed.

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3.4.6 Utility Menu

The Function Select Utility menu is divided into the following categories:

• Modulator

• Demodulator

• Interface

• System

• Modem Type

Provisions also are made for assigning data and code rates to the modulator and demodulator. These are the setting for TX or RX code Rate /Type A, B, C, and D.

Changes in the Utility menu may cause changes in other front panel menus. After entering the Utility functions level, press [←] or [→] to select the desired Utility menu, and press [ENTER]. The Factory Setup Utility menu is for Comtech EF Data service personnel only. Entering this menu without authorization may cause the modem to operate incorrectly.

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3.4.6.1 Utility Modulator Menu

Menu Item Specifications/usage

ASSIGN TRANSMIT FILTERS

MOD POWER OFFSET

MODULATOR TYPE

ENCODER TYPE FEC type select. Select VITERBI or TURBO.

TX BPSK ORDERING Transmit BPSK bit ordering selection. Select STANDARD or NON-STANDARD.

MOD SPECTRUM

TX IESS-310 MODE Select IESS-310 mode on or off.

TX R-S CODE WORD

TX SYMBOL RATE Status Only.

Filter: A, B, C, D, or V

Data rates are referenced in paragraph 3.3.

Note: These assignments are used for the selection of the TX rate in the

Configuration Modulator menu.

Modulator power offset adjust. Offsets the modulator output power readout in the Configuration menu. This feature does not actually change the modulator power level, but displays an offset value in the monitor. The modulator power offset range is -69.9 to +94.9 dB, in 0.1 dB steps.

Note: Anything except 0.0 dB will cause ADJ to be displayed in the TX power

level screen.

Transmit filter type select. Select INTELSAT OPEN or EFD CLOSED network filtering.

Note: This window is only available when CUSTOM is selected for modem type in

the Utility menu.

Note: This window is only available when CUSTOM or EFD is selected for

modem type in the Utility Menu.

Press an arrow key to make the selection. Press [ENTER] to execute the change. Programmable vector rotation. Allows the operator to select Normal or Inverted

(INVERT) for spectrum reversal of the I and Q baseband channels. Press an arrow key to make the selection. Press [ENTER] to execute the change.

IESS-310 mode is for 8 PSK 2/3 modulation with Reed-Solomon only. Press an arrow key to make the selection. Press [ENTER] to execute the change. Displays or selects the current N, K, T, and Interleave values for the Reed-Solomon

FEC. The standard code word can only be changed when CUSTOM is the selected modem type in the Utility Menu.

Displays the current TX Symbol Data Rate within 9.6 ksym/s to 10 Msym/s.

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3.4.6.2 Utility Demodulator Menu

Menu Item Specifications/usage

ASSIGN RECEIVER FILTERS Filter: A, B, C, D, or V

Data rates are referenced in paragraph 3.3.

Note: These assignments are used for the selection of the Rx rate in the

Configuration Functions menu.

DEMODULATOR TYPE

DECODER TYPE FEC type select. Select VITERBI or TURBO.

RX BPSK ORDERING

DEMOD SPECTRUM

RX IESS-310 MODE Select IESS-310 mode on or off.

RX R-S CODE WORD

RX SYMBOL RATE Status Only.

Receive filter type select. Select Type INTELSAT OPEN or EFD CLOSED network receive filtering.

Note: This window is only available when CUSTOM is selected for modem type in the Utility menu.

Note: This window is only available when CUSTOM or EFD is selected for

modem type in the Utility Menu.

Receive BPSK bit ordering selection. Select STANDARD or NONSTANDARD. Press an arrow key to make the selection. Press [ENTER] to execute the change.

Programmable vector rotation. Select NORMAL or INVERT for spectrum reversal of the I and Q baseband channels. Press an arrow key to make the selection. Press [ENTER] to execute the change.

IESS-310 mode is for 8-PSK 2/3 modulation with Reed-Solomon only. Press an arrow key to make the selection. Press [ENTER] to execute the

change. Displays or selects the current N, K, T, and Interleave values for the Reed-

Solomon FEC. The standard code word can only be changed when CUSTOM is the selected modem type in the Utility Menu.

Displays the current RX Symbol Rate within 9.6 ksym/s to 10 Msym/s.

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3.4.6.3 Utility Interface Menu

Menu Item Specifications/usage

TX OVERHEAD TYPE Select None, IDR, IBS, VSAT-IBS, IBS-309, or ASYNC for TX overhead type.

Note: This parameter is only programmable when Custom is selected for

modem type in the Utility menu.

RX OVERHEAD TYPE Select None, IDR, IBS, VSAT-IBS, IBS-309, or ASYNC for RX overhead type.

Note: This parameter is only programmable when Custom is selected for

modem type in the Utility menu.

TERRESTRIAL INTERFACE

RTS TX-IF CNTRL

BUFFER PROGRAM Buffer unit program function. Select MILLI-SECONDS or BITS.

FRAMING STRUCTURE

TX DATA PHASE

RX DATA PHASE

IDR BACKWARD ALARM CONTROL

IDR ESC TYPE Selects the IDR ESC: 2 – 32 kbps ADPCM Audio or 64 kbps data channel.

Selects the data interface to be used: J1 RS422, J6 RS422, G.703 Balanced, G.703 Unbalanced.

Note: Optional interface only. Programs the modem to allow a Request-to-Send (RTS) signal to enable the

modulator output when data is ready for transmission. Press an arrow key to make the selection. Press [ENTER] to execute the change.

Press an arrow key to make the selection. Press [ENTER] to execute the change. Select the Terrestrial interface frame structure. This function is used with the

BUFFER SIZE program to allow plesiochronous slips in the buffer. Available selections are:

T1 - NONE or *G.704 E1 - NONE or *G.704 T2 - NONE or G.704, *G.743, or G.747 E2 - NONE or G.704, *G.742, or G.745

(* default parameters) TX data phase relationship. Use this option to select Normal or Invert for the TX

data relationship to the selected TX clock. On entry, press an arrow key to make the selection. Press [ENTER] to execute the

change. RX data phase relationship. Use this option to select Normal or Invert for the TX

data relationship to the selected RX clock. On entry, press an arrow key to make the selection. Press [ENTER] to execute the

change. Controls IDR monitor and alarm functions reporting. Use this option to select on or off

for the RX and TX alarms.

On entry, the BW ALARM RX or BW ALARM TX is displayed on line 1.Press an arrow key to select BW alarm RX or TX numbers 1 through 4 on line 2. Press [ENTER] to execute the change.

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3.4.6.4 Utility System Menu

Menu Item Specifications/usage

TIME: HH:MM:SS DATE: MM/DD/YYYY

REMOTE SERIAL PORT Programs the baud rate settings and interface format in the modem.

REMOTE ADDRESS The current modem address is displayed (1 to 255).

REMOTE TYPE Select EIA-232, EIA-485 (2-wire) or EIA-485 (4-wire).

MODEM REF Programs the Modem Reference timing standard:

OPERATION MODE Operation mode. Programs the modem for Duplex, TX-only, or RX-only operation.

TEST MODE STATUS

LAMP TEST

Time of day and date display/set function. The current time (24 hour clock) and date in the modem’s memory are displayed

when selected. To change the modem time and/or date, press [ENTER]. Press [ or [

→] to position the cursor over the parameter to be changed. Press [↑] or [↓] to

←]

change the parameter. Once the parameters are displayed as desired, press [ENTER] to set the time and date.

To change the baud rate(110 to 38400 bps), press [ENTER]. Press [ position the cursor over the baud rate parameter. Press [

↑] or [↓] to select one of

←] or [→] to

the following baud rates (bps): 110, 150, 300, 600, 1200, 2400, 4800, 9600, 19200,

38400. Once the desired baud rate is displayed, press [ENTER] to set the baud rate.

To change the remote interface format of the modem is displayed press [ENTER]. Press [

←] or [→] to position the cursor over the interface format parameter. Press

↑] or [↓] to scroll through the available interface formats. Once the desired format

[ is displayed, press [ENTER] to set the baud rate.

The number of data bits, parity, and stop bits is selectable. Available formats are: 7 data bits, Even parity, and 1 stop bits (7E1); 7 data bits, Odd parity, and 1 stop bits (7O1); 7 data bits, Even parity, and 2 stop bits (7E2); 7 data bits, Odd parity, and 2 stop bits (7O2); or 8 data bits, no parity, and 1 stop bit (8N1).

To change the remote address, press [ENTER]. Press an arrow key to make the selection. Press [ENTER] to execute the change.

To change the remote type, press [ENTER]. Press an arrow key to make the selection. Press [ENTER] to execute the change.

