CDM-Qx Multi-Channel Satellite Modem with DoubleTalk™ Carrier-in-Carrier® Installation and Operation Manual Note: This manual incorporates data for the CDM-Qx and CDM-QxL. IMPORTANT NOTE: The information contained in this document supersedes all previously published information regarding this product. Product specifications are subject to change without prior notice. Part Number MN/CDMQX.
Errata A Comtech EF Data Documentation Update Subject: Revised Acquisition Range for Demodulator Date: Document: January 23, 2007 CDM-Qx, Multi-Channel Satellite Modem, Installation and Operation Manual, Revision 5, dated January 20, 2007 MN/CDMQx.EA5 Attach this page to page A-3 Part Number: Collating Instructions: Comments: The following changes affects the acquisition rate specified in Section A.2.
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Errata B Comtech EF Data Documentation Update Subject: Delete COMBINED TRANSMIT POWER Menu Date: Document: January 23, 2007 CDM-Qx, Multi-Channel Satellite Modem, Installation and Operation Manual, Revision 5, dated January 20, 2007 MN/CDMQx.EB5 Attach this page to page 5-22 Part Number: Collating Instructions: Comments: Delete Combined Transmit Power menu. s:\tpubs\manuals\released_word\modems\cdmqx_rev5\text\errata b.
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Errata C Comtech EF Data Documentation Update Subject: Revise Sub-Menu for Vit+RS and TCM+RS Date: Document: January 23, 2007 CDM-Qx, Multi-Channel Satellite Modem, Installation and Operation Manual, Revision 5, dated January 20, 2007 MN/CDMQx.EC5 Attach this page to page 5-25 Part Number: Collating Instructions: Comments: Revised Sub-Menu for Vit+RS and TCM+RS to delete Viterbi and TPC.
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Errata D Comtech EF Data Documentation Update Subject: Add Sub-Menu for Vit+RS and TCM+RS Date: Document: January 23, 2007 CDM-Qx, Multi-Channel Satellite Modem, Installation and Operation Manual, Revision 5, dated January 20, 2007 MN/CDMQx.ED5 Attach this page to page 5-16 Part Number: Collating Instructions: Comments: Added requirements for IESS-310 mode to Tx menu.
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CDM-Qx Multi-Channel Satellite Modem with DoubleTalk™ Carrier-in-Carrier Installation and Operation Manual Note: This manual incorporates data for the CDM-Qx and CDM-QxL. Comtech EF Data is an ISO 9001 Registered Company Part Number MN/CDMQx.
CDM-Qx Satellite Modem Preface Revision 5 MN/CDMQx.IOM CUSTOMER SUPPORT Contact the Comtech EF Data Customer Support Department for: Product support or training Information on upgrading or returning a product Reporting comments or suggestions concerning manuals Contact Customer Support using any of the following methods: Mail: Comtech EF Data Email: service@comtechefdata.com Customer Support Department 2114 West 7th Street Internet: www.comtechefdata.com Tempe, Arizona 85281 USA Phone: 480.333.
CDM-Qx Satellite Modem Preface Revision 5 MN/CDMQx.IOM Table of Contents CHAPTER 1. 1.1 INTRODUCTION................................................................................ 1–1 Introduction................................................................................................................................1–1 1.2 Features.......................................................................................................................................1–2 1.2.
CDM-Qx Satellite Modem Preface Revision 5 MN/CDMQx.IOM CHAPTER 3. FUNCTIONAL DESCRIPTION .......................................................... 3–1 CHAPTER 4. EXTERNAL CONNECTIONS ............................................................ 4–1 4.1 Introduction................................................................................................................................4–1 4.2 Front Panel ..........................................................................................
CDM-Qx Satellite Modem Preface Revision 5 MN/CDMQx.IOM 5.6 TOP LEVEL SELECTION ......................................................................................................5–8 5.6.1 CONFIG..............................................................................................................................5–9 5.6.2 MONITOR ........................................................................................................................ 5–49 5.6.3 TEST: ...............................
