Comtech EF Data SNM-1002 User Manual

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SN
O
eration and Maintenance Manual
LinkSync Modem
Part Number MN/SNM1002.OM Revision 2
SNM-1002
LinkSync™ Modem
Operation and Maintenance Manual
Part Number MN/SNM1002.OM
Comtech EFData is an ISO 9001
Registered Company.
Revision 2
May 15, 2002
Comtech EFData, 2114 West 7th Street, Tempe, Arizona 85281 USA, 480.333.2200, FAX: 480.333.2161.
Copyright © Comtech EFData, 2000. All rights reserved. Printed in the USA.
SNM-1002 LinkSync™ Modem Revision 2 Preface MN/SNM1002.OM

Network Customer Support

The Network Customer Support Plan identifies the steps to be followed in resolving the Customer’s concern.
The resolution efforts will follow these levels of contact:
Level One Contact – Factory Authorized Service Center.
Level Two Contact – Comtech EF Data Customer Support.
Level Three Contact – Network Test and Field Support
Procedural Steps
Step Procedure
1
2
3
4
5
The Customer raises a concern with the Level One Contact.
The Level One Contact will perform Hardware repairs and Network Operations troubleshooting in accordance with the Comtech EF Data Service Center agreement.
If the Level One Contact is unable to resolve the concern, then the Level One Contact will inform the Level Two Contact of the concern in accordance with the instructions found within the attached Comtech EF Data Customer Support Department’s document.
The Level Two Contact will enter the concern into the Comtech EF Data database and determine whether the concern is a Hardware concern or a Network Operations concern
The Level Two Contact will interface with the Level One Contact and provide the appropriate hardware support and enter all correspondence into the Comtech EF Data database.
6
7
8
If the Level Two Contact determines that the concern is a Network Operations concern, then the Level Two Contact will inform the Level Three Contact.
The Level Three Contact will interface with the Level One Contact and provide the appropriate support and enter all correspondence into the Comtech EF Data database.
If the Level Three Contact determines that there is a Hardware failure then the Level Three Contact will inform the Level Two Contact. Go to Step 5.
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Network Customer Support Plan
Customer
Yes
Midas Network is functioning
properly?
No
Level One Contact is notified
Authorized Factory Service
Center
Resolved by Hardware repair
or Network Operations
troubleshooting?
No
Level Two Contact is notified
CEFD Customer Support
Hardware or Network
Operations issue?
*Note: If equipment was purchased
directly from Comtech EFData (not
through a Factory Authorized
Service Center), then CEFD
Customer Support will be the initial
point of contact.
Yes
CEFD Customer Support
provides HW support
Hardware
Hardware
Network
Operations
Level Three Contact is notified
CEFD Network Test and Field
Support
Hardware or Network
Operations issue?
CEFD Network Test and Field
Support
provides Network Operations
support
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See the Comtech EF Data website at http://www.comtechefdata.com Service Center. Contact the Factory Authorized Service Center for:
for contact information for a Factory Authorized
Product support
Information on upgrading or returning a product
Contact the Comtech EF Data Customer Support Department for:
Product support or training
Information on upgrading or returning a product
A Customer Support representative may be reached at:
Comtech EF Data Attention: Customer Support Department 2114 West 7th Street Tempe, Arizona 85281 USA
480.333.2200 (Main Comtech EF Data Number)
480.333.4357 (Customer Support Desk)
480.333.2500 FAX
or, E-Mail can be sent to the Systems Support Engineering at:
midasfss@comtechefdata.com
To return a Comtech EF Data product (in-warranty and out-of-warranty) for repair or replacement:
1. Request a Return Material Authorization (RMA) number from the Comtech EF Data Customer Support Department.
2. Be prepared to supply the Customer Support representative with the model number, serial number, and a description of the problem.
3. To ensure that the product is not damaged during shipping, pack the product in its original shipping carton/packaging.
4. Ship the product back to Comtech EF Data. (Shipping charges should be prepaid.)
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Contact the Comtech EF Data Network Test and Field Support for:
System level Network Operations support
Information on upgrading Network Operation software
Reporting comments or suggestions concerning manuals
A Network Test and Field Support representative may be reached at:
Comtech EF Data Attention: Network Test and Field Support 2114 West 7th Street Tempe, Arizona 85281 USA
480.333.2200 (Main Comtech EF Data Number)
480.333.3693 (Network Test and Field Support)
480.333.2161 (FAX)
or, E-Mail can be sent to the Network Test and Field Support Department at:
mailto:midasfss@comtechefdata.com
Contact us via the web at www.comtechefdata.com
.
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Table of Contents

CHAPTER 1. INTRODUCTION......................................................................................................1–1
Overview......................................................................................................................................1–1
1.1
1.2 Mode of Operation......................................................................................................................1–2
1.3 Options.........................................................................................................................................1–5
1.4 Specifications...............................................................................................................................1–6
1.4.1 Summary Specifications........................................................................................................................ 1–6
1.4.2 Environmental and Physical.................................................................................................................. 1–8
1.5 Bit Error Rate Performance ......................................................................................................1–8
1.6 Typical Spectral Occupancy ....................................................................................................1–10
1.7 Dimensional Envelope ..............................................................................................................1–11
CHAPTER 2. INSTALLATION................................................................................... 2–1
2.1 Unpacking....................................................................................................................................2–1
2.2 Installation...................................................................................................................................2–2
2.2.1 Typical Single-Thread Cable Installation.............................................................................................. 2–4
2.2.2 Typical Redundant Cable Installation................................................................................................... 2–5
2.3 Rear Panel Connections..............................................................................................................2–7
2.3.1 Remote Connector and Pinouts (J6)...................................................................................................... 2–8
2.3.2 Data I/O Interface Connector (J8)......................................................................................................... 2–8
2.3.3 RF Output Connector (CP1).................................................................................................................. 2–8
2.3.4 RF Input Connector (CP2) .................................................................................................................... 2–8
2.3.5 External Reference (CP3)...................................................................................................................... 2–9
2.3.6 AC Power Connector ............................................................................................................................ 2–9
2.3.7 DC Power - Optional............................................................................................................................. 2–9
2.3.8 Ground Connector (GND)..................................................................................................................... 2–9
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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............................................................................................................................... 3–3
3.2 Menu System ...............................................................................................................................3–4
3.3 Front Panel Menu.......................................................................................................................3–5
3.4 OPENING SCREEN...................................................................................................................3–6
3.4.1 FUNCTION SELECT:CONFIGURATION......................................................................................... 3–6
3.4.1.1 CONFIGURATION:MODULATOR..............................................................................................3–7
3.4.1.2 CONFIGURATION:DEMODULATOR......................................................................................3–11
3.4.1.3 CONFIGURATION:INTERFACE...............................................................................................3–15
3.4.1.4 CONFIGURATION:SAVE...........................................................................................................3–20
3.4.1.5 CONFIGURATION:RECALL......................................................................................................3–20
3.4.2 FUNCTION SELECT:MONITOR ....................................................................................................... 3–21
3.4.2.1 MONITOR:RAW BER.................................................................................................................3–21
3.4.2.2 MONITOR:CORRECTED BER...................................................................................................3–21
3.4.2.3 MONITOR:EB/NO.......................................................................................................................3–21
3.4.2.4 MONITOR:RECEIVE SIGNAL...................................................................................................3–22
3.4.2.5 MONITOR:SWEEP FREQUENCY.............................................................................................3–22
3.4.2.6 MONITOR:BUFFER FILL...........................................................................................................3–22
3.4.3 FUNCTION SELECT:FAULTS/ALARMS......................................................................................... 3–23
3.4.3.1 FAULTS AND ALARMS:MODULATOR..................................................................................3–24
3.4.3.2 FAULTS AND ALARMS:DEMODULATOR............................................................................. 3–24
3.4.3.3 FAULTS AND ALARMS:TX INTERFACE...............................................................................3–25
3.4.3.4 FAULTS AND ALARMS:RX INTERFACE...............................................................................3–26
3.4.3.5 FAULTS AND ALARMS:COMMON.........................................................................................3–27
3.4.4 FUNCTION SELECT:STORED FLTS/ALMS.................................................................................... 3–28
3.4.4.1 STORED FLTS/ALMS:MODULATOR ......................................................................................3–29
3.4.4.2 STORED FLTS/ALMS:DEMODULATOR.................................................................................3–29
3.4.4.3 STORED FLTS/ALMS:TX INTERFACE....................................................................................3–30
3.4.4.4 STORED FLTS/ALMS:RX INTERFACE....................................................................................3–31
3.4.4.5 STORED FLTS/ALMS:COMMON..............................................................................................3–32
3.4.4.6 STORED FLTS/ALMS:CLEAR...................................................................................................3–32
3.4.5 FUNCTION SELECT:UTILITY.......................................................................................................... 3–33
3.4.5.1 UTILITY:MODULATOR.............................................................................................................3–34
3.4.5.2 UTILITY:DEMODULATOR.......................................................................................................3–37
3.4.5.3 UTILITY:INTERFACE................................................................................................................3–39
3.4.5.4 UTILITY:SYSTEM......................................................................................................................3–43
3.4.5.5 UTILITY:MODEM TYPE............................................................................................................3–48
3.4.5.6 UTILITY:FACTORY SETUP (NOT APPLICABLE)..................................................................3–53
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CHAPTER 4. THEORY OF OPERATION................................................................. 4–1
4.1 Monitor and Control (M&C).....................................................................................................4–1
4.2 Modulator....................................................................................................................................4–3
4.2.1 Modulator Specifications ...................................................................................................................... 4–5
4.2.2 Theory of Operation.............................................................................................................................. 4–6
4.2.3 Theory of Modulation Types................................................................................................................. 4–7
4.3 Demodulator................................................................................................................................4–9
4.3.1 Demodulator Specifications.................................................................................................................. 4–10
4.3.2 Theory of Operation.............................................................................................................................. 4–11
CHAPTER 5. MAINTENANCE.................................................................................. 5–1
5.1 System Checkout.........................................................................................................................5–1
5.1.1 Interface Checkout ................................................................................................................................ 5–2
5.1.2 Modulator Checkout.............................................................................................................................. 5–3
5.1.3 Demodulator Checkout ......................................................................................................................... 5–6
5.2 Fault Isolation..............................................................................................................................5–8
5.2.1 System Faults/Alarms ........................................................................................................................... 5–8
5.2.2 Faults/Alarms Display........................................................................................................................... 5–12
5.2.3 Faults/Alarms Analysis......................................................................................................................... 5–12
APPENDIX A. REMOTE CONTROL OPERATION..................................................A–1
APPENDIX B. REDUNDANT WIRING SCHEMATIC...............................................B–1
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Figures
Figure 1-1. SNM-1002 .............................................................................................................................................1–1
Figure 1-2. Typical NMS Configuration..................................................................................................................1–2
Figure 1-3. Typical Redundancy for the Network and LinkSync Modems..............................................................1–3
Figure 1-4. Modular Design .....................................................................................................................................1–3
Figure 1-5. Block Diagram.......................................................................................................................................1–5
Figure 1-6. Viterbi BER Performance Curves..........................................................................................................1–9
Figure 1-7. Typical Spectral Occupancy................................................................................................................1–10
Figure 1-8. SNM-1002 Dimensional Envelope......................................................................................................1–11
Figure 2-1. Installation of the Mounting Bracket.....................................................................................................2–3
Figure 2-2. Typical Single-Thread Installation.........................................................................................................2–4
Figure 2-3. Typical Redundant Wiring Schmetic.....................................................................................................2–6
Figure 2-2. View of Rear Panel................................................................................................................................2–7
Figure 3-1. Front Panel View...................................................................................................................................3–1
Figure 3-2. Keypad...................................................................................................................................................3–3
Figure 3-3. Main Menu.............................................................................................................................................3–5
Figure 3-4. Baseband Loopback.............................................................................................................................3–18
Figure 4-1. M&C Block Diagram.............................................................................................................................4–2
Figure 4-2. Modulator Block Diagram.....................................................................................................................4–4
Figure 4-3. Demodulator Block Diagram.................................................................................................................4–9
Figure 5-1. Fault Isolation Test Setup ......................................................................................................................5–2
Figure 5-2. Typical Output Spectrum (with Noise)..................................................................................................5–5
Figure 5-3. Typical Output Spectrum (without Noise).............................................................................................5–5
Figure 5-4. Typical Eye Constellations....................................................................................................................5–7
Tables
Table 1-1. Summary Specifications..........................................................................................................................1–6
Table 1-2. Environmental and Physical....................................................................................................................1–8
Table 2-1. Rear Panel Connectors............................................................................................................................2–4
Table 2-2. Remote Connector and Pinouts (J6)........................................................................................................2–5
Table 3-1. LED Indicators........................................................................................................................................3–2
Table 4-1. Modulator Specifications ........................................................................................................................4–5
Table 4-2. Demodulator Specification....................................................................................................................4–10
Table 5-1. Conversion to S/N and Eb/N0 Chart.........................................................................................................5–4
Table 5-2. SNM-1002 Fault Tree .............................................................................................................................5–9
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About this Manual