Internal reference. External 1, 5, 10, and 20 MHz (Input is REF (CP3) on the rear panel)

On entry, the current timing source is displayed. Press [

↑] or [↓] to make the

selection. Press [ENTER] to execute the change.

On entry, the operational status may be changed. Press an arrow key to make the selection. Press [ENTER] to execute the change.

Note: When TX-only or RX-only are selected, the appropriate faults are masked

from the Faults and Stored Faults menus.

Test mode status indicator. The following modem test points are listed in this window and display a “+” when a test mode is active:

REED-SOLOMON-CORR OFF B-BAND LOOPBACK IF LOOPBACK CARRIER MODE RX 2047 PATTERN

TX 2047 PATTERN To view the test modes, press [ENTER]. Press an arrow key to make the selection. Lamp test function. Press [ENTER] to turn the front panel indicators on for 3

seconds.

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Menu Item Specifications/usage

M&C FIRMWARE

Displays the M&C module firmware version. The display includes the month, day, and year.

BOOT FIRMWARE

Displays the BOOT module firmware version. The display includes the month, day, and year.

BULK FIRMWARE

Displays the BULK module firmware version. The display includes the month, day, and year.

DISPLAY BRIGHTNESS Sets the brightness setting of the front panel menu.

Press [ENTER] to begin. Press [↑] or [↓] to increment or decrement the number at the flashing cursor, from 25 to 100%. Press [ENTER] to execute the change.

EXT AGC: MIN PWR Sets the AGC voltage for receive signal level of -60.0 dBm.

EXT AGC: MAX PWR Sets the AGC voltage for receive signal level of -15.0 dBm

USB REFLASH Configures the modem for upgrade via the USB connector on the front panel.

MASTER RESET Master reset function.

CAUTION

Initiating a hard reset will reset the modem and set the default configuration settings. Initiating a soft reset will reset the modem hardware, but saves the current configuration settings.

Select [ENTER] once to access HARD or SOFT. Press [←] or [→] to make the selection. Press [ENTER]. Select Yes or No, and press [ENTER] again.

Note: The following system settings will not revert to the default values upon a

hard reset:

Remote Format Remote Address Remote Baud Rate

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3.4.6.5 Utility Modem Type Menu

Menu Item Specifications/usage

MODEM TYPE Selects the following types of modem operation:

7650-00 7650-02 IDR IBS VSAT-IBS IBS-309 EFD ASYNC CUSTOM

When the modem is changed from one mode of operation to another, the modem will be reset to the default configurations of the new modem type. Note that the RFIF output must be turned on to get the modem to lock. If the modem type is entered as the same configuration, the modem will not change any parameters. If the modem is changed to custom, no parameters will be changed.

CAUTION

Use caution when modifying the Custom Mode Type. The user has the capability to change all of the modem settings, including incompatible parameters. It is recommended that qualified personnel use the “Custom Mode” only, as the Custom Mode was designed for special case configurations.

MODEM OPTIONS Status Only.

Displays the installed modem options. If the option is installed a “+” symbol is displayed. To view the available options,

press {ENTER}. Observe for the flashing cursor. Press the directional arrow to move from one symbol to the next. The first line will display the option. The second line will display the status.

A “+” symbol indicates the option is installed. A”–“ symbol indicates the option is Not Installed or FAST Upgradeable. A “0” symbol indicates the option is Not Installed or Not Upgradeable. OPTIONS:

MODEM SERIAL # Status Only. Displays the modem serial number.

CONFIGURATION CODE – MODEM

Comtech EF Data-supplied code.

FULL RATE VAR 8PSK 2/3 & 5/6 IBS/IDR FRAMING ASYNC OVERHEAD REED-SOLOMON 16QAM 3/4 & 7/8 MOD ENABLED DEMOD ENABLED TURBO OPTION G.703/50 PIN OPTION D&I/ESC

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3.5 Modes of Operation

The modem has multiple modes of operation that are selectable from any of the control interfaces. These modes simplify the configuration of the modem by setting up default values that are consistent with network requirements. The modes of operation are selected in the Utility: Modem Type menu (Paragraph 3.4.6.5).

When a mode of operation is selected, the modem will be configured for a particular set of default operating parameters. Certain menus will be displayed, blanked, or disabled based on the requirements for that particular operating mode.

The following paragraphs will detail each of the modes of operation and provide a table with the default parameters.

3.5.1 7650-00 Operation

The 7650-00 mode of operation is the basic OM-73 interoperability mode. This mode is compatible with MIL-STD-188-165 Rev. – and Rev. A with some extended capability. The additional capability includes 8-PSK and 16-QAM. This mode is similar to, and compatible with, the 8650-00 mode in the Comtech EF Data SLM-8650 satellite modem.

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Table 3-4. 7650-00 Default Parameters

Function Configuration

Modulator Demodulator

Data Rate A Data Rate A TX-A 64 kbps QPSK 1/2 RX-A 64 kbps QPSK 1/2 TX IF Frequency 70 MHz RX-IF Frequency 70 MHz TX-IF Output Off Descrambler Type OM73 TX Power Level -20 dBm Descrambler On Scrambler Type OM73 Diff Decoder On Scrambler On IF Loopback Off Diff. Encoder On BER Threshold None Carrier Mode Normal-Modulated Sweep Center 0 Hz RS Decoder Off Sweep Range 60000 Hz Reacquisition 0 seconds RS Decoder Off

Interface

TX Clock Source TX Terrestrial B-Band Loopback Off TX Clock Phase Normal Loop Timing Off SCT PLL REF Modem Reference TX Data Fault None EXT REF Frequency 1544 kHz RX Data Fault None Buffer Clock RX (Satellite) TX 2047 Pattern Off Buffer Size 384 bits RX 2047 Pattern Off RX Clock Phase Normal

Utility

Modulator Demodulator

TX-A 64 kbps QPSK 1/2 RX-A 64 kbps QPSK 1/2 TX-B 256 Kbps QPSK 1/2 RX-B 256 Kbps QPSK 1/2 TX-C 768 kbps QPSK 1/2 RX-C 768 kbps QPSK 1/2 TX-D 2048 kbps QPSK 1/2 RX-D 2048 kbps QPSK 1/2 TX-V 128 kbps QPSK 1/2 RX-V 128 kbps QPSK 1/2 Modulator Power Offset 0.0 dB Demodulator Type EFD Closed Modulator Type EFD Closed RX BPSK Ordering Standard TX BPSK Ordering Standard DEMOD Spectrum Normal MOD Spectrum Normal RX IESS-310 Mode Off TX IESS-310 Mode Off Encoder Type Viterbi Decoder Type Viterbi

Interface

TX Overhead Type None TX Data Phase Normal RX Overhead Type None RX Data Phase Normal RTS TX-IF CNTRL Off FRAMING See 3.2.7.3 Buffer Program Bits

System

Modem Reference Internal USB Re-Flash Disabled Operation Mode Duplex

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3.5.2 7650-02 Operation

The 7650-02 mode of operation is compatible with the 8650-02 operating mode of the SLM-8650 modem up to the 9.3 Mbps data rate limit of the SLM-8650. Operation in this mode requires the ASYNC framing option to be activated.