CDM-Qx Satellite Modem Preface Revision 5 MN/CDMQx.IOM CHAPTER 9. DOUBLETALK™ CARRIER-IN-CARRIER® OPERATION ............... 9–1 CHAPTER 10. REDUNDANCY .............................................................................. 10–1 CHAPTER 11. ETHERNET MANAGEMENT ......................................................... 11–1 11.1 Introduction................................................................................................................. 11–1 11.
CDM-Qx Satellite Modem Preface Revision 5 MN/CDMQx.IOM About this Manual This manual provides installation and operation information for the Comtech EF Data CDM-Qx Multi-Channel Modem with DoubleTalk™ Carrier-in-Carrier®. This is a technical document intended for earth station engineers, technicians, and operators responsible for the operation and maintenance of the CDM-Qx. CONVENTIONS AND REFERENCES METRIC CONVERSION Metric conversion information is located on the inside back cover of this manual.
CDM-Qx Satellite Modem Preface Revision 5 MN/CDMQx.IOM ELECTRICAL SAFETY The CDM-Qx Multi-Channel Modem with DoubleTalk™ Carrier-in-Carrier® 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 100 to 240 VAC. It has a maximum power consumption of 60 watts, and draws a maximum of 600 mA.
CDM-Qx Satellite Modem Preface Revision 5 MN/CDMQx.IOM INSTALLATION The installation and connection to the line supply must be made in compliance to local or national wiring codes and regulations. The CDM-Qx 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 CDM-Qx is shipped with a line inlet cable suitable for use in the country of operation.
CDM-Qx Satellite Modem Preface Revision 5 MN/CDMQx.IOM TELECOMMUNICATIONS TERMINAL EQUIPMENT DIRECTIVE In accordance with the Telecommunications Terminal Equipment Directive 91/263/EEC, this equipment should not be directly connected to the Public Telecommunications Network. CE MARK Comtech EF Data declares that the CDM-Qx meets the necessary requirements for the CE Mark. TRADEMARKS Carrier-in Carrier is a registered trademark of Comtech EF Data Corporation.
CDM-Qx Satellite Modem Preface Revision 5 MN/CDMQx.IOM 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.
CDM-Qx Satellite Modem Preface Revision 5 MN/CDMQx.
Chapter 1. INTRODUCTION 1.1 Introduction The CDM-Qx, Multi-Channel Satellite Modem with DoubleTalk™ Carrier-in-Carrier® is a 70/140 MHz (or CDM-QxL with 950MHz-1950MHz L Band operation) modular multichannel modem with redundancy contained in a single rack unit (1RU) chassis. The Modem offers flexibility, redundancy, integration, and performance with four slots configurable as modulators or demodulators.
CDM-Qx Satellite Modem Introduction 1.2 Revision 5 MN/CDMQx.
CDM-Qx Satellite Modem Introduction 1.2.1 Revision 5 MN/CDMQx.IOM DoubleTalk™ Carrier-in-Carrier® Designed for bandwidth compression, Carrier-in-Carrier is based on Applied Signal Technology’s DoubleTalk which uses “Adaptive Cancellation,” a patented (Unites States Patent # 6,859,641) technology that allows full duplex satellite links to transmit concurrently in the same segment of transponder bandwidth.
CDM-Qx Satellite Modem Introduction 1.2.4 Revision 5 MN/CDMQx.IOM Data Interfaces The Modem can be ordered with a number of interfaces. Each data interface can operate on a Modulator or Demodulator. This allows the user to exchange interface cards for different applications. The interfaces offered include: • • • • • 1.2.5 EIA/TIA-530 • (EIA-422) DCE (at rates up to 12 Mbps) • V.35 DCE (at rates up to 12 Mbps) G.703 Balanced T1 & E1 (DB-15) with D&I G.
CDM-Qx Satellite Modem Introduction 1.3 Revision 5 MN/CDMQx.IOM Major Assemblies Assembly PL/10570-1 PL/10570-2 PL/10070-1 PL/10069 PL/10073 PL/11128 PL/10635 PL/10071 PL/10072 AS/11014 PL/10678 PL/10697 PL/10698 PL/12608-1 PL/10898-1 PL/10416-1 PL/10416-2 PL/12798-1 PL/12798-2 Description 1 PPM Reference IF Backplane 70/140 MHz IF 0.1 PPM Reference IF Backplane 70/140 MHz IF 0.