This manual provides installation and operation information for the Comtech EF Data SNM-1002 LinkSync™ Modem. This is a technical document intended for earth station engineers, technicians, and operators responsible for the operation and maintenance of the SNM-1002 LinkSync™ Modem.

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
WARNING
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
IMPORTANT
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 have been superseded by the new designation of the Electronic Industries Association (EIA). References to the old designations are shown only when depicting actual text displayed on the screen of the unit (RS-232, RS­485, etc.). All other references in the manual will be shown with the EIA designations (EIA-232, EIA-485, etc.) only. For more information, refer to the Department of Defense (DOD) MIL-STD-188-114A, “Electrical Characteristics of Digital Interface Circuits.”
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Trademarks
Products 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 Technical Publications department: techpub@comtechefdata.com

Electrical Safety

The SNM-1002 LinkSync Modem has been shown to comply with the following safety standard:
EN 60950: Safety of Information Technology Equipment, including electrical business machines.
The equipment is rated for operation over the range 85 to 264 volts AC. It has a maximum power consumption of 60 watts.

Fuses

The SNM-1002 LinkSync Modem is fitted with two fuses, one each for line and neutral connections. These are contained within the body of the IEC power connector, behind a small plastic flap.
For 230 volt AC operation, use T0.75A, 20mm fuses.
For 115 volt AC operation, use T1.25A fuses, 20mm fuses.
IMPORTANT

Environmental

The SNM-1002 must not be operated in an environment where the unit is exposed to extremes of temperature outside the ambient range 0 to 50°C (32 to 122°F), precipitation, condensation, or humid atmospheres above 95% RH, altitudes (un-pressurised) greater than 2000 metres, excessive dust or vibration, flammable gases, corrosive or explosive atmospheres.
Operation in vehicles or other transportable installations that are equipped to provide a stable environment is permitted. If such vehicles do not provide a stable environment, safety of the equipment to EN60950 may not be guaranteed.
For continued operator safety, always replace the fuses with the correct type and rating.
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Installation

The installation and connection to the line supply must be made in compliance to local or national wiring codes and regulations.
The SNM-1002 is designed for connection to a power system that has separate ground, line and neutral conductors. The equipment is not designed for connection to power system that has no direct connection to ground.
The SNM-1002 is shipped with a line inlet cable suitable for use in the country of operation. If it is necessary to replace this cable, ensure the replacement has an equivalent specification. Examples of acceptable ratings for the cable include HAR, BASEC and HOXXX-X. Examples of acceptable connector ratings include VDE, NF-USE, UL, CSA, OVE, CEBEC, NEMKO, DEMKO, BS1636A, BSI, SETI, IMQ, KEMA-KEUR and SEV.
International Symbols:
Symbol Definition Symbol Definition
~
Alternating Current
Fuse

Telecommunications Terminal Equipment Directive

In accordance with the Telecommunications Terminal Equipment Directive 91/263/EEC, this equipment should not be directly connected to the Public Telecommunications Network.
Protective Earth
Chassis Ground
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EMC (Electromagnetic Compatibility)

In accordance with European Directive 89/336/EEC, the SNM-1001 Network Modem has been shown, by independent testing, to comply with the following standards:
Emissions: EN 55022 Class B - Limits and methods of measurement of radio interference characteristics of Information Technology Equipment.
(Also tested to FCC Part 15 Class B)
Immunity: EN 50082 Part 1 - Generic immunity standard, Part 1: Domestic, commercial and light industrial environment. Additionally, the SNM-1001-has been shown to comply with the following standards:
EN 61000-3-2 Harmonic Currents Emission EN 61000-3-3 Voltage Fluctuations and Flicker EN 61000-4-2 ESD Immunity EN 61000-4-4 EFT Burst Immunity EN 61000-4-5 Surge Immunity EN 61000-4-6 RF Conducted Immunity EN 61000-4-8 Power frequency Magnetic Field Immunity EN 61000-4-9 Pulse Magnetic Field Immunity EN 61000-4-11 Voltage Dips, Interruptions, and Variations Immunity EN 61000-4-13 Immunity to Harmonics
In order that the Modem continues to comply with these standards, observe the following instructions:
IMPORTANT
Connections to the transmit and receive IF ports (BNC female connectors) should be made using a good quality coaxial cable - for example RG58/U (50 or RG59/U (75 Ω).
All 'D' type connectors attached to the rear panel must have back-shells that provide continuous metallic shielding. Cable with a continuous outer shield (either foil or braid, or both) must be used, and the shield must be bonded to the back-shell.
The equipment must be operated with its cover on at all times. If it becomes necessary to remove the cover, the user should ensure that the cover is correctly re-fitted before normal operation commences.
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Warranty Policy

This Comtech EF Data product is warranted against defects in material and workmanship for a period of two years 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-to-use guide to your equipment. All statements, technical information, and recommendations in this manual and in any guides or related documents are believed reliable, but the accuracy and completeness thereof are not guaranteed or warranted, and they are not intended to be, nor should they be understood to be, representations or warranties concerning the products described. Further, 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 you have any questions regarding your equipment or the information in this manual, please contact the Comtech EF Data Network Customer Support Department.
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Chapter 1. INTRODUCTION
This chapter provides an overview of the SNM-1002 LinkSync Modem, referred to in this manual as “the modem” (Figure 1-1).
Figure 1-1.
SNM-1002 LinkSync Modem
1.1 Overview
The SNM-1002 LinkSync™ modem is a high performance, digital modem designed to provide LinkSync™ functionality for Comtech EF Data ' s Bandwidth-on-demand (BOD) Multimedia Integrated Digital Access System (MIDAS).
Features of the SNM-1002 include:
19.2 kbit/s, QPSK, 1/2 rate continuous demodulator.
2.4 kbit/s to 4.375 mbit/s continuous modulator.
50/180 MHz operation.
Extensive online monitoring.
Built in Self-test.
1–1
SNM-1002 LinkSync™ Modem Revision 2
V
A
V
A
A
ALA
A
A
A
Introduction MN/SNM1002.OM

1.2 Mode of Operation

The SNM-1002 is an integral component of the MIDAS Network Management System (NMS), providing the LinkSync™ monitor and control communication between the NMS and the MIDAS network.
LinkSync™ provides three key functions for the MIDAS network.
Automatic Frequency Control (AFC) for all modems within the network.
Power Management for all active traffic circuits within the network.
Circuit Disruption capability which allows the NMS to terminate circuits
between any two internal traffic nodes (SNM-1010/1010L)in the network.
The SNM-1002 performs a critical roll for each of these three LinkSync™ capabilities under the direct control of the MIDAS NMS. Refer to Chapter 4. Theory of Operation.
OPERATOR
WORKSTATION
OPTIONAL PRINTER
(USER SUPPLIED)
ETHERNET
NETWOR K C ONTROL M O D EM
NMS
CONTROLLER
EIA-422 EIA-232
EIA-232
(SNM-1001)
SNM -1001 Network Control Modem
TR
TRANSMIT
NSMIT
F
E
E
RECEI
RECEI
SDT-1200
U L
R
COMMON
SATELLITE TERMINAL
T
M
S
S
STORED
LinkSync MODEM
(SNM-1002)
ENTER
R
CLE
POWERON
ENTER
TR
NSMITTERON
RRIERDETECT
C
R
CLE
TESTMODE
TM
Figure 1-2. Typical NMS Configuration
IF
(50-180 MHz)
RFT
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Figure 1-3. Typical LinkSync Redundancy
1.2.1 Description
The modem contains:
Built-in scramblers/descramblers TX and RX frequency synthesizers Differential encoder/decoder Multi-rate FEC convolutional Viterbi Decoder
The modem is a complete, self-contained unit in a standard, one-rack unit (1 RU), 19­inch (48 cm), rack-mountable enclosure weighing approximately 9 lbs. (4 kg). The unit was constructed using modular design (Figure 1-4), and consists of from two to five Printed Circuit Boards (PCBs), depending on the configuration. The modem consists of two, major, replaceable assemblies as follows:
Rear panel, main PCB, and power supply
Upper and lower enclosures (chassis) and the front panel
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Figure 1-4. Modular Design
The front panel of the modem contains all Monitor and Control (M&C) function indicators used for operating the modem. The modem can be operated remotely via the M&C connection on the rear panel. Refer to Chapter 2 for connector information and Appendix A for remote control operation information.
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Refer to Figure 1-5 for a system block diagram.
1.3 Options
Option Remarks
Primary Input Power: 90-264 VAC KT/8000-3
-48 VDC KT/8000-4 IF Impedance : 75 50
Figure 1-5. Block Diagram
PL/6093-1 PL/6093-3
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1.4 Specifications