Table 3-5. 7650-02 Default Parameters

Data Rate A Data Rate A

Modulator Demodulator

TX-A 64 kbps QPSK 1/2 RX-A 64 kbps QPSK 1/2

TX IF Frequency 70 MHz RX-IF Frequency 70 MHz

TX-IF Output Off Descrambler Type OM73

TX Power Level -20 dBm Descrambler On

Scrambler Type OM73 Diff Decoder On

Scrambler On IF Loopback Off

Diff. Encoder On BER Threshold None

Carrier Mode Normal-Modulated Sweep Center 0 Hz

RS Decoder Off Sweep Range 60000 Hz

Reacquisition 0 seconds

RS Decoder Off

TX Clock Source TX Terrestrial Loop Timing Off

TX Clock Phase Normal TX Data Fault None

SCT PLL REF Modem Reference RX Data Fault None

EXT REF Frequency 1544 kHz TX 2047 Pattern Off

Buffer Clock RX (Satellite) RX 2047 Pattern Off

RX Clock Phase Normal ASYNC TX Baud=1200

B-Band Loopback Off ASYNC RX Baud=1200

Buffer Size 384 bits ASYNC COMM TYPE EIA-232

AUPC Enable Off Target Eb/N0 6.0 dB

Nominal Power –10 dBm Tracking Rate 1.0 dB/min

Minimum Power –30 dBm Local CL Action Hold

Maximum Power –5 dBm Remote CL Action Hold

AUPC Enable Off TX 2047 Pattern Off

B-Band Loopback Off

Modulator Demodulator

TX-A 64 kbps QPSK 1/2 RX-A 64 kbps QPSK 1/2

TX-B 256 Kbps QPSK 1/2 RX-B 256 Kbps QPSK 1/2

TX-C 768 kbps QPSK 1/2 RX-C 768 kbps QPSK 1/2

TX-D 2048 kbps QPSK 1/2 RX-D 2048 kbps QPSK 1/2

TX-V 128 kbps QPSK 1/2 RX-V 128 kbps QPSK 1/2

Modulator Power Offset 0.0 dB Demodulator Type EFD Closed

Modulator Type EFD Closed RX BPSK Ordering Standard

TX BPSK Ordering Standard DEMOD Spectrum Normal

MOD Spectrum Normal RX IESS-310 Mode Off

TX IESS-310 Mode Off

Encoder Type Viterbi Decoder Type Viterbi

TX Overhead Type ASYNC TX Data Phase Normal

RX Overhead Type ASYNC RX Data Phase Normal

RTS TX-IF CNTRL Off FRAMING See 3.2.7.3

Buffer Program Bits

Modem Reference Internal USB Re-Flash Disabled

Operation Mode Duplex

Function Configuration

Interface

Format=7E2

Local AUPC

Function Select Remote AUPC

Utility

Interface

System

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3.5.3 IDR Operation

The IDR mode of operation configures the modem for basic IDR operation without the addition of the overhead card. The IDR mode is used for open network applications operating in compliance with the IESS-308 (IDR) and IESS-310 (TCM-IDR) Intelsat standards. When the IDR mode is active, a fixed overhead of 96 kbps will be added to the selected data rates. Within the data rate range of the modem, there are four IDR operating rates, 1.544, 2.048, 6.312, and 8.448 Mbps.

Optional Reed-Solomon (R-S) concatenated outer coding compatible with the IESS-308 and IESS-310 standards is supported in this mode. Refer to the modem specification for the specific R-S parameters that apply to each data rate.

Operation in this mode requires the IDR framing option to be activated. The data type will be MIL-188 (RS-422) and there will not be any access to the Intelsat defined ESC overhead data. An optional overhead card is required for G.703 or any other baseband interface and to gain access to the ESC overhead data.

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Table 3-6. IDR Default Parameters

Function Configuration

Modulator Demodulator

Data Rate A Data Rate A TX-A 1544 kbps QPSK 3/4 RX-A 1544 kbps QPSK 3/4 TX IF Frequency 70 MHz RX-IF Frequency 70 MHz TX-IF Output Off Descrambler Type IESS TX Power Level -20 dBm Descrambler On Scrambler Type IESS Diff Decoder On Scrambler On IF Loopback Off Diff. Encoder On BER Threshold None Carrier Mode Normal-Modulated Sweep Center 0 Hz RS Decoder Off Sweep Range 60000 Hz Reacquisition 0 seconds RS Decoder Off

Interface

Utility

Modulator Demodulator

TX-A 1544 kbps QPSK 3/4 RX-A 1544 kbps QPSK 3/4 TX-B 2048 Kbps QPSK 3/4 RX-B 2048 Kbps QPSK 3/4 TX-C 6312 kbps QPSK 3/4 RX-C 6312 kbps QPSK 3/4 TX-D 8448 kbps QPSK 3/4 RX-D 8448 kbps QPSK 3/4 TX-V 1544 kbps QPSK 3/4 RX-V 1544 kbps QPSK 3/4 Modulator Power Offset 0.0 dB Demodulator Type INTELSAT Open Modulator Type INTELSAT Open RX BPSK Ordering Standard

TX BPSK Ordering Standard DEMOD Spectrum Normal MOD Spectrum Normal RX IESS-310 Mode Off TX IESS-310 Mode Off Encoder Type Viterbi Decoder Type Viterbi

Interface

TX Overhead Type IDR TX Data Phase Normal RX Overhead Type IDR RX Data Phase Normal RTS TX-IF CNTRL Off FRAMING See 3.2.7.3 Buffer Program Bits

System

Modem Reference Internal USB Re-Flash Disabled Operation Mode Duplex

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3.5.4 IBS Operation

The IBS mode of operation configures the modem for basic IBS operation without the addition of the overhead card. The IBS mode is used for open network applications operating in compliance with the IESS-309 Intelsat standard. When the IBS mode is active, an overhead of 6.667% will be added to the selected data rates. The available IBS data rates are n x 64 kbps from 64 kbps to 2.048 Mbps.

Optional Reed-Solomon (R-S) concatenated outer coding compatible with the IESS-308 (IDR-small carrier) standard is supported in this mode. The R-S parameters that are selected for this mode of operation are n=126, k=112, t=7 with an interleaver depth of 4.

Operation in this mode requires the IBS framing option to be activated. The data type will be MIL-188 (RS-422) and there will not be any access to the Intelsat defined ESC overhead data. An optional overhead card is required for G.703 or any other baseband interface and to gain access to the ESC overhead data.

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Table 3-7. IBS Default Parameters

Function Configuration

Modulator Demodulator

Data Rate A Data Rate A TX-A 64 kbps QPSK 1/2 RX-A 64 kbps QPSK 1/2 TX IF Frequency 70 MHz RX-IF Frequency 70 MHz TX-IF Output Off Descrambler Type IESS TX Power Level -20 dBm Descrambler On Scrambler Type IESS Diff Decoder On Scrambler On IF Loopback Off Diff. Encoder On BER Threshold None Carrier Mode Normal-Modulated Sweep Center 0 Hz RS Decoder Off Sweep Range 60000 Hz Reacquisition 0 seconds RS Decoder Off

Interface

Utility

Modulator Demodulator

TX-A 64 kbps QPSK 1/2 RX-A 64 kbps QPSK 1/2 TX-B 256 Kbps QPSK 1/2 RX-B 256 Kbps QPSK 1/2 TX-C 768 kbps QPSK 1/2 RX-C 768 kbps QPSK 1/2 TX-D 2048 kbps QPSK 1/2 RX-D 2048 kbps QPSK 1/2 TX-V 128 kbps QPSK 1/2 RX-V 128 kbps QPSK 1/2 Modulator Power Offset 0.0 dB Demodulator Type INTELSAT Open Modulator Type INTELSAT Open RX BPSK Ordering Standard TX BPSK Ordering Standard DEMOD Spectrum Normal MOD Spectrum Normal RX IESS-310 Mode Off TX IESS-310 Mode Off Decoder Type Viterbi Encoder Type Viterbi

Interface

TX Overhead Type IBS TX Data Phase Normal RX Overhead Type IBS RX Data Phase Normal RTS TX-IF CNTRL Off FRAMING See 3.2.7.3 Buffer Program Bits

System

Modem Reference Internal USB Re-Flash Disabled Operation Mode Duplex

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3.5.5 VSAT-IBS Operation

The VSAT-IBS mode of operation configures the modem for open and closed network applications operating in compliance with Appendix K of the IESS-309 Intelsat standard. The VSAT-IBS mode does not allow any overhead to be added to the selected data rates but requires Reed-Solomon concatenated outer coding. The R-S parameters that are required for this mode of operation are n=219, k=201, t=9 with an interleaver depth of 4. The available IBS data rates are n x 64 kbps from 64 kbps to 8.448 Mbps.

The data type will be MIL-188 (RS-422) and an optional overhead card is required for G.703 or any other baseband interface.

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Table 3-8. VSAT-IBS Default Parameters

Function Configuration

Modulator Demodulator

Interface

Utility

Modulator Demodulator

TX-A 64 kbps QPSK 1/2 RX-A 64 kbps QPSK 1/2 TX-B 256 Kbps QPSK 1/2 RX-B 256 Kbps QPSK 1/2 TX-C 768 kbps QPSK 1/2 RX-C 768 kbps QPSK 1/2 TX-D 2048 kbps QPSK 1/2 RX-D 2048 kbps QPSK 1/2 TX-V 128 kbps QPSK 1/2 RX-V 128 kbps QPSK 1/2 Modulator Power Offset 0.0 dB Demodulator Type INTELSAT Open Modulator Type INTELSAT Open RX BPSK Ordering Standard TX BPSK Ordering Standard DEMOD Spectrum Normal MOD Spectrum Normal RX IESS-310 Mode Off TX IESS-310 Mode Off Decoder Type Viterbi Encoder Type Viterbi

Interface

TX Overhead Type VSAT-IBS TX Data Phase Normal RX Overhead Type VSAT-IBS RX Data Phase Normal RTS TX-IF CNTRL Off FRAMING See 3.2.7.3 Buffer Program Bits

System

Modem Reference Internal USB Re-Flash Disabled Operation Mode Duplex

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3.5.6 IBS-309 Operation

The IBS-309 mode of operation configures the modem for basic IBS operation without the addition of the overhead card. The IBS-309 mode is used for open network applications operating in compliance with TN309.5 of the IESS-309 Intelsat standard. When the IBS-309 mode is active, an overhead of 6.667% will be added to the selected data rates. The available IBS data rates are n x 64 kbps from 64 kbps to 2.048 Mbps.