CDM-Qx Satellite Modem Introduction 1.4 Revision 5 MN/CDMQx.IOM FAST Options and Hardware Options The Modem is extremely flexible and powerful, and incorporates a large number of optional features. Some customers may not require all of these features, and therefore, in order to permit a lower initial cost, the Modem may be purchased with only the desired modules and features enabled.
CDM-Qx Satellite Modem Introduction 1.4.1 Revision 5 MN/CDMQx.IOM FAST Accessible Options Comtech EF Data’s FAST system allows immediate implementation of different options through the user interface keypad. All FAST options are available through the basic platform unit. 1.4.2 FAST System Theory FAST is an enhancement feature available in Comtech EF Data products, enabling onlocation upgrade of the operating feature set - in the rack - without removing a modem from the setup.
CDM-Qx Satellite Modem Introduction Revision 5 MN/CDMQx.IOM Turbo Product Coding provides one of the best Forward Error Correction technologies currently available, and is now offered with a sufficient range of code rates and modulation types to optimize link performance under any conditions. The second hardware option is the Internal Reference Stability.
CDM-Qx Satellite Modem Introduction 1.5 Revision 5 MN/CDMQx.IOM L-Band Fully configured, the modem will meet or exceed all of the applicable requirements in IESS-315 and is available with a full range of industry standard digital interfaces. The modem expands the capabilities into L-Band frequencies.
CDM-Qx Satellite Modem Introduction Revision 5 MN/CDMQx.
Chapter 2. INSTALLATION 2.1 Unpacking Inspect shipping containers for damage. If shipping containers are damaged, keep them until the contents of the shipment have been carefully inspected and checked for normal operation. The 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.
CDM-Qx Satellite Modem Installation 2.2 Revision 5 MN/CDMQx.IOM Mounting If the modem is to be mounted in a rack, ensure that there is adequate clearance for ventilation, particularly at the sides. In rack systems where there is high heat dissipation, forced air-cooling must be provided by top or bottom mounted fans or blowers. Under no circumstance should the highest internal rack temperature be allowed to exceed 50°C (122°F). 2.2.
CDM-Qx Satellite Modem Installation Revision 5 MN/CDMQx.IOM Equipment Rack Rear Mounting Rail #10 Shoulder Screw Support Bracket #10 Flat Washer #10 Flat Washer #10 Bracket Bolt #10 Split Washer #10 Hex Nut Back of unit Figure 2-1.
CDM-Qx Satellite Modem Installation 2.3 Revision 5 MN/CDMQx.IOM Configuration There are no internal jumpers to configure. All configuration is carried out entirely in software. The unit should first be configured locally, using the front panel keypad and display. The unit will ship with a default Viterbi 128 kbps, QPSK, Rate 3/4 configuration. Refer to the ‘FRONT PANEL OPERATION’ chapter for details on how to fully configure the unit for the desired operating parameters.
Chapter 3. FUNCTIONAL DESCRIPTION The modem has two fundamentally different types of interface: IF and Data. • • The Data interface can be a bi-directional path, which connects with the customer’s equipment (assumed to be the DTE) and the modem (assumed to be the DCE). The IF interface provides a bi-directional link with the satellite via the uplink and downlink equipment.
CDM-Qx Satellite Modem Functional Description Revision 5 MN/CDMQx.IOM The RX IF signal is translated and filtered at an intermediate frequency (IF) using the coarse step synthesizer. This is mixed with a second synthesizer, resulting in the signal being IF sampled with a high-speed analog to digital converter (A to D). The sampled IF is then digitally split into an in-phase (I) and a quadrature (Q) component. An AGC circuit keeps the desired signal level constant over a broad range of input levels.
CDM-Qx Satellite Modem Functional Description Revision 5 MN/CDMQx.IOM Figure 3-1.
CDM-Qx Satellite Modem Functional Description Revision 5 MN/CDMQx.