1.4.1 Summary Specifications

Table 1-1 lists a summary of the specifications.
Table 1-1. Summary Specifications
Parameter Specification
Operating Frequency Range 50 to 180 MHz, in 1 Hz steps Modulation Type QPSK
BPSK
Operating Channel Spacing Less than 0.5 dB degradation operating with 2 adjacent-like channels,
each 10 dB higher at 1.3 times the symbol rate. Digital Interface EIA-422/449 on 37-pin D Digital Data Rate QPSK, R=1/2, 2.4 kbps to 4.375 Mbps Scrambling/Descrambling CCIT INTELSAT V.35 Forward Error Correction Viterbi, K=7, Rate 1/2, 3/4, 7/8 Filter Mask Types Closed net (Comtech EF Data)
Modulator
Output Power -5 to –30 dBm, adjustable in 0.1 dB steps Output Spurious < -55 dBc, 0 to 500 MHz
Output Impedance Output Return Loss 20 dB Data Clock Source
Demodulator
Input Power:
Desired Carrier Adjacent Carriers
Maximum Total Input Impedance Input Return Loss 20 dB Carrier Acquisition Range Clock Acquisition Range AGC Output 0 to 10V at 10 mA maximum
75 (Optional: 50)
-5
Internal , ± 1 x 10
-30 to –55 dBm +30 dBc total power within 10 MHz from desired carrier +40 dBc in-band (0 to 500 MHz)
-5 dBm 75 (Optional: 50)
± 35 kHz maximum ± 100 PPM
Default Levels: 0V for –60 dBm 10V for –25 dBm Levels can be programmed in 0.5V increments.
stability
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Table 1-1. Summary Specifications (Continued)
Remote Control Specification
Signal Interface EIA-232 Baud Rate 19.2 kbps Signals Controlled/Monitored Acquisition Sweep Parameters
Baseband Loopback Buffer Clock TX/RX/INT Buffer Size Code and decode Rate Data Rate Select Descrambler On/Off Descrambler Type Differential Encoding and Decoding IF Loopback Interface Loopback MOD/DEMOD Spectrum Normal/Invert Rev Emulation Current/Function RF Loopback RX Clock Normal/Invert RX Frequency Scrambler On/Off Scrambler Type Self Test Transmitter On/Off TX Frequency TX Power TX/RX Filter Mask
Signals Monitored Corrected BER
Fault Status Power Supply Voltage Raw Error Rate RX Carrier Detect RX Eb/No RX Signal Level
Stored Fault Status Configuration Retention Will maintain current configuration for at least 1 year without power. Addressing Programmable from 1 to 255 possibilities
Address 0 is reserved for global addressing.
Diagnostic
Diagnostic Features BER Monitoring
Buffer Fill Status Monitoring
Fault Monitoring (include current and stored faults)
IF Loopback
Input IF Power Monitoring
Remote Control via Serial Port
RF Loopback
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1.4.2 Environmental and Physical

Table 1-2. Environmental and Physical
Parameter Specifications
Size 1 rack unit (1RU)
1.75" H x 19.0" W x 14" D (4.4 H x 48 W x 36 D cm)
Power Prime power 90 to 264 VAC, 47 to 63 Hz,
40W maximum, fused at 2A
Optional: 38 to 64 VDC Operating Temperature Storage Temperature Humidity 0 to 95% non-condensing Mounting Standard 19-inch (48.3 cm) rack mounts
Operational Shock When any one corner of the modem is dropped from 1 cm
Survivability Shock and Vibration MIL-STD-810D Method 514.4, Procedure 8, 1 hour/axis Weight 9 lbs. Maximum
Shipping: Weight Size
0 to 50°C (32 to 122° F)
-55 to +70° C (-67 to 158° F)
Note: Front and rear accepts standard rack mount slides
onto a hard surface, the modem will not take any errors or
faults
MIL-STD-167-1
(4 kg Maximum)
15 lbs. (7 kg)
20 x 21 x 9 inch (51 x 53 x 23 cm)

1.5 Bit Error Rate Performance

The following specifications for the Eb/N0 required to achieve 10-3 to 10 different coding configurations. All values are for operating in QPSK mode. Without coding, the modem provides QPSK operation within 0.8 dB of theoretical for BER in the range 10 connected back-to-back through an additive white Gaussian noise channel. Refer to Figure 1-6 for the performance BER curves.
-1
to 10-6. Performance measurements were recorded with transmit and receive IF
Eb/N0 (dB) Specification
BER 1/2 Rate 3/4 Rate 7/8 Rate
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 10-7 6.7 8.2 9.2 10-8 7.2 8.8 9.9
-8
BER for
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SNM-1002 LinkSync™ Modem Revision 2 Introduction MN/SNM1002.OM
1.5.1 BER Threshold
The modem will have a programmable BER threshold function. This will allow the operator to set the threshold from 1.0 E-3 to 1.0 E-8.
10-2
-3
10
10-4
10
10
BER
10-7
10
10
-10
10
-5
-6
-8
-9
1/2 Rate 3/4 Rate 7/8 Rate
SPECIFICATIONS
3.0 4.0 5.0 6.0
7.0 8.0 9.0 10.0 11.0
E
(dB)
b/N0
Figure 1-6. Viterbi BER Performance Curves
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1.6 Typical Spectral Occupancy

Figure 1-7. Typical Spectral Occupancy
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1.7 Dimensional Envelope
Note: All dimensions are in English units (centermeters are in parenthesis).
Figure 1-8. SNM-1002 Dimensional Envelope
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Chapter 2. INSTALLATION
This chapter provides unpacking and installation instructions, and a description of external connections information.
The equipment contains parts and assemblies sensitive to damage by Electrostatic Discharge (ESD). Use ESD precautionary procedures when
CAUTION
touching, removing, or inserting PCBs.
2.1 Unpacking
The modem and manual are packaged in pre-formed, reusable, cardboard cartons containing foam spacing for maximum shipping protection.
Do not use any cutting tool that will extend more than 1 inch into the container. This can cause damage to the modem.
CAUTION
Unpack the modem as follows:
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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2.2 Installation
The modem arrives fully assembled from the factory. After unpacking the modem, install the modem as follows:
1. If required, install the mounting bracket in equipment rack (Figure 2-1). Install and tighten the bracket bolts.
2. Loosen the screw with flat washer located on the left side of modem chassis. Mount the modem chassis into the equipment rack and slide the screw with flat washer through the slot of the mounting bracket. Tighten the screw sufficiently to allow the modem chassis to slide in the bracket.
3. Connect the cables to the proper locations on the rear panel. Refer to Section 2.3 for connector pinouts, placement, and function.
4. Connect the primary power cable to the power source. Before turning on the power switch, become familiar with the front panel operation in Chapter 3.
5. If problems exist with the installation, refer to Chapter 5 for troubleshooting information.
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Figure 2-1. Installation of the Mounting Bracket
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2.2.1 Typical Single-Thread Cable Installation

Note: Cables may be procured from Comtech EF Data by contacting Comtech EF Data Network Customer Support department for information.
1. Connect supplied Y-Cable (Figure 2-2) as follows:
a. Connect the supplied-cable base connector to the FASTCOM card. b. Connect supplied-cable Port 1 connector to the Comtech EF Data
supplied EIA-422 cable from SNM-1001 Modem.
c. Cable Port 2 connector is not connected.
2. Connect 9-pin EIA-232 cable from Controller Server COM 1 port to SNM-1001 Remote port (J6). a. If non-redundant SNM-1001, the following remote settings are required:
EIA-232
19.2 Baud rate
8N1
3. Connect 9-pin EIA-232 cable from Controller Server COM 2 port to SNM-1002 Remote port (J6).
4. Connect 25-pin pre-programmed dongle (security key) to Controller Server 25-pin I/O port.
Figure 2-2. Typical Single-Thread Installation
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SNM-1002 LinkSync Modem Revision 2 Installation MN/SNM1002.OM
Item No. Cable Description From To
1 Comtech EF Data
Supplied 2 CA/5684 Supplied Y-Cable Port 1 of the SNM-1001 3 EIA-232 MIDAS Controller COM 2 SNM-1002 Remote port (J6) 4
EIA-232 MIDAS Controller COM 1 SNM-1001Remote port (J6)
FASTCOM Card CA/5684

2.2.2 Redundant LinkSync (Network Control) Modem Installation

A typical redundant wiring schematic is included to assist the user in establishing a redundant configuration. The following table can assist the user in cable selection and location. One or both of the 1:1 redundant configurations can be installed in a MIDAS System. Figure 2-3 shows both Network Control Modem and LinkSync Modem Redundancy.
Item No. Cable Description From To
1 CA/5684 MIDAS Controller SMS-301 J1 COM 2 EIA-422 37-pin SMS-301 (J2) SNM-1001(A) (J8) 3 EIA-422 37-pin SMS-301 (J3) SNM-1001 (B) (J8) 4 BNC SMS-301 (J4) (TX-IF) Combiner 5 BNC SMS-301 (J8) (RX-IF) Combiner 6 BNC SMS-301 (J9) A SNM-1001(A) CP2 TX/IF 7 BNC SMS-301 (J6) B SNM-1001(B) CP1 TX/IF 8 BNC SMS-301 (J7) B SNM-1001(B) CP2 RX/IF 9 BNC SMS-301 (J5) A SNM-1001(A) CP1 TX/IF
10 EIA-232 9-pin
Network Control Modem
11 EIA-232 SMS-301 (J10)
12 EIA-422 37-pin SMS-301 (J2) SNM-1002 (A) Data I/O 13 EIA-422 37-pin SMS-301 (J3) SNM-1002 (B) Data I/O 14 EIA-232 9-pin
15 BNC SMS-301 (J9) A SNM-1002 A) CP2 RX-IF 16 BNC SMS-301 (J8) RX-IF Combiner 17 BNC SMS-301 (J4) TX-IF Combiner 18 BNC SMS-301 (J5) A SNM-1002(A) CP1 TX-IF 19 BNC SMS-301 (J7) B SNM-1002(B) CP2 RX-IF
LinkSync Modem
20 BNC SMS-301 (J6) B SNM-1002(B) CP1 TX-IF 21 EIA-232 SMS-301 (J10)
Ribbon Cable
Ribbon Cable
SMS-301 (J13) Modem COM
Remote Control
SMS-301 (J13) Modem COM
Remote Control
SNM-1001(A) (J6) Remote SNM-1001(B) (J6) Remote MIDAS Controller COM1
SNM-1002(A) (J6) Remote SNM-1002(B) (J6) Remote
MIDAS Controller COM2
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Figure 2-3. Typical Redundant Wiring Schematic
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2.3 Rear Panel Connections

The rear panel connectors provide all necessary external connections between the modem and other equipment.
Table 0-1 lists these connectors, and Figure 2-4 shows their locations.
Figure 2-4. View of Rear Panel
Table 0-1. Rear Panel Connectors
Name
REMOTE J6 9-pin D Remote Interface FAULT Connector is not used. DATA I/O J8 37-pin D EIA-422 AUX 1 Connector is not used.
ALARMS Connector is not used. TX/IF OUTPUT CP1 BNC RF Output RX/IF INPUT CP2 BNC RF Input EXTERNAL REF CP3 BNC Input AC INPUT NONE IEC GROUND NONE 10-32 Stud
REF DES Connector Type
J7 9-pin D FORM C Fault Relay Contacts
J9 9-pin D (TTL) Faults
Satellite Clock Demod I/Q Automatic Gain Control (AGC) Out
J10 9-pin D FORM C Alarm
Relay Contacts
Function
Note: The European EMC Directive (EN55022, EN50082-1) requires using properly shielded
cables for DATA I/O. These cables must be double-shielded, ensuring a continuous ground shield.
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2.3.1 Remote Connector and Pinouts (J6)

The remote connector is a 9-pin female D connector (J6) located on the rear panel of the modem. Screw locks are provided for mechanical security of the mating connector.
The remote connector interfaces the M&C functions to the MIDAS Controller. This is an EIA-232 DCE interface. Refer to Appendix A for a description of the remote interface.
Refer to Table 0-2 for pinout information.
Table 0-2. Remote Connector and Pinouts (J6)
EIA-232
Pin # Name
1 2 RD (RX) 3 TD (TX) 4 5 GND 6 DSR 7 RTS 8 CTS 9

2.3.2 Data I/O Interface Connector (J8)

This connector is only utilized when the modem is operating in a Redundant LinkSync Configuration. In a Redundant LinkSync Configuration, the Data I/O cable connects between an SNM-301 1:1 Switch and J8 of the LinkSync modem. Refer to Chapter 1, Figure 1-3.