Optional Reed-Solomon (R-S) concatenated outer coding compatible with TN309.5 of the IESS-309 (IBS) standard is supported in this mode. The R-S parameters that are selected for this mode of operation are n=219, k=201, t=9 with an interleaver depth of 4.

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Table 3-9. IBS-309 Default Parameters

Function Configuration

Modulator Demodulator

Interface

Utility

Modulator Demodulator

TX-A 64 kbps QPSK 1/2 RX-A 64 kbps QPSK 1/2 TX-B 256 Kbps QPSK 1/2 RX-B 256 Kbps QPSK 1/2 TX-C 768 kbps QPSK 1/2 RX-C 768 kbps QPSK 1/2 TX-D 2048 kbps QPSK 1/2 RX-D 2048 kbps QPSK 1/2 TX-V 128 kbps QPSK 1/2 RX-V 128 kbps QPSK 1/2 Modulator Power Offset 0.0 dB Demodulator Type INTELSAT Open Modulator Type INTELSAT Open RX BPSK Ordering Standard TX BPSK Ordering Standard DEMOD Spectrum Normal MOD Spectrum Normal RX IESS-310 Mode Off TX IESS-310 Mode Off Encoder Type Viterbi Decoder Type Viterbi

Interface

TX Overhead Type IBS-309 TX Data Phase Normal RX Overhead Type IBS-309 RX Data Phase Normal RTS TX-IF CNTRL Off FRAMING See 3.2.7.3 Buffer Program Bits

System

Modem Reference Internal USB Re-Flash Disabled Operation Mode Duplex

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3.5.7 ASYNC/AUPC Operation

Asynchronous Overhead (ASYNC) with AUPC is a closed network application that gives the user the ability to communicate from the hub site to the remote site through the added overhead. The user can use the AUPC feature that remotely controls the remote modem’s power level, according to parameters programmed by the user. The user can also remotely monitor and control the remote modem by sending remote commands over the link via the overhead. This can be done by a local terminal or Monitor and Control system. The interface for the selectable EIA/TIA-232/485 ASYNC data channel is on the rear panel 9-pin ASYNC connector J2.

The ASYNC mode of operation is compatible with the ASYNC operating mode of any Comtech EF Data satellite modem. Operation in this mode requires the ASYNC framing option to be activated.

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Table 3-10. ASYNC/AUPC Default Parameters

Function Configuration

Modulator Demodulator

Data Rate A Data Rate A

TX-A 64 kbps QPSK 1/2 RX-A 64 kbps QPSK 1/2

TX IF Frequency 70 MHz RX-IF Frequency 70 MHz

TX-IF Output Off Descrambler Type IESS

TX Power Level -20 dBm Descrambler On

Scrambler Type IESS Diff Decoder On

Scrambler On IF Loopback Off

Diff. Encoder On BER Threshold None

Carrier Mode Normal-Modulated Sweep Center 0 Hz

RS Decoder Off Sweep Range 60000 Hz

Reacquisition 0 seconds

RS Decoder Off

Interface

TX Clock Source TX Terrestrial Loop Timing Off

TX Clock Phase Normal TX Data Fault None

SCT PLL REF Modem Reference RX Data Fault None

EXT REF Frequency 1544 kHz TX 2047 Pattern Off

Buffer Clock RX (Satellite) RX 2047 Pattern Off

RX Clock Phase Normal ASYNC TX Baud=1200

B-Band Loopback Off ASYNC RX Baud=1200

Buffer Size 384 bits ASYNC COMM TYPE EIA-232

Local AUPC

AUPC Enable Off Target Eb/N0 6.0 dB

Nominal Power –10 dBm Tracking Rate 1.0 dB/min

Minimum Power –30 dBm Local CL Action Hold

Maximum Power –5 dBm Remote CL Action Hold

Function Select Remote AUPC

AUPC Enable Off TX 2047 Pattern Off

B-Band Loopback Off

Utility

Modulator Demodulator

TX-A 64 kbps QPSK 1/2 RX-A 64 kbps QPSK 1/2

TX-B 256 Kbps QPSK 1/2 RX-B 256 Kbps QPSK 1/2

TX-C 768 kbps QPSK 1/2 RX-C 768 kbps QPSK 1/2

TX-D 2048 kbps QPSK 1/2 RX-D 2048 kbps QPSK 1/2

TX-V 128 kbps QPSK 1/2 RX-V 128 kbps QPSK 1/2

Modulator Power Offset 0.0 dB Demodulator Type EFD Closed

Modulator Type EFD Closed RX BPSK Ordering Standard

TX BPSK Ordering Standard DEMOD Spectrum Normal

MOD Spectrum Normal RX IESS-310 Mode Off

TX IESS-310 Mode Off

Encoder Type Viterbi Decoder Type Viterbi

Interface

TX Overhead Type ASYNC TX Data Phase Normal

RX Overhead Type ASYNC RX Data Phase Normal

RTS TX-IF CNTRL Off FRAMING See 3.2.7.3

Buffer Program Bits

System

Modem Reference Internal USB Re-Flash Disabled

Operation Mode Duplex

Format=7E2

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3.5.8 EFD Operation

The EFD mode of operation is the basic closed network, non-OM-73 operating mode of the modem compatible with the EFD mode in any Comtech EF Data legacy satellite modem. The modem does not require any additional hardware installed to operate in EFD mode. The EFD mode does not allow any overhead to be added to the selected data rates but the full range of data rate, code rate, FEC options, and modulation types are available.

The data type will be MIL-188 (RS-422). An optional overhead card is required for G.703 or any other baseband interface

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Table 3-11. EFD Default Parameters

Function Configuration

Modulator Demodulator

Interface

Utility

Modulator Demodulator

Interface

TX Overhead Type NONE TX Data Phase Normal RX Overhead Type NONE RX Data Phase Normal RTS TX-IF CNTRL Off FRAMING See 3.2.7.3 Buffer Program Bits

System

Modem Reference Internal USB Re-Flash Disabled Operation Mode Duplex

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3.5.9 Custom Operation

The CUSTOM mode of operation allows access to all front panels menus, including the Utility menus. When selecting this mode of operation the modem does not change the settings when from the previous operating mode. All currently programmed parameters will remain as they were. The CUSTOM operation mode is used when the modem must function in a non-standard operating mode. For example, to use the modem in an IBS closed network application (per IESS-309), the following steps are taken:

1. Select the IBS modem type, so that the modem loads the IBS default parameter.

2. Select the Custom modem type, which allows Access to the Tx and Rx overhead type.

3. Select NONE for the Tx and Rx overhead types.

Use caution when operating in the Custom mode. This mode accepts all modem settings, including incompatible parameters. Users should become familiar with the procedures

CAUTION

prior to operating the modem.

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This page is intentionally left blank.

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Chapter 4. THEORY OF

This chapter describes theory of operation for the SLM-7650.

4.1 Overview

The SLM-7650 is a duplex modem in a 1 RU chassis. The modem consists of three basic sub-sections. The modulator section, the demodulator section , and the baseband interface and monitor and control section.

The modem operates on 110/220 VAC (auto-selecting) and provides 50 to 90 MHz and 100 to 180 MHz transmit and receive intermediate frequency interfaces. The primary baseband interface to the modem is MIL-STD-188-114 type II and III. An optional interface card is available as a baseband interface for special applications. (Refer to Figure 4-1 for the system operation.)

4.2 Built in Test

Hardware provisions are included for built in test. This built in test means that the modem is constantly monitored for fault or alarm conditions. The fault and alarm status of the modem is reported in the FAULT/ALARM menu. Summary faults are reported on the front panel LED display. The Fault connector on the back of the interface will also reports these summary faults through dry contact closures. The fault tree (Chapter 5, Table 5-1) in the maintenance section is a guide for fault and alarm reporting.