Chapter 4. EXTERNAL CONNECTIONS 4.1 Introduction The modem is constructed as a 1RU high rack-mounting chassis, which can be freestanding, if desired. Rack handles at the front facilitate removal from and placement into a rack. Figure 4-1 shows the front panel of the modem. Figure 4-1.
CDM-Qx Satellite Modem External Connections 4.2 Revision 5 MN/CDMQx.IOM Front Panel LED Keypad Indicators Display (VFD) The Modem front panel features a Vacuum Fluorescent Display (VFD), a keypad, and eight LED indicators. The user enters data via the keypad, and messages are displayed on the VFD. The LEDs indicate, in a summary fashion, the status of the selected module. The VFD is an active display showing 2 lines, each of 40 characters.
CDM-Qx Satellite Modem External Connections 4.3 Revision 5 MN/CDMQx.IOM Rear Panel The rear panel can be customized to meet the customer’s requirements. Figure 4-2 shows three configurations that are available. Table 4-1 lists these connectors and Figure 4-2 shows the locations. Figure 4-2. Rear Panel Prime Power & Control Slot 1 Slot 2 Slot 3 Slot 4 IF I/O Configuration #1 Modem 1 with G.703 T1/E1 Balanced (DB-15) Modem 2 with EIA-422 (DB-25) Configuration #2 Modem 1 with G.
CDM-Qx Satellite Modem External Connections Revision 5 MN/CDMQx.IOM Notes: 1. One interface per Modem (i.e. Modulator and Demodulator card combination) or one interface per Modulator card and Demodulator card are required if used independently. 2. When grouping a modulator and demodulator together to use as a modem, the modulator must be located above the demodulator. 3. For redundant operation the backup unit does not need an interface. 4.
CDM-Qx Satellite Modem External Connections Revision 5 MN/CDMQx.IOM Table 4-1. Modem Rear Panel Connectors Name Ref. Desig. Connector Type Function Configuration #1 - Modem1 with G.703 T1/E1 Balanced (DB-15) Modem2 with EIA-422 (DB-25) M&C 10/100BaseT 485/232 Slot #1 Mod: Alarms G.703 Slot #2 Demod: Alarms G.703 Slot #3 Mod: Alarms EIA-530 Slot #4 Demod: Alarms EIA-530 70/140 Tx /Rx: Tx Rx RJ-45 9-Pin D Male Remote Interface Remote Interface 15-Pin Male 15-Pin Female Form-C Alarms Balanced G.
CDM-Qx Satellite Modem External Connections Name Revision 5 MN/CDMQx.IOM Ref. Desig. Connector Type Function Configuration #3 - Modem 1 with G.703 T1/E1 Balanced (DB-15) and Quad E1IInterface (1-4 Ports E1,w/ D&I) M&C 10/100BaseT RJ-45 Remote Interface 485/232 9-Pin D Male Remote Interface Slot #1 Mod: Alarms 15-Pin Male Form-C Alarms G.703 BNC Unbalanced G.703 Data Output (incorrect slot for IO) Slot #2 Demod: Alarms 15-Pin Male Form-C Alarms G.703 BNC Unbalanced G.
CDM-Qx Satellite Modem External Connections Revision 5 MN/CDMQx.IOM Note: The European EMC Directive (EN55022, EN50082-1) requires using properly shielded cables for DATA I/O. 4.4 Chassis Connections 4.4.1 USB Port This port is used to reflash firmware. For continued operator safety, always replace the fuses with the correct type and rating. IMPORTANT 4.4.
CDM-Qx Satellite Modem External Connections 4.4.4 Revision 5 MN/CDMQx.IOM Alarms Connector All modules contain an alarm connector. The Alarms connector is a 15-pin 'D' type male (DB15 M). This provides the user with access to the Form-C relay contacts, which indicate the fault status of the unit. These are typically connected to an external fault monitoring system, often found in satellite earth stations. For a Modulator, TX fault and Unit Fault are supported.
CDM-Qx Satellite Modem External Connections 4.4.5 Revision 5 MN/CDMQx.IOM Balanced G.703 Connector Tx/Rx Connector The Balanced G.703 connection is a 15-pin female connector located on the rear mounting plate of the modulator or demodulator. If a Modulator and Demodulator are vertically grouped together as a modem, the data interface connector on the Demodulator switches to duplex. This feature allows a single data interface connection to be used for a modem instead of needing a “Y” cable.