2.3.3 RF Output Connector (CP1)

CP1 is a BNC connector for the transmit IF signal. The standard output impedance is 75Ω, and the output power level is -5 to -30 dBm. In normal operation, the output will be a QPSK- or BPSK-modulated signal between 50 and 180 MHz, in 1 Hz steps.

2.3.4 RF Input Connector (CP2)

CP2 is a BNC connector for the receive IF signal. The standard input impedance is 75. For normal operation, the desired carrier signal level should be between -30 and -55 dBm. Signals between 50 and 180 MHz are selected and demodulated to produce clock and data at the Data I/O connector.
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2.3.5 External Reference (CP3)

CP3 is a BNC connector for an external reference. The input impedance is 75. For normal operation, the reference signal is
0 dBm.

2.3.6 AC Power Connector

The AC power is supplied to the SNM-1002 by a standard, d etachab le, non-locking, 3-prong power cord. Refer to the following listing for AC power specifications.
Input power Input voltage
Connector type Fuse protection
50W max. 90 to 264 VAC, 47 to 63Hz. Note: Unit switches ranges automatically. IEC 1A slo-blo line and neutral fusing 5 mm type fuses.

2.3.7 DC Power - Optional

For DC supplied units, the DC Power is supplied by terminal lugs installed on the back panel. Refer to the following table for specifications
Input power Input voltage Connector type Fuse protection
50W max. 38 to 64 VDC. Terminal Lug 1A slo-blo 5 mm type fuses.

2.3.8 Ground Connector (GND)

A #10-32 stud on the rear panel of the modem is used for connecting a common chassis ground among all equipment.
Note: The AC power connector provides the safety ground.
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Chapter 3. OPERATION
3.1 Front Panel
Note: Front panel operation of the LinkSync modem is only required for initial installation for setting the remote communication parameters. Under normal operation, the MIDAS NMS configures and controls the LinkSync for all of the functions it provides. A complete menu tree is shown for navigational purposes only.
The modem front panel (Figure 3-1) enables control of modem configurations parameters and displays the modem status.
Figure 3-1. Front Panel View
The front panel features include:
32-character, 2-line LCD display
6-button keypad for local control
10 LEDs to provide overall status at a glance
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3.1.1 LED Indicators
The 10 LEDs on the front panel indicate:
General modem summary faults
Status
Alarms
The indicators are defined in Table 3-1 as follows:
Table 3-1. LED Indicators
Name LED Meaning
Faults
Transmit Red A fault condition exists in the transmit chain. Receive Red A fault condition exists in the receive chain. Common Red A common equipment fault condition exists. Stored Yellow A fault has been logged and stored.
The fault may or may not be active.
Status
Power On Green Power is applied to the modem. Transmitter On Green Transmitter is currently on.
This indicator reflects the actual condition of the transmitter, as
opposed to the programmed condition. Carrier Detect Green Decoder is locked. Test Mode Yellow Flashes when the modem is in a test configuration.
Alarms
Transmit Yellow A transmit function is in an alarm condition. Receive Yellow A receive function is in an alarm condition.
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3.1.2 Front Panel Keypad

The front panel keypad permits local operation of the modem. The keypad consists of six keys (Figure 3-2). It is locked out for normal use.
ENTER
CLEAR
Figure 3-2. Keypad
Each key provides one or more logical functions. These functions are defined in the following table.
ENTER This key is used to select a displayed function or to execute a modem
configuration change.
CLEAR 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. Left and Right Diamond Keys
Top and Bottom Diamond Keys
These keys are used to move to the next selection or to move the cursor for
certain functions.
Note: Throughout this chapter, [
diamond keys.
These keys are used primarily to change configuration data (numbers). At times,
they are also used to move from one section to another.
Note: Throughout this chapter, [
diamond keys.
] and [] are used to indicate left and right
] and [] are used to indicate top and bottom
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.
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3.2 Menu System
Use the Main menu in Figure 3-3 as a quick reference for accessing the modem functions.
When the modem power is applied, the base level of the menu system displays the sign-on message:
Line 1 of the sign-on message is the modem type.
Line 2 is the node address.
The main level of the menu system is Function Select. To access this level from the sign-on message, press the [] or [] keys. From the Function Select menu, select one of the functional categories:
Configuration
Monitor
Faults/Alarms
Stored Faults/Alarms
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.
To view 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
Save
Recall
Press [ENTER] to select the desired Configuration menu option. To view the options for the selected configuration parameters, press [] or [].
Notes:
1. Menus or commands 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 windows are accessible in the Custom mode. Take caution not to select incompatible parameters, as the modem does not shut out incompatible command choices in the Custom mode.
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3.3 Front Panel Menu