OPERATION

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4–2

TURBO CODEC

W/ SCRAMBLER

& DESCRAMBLER

& SYMBOL

FORMATTING

OM73

SCRAMBLER

CONV/TCM

ENCODE

TX DE-JITTER TX FILTERING

TX IF

70/140MHz

SCRAMBLER R-S ENCODER INTERLEAVER

(PROGRAMMABLE)

UNCODED

FORMATTING

OVERHEAD

MUX

(INTELSAT, NON-

INTELSAT, DEMAC)

PROGRAMMABLE

TEST PATTERN

GENERATOR

OVERHEAD INTERFA CE

OVERHEAD

DE-MUX

(INTELSAT, NON-

INTELSAT, DEMAC)

DESCRAMBLER

R-S DECODER

DE-INTERLEAVER

(PROGRAMMABLE)

RX IF

70/140MHz

DEMOD

MAPPER

QAM PRE-

PROCESSING

CARRIER/

CLOCK

LOOP &

FILTER

I_R

Q_R

VITERBI/TCM

DECODE

OM73

DESCRAMBLER

I_SOFT

Q_SOFT

UNCODED

FORMATTING

BUFFER

PROGRAMMABLE

TEST PATTERN

DETECTOR

PLL

BUFFER

PLL

INT_REF

RX_CLK

TX R-S

BYPASS

RX R-S

BYPASS

INT_REF

RX_CLK

BUFF REF SEL

ST REF SEL

RX_D

RX_C

RX_CLK RX_DAT

EIA 422/530

MOD

TIMING

SOURCE

TX OVER

HEAD

TX OVER

HEAD

RX OVER

HEAD

RX OVER

HEAD

EXT REF

(1,5,10MHz)

REF PLL

PROCESSOR

M C

KEYPAD

DISPLAY

CLOCK

DISTRIBUTION

DDS

CLOCK

RECOVERY

OPTIONAL

PLUG-IN

INTERFA CE

FAULT

INTERFA CE

SERIAL

M&C

ALARM

INTERFA CE

I F LOOP BACK

M C

DATA

INT_REF

OSC

INT_RE

ETHERNET

(Optional)

Figure 4-1. System Block Diagram

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4.3 Definitions

4.3.1 Differential Encoding/Decoding

A process of manipulating the data in order to maintain bit integrity. There is a possibility that the demodulator may lock to one of the two-quadrature positions for QPSK modulation. If the demod locks to the wrong quadrature state then the data output will not be correct. The use of differential encoding/decoding will ensure the data bits will be correct whether the quadrature locks to the wrong state or not.

4.3.2 Scrambler/Descrambler

Scrambling will ensure that there will not be an excessive amount of consecutive 1s and 0s in the data stream. It is not an encryption method. It serves to give the IF signal a consistent and uniform shape. The output IF signal will not look correct if the scrambler is Off and no data is applied. Scrambling is often referred to as Energy dispersal. There are generally two types of scramblers in satellite modems:

• The self-synchronizing scrambler

• The synchronous scrambler

The descrambler simply works in the reverse direction as a scrambler to provide the proper data output from the modem.

4.3.2.1 Self-Synchronizing Scrambler/Descrambler

The Self-Synchronizing Scrambler uses the input data stream to assist in the scrambling method. This will result in three output data errors for every single error out of the descrambler. There are many variations in the design of the V.35 scramblers. The ITU-RS.524-4 is the source document for this scrambler. Selecting one of the following scrambling methods does not guarantee compatibility with other manufacturers scrambling methods. The self-synchronizing scrambler is used in the following:

• EF Data closed network

• Open network IDR IESS-308

• OM73

• MD 1002

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4.3.2.2 Synchronous Scrambler/Descrambler

The Synchronous Scrambler does not multiply errors and is very suited for framed data applications. The initial sequence of the frame may be used to start the scrambler. Because there is no error multiplication, there is a 0.2 dB BER gain for the synchronous scrambler. The synchronous scrambler is used in the following applications:

• IDR/Small carrier IESS-308

• IDR IESS-308 with Reed-Solomon

• IBS-309 Intelsat Business Service

• IESS-310, 8PSK 2/3 with Reed-Solomon

• Comtech CDM-550 framed operation

Note: Compatibility issues do come up when dealing with scrambling. The scramblers

may be turned off if the modems are not compatible. An IF spectral inversion also can be tried. Realize that the output IF signal will not look correct if the scrambler is Off and no data is applied.

4.3.3 Encoding/Decoding

Various FEC methods are available in the modem to enable operation in the noisy satellite environment. These multiple FEC rates in combination with the various modulation types enables the satellite operator to balance the power and bandwidth availability of each transponder. These include convolutional encoding with Viterbi decoding (CEVD) and Trellis encoding/decoding for 8PSK operation, and concatenation of these with Reed-Solomon outer coding. Turbo Product Coding (TPC) is also available as an option.

4.3.3.1 Convolutional/Viterbi (CEVD)

The combination of convolutional coding and Viterbi decoding has become an almost universal standard for satellite communications. The modem complies with the Intelsat IESS-308/309 standards for Viterbi decoding with a constraint length of seven. This is a de facto standard, even in a closed network environment, which means almost guaranteed inter-operability with other manufacturer’s equipment. It provides very useful levels of coding gain, and its short decoding delay and error-burst characteristics make it particularly suitable for low data rate coded voice applications. It has a short constraint length, fixed at 7, for all code rates. (The constraint length is defined as the number of output symbols from the encoder that are affected by a single input bit.) By choosing various coding rates (Rate 1/2, 3/4 or 7/8) the user can trade off coding gain for bandwidth expansion. Rate 1/2 coding gives the best improvement in error rate, but doubles the transmitted data rate, and hence doubles the occupied bandwidth of the signal. Rate 7/8 coding, at the other extreme, provides the most modest improvement in performance, but only expands the transmitted bandwidth by 14 %. A major advantage of the Viterbi decoding method is that the performance is independent of data rate, and does not display a pronounced threshold effect (i.e., does not fail rapidly below a certain value of Eb/No). Because the method of convolutional coding used with Viterbi, the encoder does not preserve the original data intact, and is called non-systematic.

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The available CEVD rates offered are:

• Rate 1/2 is offered for BPSK

• Rates 1/2, 3/4, and 7/8 for QPSK and OQPSK

• Rates 3/4 and 7/8 are offered for 16-QAM.

Table 4-1. Viterbi Decoding Summary

FOR AGAINST

Good BER performance - very useful coding gain.

Almost universally used, with de facto standards for constraint length and coding polynomials

Shortest decoding delay (~100 bits) of any FEC scheme good for coded voice, VOIP, etc

Short constraint length produce small error bursts - good for coded voice.

No pronounced threshold effect - fails gracefully.

Coding gain independent of data rate.

Higher coding gain possible with other methods

4.3.3.2 Reed-Solomon

Reed-Solomon is an added coding method to convolutional encoding and Viterbi decoding. This is called Concatenated Code when more than one error correction methods is used at the same time.

The concatenation of an outer Reed-Solomon Codec with Viterbi decoder first became popular when it was introduced by Intelsat in the early 1990's. It permits significant improvements in error performance without significant bandwidth expansion. The coding overhead added by the RS outer Codec is typically around 10%, which translates to a 0.4 dB power penalty for a given link. Reed-Solomon codes are block codes (as opposed to Viterbi which is convolutional), and in order to be processed correctly the data must be framed and de-framed. Additionally, Reed-Solomon codes are limited in how well they can correct errors that occur in bursts. This, unfortunately, is the nature of the uncorrected errors from the Viterbi decoder, which produce clusters of errors that are multiples of half the constraint length. For this reason, the data must be interleaved following R-S encoding, and is then de-interleaved prior to R-S decoding. This ensures that a single burst of errors leaving the Viterbi decoder is spread out over a number of interleaving frames, so errors entering the R-S decoder do not exceed its capacity to correct those errors.

In the case of the modulator, different RS code rates are used, according to the mode of operation. Refer to the modulator specification in Appendix C for details on the code rates and interleave depth for each operating mode.

A characteristic of concatenated RS coding is the very pronounced threshold effect. For any given modem design, there will be a threshold value of Eb/No below which the demodulator cannot stay synchronized. This may be due to the carrier-recovery circuits, or the synchronization threshold of the primary FEC device, or both. In the SLM-7650, and Rate 1/2 operation, this threshold is around 4 dB Eb/No. Below this value, operation is not possible, but above this value, the error performance of the concatenated RS system produces exceptionally low error rates for a very small increase in Eb/No.

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Care should be taken not to operate the demodulator near its sync threshold. Small fluctuations in Eb/No may cause total loss of the link, with the subsequent need for

CAUTION

the demodulator to re-acquire the signal.

It cannot be emphasized strongly enough that the purpose of the concatenated ReedSolomon is to dramatically improve the BER performance of a link under given

IMPORTANT

noise conditions. It should NOT be considered as a method to reduce the link EIRP requirement to produce a given BER. Factors such as rain-fade margin, particularly at Ku-band, are extremely important, and reducing link Effective Isotropic Radiated Power (EIRP) can seriously degrade the availability of such a link.