CDM-Qx Satellite Modem External Connections 4.4.7 Revision 5 MN/CDMQx.IOM RS-530 Data Interface Connector The Data connector is a 25-pin ‘D’ type female (DB-25F). This connector conforms to the RS-530 pinout, which allows for connection of different electrical standards, including EIA-422, V.35, and EIA-232. IMPORTANT All data interfaces are duplex! They will only operate as duplex if a Modulator and Demodulator are vertically grouped together as a modem.
CDM-Qx Satellite Modem External Connections 4.4.8 Revision 5 MN/CDMQx.IOM Quad E1 Data Interface Connectors The (2) Data connectors on the Quad E1 interface card are 9-pin ‘D’ type female (DB9F). Refer to Table 4-xx for pin assignments. J1 and J2 are shown below. Also available is an adapter y-cable to adapt the DB9 to (2) RJ45 jacks, (part number PL/xxxTBD), see Table xx and figure xx. Table 4-xx6.
CDM-Qx Satellite Modem External Connections 4.4.9 Revision 5 MN/CDMQx.IOM RX and TX IF Connectors The IF connectors will depend on the configuration ordered. The following reflects configurations available. BNC 75Ω is standard for 70/140MHz IF, N-Type 50Ω for LBand, and BNC Ref Connector. This 50Ω BNC female connector provides an external reference input for the Tx and Rx IF synthesizers, and for the internal transmit clock. The load impedance is 60.4Ω, so the VSWR is less than 1.
CDM-Qx Satellite Modem External Connections 4.7 Revision 5 MN/CDMQx.IOM Ground Connector A #10-32 stud on the rear panel of the modem is used for connecting a common chassis ground among equipment. Note: The AC power connector provides the safety ground.
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Chapter 5. FRONT PANEL OPERATION 5.1 Introduction Figure 5-1. Front Panel Display The user can fully control and monitor the operation of the Modem from the front panel (Figure 5-1), using the keypad and display. Nested menus are used, which display all available options, and prompt the user to carry out a required action. The display has two lines of 40 characters each. The display is divided into two areas.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM On most menu screens, the user will observe a flashing solid block cursor, which blinks at a once-per-second rate. This indicates the currently selected item, digit, or field. Where this solid block cursor would obscure the item being edited (for example, a numeric field) the cursor will automatically change to an underline cursor.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM The keypad is shown in Figure 5-2: Diamond Keypad (Presently used on all Units) Button Keypad (New Configuration for Units) Figure 5-2. Keypad The function of these keys is as follows: IMPORTANT ENT (Enter) This key is used to select a displayed function or to execute a modem configuration change. CLR (Clear) This key is used to back out of a selection or to cancel a configuration change, which has not been executed using ENT.
CDM-Qx Satellite Modem Front Panel Operation 5.2 Revision 5 MN/CDMQx.IOM Left-Hand Display Area The left side of the display (or slot screen) efficiently indicates what is in the four plug-in slots and which slot is currently being addressed. Four ungrouped plug-ins are displayed as in this example: TX TX RX | (right hand display area) | (right hand display area) This display indicates modulators in the top slots, and demodulators in the bottom.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM Two modems can share a modem: MD | (right hand display area) | (right hand display area) The selected modem is the modulator demodulator pair on the right side of the chassis (when viewed from the back). When modem is in CnC™ mode, the brackets (<>) will turn into bold characters. 5.2.2 Redundancy Modules, (modulators and demodulators) can be upgraded to operate as redundant units.
CDM-Qx Satellite Modem Front Panel Operation 5.2.3 Revision 5 MN/CDMQx.IOM Spectrum Analyzer The built-in spectrum analyzer mode is available, accessible via remote control, front panel or web browser. When it is active, the selected demod will not respond to specific Rx front panel settings, nor will it carry traffic. It is marked with an S suffix. It has it’s own front panel menu controls under “Test” menu.