SELECT
CONFIGURATION MONITOR FAULTS/ALARMS STORED FLTS/ALMS UTILITY
FACTORY SETUP (NOT APPL ICABLE
MODULATOR DEMODULATOR INTERFACE SAVE RECALL
RAW BER CORRECTED BER EB/NO RECEIVE SIGNAL SWEEP FREQUENCY BUFFER FILL
MODULATOR DEMODULATOR TX INTERFACE RX INTERFACE COMMON
MODULATOR DEMODULATOR TX INTERFACE RX INTERFACE COMMON CLEAR
MODULATOR DEMODULATOR INTERFACE SYSTEM MODEM TYPE
CODE/DATA RATE TX-IF FREQUENCY TX-IF OUTPUT TX POWER LEVEL SCRAMBLER DIFF ENCODER CARRIER MODE MODEM REFERENCE
CODE/DATA RATE RX-IF FREQUENCY DESCRAMBLER DIFF DECODER RF LOOP BACK IF LOOP BACK BER THRESHOLD SWEEP CENTER SWEEP RANGE REACQUISITION
TX CLOCK SOURCE TX CLOCK PHASE EXT-CLK FREQ BUFFER CLOCK RX CLOCK PHASE B-BAND LOOP BACK BUFFER SIZE BUFFER CENTER LOOP TIMING
ASSIGNED FILTERS MOD POWER OFFSET MODULATOR TYPE ENCODER TYPE TX BPSK OREDERING MOD SPECTRUM TX SYMBOL RATE
ASSIGNED FILTERS DEMODULATOR TYPE DECODER TYPE RX BPSK ORDERING DEMOD SPECTRUM RX SYMBOL RATE
TX OVERHEAD TYPE RX OVERHEAD TYPE TX TERR INTERFACE RX TERR INTERFACE BUFFER PROGRAM FRAMING STRUCTURE RTS TX-IF CNTRL TX DATA PHASE RX DATA PHASE CTS DELAY
TIME/DATE REMOTE BAUD RATE REMOTE ADDRESS REMOTE TYPE OPERATION MODE YEAR DISPLAY TEST MODE STATUS LAMP TEST SELF TEST DISPLAY CONTRAST M&C FIRMWARE BOOT FIRMWARE FPGA FIRMWARE DEMO MODE EXT AGC: MAX PWR EXT AGC: MIN PWR MASTER RESET
MODEM TYPE MODEM EMULATION REV EMULATION MODEM OPTIONS LOCAL MODEM AUPC MODEM SERIAL CONFIGURATION CODE
Figure 3-3. Main Menu
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Note: The following menus tree shows the modem functions available for an SNM-1002 LinkSync Modem. The defaulkt settings used when deployed in a MIDAS Network are underlined.
3.4 OPENING SCREEN
SNM 1002 Ver:X.X.X
3.4.1 FUNCTION SELECT:CONFIGURATION
FUNCTION SELECT
CONFIGURATION
The main level of the menu system is Function Select. To access this level from the sign-on message, press the [] or [] keys. From the Function Select menu, select one of the functional categories:
Configuration
Monitor
Faults/Alarms
Stored Faults/Alarms
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.
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3.4.1.1 CONFIGURATION:MODULATOR
CONFIGURATION
MODULATOR
To view 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
Save
Recall
Press [ENTER] to select the desired Configuration menu option. To view the options for the selected configuration parameters, press [] or [].
3.4.1.1.1 MODULATOR: CODE RATE/TYPE
TX-X QPSK 1/2
19.200 kbps
Transmit code rate/type as follows:
TX-A QPSK 1/2 19.200 kbps TX-B QPSK 1/2 19.200 kbps TX-C QPSK 1/2 19.200 kbps TX-D QPSK 1/2 19.200 kbps TX-V QPSK 1/2 19.200 kbps
Upon entry, the current transmitter rate is displayed.
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3.4.1.1.2 MODULATOR:TX-IF FREQENCY
TX-IF FREQUENCY
70.000000 MHz
Displays the modulator TX IF frequency between 50 and 180 MHz, in 1 Hz steps.
Upon entry, the current transmitter frequency is displayed with the flashing cursor on the first character. Press [ ] or [] to move the flashing cursor, and [ ] or [ ] to increase or decrease the digit at the flashing cursor. Press <ENTER> to execute the change.
3.4.1.1.3 MODULATOR:TX-IF OUTPUT
TX-IF OUTPUT
ON
Displays the modulator output status, either On
Upon entry, the current TX-IF output is displayed with the flashing cursor on the first character. Press [ ] or [ ] to On or Off. Press <ENTER> to execute the change.
or Off.
3.4.1.1.4 MODULATOR:TX POWER LEVEL
TX POWER LEVEL
-10.0 dBm
Displays the modulator output level from:
-5.0 to –30.0 dBm (Normal Range)
Upon entry, the current TX power level is displayed with the flashing cursor on the first character. Press [ ] or [] to move the flashing cursor, and [ ] or [ ] to increase or decrease the digit at the flashing cursor. Press <ENTER> to execute the change.
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3.4.1.1.5 MODULATOR:SCRAMBLER
SCRAMBLER
ON
Displays the scrambler status, either On
Upon entry, the current scrambler is displayed with the flashing cursor on the first character. Press [ ] or [ ] to change the carrier mode. Press <ENTER> to execute the change
or Off.
3.4.1.1.6 MODULATOR:DIFF. ENCODER
DIFF. ENCODER
ON
Displays the differential encoder status, either On
Upon entry, the current differential decoder is displayed with the flashing cursor on the first character. Press [ ] or [ ] to change the carrier mode. Press <ENTER> to execute the change.
or Off.
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3.4.1.1.7 MODULATOR:CARRIER MODE
CARRIER MODE
NORMAL-MODULATED
Displays the carrier mode of operation as follows:
Normal-Modulated
Center-CW
Offset-CW
Dual-CW
Upon entry, the current carrier mode is displayed with the flashing cursor on the first character. Press [ ] or [ ] to change the carrier mode. Press <ENTER> to execute the change.
The carrier mode in normally in this Modulated position.
Generates a carrier at the current modulator frequency. This can be used to measure the output frequency.
Generates a single, upper, side-band-suppressed carrier signal. The upper side­band is at one-quarter of the symbol rate from the carrier. When inverted spectrum is selected, this generates a single, lower, side-band-suppressed carrier.
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.
3.4.1.1.8 MODULATOR:MODEM REFERENCE
MODEM REFERENCE
INTERNAL
Displays the following references to the modulator:
INTERNAL
EXT1, EXT5, EXT10, and EXT20 MHz
Note: If any EXT REF is selected for the modem reference and there is no input to CP3, the modem will detect an alarm and switch to the INTERNAL clock.
Upon entry, the current modem reference is displayed with the flashing cursor on the first character. Press [ ] or [ ] change the modem reference. Press <ENTER> to execute the change.
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3.4.1.2 CONFIGURATION:DEMODULATOR
CONFIGURATION
DEMODULATOR
3.4.1.2.1 DEMODULATOR:CODE RATE/TYPE
RX-X QPSK 1/2
19.200 kbps
Receive code rate/type as follows:
RX-A QPSK 1/2 19.200 kbps RX-B QPSK 1/2 19.200 kbps RX-C QPSK 1/2 19.200 kbps RX-D QPSK 1/2 19.200 kbps RX-V QPSK 1/2 19.200 kbps
Upon entry, the current transmitter rate is displayed. Press [ ] or [ ] change the assigned filter. Press <ENTER> to execute the change.
3.4.1.2.2 DEMODULATOR:RX-IF FREQUENCY
RX-IF FREQUENCY
70.000000 MHZ
Displays the demodulator receive frequency, between 50 and 180 MHz, in 1 Hz steps.
Upon entry, the current RF-IF frequency is displayed. Press [ ] or [ ] change the assigned filter. Press <ENTER> to execute the change.
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3.4.1.2.3 DEMODULATOR:DESCRAMBLER
DESCRAMBLER
ON
Displays the descrambler status, either On
Upon entry, the current descrambler is displayed. Press [ ] or [ ] change the assigned filter. Press <ENTER> to execute the change.
or Off.
3.4.1.2.4 DEMODULATOR:DIFF.DECODER
DIFF. DECODER
ON
Displays the differential decoder status, either On
Upon entry, the current differential decoder is displayed. Press [ ] or [ ] change the
assigned filter. Press <ENTER> to execute the change.
or Off.
3.4.1.2.5 DEMODULATOR:RF LOOP BACK
RF LOOP BACK
OFF
Displays the RF loop back status, either On or Off
Upon entry, the current RF loop back is displayed. Press [ ] or [ ]. Press <ENTER> to
execute the change.
.
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3.4.1.2.6 DEMODULATOR:IF LOOP BACK
IF LOOP BACK
OFF
Displays the IF loop back status, either On or Off
Upon entry, the current IF loop back is displayed. Press [ ] or [ ]. Press <ENTER> to
execute the change.
.
3.4.1.2.7 DEMODULATOR:BER THRESHOLD
BER THRESHOLD
NONE
Displays the BER threshold .
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
Upon entry, the current BER threshold is displayed. Press [ ] or [ ]. Press <ENTER> to execute the change.
.
3.4.1.2.8 DEMODULATOR:SWEEP CENTER
SWEEP CENTER
+ 0 HZ
Displays the sweep center frequency for the directed sweep function. 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. The sweep center frequency can be set in the range from –35000 to +35000 Hz. Default: 0 Hz
Upon entry, the current sweep center frequency is displayed with the flashing cursor on the first character. Press [ ] or [] to move the flashing cursor, and [ ] or [ ] to increase or decrease the digit at the flashing cursor. Press <ENTER> to execute the change.
3.4.1.2.9 DEMODULATOR:SWEEP RANGE
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SWEEP RANGE
60000 HZ
Displays 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. Default: 60000 Hz
When set at 70000 Hz, the modem is in Normal acquisition mode. The smaller the range, the faster the modem will lock, provided the receive carrier center frequency is within the RX-IF frequency sweep range.
.
3.4.1.2.10 DEMODULATOR:REACQUISITION
REACQUISITION
0 SECONDS
Displays the sweep reacquisition mode time duration. This is the time that the modem will remain in a narrow sweep 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. Default: 0 seconds
.
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3.4.1.3 CONFIGURATION:INTERFACE
CONFIGURATION
INTERFACE
3.4.1.3.1 INTERFACE:TX CLOCK SOURCE
TX CLOCK SOURCE
SCT (INTERNAL)
Programs the clock source for the modem transmitter clock to the following configurations:
TX TERRESTRIAL
SCT (INTERNAL)
RX (SATELLITE)
EXT CLOCK
Upon entry, the current TX clock source is displayed. Press [ ] or [ ] to make the selection. Press <ENTER> to execute the change.
Sets the TX clock to recover timing from the incoming clock/data.
Sets the TX clock to operate from the modem internal clock (this also is the fallback clock).
Note: When loop timing is enabled, SCT (LOOP) is displayed instead of SCT (INTERNAL).
Sets the RX clock to recover timing from the output clock/data.
Sets the TX clock to operate from the EXT-CLK clock. Transmit clock source must be phase/frequency locked to the data that is being transmitted. The correct frequency must be programmed into EXT-CLK FREQ.
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3.4.1.3.2 INTERFACE:TX CLOCK PHASE
TX CLOCK PHASE
INVERT
Programs the TX clock phase to AUTO, NORMAL, INVERT
Upon entry, the current TX clock phase is displayed. Press [ ] or [ ] to make the selection. When AUTO is s elected, the modem will automatically select NORMAL or INVERT to properly phase the TX clock with the TX data. Press <ENTER> to execute the change.
.
3.4.1.3.3 INTERFACE:EXT-CLK FREQ
EXT-CLK FREQ
1544.000 KHZ