Table 4-2. Concatenated RS Coding Summary

FOR AGAINST

Exceptionally good BER performance

- several orders of magnitude improvement in link BER under given link conditions.

Very small additional bandwidth expansion

Adds to demod acquisition time.

Very pronounced threshold effect - does not fail gracefully in poor Eb/No conditions. Additional coding overhead actually degrades sync threshold, and reduces link fade margin.

Significant processing delay (~25 kbit/s) - not good for voice, or IP applications

4.3.3.3 Trellis Coding

In the other FEC methods described here, the processes of coding and modulation are independent - the FEC codec has no knowledge of, or interaction with the modulator. However, there are schemes in which the coding and modulation are combined together, where the encoder places FEC symbols in a precise manner into the signal constellation. This can yield an overall improvement in performance, and is used in higher-order modulation schemes, such as 8PSK, 16-PSK, 16QAM, etc. When convolution coding is used, the overall coded modulation approach is referred to as Trellis Coded Modulation (TCM). Ungerboeck was an early pioneer, and developed optimum mapping and decoding schemes. However, the decoding scheme was seen as complex, and expensive, and Qualcomm Inc. developed a variation on the theme, which uses a Viterbi decoder at the core, surrounded by adjunct processing. The scheme is able to achieve performance very close to the optimum Ungerboeck method, but with far less complexity, and is called pragmatic Trellis Coded Modulation.

Intelsat recognized that as more and more high power transponders are put in to service, the transponders are no longer power limited, but bandwidth limited. In order to maximize transponder capacity, they looked at 8PSK as a method of reducing the occupied bandwidth of a carrier, and adopted Qualcomm’s pragmatic TCM, at Rate 2/3.

A Rate 2/3 8PSK/TCM carrier occupies only 50% of the bandwidth of a Rate 1/2 QPSK carrier. However, the overall coding gain of the scheme is not adequate by itself, and so Intelsat’s IESS-310 specification requires that the scheme be concatenated with an outer R-S codec. When combined, there is a threshold value of Eb/No of around 6 dB, and above approximately 7 dB, the bit error rate is better than 1 x 10

-8

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The detractions of the concatenated R-S approach apply here also, along with more stringent requirements for phase noise and group delay distortion – the natural consequences of the higher-order modulation.

Table 4-3. 8PSK/TCM Coding Summary

FOR AGAINST

Exceptionally bandwidth efficient compared to QPSK

Demod acquisition threshold much higher than for

Needs concatenated RS outer codec to give acceptable coding gain performance

QPSK

8PSK is more sensitive to phase noise and group delay distortion than QPSK

4.3.3.4 Turbo Product Codec (Hardware Option)

4.3.3.4.1 Introduction

Turbo coding is an FEC technique developed within the last few years, which delivers significant performance improvements compared to more traditional techniques. Two general classes of Turbo Codes have been developed, Turbo Convolutional Codes (TCC), and Turbo Product Codes (TPC, a block coding technique). Comtech EF Data has chosen to implement an FEC codec based on TPC. A Turbo Product Code is a 2 or 3 dimensional array of block codes. Encoding is relatively straightforward, but decoding is a very complex process requiring multiple iterations of processing for maximum performance to be achieved.

Unlike the popular method of concatenating a Reed Solomon codec with a primary FEC codec, Turbo Product Coding is an entirely stand-alone method. It does not require the complex interleaving/de-interleaving of the R-S approach, and consequently, decoding delays are significantly reduced. Furthermore, the traditional concatenated R-S schemes exhibit a very pronounced threshold effect – a small reduction in Eb/No can result in total loss of demod and decoder synchronization. TPC does not suffer from this problem – the demod and decoder remain synchronized down to the point where the output error rate becomes unusable. This is considered to be a particularly advantageous characteristic in a fading environment. Typically, in QPSK, 8-PSK and 16-QAM TPC modes the demod and decoder can remain synchronized 2 – 3 dB below the CEVD/R-S or TCM cases

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Comtech EF Data now offers a very broad range of TPC code rates, combined with the entire range of modulation types, from BPSK to 16-QAM.

Table 4-4 is a listing of all the available TPC modes and rates in the modulator.

Table 4-4. Available TPC Modes

Code Rate/Modulation Data Rate Range

Rate 21/44 BPSK 9.6 kbps to 4.772 Mbps

Rate 5/16 BPSK 9.6 kbps to 3.125 Mbps

Rate 1/2 QPSK/OQPSK 9.6 kbps to 9.54 Mbps

Rate 3/4 QPSK/OQPSK 14.4 kbps to 15.0 Mbps

Rate 7/8 QPSK/OQPSK 16.8 kbps to 17.5 Mbps

Rate 17/18 QPSK/OQPSK 18.13 kbps to 18.88 Mbps

Rate 3/4 8PSK 72.0 kbps to 20 Mbps

Rate 7/8 8PSK 84.0 kbps to 20 Mbps

Rate 17/18 8PSK 90.6 kbps to 20 Mbps

Rate 3/4 16QAM 256.0 kbps to 20 Mbps

Rate 7/8 16QAM 256.0 kbps to 20 Mbps

4.3.3.4.2 End-to-End Processing Delay

In many cases, FEC methods that provide increased coding gain do so at the expense of increased processing delay. However, with TPC, this increase in delay is very modest. Table 4-5 below shows the processing delays for the major FEC types, including three TPC modes. Note that in all cases, the delay is inversely proportional to data rate, so for 128 kbps, the delay values would be half of those shown above. It can be clearly seen that the concatenated Reed-Solomon cases increase the delay very significantly, due mainly to interleaving/de-interleaving.

Table 4-5. Turbo Product Coding processing delay comparison

FEC Mode (64 kbps data rate) End-to-end delay, ms

Viterbi, Rate 1/2 12

Viterbi Rate 1/2 + Reed Solomon 266

Turbo Product Coding, Rate 3/4, QPSK/OQPSK 79

Turbo Product Coding, Rate 21/44, BPSK 64

Turbo Product Coding, Rate 5/16, BPSK 48

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4.3.3.5 Uncoded Operation (No FEC)

There are occasions where a user may wish to operate a satellite link with no forward error correction of any kind. For this reason, the modulator offers this uncoded mode for three modulation types - BPSK, QPSK and OQPSK. However, the user should be aware of some of the implications of using this approach.

PSK demodulators have two inherent undesirable features. The first of these is known as ‘phase ambiguity’, and is due to the fact the demodulator does not have any absolute phase reference, and in the process of carrier recovery, the demodulator can lock up in any of K phase states, where K = 2 for BPSK, K = 4 for QPSK/OQPSK. Without the ability to resolve these ambiguous states there would be a 1-in-2 chance that the data at the output of the demodulator would be wrong, in the case of BPSK. For QPSK, the probability would be 3 in 4.

The problem is solved in the case of BPSK by differentially encoding the data prior to transmission, and then performing the inverse decoding process. This is a very simple process, but has the disadvantage that it doubles the receive BER. For every bit error the demodulator produces, the differential decoder produces two.

The problem for QPSK is more complex, as there are 4 possible lock states, leading to 4 ambiguities. When FEC is employed, the lock state of the FEC decoder can be used to resolve two of the four ambiguities, and the remaining two can be resolved using serial differential encoding/decoding. However, when no FEC is being used, an entirely different scheme must be used. Therefore, in QPSK, a parallel differential encoding/decoding technique is used, but has the disadvantage that it again doubles the receive BER.

OQPSK is a different situation again, where the ambiguities result not only from not having an absolute phase reference, but also not knowing which of the two parallel paths in the demod, I or Q, contains the half-symbol delay. Another type of differential encoding is used, but yet again the error rate is doubled, compared to ideal.

The second problem inherent in PSK demodulators is that of ‘data false locking’.

When data at a certain symbol rate is used to modulate the carrier, the demodulator can lock at incorrect frequencies, spaced at intervals of one-quarter of the symbol rate away from the carrier. Fortunately, when FEC decoding is used, the decoder synchronization state can be used to verify the correct lock point has been achieved, and to reject the false locks. However, if uncoded operation is used, there is no way to recognize a data false lock. The demodulator will indicate that it is correctly locked, but the data out will not be correct.

Comtech EF Data strongly cautions users when using uncoded operation. If the acquisition sweep width exceeds one quarter of the symbol rate, there is a very

CAUTION

high probability that the demodulator will false lock.

As an example, if 64 kbps QPSK uncoded is used, the symbol rate will be half of this rate, or 32 ksymbols/second. One quarter of this equals 8 kHz. Therefore, the absolute maximum acquisition sweep range, which should be considered, is +/- 8 kHz. If there is any frequency uncertainty on the incoming carrier, this should be subtracted from the sweep width. The problem becomes progressively better with increasing symbol rate.