CDM-Qx Satellite Modem Front Panel Operation Para 5.5 5.6 5.61 5.6.1.1 5.6.1.2 5.6.1.3 5.6.1.4 5.6.1.5 5.6.1.6 5.6.1.7 5.6.1.8 5.6.1.9 5.6.2 5.6.2.1 5.6.2.2 5.6.2.3 5.6.2.4 5.6.2.5 5.6.2.6 5.6.2.7 5.6.3 5.6.4 5.6.5 5.6.6 5.6.
CDM-Qx Satellite Modem Front Panel Operation 5.5 Revision 5 MN/CDMQx.IOM Opening Screen Comtech EF Data CDM-Qx Firmware Version: 1.1.1 This screen is displayed whenever power is first applied to the unit (70/140 MHz version). The word “CDM-Qx” will be replaced with “CDM-QxL” for L-Band units. Pressing any key will take the user to the top-level selection screen: 5.
CDM-Qx Satellite Modem Front Panel Operation 5.6.1 Revision 5 MN/CDMQx.IOM CONFIG The sub-branches available are: CONFIG: Remote Tx Rx Group Frame Interface Ref Mask ODU Remote (Remote Control) This menu sub-branch permits the user to define whether the unit is being controlled locally, or remotely. NOTE: The unit may be monitored over the remote control bus at any time. When in Local mode, however, configuration parameters may only be changed through the front panel.
CDM-Qx Satellite Modem Front Panel Operation 5.6.1.1 Revision 5 MN/CDMQx.IOM (ConfigRemote) – REMOTE CONTROL Select Local, Serial, or Ethernet using the (◄ ►)arrow keys, then press ENT. Remote Control Entry: Local Serial Ethernet (◄ ►,ENT) If Local is selected then remote control will be disabled. Remote monitoring is still possible.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM (ConfigRemoteSerialInterfaceRS485) - RS-485 Bus Address However, if either RS-485 mode is selected, the user will be further prompted: Edit RS-485 Serial Bus Base Address: 0245 (◄ ►,▲▼,ENT) Edit the RS-485 bus address of this unit. This is accomplished by selecting the digit to be edited, using the efarrow keys. The value of the digit is then changed using the dcarrow keys. The user should then press ENT.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM (ConfigRemoteEthernetGateway) If Gateway is selected, the submenu will display: M&C Ethernet IP Gateway: 192.128.001.001 (◄ ►▲ ▼, ENT) Edit the IP Gateway Address for the Ethernet M&C port for this unit. This is accomplished by selecting the digit to be edited, using the ◄ ► arrow keys. The value of the digit is then changed using the ▲ ▼ arrow keys. The user should then press ENT.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM (ConfigRemoteEthernetSNMPCommunities) If Communities is selected: SNMP Communities: Read Write (◄ ►, ENT) If Read is selected, the following sub-menu is displayed: Read Community: public (◄ ► ▲ ▼, ENT) If Write is selected, the following sub-menu is displayed: Write Community: private (◄ ► ▲ ▼, ENT) Edit the SNMP Read or Write Community string using the ◄ ► and ▲ ▼ arrow keys.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM If Community is selected, the following sub-menu is displayed. Trap Community: comtech (◄ ► ▲ ▼, ENT) Edit the Trap Community string using the ◄ ► and ▲ ▼ arrow keys. Only the first 20 characters on the bottom line are available. The cursor selects the position on the bottom line (◄ ►) and the character is then edited (▲ ▼).