Programs the external reference clock input frequency between 8.0 kHz and 10.0 MHz. Default: 1544 kHz
Note: The clock rate must be equal to the data rate unless the asymmetrical loop timing option is present.
This clock frequency can be any multiple of 600 Hz from 2.4 to 64 kHz, and can be any multiple of 8 kHz from 64 kHz to 4.376 MHz.
This can be used for the Doppler/plesiochronous buffer reference. It can be a reference to SCT. Use the master clock input on J8 for the external master reference. The EXT REF on CP3 only allows for 1, 5, 10, and 20 MHz external reference input.
Upon 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.
.
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SNM-1002 LinkSync Modem Revision 2 Operation MN/SNM1002.OM
3.4.1.3.4 INTERFACE:BUFFER CLOCK
BUFFER CLOCK
RX (SATELLITE)
Programs the interface buffer output clock to one of the following modes:
RX (SATELLITE)
SCT (INTERNAL)
EXT. CLOCK
TX TERRESTRIAL
INSERT CLOCK
Upon entry, the current setting of the plesiochronous buffer clock is displayed. Press [] or [] to make the selection. Press [ENTER] to execute the change.
Sets the output buffer clock to the satellite clock. (This is a Bypass.)
Sets the buffer clock to operate from the modem internal clock. This is also the fallback clock.
Sets this clock source to the external clock.
Sets the buffer output clock to recover timing from the incoming TX data clock.
Selects the recovered clock from the insert send data input received from the terrestrial equipment.
3.4.1.3.5 INTERFACE:RX CLOCK PHASE
RX CLOCK PHASE
NORMAL
Programs the RX clock phase to Normal
Upon entry, the status of the RX Clock is displayed. Press [] or [] to make the selection. Press [ENTER] to execute the change.
or Inverted.
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Operation MN/SNM1002.OM
3.4.1.3.6 INTERFACE:B-BAND LOOP BACK
B-BAND LOOP BACK
OFF
Programs the modem for baseband loopback operation, On or Off
When baseband loopback is turned on, the data and timing signals are switched from the demodulator to the modulator on the modem side of the interface. The DTE baseband signals are also looped back from the transmitter data and clock to receiver data and clock on the customer side of the interface. This is a bi-directional loopback of the baseband data. Refer to figure 3-4 for a block diagram of baseband loopback operation.
Upon entry, the status is displayed. Press [] or [] to make the selection. Press [ENTER] to execute the change.
.
CUSTOMER
DATA
REMOTE SERIAL
INTERFACE
FAULT INDICATORS
IBS OR IDR
INTERFACE
SATELLITE MODEM
ENCODER/
MODULATOR
MICRO-
COMPUTER
DEMODULATOR
DECODER
POWER SUPPLY
TRANSMIT RF
EQUIPMENT
AC POWER
RECEIVE RF EQUIPMENT
Figure 3-4. Baseband Loopback
Note: When baseband loopback is turned on, data is looped back on the customer side of the
interface. This is a bi-directional loopback of the baseband data. This test mode will verify the customer equipment and cabling between the modem and the customer equipment. The baseband loopback is not bi-directional in D&I.
ANTENNA
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SNM-1002 LinkSync Modem Revision 2 Operation MN/SNM1002.OM
3.4.1.3.7 INTERFACE:BUFFER SIZE
BUFFER SIZE
0 (BYPASS)
Sets the size of the buffer, 32 to 262144 bits, 1 to 99 mS , or 0 (Bypass)
Upon 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 Utility Interface menu to change the buffer units to seconds or bits.
If selecting seconds, choose from 1 to 99 ms, in increments of 1 ms,
or 0 (Bypass).
If selecting bits, choose from 32 to 262144 bits, in increments of 16 bits.
Press [ENTER] to execute the change.
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.
3.4.1.3.8 INTERFACE:BUFFER CENTER
BUFFER CENTER
YES/NO
This configuration function is used to center the buffer. Choosing YES centers the buffer.
Press <ENTER> twice to center the buffer.
3.4.1.3.9 INTERFACE:LOOP TIMING
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SNM-1002 LinkSync Modem Revision 2 Operation MN/SNM1002.OM
LOOP TIMING
OFF
The SCT output will become phase-locked to the RX satellite clock.
TX and RX data rates must be equal unless the asymmetrical loop timing option is On or
.
Off
Upon entry, the status is displayed. Press [] or [] to make the selection. Press [ENTER] to execute the change.
3.4.1.4 CONFIGURATION:SAVE
CONFIGURATION
SAVE
The Configuration Save menu allows programming of 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. 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.
3.4.1.5 CONFIGURATION:RECALL
CONFIGURATION
RECALL
The Configuration Recall menu allows the user to recall a previously saved configuration setup. Upon entry, select memory location 1 through 5 by pressing [] or [].
Press [ENTER] to execute the recall.
3.4.2 FUNCTION SELECT:MONITOR
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SNM-1002 LinkSync Modem Revision 2 Operation MN/SNM1002.OM
FUNCTION SELECT
MONITOR
3.4.2.1 MONITOR:RAW BER
RAW BER NO DATA
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.
3.4.2.2 MONITOR:CORRECTED BER
CORRECTED BER
NO DATA
Displays the current corrected BER or “No Data” (if carrier is not locked).
Range: 1.0 E-3 to 1.0 E-12.
Note: Low limit is based on performance. High limit is 1.0 E-12.
3.4.2.3 MONITOR:EB/NO
EB/NO
16.0
Displays the current Eb/N0 or “No Data” (if carrier is not locked).
Range: 2.0 to 16.0 dB.
Note: Low limit is based on the data rate. High limit is 16.0 dB.
3.4.2.4 MONITOR:RECEIVE SIGNAL
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RECEIVE SIGNAL
-60.0 DBM
Displays the current receive signal level.
Range: -25.0 to -60.0 dBm.
3.4.2.5 MONITOR:SWEEP FREQUENCY
SWEEP FREQUENCY
+ 0 HZ
Displays the current offset frequency or “No Data” (if carrier is not locked).
Range: -35,000 to +35,000 Hz.
3.4.2.6 MONITOR:BUFFER FILL
BUFFER FILL
50%
Displays the current plesiochronous buffer fill status percent.
Range: 1 to 99%.
3.4.3 FUNCTION SELECT:FAULTS/ALARMS
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SNM-1002 LinkSync Modem Revision 2 Operation MN/SNM1002.OM
FUNCTION SELECT
FAULTS/ALARMS
The Faults/Alarms menu 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 Faults/Alarms groups:
Modulator
Demodulator
Transmit Interface
Receive Interface
Common Equipment
Line 2 of the display shows the current Faults/Alarms status 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.
Unlike faults, 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.
The following sections outline the faults and alarms monitored and displayed in each group.
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SNM-1002 LinkSync Modem Revision 2 Operation MN/SNM1002.OM
3.4.3.1 F AUL TS AND ALARMS:MODULATOR
MODULATOR +--------
IF SYNTHESIZER
DATA CLOCK SYN
I CHANNEL
Q CHANNEL
AGC LEVEL
MODEM REF ACT
MODEM REF PLL
MODULE
CONFIGURATION
Modulator IF synthesizer fault.
Transmit clock synthesizer fault. Indicates the internal Voltage Controlled Oscillator (VCO) has not locked to the incoming data clock.
I channel data activity fault.
Q channel data activity fault.
TX IF AGC level fault.
MODEM REF activity alarm.
MODEM REF PLL not locked.
Modulator module fault.
Modulator configuration fault.
3.4.3.2 FAULTS AND ALARMS:DEMODULATOR
DEMODULATOR +-++-----
CARRIER DETECT IF SYNTHESIZER
I CHANNEL
Q CHANNEL
BER THRESHOLD
MODULE
CONFIGURATION
Carrier detect fault. Indicates the decoder is not locked. Demodulator IF synthesizer fault. Indicates the IF synthesizer is
not locked.
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.
Demodulator/decoder module fault.
Demodulator/decoder configuration fault.
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3.4.3.3 F AUL TS AND ALARMS:TX INTERF ACE
TX INTERFACE
---------
TX DROP
TX DATA/AIS
TX CLK PLL
TX CLK ACTIVITY
TX AUDIO 1 CLIP
TX AUDIO 2 CLIP
CONFIGURATION
Not Applicable.
Data or AIS. When data fault is selected in the Interface Configuration 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 in the Interface Configuration menu, the TX Data/AIS Fault/Alarm is not activated.
Note: AIS is an alarm, not a switching fault.
Transmitter phase-locked loop fault. Indicates the transmitter Phase-Locked Loop (PLL) is not locked.
Activity detector alarm of the selected interface transmit clock. The interface will fall back to the internal clock when this alarm is active.
Not Applicable.
Not Applicable.
TX interface configuration fault.
Indicates the TX interface cannot execute a programmed configuration parameter.
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SNM-1002 LinkSync Modem Revision 2 Operation MN/SNM1002.OM
3.4.3.4 F AUL TS AND ALARMS:RX INTERF ACE
RX INTERFACE
---------
BUFFER UNDERFLOW
BUFFER OVERFLOW
RX DATA/AIS
FRAME BER
BACKWARD ALARM
BUFFER CLK PLL
BUFFER CLK ACT
DEMUX LOCK
RX 2047 LOCK
BUFFER FULL
RX INSERT RX AUDIO 1 CLIP RX AUDIO 2 CLIP CONFIGURATION
Buffer underflow alarm. Indicates that a buffer underflow has occurred.
Buffer overflow alarm. Indicates that a buffer overflow has occurred.
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 in the Configuration Interface menu, the RX Data/AIS Fault/Alarm is not activated.
Note: AIS is an alarm, not a switching fault.
Frame BER fault. Indicates that the frame BER exceeds 1-3.
Not Applicable.
Buffer clock phase-locked loop fault. Indicates the buffer clock PLL is not locked.
Activity detector alarm of the selected interface receive clock. The interface will fall back to the satellite clock when this fault is active.
DEMUX lock fault. Indicates that the DEMUX is not locked.
RX 2047 lock alarm. Indicates the RX 2047 data pattern is not locked.
Note: This alarm is only active if RX 2047 is ON.
Buffer full alarm. Indicates the buffer is less than 10% or greater than 90% full.
Not Applicable. Not Applicable. Not Applicable. Configuration alarm.
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3.4.3.5 F AUL TS AND ALARMS:COMMON
COMMON
---------
BATTERY/CLOCK
-12V SUPPLY
+12V SUPPLY
+5V SUPPLY
SELF TEST
CONTROLLER
INTERFACE MODULE
Battery or clock fault.
-12V power supply fault.
+12V power supply fault.
+5V power supply fault.
Self Test Fault. Indicates a selt test fault if the transmitted signal is not not received.
Controller fault. Typically indicates the controller has gone through a power on/off cycle.
Interface module fault. Typically indicates that the interface module is missing or will not program.
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3.4.4 FUNCTION SELECT:STORED FL TS/ALMS