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4.3.4 Modulation Types

4.3.4.1 BPSK

Binary Phase Shift Keying uses vector analysis of the constellation pattern to represent one symbol per carrier phase at either 0 or 180 degrees. The rate 1/2 provides 2 symbol outputs for every input bit. The symbol rate is two times the data rate for BPSK 1/2. Decoder lock is achieved very quickly

4.3.4.2 QPSK

Quaternary Phase Shift Keying differs from BPSK by representing two symbols in one of four phase angle positions; 45, 135, 225, or 315 degrees. Uncoded 1/1, 1/2, 3/4, and 7/8 FEC rates are used for QPSK. The symbol rate for QPSK with an FEC of 1/2 is the same as the data rate. The symbol rate is 2/3 of the data rate for 3/4.

4.3.4.3 Offset QPSK

Offset Quaternary Phase Shift Keying is a variation of QPSK. The offset prevents any succession of symbols going through the zero point of the quadrature. The RF envelope will not collapse when the modulation format is set to OQPSK. It is possible to operate high power amplifiers with less then recommended back off when using this type of modulation.

4.3.4.4 8-PSK

8-Phase Shift Keying Pragmatic trellis coded modulation encoding is used to transmit baseband data for 8 phase shift keying. Eight discrete phase angles represent the 8 possible symbol combinations of three bits. The symbol rate for 2/3 rate 8PSK is 1/2 of the data rate. The symbol rate for 5/6 FEC 8PSK is 3/5 of the data rate.

Reed Solomon is recommended to achieve acceptable performance.

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4.3.4.5 16-QAM

16-phase Quaternary Amplitude Modulation The modulator generates a constellation with 16 discrete phase angle/amplitude states for 16-QAM. There is a large reduction of the symbol rate when using 16-QAM. The symbol rate for 3/4 FEC is 1/3 of the data rate. This severe reduction in symbol rate requires more power on the satellite transponder. Reed Solomon encoding is absolutely necessary.

Phase noise and non-linear links will have a detrimental effect on 16-QAM.

4.3.5 Bit Error Rate

The Bit Error Rate of any digital circuit is the number of bit errors, divided by the bit rate, divided by the total time of the test.

BE/Rate/time

Example: What is the bit error rate when 2 errors occurred in 10 minutes with a data rate of 256 kHz?

2/256k/(10x60) = 1.3 x 10

A communications link that is free of errors is always desired, but most links will operate with a certain number of uncorrectable errors over a period of time. Forward Error Correction is necessary to reduce the errors to an acceptable level.

The BER performance curves are an important reference for modem performance. The slope of the BER curve is an indication of the speed at which the BER performance can degrade under link impaired conditions. There is a point that the modems will not operate any more. This point is referred to as the BER Threshold point. Once the BER Threshold point is reached then the modem will lose lock. The performance of a modem at or near threshold is dependent on the type of FEC that is in operation. The Turbo Product Codec will have the least pronounced threshold effect. The modem will stay locked at very low EbNo values where the bit error correction is as low as 1 x 10 is, of course, unusable at that point, but the error correction will regain substantial error correction for very small increases in signal input.

-8

-2

. Data

4.3.6 Symbol Rate

Symbol rate is the rate that the modulated output signal changes from one phase or amplitude state to another. It is represented by the actual bandwidth of the transmitted carrier at the 3 dB down points from the top of the spectral waveform. It is useful for determining the frequency allocation of the satellite transponder. It is also used to calculate the frequency separation for each carrier on the satellite.

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4.3.7 Symbol Rate Calculations

SR = (DR + OH) * 1/FEC * MF * RSF

FEC

RSF

Overhead for IDR

Overhead for IBS/ASYNC

FEC

Reed-Solomon Factor: RSF = 1.0 if Reed-Solomon is disabled, else refer to Table 4-6: For the N/K values listed the Overhead varies from 8.96% to 12.5%

Symbol Rate

Data Rate

Overhead Rate

Forward Error Correction

Modulation Format

Reed-Solomon Factor

96 kbps (Data rates are 1544, 2048, 6312, and 8448 Mbit/s)

DR * 1/15 (IBS Data rates are n x 64 kbit/s to 2.048 Mbit/s)

1/2 3/4 7/8 2/3 5/6 21/44 5/16 17/18

BPSK = 1, QPSK = 1/2, OQPSK = 1/2, 8PSK = 1/3, 16QAM = 1/4

Mode Overhead Type RSF N K T I

IESS-310 Compliant (8PSK 2/3 only)

Non-IESS-310 Compliant 8PSK 2/3 and all other modulation types and code rates.

Table 4-6. Reed-Solomon Factor

None/ASYNC

IBS (TCM/IDR Small Carrier)

IDR (TCM/IDR at T1, E1,T2, E2)

None

VSAT-IBS

IBS-309

IBS (IDR Small Carrier)

IDR, T1

IDR, E1

IDR, T2

IDR, E2

1.0896

1.0976

1.0896

1.1250

1.0976

1.0896

1.0899

219

225

219

126

225

219

194

201

205

201

112

205

201

178

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4.4 Theory of Operation

4.4.1 Modulator

The modulator converts the input data and clock to a modulated Intermediate Frequency (IF) output in the frequency range of 70 +/- 20 MHz or 140 +/- 40 MHz. The modulator is controlled by commands from the M&C/Interface CCA and fault information from the modulator is sent to the M&C/Interface. The modulator is composed of eight basic subsections.

The major modulator subsections are:

• Scrambler/Differential Encoder

• Convolutional Encoder

• Programmable Vector Rotation

• I/Q Nyquist Filters

• Modulator

• IF Synthesizer

• Output Amplifier

• Output Level Control

The data from the baseband interface section is first processed through the scrambler for energy dispersal, and then to the differential encoder. The differential encodes the data in a way that the demodulator will be able to resolve the various ambiguities that result from the different modulation types. After the differential encoder, the data is passed to the FEC encoding section.

If Reed-Solomon outer coding is selected, the data will be processed first by the R-S encoder before being passed to the convolutional or trellis encoder. The available convolutional code rates are 1/2, 3/4, and 7/8, and the trellis code rates are 5/6, and 2/3 are based on the symbol rate range of 9.6 kbit/s to 10 Mbit/s. For Viterbi codes, the convolutional encoder encodes the data at 1/2 rate. If the selected code rate is 3/4, then 2 of every 6 symbols are punctured. For 3 bits in, there are 4 symbols out. When TPC is selected, the data bypasses the R-S encoder and enters the Turbo encoder block. This block contains all the necessary functions required for Turbo code operation including scrambling, unique word insertion, and formatting.

After the FEC encoder, the data is sent to a programmable vector rotation circuit. This feature provides the user with data communications compatibility for spectrum reversal of the I and Q channels before and after satellite transmission. The I and Q channel data then pass through a set of variable rate digital Nyquist filters. The two identical digital Nyquist filters are followed by the modulator function. Symbol rates up to 10 Msym/s can be achieved automatically.

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The modulated carrier is applied to the IF section for conversion to the correct output frequency. The spectral shape will be identical to that of the input data streams, but double-sided about the carrier frequency.

The IF synthesizer provides the proper frequencies to convert the modulator IF to the desired output frequency in the 70 or 140 MHz range. The synthesizer incorporates a Direct Digital Synthesis (DDS) chip to accommodate 1 Hz steps over the full IF range. The frequency stability of the IF signal will match the stability of the modem reference.

The signal is sent to the output amplifier. The amplifier takes the low level signal from the modulator section and amplifies the signal to the proper level for output from the module. The amplifier circuitry provides programmable control of the output level over a range of +5 to -30 dB, in 0.1 dB steps. The amplifier has power leveling of

± 0.5 dB to

maintain the stability of the output level over time and temperature.

4.4.2 Demodulator

The demodulator will provide baseband data and clock to the customer by processing the down-converted RF signal from the satellite. The frequency of the input IF signal for the demodulator is 70 ± 20 MHz or 140 ± 40 MHz. The input level is between -15 dBm and

-55 dBm. The demodulator uses Viterbi or trellis decoding with or without concatenated Reed Solomon decoding (optional Turbo Product Code). A large receive buffer is available to compensate for any frequency changes caused by the satellite link.

The demodulator functions as an advanced digital coherent phase-lock receiver with selectable FEC decoders. The demodulator is controlled by commands from the M&C and fault information from the demodulator is sent to the M&C. The demodulator is composed of eight basic subsections.