CDM-Qx Satellite Modem Front Panel Operation 5.6.1.2 Revision 5 MN/CDMQx.IOM (ConfigTx) - TRANSMIT Tx: FEC Mod Code Data Freq On/Off Pwr Scram Clk Inv Txα Select FEC, Mod, Code, Data, Freq, On/Off, Pwr, Scram, Clk, Inv, or Txα using the ◄ ► arrow keys, then press ENT. The user will then be taken to a further submenu.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM If the user changes a parameter within this hierarchy, the other parameters may become invalid. In this case, the software will change those other parameters, in order that the configuration remains valid at all times. Example: Suppose the user has selected Viterbi + Reed Solomon, QPSK, Rate 1/2. Now, the user changes the modulation type from QPSK to 16-QAM.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM (ConfigTxCode) – TX CODE RATE Tx Code Rate: 5/16 21/44 1/2 2/3 3/4 7/8 17/18 (◄ ►) IMPORTANT CASE 5/16 21/44 1/2 2/3 3/4 7/8 17/18 All possible choices are presented at all times. If an option is not installed (either Hardware, or FAST) or valid, the ◄ ► arrow keys will force the cursor to skip past the unavailable choice.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM FEC Type Viterbi Modulation Code Rate BPSK Rate 1/2 Data Rate Range Viterbi QPSK Rate 1/2 32 kbps to 10 Mbps Yes – see note below Viterbi QPSK Rate 3/4 32 kbps to 15 Mbps Yes – see note below Viterbi QPSK Rate 7/8 32 kbps to 17.5 Mbps Yes – see note below Viterbi + R-S BPSK Rate 1/2 32 kbps to 4.5 Mbps Yes – see note below Viterbi + R-S QPSK Rate 1/2 32 kbps to 9.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM If (using the ODU, BUC menus) the user has selected a BUC LO frequency (other than zero) and defined whether the mix is high side or low side, the display will be modified as shown below, to include the calculated Transmit RF frequency of the modem/BUC combination: Tx IF Freq: 1156.3456 MHz RF=14156.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM (ConfigTxPwr) – TRANSMIT POWER LEVEL MODE Select the output power level mode, either Manual or AUPC, then press ENT. Output Power Level Mode: Manual AUPC (◄ ►, ENT) If the user selects Manual, the following menu is displayed: (ConfigTxPwrManual) – MANUAL MODE Tx Output Power Level: -03.9 dBm (◄ ►, ▲ ▼, ENT) Edit the output power level using the ◄ ► and STarrow keys, then press ENT.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM (ConfigTxPwrAUPC) – TARGET Eb/No Remote Demod - Target Eb/No Min Eb/No:9.9dB (◄ ►, ▲ ▼, ENT) Edit the target Eb/No of the remote demod, using the ◄ ► and STarrow keys. Default value is 3.0 dB, and upper limit is 9.9 dB. The user should then press ENT. (ConfigTxPwrAUPC) – MAX RANGE Maximum-permitted Power increase: 01dB (▲ ▼, ENT) Edit the maximum permitted increase in power level (when in AUPC mode), using the STarrow keys.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM (ConfigTxPwrCombined) – COMBINED TRANSMIT POWER Tx Combined Output Power: -3.9 dBm (◄ ►,▲ ▼,ENT) The combined power adjusts the level after all modulators in the chassis have been combined. It has a range of –5 dBm to +5 dBm. This level is fixed, and is not adjusted by AUPC.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM Internal indicates that the CDM-QX will supply a clock to the DTE, which is derived from its internal high-stability source. External indicates that the CDM-QX expects to receive a clock from the DTE, to which the unit can phase-lock its internal circuits. (If G.703 is selected as the Interface type, the software will force the clock mode to External.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM (ConfigTxTxα) – TX Roll-Off (α) factor Tx Roll-off: 20% 35% (◄ ►, ENT) Select 20% or 35%, using the ◄ ► arrow keys, then press ENT. The default is 35%. 5.6.1.3 (ConfigRx) - RECEIVE The sub-branches available are: Rx:FEC Demod Code Data Freq Acq Descram Buf Inv Misc CnC Select FEC, Dem, Code, Data, Frq, Acq, Descram, Buf, Inv, Misc, or CnC® using the WXarrow keys, then press ENT. The user will then be taken to a further sub-menu.