FUNCTION SELECT
STORED FLTS/ALAMS
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 of the fault. 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 last known time and date. In addition, on power-up, an additional common equipment fault is logged (Flt1) to indicate the power-up 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 has 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 currently logged stored faults, 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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3.4.4.1 STORED FLTS/ALMS:MODULATOR
MODULATOR X
STORED TIME/DATE
(FAULT LABEL)
---------
IF Synthesizer DATA CLOCK SYN I CHANNEL Q CHANNEL AGC LEVEL MODEM REF ACT MODEM REF PLL MODULE CONFIGURATION
3.4.4.2 STORED FLTS/ALMS:DEMODULATOR
DEMODULATOR X
STORED TIME/DATE
(FAULT LABEL)
---------
CARRIER DETECT IF SYNTHESIZER I CHANNEL Q CHANNEL BER THRESHOLD MODEL CONFIGURATION
3.4.4.3 STORED FLTS/ALMS:TX INTERFACE
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TX INTERFACE X
STORED TIME/DATE
(FAULT LABEL)
---------
TX DROP (Not Applicable) TX DATA/AIS TX CLK PLL TX CLK ACTIVITY TX AUDIO 1 CLIP (Not Applicable) TX AUDIO 2 CLIP (Not Applicable) CONFIGURATION
3.4.4.4 STORED FLTS/ALMS:RX INTERFACE
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RX INTERFACE X
STORED TIME/DATE
(FAULT LABEL)
---------
BUFFER UNDERFLOW BUFFER OVERFLOW RX DATA/AIS FRAME BER BACKWARD ALARM (Not Applicable) BUFFER CLK PLL BUFER CLK ACT DEMUX LOCK RX 2047 LOCK BUFFER FULL RX INSERT (Not Applicable) RX AUDIO 1 CLIP (Not Applicable) RX AUDIO 2 CLIP (Not Applicable) CONFIGURATION
3.4.4.5 STORED FLTS/ALMS:COMMON
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COMMON X
STORED TIME/DATE
(FAULT LABEL)
---------
BATTERY/CLOCK
-12 VOLT SUPPLY +12 VOLT SUPPLY +5 VOLT SUPPLY SELF TEST CONTROLLER INTERFACE MODULE
3.4.4.6 STORED FLTS/ALMS:CLEAR
CLEAR ??
STORED FAULTS
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3.4.5 FUNCTION SELECT:UTILITY
FUNCTION SELECT
UTILITY
The Function Select Utility menu is divided into the following categories:
Modulator
Demodulator
Interface
Network
System
Modem Type
Factory Setup
The menu information includes:
Filter Types
Terrestrial Interface Types
Mod/Demod Types
Time/Date
Encoder/Decoder Types
Modem Types
Current Firmware
Test Mode Status
Overhead Type
Revision Emulation
Lamp Test
Provisions are also made for assigning data and code rates to the modulator and demodulator.
After entering the Utility menu, press [] or [] to select the desired sub-menu, and press [ENTER].
Notes:
1. The Utility Factory Setup menu is for Comtech EF Data service personnel only. Entering this menu without authorization may cause the modem to operate incorrectly.
2. Changes in the Utility menu may cause changes in other front panel menus.
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3.4.5.1 UTILITY:MODULATOR
UTILITY
MODULATOR
3.4.5.1.1 MODULATOR: ASSIGN TRANSMIT FILTERS
ASSIGN
TRANSMIT FILTERS
Transmit code rate/type as follows:
TX-A QPSK 1/2 19.200 kbps TX-B QPSK 1/2 19.200 kbps TX-C QPSK 1/2 19.200 kbps TX-D QPSK 1/2 19.200 kbps TX-V QPSK 1/2 19.200 kbps
Upon entry, the current transmitter rate is displayed.
3.4.5.1.2 MODULATOR:MOD POWER OFFSET
MODEM POWER OFFSET
+ 0.0 DB
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 -99.9 to +99.9 dB, in 0.1 dB steps.
Note: Anything except 0.0 dB will cause ADJ to be displayed for the TX power level.
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3.4.5.1.3 MODULATOR:MODULATOR TYPE
MODULATOR TYPE
INTELSAT OPEN
Transmit filter type select. Select one of the following for network filtering:
Note: Change in EFD, ASYNC, or Custom modem types only.
INTELSAT OPEN EFD CLOSED SDM-51 COMPATIBLE CSC CLOSED
Notes:
1. TX filter type is selectable only when CUSTOM is selected for the modem type in the Utility Modem Type menu.
2. Code Rate 3/4 is not compatible with a combination of a CSC CLOSED Modulator Type and Sequential Encoder.
FDC CLOSED
3.4.5.1.4 MODULATOR:ENCODER TYPE
ENCODER TYPE
VITERBI
Encoder type selection. Select VITERBI
Notes:
1. Change in EFD, ASYNC, or Custom modem types only.
2. A Sequential Encoder Type and a 3/4 Code Rate combination is not compatible with a CSC CLOSED Modulator Type.
Press[], [], [], or [] to move the flashing cursor. Press [ENTER] to execute the change.
or SEQUENTIAL encoder type.
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3.4.5.1.5 MODULATOR:TX BPSK ORDERING
TX BPSK ORDERING
STANDARD
Transmit BPSK bit ordering selection. Select STANDARD
Press[], [], [], or [] to move the flashing cursor. Press [ENTER] to execute the change.
or NON-STANDARD
3.4.5.1.6 MODULATOR:MOD SPECTRUM
MOD SPECTRUM
NORMAL
Programmable vector rotation allows the operator to select NORMAL spectrum reversal of the I and Q baseband channels.
Press[], [], [], or [] to move the flashing cursor. Press [ENTER] to execute the change
or INVERT for
3.4.5.1.7 MODULATOR:TX SYMBOL RATE
TX SYMBOL RATE
19.200 KSPS
Status only. Selects TX Symbol Data rate.
3.4.5.2 UTILITY:DEMODULATOR
UTILITY
DEMODULATOR
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SNM-1002 LinkSync Modem Revision 2 Operation MN/SNM1002.OM
3.4.5.2.1 DEMODULATOR:ASSIGN RECEIVE FILTERS
ASSIGN
RECEIVE FILTERS
Receive code rate/type as follows:
RX-A QPSK 1/2 19.200 kbps RX-B QPSK 1/2 19.200 kbps RX-C QPSK 1/2 19.200 kbps RX-D QPSK 1/2 19.200 kbps RX-V QPSK 1/2 19.200 kbps
Upon entry, the current transmitter rate is displayed.
3.4.5.2.2 DEMODULATOR: DEMODULATOR TYPE
DEMODULATOR TYPE
INTELSAT OPEN
Transmit filter type select. Select one of the following for network filtering:
Note: Change in EFD, ASYNC, or Custom modem types only.
INTELSAT OPEN EFD CLOSED SDM-51 COMPATIBLE CSC CLOSED
Notes:
1. TX filter type is selectable only when CUSTOM is selected for the modem type in
the Utility Modem Type menu.
2. Code Rate 3/4 is not compatible with a combination of a CSC CLOSED
Modulator Type and Sequential Encoder.
FDC CLOSED
3.4.5.2.3 DEMODULATOR:DECODER TYPE
DECODER TYPE
VITERBI
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SNM-1002 LinkSync Modem Revision 2 Operation MN/SNM1002.OM
Decoder type selection. Select VITERBI
Notes:
1. Change in EFD, ASYNC, or Custom modem types only.
2. A Sequential Decoder Type and a 3/4 Code Rate combination is not compatible with a CSC CLOSED Modulator Type.
Press[], [], [], or [] to move the flashing cursor. Press [ENTER] to execute the change.
or SEQUENTIAL decoder type.
3.4.5.2.4 DEMODULATOR:RX BPSK ORDERING
RX BPSK ORDERING
STANDARD
Receive BPSK bit ordering selection. Select STANDARD
Press[], [], [], or [] to move the flashing cursor. Press [ENTER] to execute the change.
or NON-STANDARD
3.4.5.2.5 DEMODULATOR:DEMOD SPECTRUM
DEMOD SPECTRUM
NORMAL
Programmable vector rotation allows the operator to select NORMAL spectrum reversal of the I and Q baseband channels.
Press[], [], [], or [] to move the flashing cursor. Press [ENTER] to execute the change.
3.4.5.2.6 DEMODULATOR:RX SYMBOL RATE
RX SYMBOL RATE
or INVERT for
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SNM-1002 LinkSync Modem Revision 2 Operation MN/SNM1002.OM
19.200 KSPS
Status only.
Selects RX Symbol Data rate, with 4.800 to 2500.000 ksps.
3.4.5.3 UTILITY:INTERFACE
UTILITY
INTERFACE
3.4.5.3.1 INTERFACE:TX OVERHEAD TYPE
TX OVERHEAD TYPE
NONE
Select None for TX overhead type.
Note: Overhead types are selectable only when Custom is selected for modem type in the Utility Modem Type menu.
3.4.5.3.2 INTERFACE:RX OVERHEAD TYPE
RX OVERHEAD TYPE
NONE
Select None RX overhead type.
Note: Overhead types are selectable only when Custom is selected for modem type in the Utility Modem Type menu.
3.4.5.3.3 INTERFACE:TX TERR INTERF ACE
TX TERR INTERFACE
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SNM-1002 LinkSync Modem Revision 2 Operation MN/SNM1002.OM
RS422
Displays the TX interface type RS-232, RS-422, or V.35.
3.4.5.3.4 INTERFACE:RX TERR INTERF ACE
RX TERR INTERFACE
RS422
Displays the RX interface type RS-232, RS-422, or V.35.
3.4.5.3.5 INTERFACE:BUFFER PROGRAM
BUFFER PROGRAM
BITS
Buffer unit program function. Select MILLI-SECONDS or BITS
Note: To have the modem calculate the plesiochronous shift, set the buffer units to MILLI­SECONDS. For a specific buffer depth, set the buffer units to BITS.
.
3.4.5.3.6 INTERFACE:FRAMING STRUCTURE
FRAMING STRUCTURE
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SNM-1002 LinkSync Modem Revision 2 Operation MN/SNM1002.OM
T1 FRAMING
STRUCTURE: G.704
E1 FRAMING
STRUCTURE: G.704
Displays the currently selected framing type and structure of the data. This function is used with the buffer program in ms for plesiochronous buffer slips.
Upon entry, the framing type (T1 or E1) is displayed on Line 1. The framing structure of each type (None or G.704) is displayed on Line 2. Press [] or [] and [] or [] to select framing structure and type. Press [ENTER] to execute the change.
3.4.5.3.7 INTERFACE:RTS TX-IF CNTRL
RTS TX-IF CNTRL
OFF
Programs the modem to allow a Request To Send (RTS) signal to On or Off when data is ready for transmission.
Press[], [], [], or [] to move the flashing cursor. Press [ENTER] to execute the change.
the output
3.4.5.3.8 INTERFACE:TX DATA PHASE
TX DATA PHASE
NORMAL
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SNM-1002 LinkSync Modem Revision 2 Operation MN/SNM1002.OM
TX data phase relationship. Use this option to select NORMAL data relationship to the selected TX clock.
Upon entry, press [] or [] to make the selection. Press [ENTER] to execute the change.
or INVERT for the TX
3.4.5.3.9 INTERFACE:RX DATA PHASE
RX DATA PHASE
NORMAL
RX data phase relationship. Use this option to select NORMAL data relationship to the selected RX clock.
Upon entry, press [] or [] to make the selection. Press [ENTER] to execute the change.
or INVERT for the RX
3.4.5.3.10 INTERFACE:CTS DELAY
CTS DELAY X SECONDS
Sets the delay in seconds (0 to 60) for the Clear To Send (CTS) signal. Default: 0 Seconds
.
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3.4.5.4 UTILITY:SYSTEM
UTILITY
SYSTEM
3.4.5.4.1 SYSTEM:TIME/DATE
TIME: 12:00:00AM
DATE: 7/04/1976
Time of day and date display/set function.
The current time 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.
3.4.5.4.2 SYSTEM:REMOTE BAUD RATE
REMOTE BAUD RATE
19.200 BPS NONE
The parity and baud rate settings of the modem are displayed.
To change the modem parity, 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 baud rate
and parity.
The parity can be set to EVEN, ODD, or NONE
The baud rate is 19200 bit/s.
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SNM-1002 LinkSync Modem Revision 2 Operation MN/SNM1002.OM
3.4.5.4.3 SYSTEM:REMOTE ADDRESS
REMOTE ADDRESS
1
The current modem address is displayed (1
Note: 0 is reserved as a global address.
To change the remote address, press [ENTER]. Press [] or [] to make the selection. Press [ENTER] to execute the change.
to 255).
3.4.5.4.4 SYSTEM:REMOTE TYPE
REMOTE TYPE
RS-232
Select RS-485 (2-Wire), RS-485 (4-Wire), or RS-232
.
3.4.5.4.5 SYSTEM:OPERATION MODE
OPERATION MODE
DUPLEX
Programs the modem for DUPLEX
Upon entry, the operational status may be changed. Press [] or [] to make the selection. Press [ENTER] to execute the change.
Note: When TRANSMIT ONLY or RECEIVE ONLY are selected, the appropriate faults are masked from the Faults and Stored Faults menus.
, TRANSMIT ONLY, or RECEIVE ONLY operation.
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3.4.5.4.6 SYSTEM:YEAR DISPLAY
YEAR DISPLAY
2 - DIGIT
Selects the display for the year in either 2-digit or 4-digit format.
Upon entry, the year display may be changed. Press [] or [] to make the selection. Press [ENTER] to execute the change
3.4.5.4.7 SYSTEM:TEST MODE STATUS
TEST MODE STATUS
---------
Test mode status indicator. The following modem test points are listed and display a “+” when a test mode is active:
RS CORR OFF
INTRFC LOOP BACK
B-BAND LOOP BACK
RF LOOP BACK
IF LOOP BACK
CARRIER MODE
RX 2047 PATTERN
TX 2047 PATTERN
To view the test modes, press [ENTER]. Press [] or [] to make the selection.
3.4.5.4.8 SYSTEM:LAMP TEST ??
LAMP TEST ??
PRESS ENTER
Lamp test function. Press [ENTER] to turn the front panel indicators on for 3 seconds.
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3.4.5.4.9 SYSTEM:SELF TEST
SELF TEST
AUTO
Select OFF, AUTO, or RUN. After completion of the test, SELF TEST (“PASSED” or “FAILED”) is displayed.
OFF bypasses built-in self test
AUTO initiates built-in self test when turning on modem
RUN initializes self test
3.4.5.4.10 SYSTEM:DISPLAY CONTRAST
DISPLAY CONTRAST
LEVEL: 64
Sets the contrast setting of the Front Panel menu.
Press [ENTER] to begin. Press [] or [] to increment or decrement the number at the flashing cursor, from 0 to 100. Press [ENTER] to execute the change.
3.4.5.4.11 SYSTEM:M&C FIRMWARE
M&C FIRWARE
FW/NNNNNN-DDR
Displays the M&C module firmware version. The display includes the month, day, and year.
3.4.5.4.12 SYSTEM:BOOT FIRMWARE
BOOT FIRWARE
FW/NNNNNN-DDR
Displays the boot module firmware version. The display includes the month, day, and y ear
3.4.5.4.13 SYSTEM:FPGA FIRMWARE
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FPGA FIRWARE
FW/NNNNNN-DDR
Displays the FPGA module firmware version.
The display includes the month, day, and year.
3.4.5.4.14 SYSTEM:DEMO MODE
DEMO MODE
OFF
Turn all FAST features ON that are installed in the modem for 60 minutes. During this time period, the operator is encouraged to implement the features and discover the capablilites of the different options. After the 60-minute time limit, the modem resets to its previous configuration.
3.4.5.4.15 SYSTEM:EXT AGC: MAX PWR
EXT AGC: MAX PWR
0.0 VOLTS
Sets the AGC voltage for a receive signal level of -60.0 dBm. The voltage range is 0.0
10.0V, in 0.5V steps.
Upon entry, the current external AGC voltage level is displayed. Press [] or [] to increment or decrement the AGC voltage level in 0.5V steps. Press [ENTER] to execute the change.
Note: For any receive signal level between -25.0 and -60.0 dBm, the software will interpolate the required AGC voltage.
to
3.4.5.4.16 SYSTEM:EXT AGC: MIN PWR
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EXT AGC: MIN PWR
10.0 VOLTS
Sets the AGC voltage for a receive signal level of -25.0 dBm. The voltage range is 0.0 to
, in 0.5V steps.
10.0V
Upon entry, the current external AGC voltage level is displayed. Press [] or [] to increment or decrement the AGC voltage level in 0.5V steps. Press [ENTER] to execute the change.
Note: For any receive signal level between -25.0 and -60.0 dBm, the software will interpolate the required AGC voltage.
3.4.5.4.17 SYSTEM:MASTER RESET
MASTER RESET
HARD/SOFT
Initiating a hard reset will reset the modem and place the default configuration settings in ROM. Initiating a soft reset
CAUTION
Select [ENTER] once to access HARD or SOFT. Press [] or [] to make the selection. Press [ENTER]. Press [] five times to move the cursor to YES. Select YES and press [ENTER] again.
Note: The following parameters do not revert to default settings after a hard reset:
will reset the modem hardware, but saves the current configuration settings
.
Address
Parity
Baud Rate
Remote Type
Ext AGC: Min Pwr
Ext AGC: Max Pwr
Display Contrast
3.4.5.5 UTILITY:MODEM TYPE
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UTILITY
MODEM TYPE
3.4.5.5.1 MODEM TYPE:MODEM TYPE
MODEM TYPE
CUSTOM
Selects the following types of modem operation:
CUSTOM
EFD Closed Network Operation
When the modem is changed from one type of operation to another, the modem will be reset to the default configurations of the new modem type. The RF-IF Output must be turned on to get the modem to lock.
If the existing modem type is the same as the type entered, the modem will not change any parameters.
If the modem type is changed to Custom, no parameters will be changed.
If the modem will not allow the modem type selection, that type of operation
may not be an available option.
Select MODEM OPTIONS and OVERHEAD OPTIONS to see which modem operations are allowed.
Selections are made from the Front Panel menu
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3.4.5.5.2 MODEM TYPE:MODEM EMULATION
MODEM EMULATION
DISABLED
Selects the following types of modem emulation:
SDM-100 VER: 15.7.1 SDM-300 6.2.2 SDM-308-4 4.03 SDM-308-4 6.05 SDM-308-4 6.08 SDM-308-4 7.03 SDM-309 6.04 SDM-650 4.12A SDM-650 4.16 SDM-6000 5.1.1
or Disabled
Upon entry, the current modem emulation is displayed. Press [] or [] to change the display. Press [ENTER] to execute the change.
3.4.5.5.3 MODEM TYPE:REVISION EMULATION
REV EMULATION
CURRENT VERSION
Programs an emulation mode of a previous functional revision. This allows the user to select the CURRENT VERSION
Note: The number displayed in the CURRENT VERSION position increases with each software version change.
Upon entry, the CURRENT VERSION is displayed. Press [] or [] to select the FUNCTIONAL version. Press [ENTER] to execute the change.
or FUNCTIONAL X.
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Notes:
1. Programming a current version (default) allows all features and options (if installed) to operate normally.
2. Programming a FUNCTIONAL version (X) eliminates any changes that affect the later version. Only functional changes are affected by the revision emulation feature.
3. A correction change (e.g., VER 3.1.2) remains fixed in accordance with the latest version. Since the revision emulation default is the current version, program the functional version at the start of each operation.
4. The revision emulation feature does not affect some interface changes for the
direct operation of the modem (Configuration save/recall, test mode screen in the Utility/System, all factory setup modes, etc.).
3.4.5.5.4 MODEM TYPE:MODEM OPTIONS
MODEM OPTIONS
--------------
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 [] [] arrows to move from one symbol to the next. The first line will display the option. The second line will display the status:
HIGH POWER ( 0 ) 0 = Not Installed, Not Upgradeable HIGH STABILITY ( 0 ) - = Not Installed ASLT ( - ) + = Installed VITERBI ( + ) X = Not Installed, Field Upgradeable SEQUENTIAL ( - ) SINGLE RATE ( - ) LOW RATE VAR ( - ) FULL RATE VAR ( + ) CARD #1 PCB ( x ) CARD #2 PCB ( x ) CARD #3 PCB ( x ) 8PSK 2/3 ( - ) TX ONLY ( - ) RX ONLY ( - )
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3.4.5.5.5 MODEM TYPE:CARD #1 TYPE (NOT INSTALLED)
3.4.5.5.6 MODEM TYPE:CARD #2 TYPE (NOT INSTALLED)
3.4.5.5.7 MODEM TYPE:CARD #3 TYPE (NOT INSTALLED)
3.4.5.5.8 MODEM TYPE:LOCAL MODEM AUPC
LOCAL MODEM AUPC
OFF
Configures the modem for the self-monitoring Local Modem AUPC mode and for local TX power control (self-monitoring) due to severe rain fade.
Notes:
1. The self-monitoring Local Modem AUPC mode is not used when the ASYNC/AUPC is selected as the Modem Type.
2. Used for local control (self-monitoring) due to severe rain fade.
3.4.5.5.9 MODEM TYPE:MODEM SERIAL
MODEM SERIAL
123456789
Status Only
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3.4.5.5.10 MODEM TYPE:CONFIGURATION CODE - MODEM
CONFIGURATION
CODE - MODEM
1) AAAAAAAAAA
2) AAAAAAAAAA
If installed, Status Only Comtech EF Data supplied code. .
3.4.5.6 UTILITY:FACTORY SETUP (NOT APPLICABLE)
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Chapter 4. THEORY OF
4.1 LinkSync™
LinkSync™ is a unique MIDAS feature providing:
Automatic Frequency Control (AFC)
Uplink Power Control (UPC) at the MIDAS Controller
Circuit Power Management (Option)
! Site level call blocking based on HPA power