The major demodulator subsections are:

• Input Amplifier

• Input AGC

• IF Synthesizer

• Demodulator

• I/Q Nyquist Filters

• FEC Decoding

• Descrambler/Differential Decoder

• Buffer

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The modulated IF signal at 70 ± 20 MHz or 140 ± 40 MHz enters the IF section for conversion to I and Q analog baseband channels. The I and Q channels are then passed through identical anti-alias filters, offset amplifiers, and DAC. The digitized I and Q data is then sent to the digital Nyquist filters, resulting in a filtered, digital representation of the received signal. The digital data is then sent to four separate circuits:

• Automatic Gain/Offset Control

• Carrier Recovery (Costas) Loop

• Clock Recovery Loop

• Soft Decision Mapping

The AGC provides a gain feedback signal to the IF section to ensure that the digital representation of the I and Q channels is optimized for the Costas and Clock loops, as well as the soft decision mapping circuitry.

The digital Costas loop, in conjunction with a DDS, performs the carrier recovery function. The Costas loop consists of a Costas phase detector, loop filter, and DDS, all implemented digitally.

The DDS performs the function of a Voltage-Controlled Oscillator (VCO) in an analog implementation, but can be easily programmed to the desired center frequency via the M&C.

The output of the DDS is sent to the IF section, providing the reference to which the quadrature local oscillator is locked. The M&C sweeps the local oscillator (via DDS programming) through the user specified sweep range.

When the active decoder (Viterbi, trellis, TPC, or uncoded) determines that the modem is locked, the M&C stops the sweep and begins the de-stress process. This involves finetuning the DDS based on the phase error in the Costas loop. The de-stress process continues as long as the modem is locked. If the carrier is interrupted, the M&C resumes the sweep process.

The digital clock loop, in conjunction with another DDS, performs the clock recovery function. The clock loop consists of a phase detector, loop filter, and DDS, all implemented digitally. The DDS performs the function of a VCO in an analog implementation, but can be easily programmed to the desired center frequency via the M&C. The recovered data and symbol clocks are then used throughout the demodulator.

The soft decision mapper converts the digital I and Q data to 3-bit soft decision values. These values are then fed to the programmable vector rotation circuit, providing compatibility with spectrum reversal of the I and Q channels.

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The output of the vector rotation circuit is then sent to the FEC decoder or uncoded data formatter. The output of the FEC decoder is the final output of the demodulator section.

The uncoded data formatter is used in uncoded operation only and bypasses the FEC decoder entirely. Since in uncoded operation there is no FEC information to use for determining lock, ambiguity resolution, and lock detect are performed differently than when Viterbi or TPC FEC is used. Inversion ambiguity is resolved by:

1. Differentially encoding both the I and Q channels in the modulator.

2. Subsequently differentially decoding both the I and Q channels in the demodulator.

In Offset QPSK modulation, the bit ordering ambiguity is resolved since the ordering is inherent in the modulated carrier. By inserting the 1/2 symbol period delay in the I channel data path and using the Q channel symbol interval as the reference, I occurs before Q. Thus, the data is ordered I then Q into a single bit stream.

Carrier lock is determined by sensing the “quality” of the eye pattern. In OQPSK, both eyes should be as wide as possible. In BPSK, the I channel eye should be wide open and the Q channel eye should be closed. Special circuitry determines when the eye pattern on either channel is not within a valid range, and declares lock accordingly.

The alternate descrambler provides OM-73 compatible descrambling of the decoded data stream. The descrambler is the non-recursive counterpart to the OM-73 scrambler. The scrambled data enters an 11-bit shift register, where taps 9 and 11 are exclusive ORed to provide a synchronous reset to an 8-bit counter (adverse state detector). The following are all exclusive NORed to form the descrambled output:

• Terminal count of this counter

• Inverse of the input data

• Taps 9 and 11 of the shift register

This function may be turned ON or OFF by the M&C. The output of the alternate descrambler is the final output of the demodulator and is then sent to the baseband interface section.

Carrier acquisition in the demodulator is a function symbol rate and modulation type. Lower data rates and higher modulation types will require a longer acquisition time. For very small carrier (<25 ksym/s), there is also the possibility that the demodulator will lock to the wrong carrier if the sweep range encompasses like carriers within the sweep range. The demodulator has available functionality that can shorten the acquisition time. These are: Sweep Range, Sweep Center Frequency, and Reacquisition.

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The Sweep Range sets limits of the carrier loop during acquisition. The Sweep Center Frequency function allows the operator to target the demod center frequency to be offset from the assigned demodulator center frequency. The Reacquisition function is used to reduce the amount of time that is required to relock the demod in the event of a short outage or fade. For the time specified in the Reacquisition function, the demodulator will reduce the sweep range of the carrier loop to +/-500 Hz from the demodulator center frequency prior to the outage.

4.4.3 Baseband Interface

The baseband section of the modem consists of the Monitor and Control (M&C), the transmit and receive baseband interface section, and the reference and clock distribution section.

4.4.3.1 Monitor and Control

The remote serial monitor and control port is selectable as RS-232 or RS-485. The remote control port is used to retrieve status or provide user control of the modem from a remote location and is also used to upgrade the firmware on each CCA.

A fault connector provides Form C contacts for reporting faults on each CCA.

4.4.3.2 Transmit and Receive Baseband

The primary data channel is available on a TIA/EIA-449, 37 pin or an optional TIA/EIA530, 25 pin subminiature D-shell connector. The data and clock signals conform to MIL188-114 type II and III, and TIA/EIA-422 balanced data and clock signal levels.

The digital data baseband loopback occurs between the transmit and receive sections of the modem. This baseband loopback is a bi-directional loop at the input and output of the interface drivers and receivers. This will allow the operator to verify a valid baseband connection to the modem.

An overhead channel is available for Asynchronous (ASYNC) serial communications between the two ends of the satellite link and Automatic Uplink Power Control (AUPC). This overhead channel increases the symbol rate by 6.7%. This overhead function is a closed network application that is compatible with an SLM-8650 operating in 8650-02 mode. The interface for the overhead data is available on a 9 Pin 'D' connector at the rear panel of the modem. The electrical interface is selectable TIA/EIA-232 or TIA/EIA-485 (2 or 4 wire).

Intelsat specifies an overhead framing structure for every open network carrier. The specifications from Intelsat are IESS-308, IESS-309, and IESS-310. The modem can be configured to provide IDR and IBS framing of the data stream per the Intelsat specifications. The type of overhead framing over Intelsat is dependent on the data rate, modulation type, and service that are in operation. Refer to the IESS documents for complete details on these operating modes and framing format.

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The IESS documents define the content of the bits within the overhead frame commonly referred to as Engineering Service Channel (ESC) data. The modem does not provide access to ESC data but sets all of the bits in a 'non-inserted' state so there is no problem interfacing into an open network earth station. An optional interface card is available to provide the interface to the IESS defined ESC data.

The modem is able to provide a bit error rate if the demodulator receives a 2047 pattern and the demodulator test mode of 2047 is turned ON. The modulator is also capable of substituting the 2047 test pattern in lieu of the incoming data stream. The 2047 test pattern is a standard test pattern compatible with the FIREBERD 6000 and similar commercial BER testers. In additional to the 2047 test pattern, a special MIL test pattern is available. This MIL pattern is a modified 2047 pattern that pads the eleven 0s in a 2047 pattern to 50 (2086) once every five, 2047 patterns. This creates a 10274-bit test pattern. This MIL test pattern must be turned on in the modulator for and BER results to be displayed.

The receive baseband section contains a configurable FIFO buffer large enough to handle the link variations caused by an inclined orbit geosynchronous satellite. Generally, the buffer size may be set to 4 ms to take care of the periodic, 24-hour, link variations of the satellite. Refer to paragraph 4.4.3.3.5 for a more complete discussion on the buffer function within the modem.

4.4.3.2.1 Option Interface G.703, Overhead (AS/10175)

This interface is provided as a plug-in option card for the SLM7650 with user accessible connectors at the rear of the modem as follows:

• Two BNC type female connectors for G.703 un-balanced interface

• One 15-pin D-sub female connector for balanced G.703 interface

• One 50-pin D-sub female connector for legacy equipment interfacing

The interface provides the following features:

• G.703 data interface (balanced/un-balanced)

• EIA422/MIL188 interface (50 pin connector)

• ASYNC overhead data interface (50 pin connector)

• Access to IDR/IBS Engineering Service Channels (ESC)

• Drop & Insert

Additionally the option card is designed to support two build options as follows:

• Build Option 1 (AS/10175-1) – G.703 data interface, EIA422/MIL188 interface, ASYNC overhead data interface

• Build Option 2 (AS/10175-2) – Includes all features of build option 1 with the addition of Drop & Insert overhead and access to IDR/IBS ESC

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