4.1.1 Automatic Frequency Control

OPERATION
MIDAS provides automatic frequency control (AFC) to reduce the traffic modem acquisition time for continuous mode operation and to improve the burst acquisition performance of the SNM-1000/1001 Network Control Modem and the Node Control Modems
The outbound control channel is used as the system-wide reference, which is continuously monitored by the LinkSync™ Modem at the MIDAS Controller site and all the Node Control Modems in any part of the system.
1
Includes SNM-1000 and the integrated traffic/control modem s (SNM -1010 and SNM-1010L).
2
The integrated traffic/control modems and the network te rm inals i n a standard configurat ion
monitor the outbound control channel in the “control m ode”.
4–1
1
, by keeping the frequency drift to within ± 500 Hz.
2
. The AFC process does not depend on the absolute accuracy
SNM-1002 LinkSync Modem Revision 2 Theory of Operation MN/SNM1002.OM
The AFC process consists of three steps:
1. Removing the receive offset of the Network Control Modem at the MIDAS Controller.
2. Removing the receive offset of the Node Control Modems and the traffic modems at the traffic sites.
2. Removing the transmit offset of the Node Control Modems and the traffic modems at the traffic sites.
These three steps are performed as follows:
1. The LinkSync™ Modem measures the receive frequency of the outbound control channel and provides this information to the MIDAS Controller periodically, the period being user-configurable. The MIDAS Controller then calculates the offset from the nominal, which is used to correct the Network Control Modem’s TX frequency.
2. The Node Control Modem determines the receive offset by measuring the receive frequency of the outbound control channel.
a. This offset is used to calibrate the RX frequency of the Node Control
Modem and all the traffic modems (during call setup) at the node.
b. The traffic modems that have active calls are not adjusted. Calibrations
are periodically performed where the period is user –configurable.
3. MIDAS Controller periodically polls a Node Control Modem to transmit exclusively, and measures the receive frequency for the incoming bursts from the Node Control Modem on the inbound control channel.
a. It then estimates the offset and provides this information to the Node
Control Modem.
b. The Node Control Modem then applies this offset to correct its TX
frequency and that of all the traffic modems (during call setup).
c. The traffic modems that have active calls are not adjusted. This process
is repeated periodically, the period being user-configurable.
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4.1.2 Uplink Power Control

Uplink Power Control at the MIDAS Controller site compensates for outbound control channel uplink degradation so that it always downlinks at a constant power at the satellite.
A reference E
is calculated for the received outbound control channel at the MIDAS
b/No
Controller site for clear sky conditions. The LinkSync™ Modem, at the MIDAS Controller site, measures the received outbound control channel E
on a continuous
b/No
basis.
If the measured E
differs from the calculated reference, the MIDAS
b/No
Controller calculates the offset to be applied to the transmit power level of the outbound control channel to achieve the desired reference E
b/No
.
The transmit power is adjusted only when the difference exceeds a threshold, which is configurable.

4.1.3 Circuit Power Management (Option)

Circuit power management is provided as an option. It includes:
Circuits at setup.
Site level call blocking based on available High power Amplifiers (HPA) power.
4.1.3.1 Site Level Call Blocking
The MIDAS Controller supports dynamic site level call blocking based on the available HPA power. The MIDAS Controller keeps track of the HPA power for each site. A call originating from a site is blocked if it would cause the total transmit power for that site to exceed the recommended HPA power (less backoff). This leads to improved system stability.

4.2 Monitor and Control (M&C)

The M&C monitors the modem and provides configuration updates to other modems within the modem when necessary.
The modem configuration parameters are maintained in battery-backed RAM, which provides total recovery after power-down situation. The M&C functions include extensive fault and status reporting. All modem functions are accessible through a remote communications interface. A block diagram of the M&C is shown in Figure 4-1.
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4.2.1 Theory of Operation

The M&C card is composed of the following subsections:
Microcontroller with Universal Asynchronous Receiver/Transmitter (UART)
Digital-to-Analog Converter (DAC)
Read Only Memory (ROM)
Analog-to-Digital Converter (ADC)
Read Access Memory (RAM)
Universal ASYNC
User Interface
Fault and Alarm Relays
FAULT
MODEM
AND ALARM
RELAYS
11 MHz CLOCK
DAC
ADC
MICRO-
2
IC BUS
CONTROLLER
EIA-232
OR
EIA-485
Figure 4-1. M&C Block Diagram
ROM (M&C, BULK,
BOOT)
RAM AND
REAL
TIME
CLOCK
9-PIN
REMOTE
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The heart of the M&C card is the Dallas 80C310 microcontroller operating at 11 MHz. This microcontroller contains 256 kbytes of internal RAM. The ROM at U8 is 29F040 (512 kbytes).
ROM access times must be equal to or greater than 150 ns. The RAM can be 8 or 32 kbytes in size. This RAM chip is internally battery-backed and contains a real time clock used by the M&C.
The non-volatile RAM on the M&C module allows the module to retain configuration information without prime power for 1 year (approximately). If the modem is powered down, the following sequence is carried out by the M&C microcontroller.
1. When power is applied to the M&C, the microcontroller checks the non-volatile memory to see if valid data has been retained. If valid data has been retained, the modem is reconfigured to the parameters maintained by the RAM.
2. If the non-volatile memory fails the valid data test, a default configuration from ROM is loaded into the system.
The UART supports serial ASYNC communications channels (remote port) with a data rate of 19200 bit/s. The UART is a built-in peripheral of the microcontroller. The communications type is EIA-232.
The DAC supplies a voltage that controls the contrast of the display. The ADC monitors all the voltages from the power supply. The DAC and ADC are mapped to the microcontroller with an Integrated Circuit (IC) bus.
All functions are memory-mapped to the micro-controller.
4.3 Modulator
The modulator provides PSK modulated carriers within the 50 to 180 MHz range. The types of modulation that encode the transmitted baseband data from the interface PCB are:
BPSK
QPSK
Refer to Section 4.2.3 for a description of each modulation type.
A block diagram of the modulator is shown in Figure 4-2.
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MONITOR
SCT
REFERENCE
SCT PLL
OPTIONAL
CONVOLUTIONAL
ENCODER
&
CONTROL
LO
BPF
BPF
DIGITAL
SIGNAL
PROCESSING
POWER LEVEL
CONTROL
Figure 4-2. Modulator Block Diagram
LPF
RF LOOPBACK
OUTPUT
RF
OUTPUT
4–6
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