CDM-Qx Satellite Modem Front Panel Operation IMPORTANT Revision 5 MN/CDMQx.IOM The FEC type takes the highest configuration priority, and the selection here depends on what, if any, optional plug-in Codecs are installed. The choice of FEC type then determines what demodulation types, code rates, and data rates are available.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM (ConfigRxDemod) – DEMODULATION SCHEME Demodulation: BPSK QPSK 8-PSK 16-QAM (◄ ► ENT) IMPORTANT All possible choices are presented at all times. If an option is not installed (either Hardware, or FAST) or valid, the ◄ ► arrow keys will force the cursor to skip past the unavailable choice.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM (ConfigRxData) – RX DATA RATE Rx Data Rate: 05000.000kbps Sym:02500.000ksps In QDI mode, these data rates are read-only! The data rate will be the sum of the tributary rates for all ports. This will also show the calculated symbol rate and Nx64kbps (where N=001 to 124). IMPORTANT The overall range of data rates is from 32 to 20000 kbps. The overall range of symbol rates is up to 10000 ksps.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM (ConfigRxFreq) – RX FREQUENCY Rx IF Freq: 1156.3456 MHz (◄ ►, ▲ ▼,ENT) Edit the receive frequency. This is accomplished by selecting the digit to be edited, using the WXarrow keys. The value of the digit is then changed using the STarrow keys. The user should then press ENT. The range of frequencies depends upon the plug-in module. The above examples shows the L-Band version of CDM-Qx.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM (ConfigRxDescram) - DESCRAMBLER Descrambling: Default-On IESS-315-On Off (◄ ► ENT) Options are: Default-On the appropriate descrambler type is automatically selected. IESS-315-On this only applies when Turbo is installed and has been selected as the FEC type. Off no descrambling. As before, the options are displayed all of the time, but the ◄ ► arrow keys will force the cursor to skip past an unavailable choice.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM being slightly different from the local clock (a so-called plesiochronous offset), and to the motion of the satellite (a Doppler offset). The input to the buffer will be the signal from the satellite, with any clock offsets and jitter. The output from the buffer will be derived from the local TRANSMIT clock. In this way, the receive data will be perfectly synchronous with this local clock.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM (ConfigRxMiscEbNo) - Eb/No ALARM Eb/No Alarm Point: 02.0 dB (◄ ►,▲ ▼,ENT) Edit the Eb/No alarm point. This is accomplished by selecting the digit to be edited, using the ◄ ► arrow keys. The value of the digit is then changed using the STarrow keys. The user should then press ENT. The range of values is from 2.0 to 16.0 dB.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM (ConfigRxCnCMode) – CnC® MODE OF OPERATION CnC Mode: Off On (◄ ►, ENT) Select Off, or On using the WXarrow keys, then press ENT. The user will then be taken to a further sub-menu. If CnC On is selected, there will be some messages at the front panel as shown below: LOADING CnC SAT SEARCH... ...PLEASE WAIT! CnC SEARCH IS PROCESSING... ...
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM (ConfigRxCnCSrchDelay) – CnC SEARCH DELAY CnC Min/Max Delay (ms): Min=000 Max=290 (◄ ►,▲ ▼,ENT) Edit the Min/Max Search Delay in milliseconds by selecting the digit to be edited, using the WXarrow keys. The value of the digit is then changed using the STarrow keys. The user should then press ENT.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM (ConfigGroupRedundancy) Redundancy: Config Mode (◄ ►, ENT) Selecting “Config” allows the user to set redundancy either 1:1, 1:2, 1:3, or none. Redundancy is a FAST option and needs to be purchased to turn on this feature. Selecting “Mode” allows the unit to do auto or manual switching between prime and back-up device.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM (ConfigGroupRedundancyMode) Redundancy Mode: Manual Auto (◄ ►,ENT) Default is “Manual”. If “Auto” is selected, that means the back-up will automatically take over once the designated prime is faulted, and vice-versa. If “Manual” is selected, when the prime is faulted, the back up will not take over. Also, the user will have the option to do force switching.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM (ConfigFrameEDMAC, or ConfigFrameEDMAC-2) EDMAC or EDMAC-2 Comtech EF Data proprietary framing is included. The framing permits the bi-directional passing of M&C and AUPC data between local and distant-end units. EDMAC is backwards compatible with the CDM-500, CDM-550, CDM-550T, CDM-600 and CDM-600L. EDMAC-2 is a reduced overhead version of EDMAC, and is not backwards compatible with the modems listed above.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM Distant-end Base Address 0240 (◄ ►,▲ ▼, ENT) Edit the address of the distant-end modem that this unit will pass messages to. This is accomplished by selecting the digit to be edited, using the ◄ ► arrow keys. The value of the digit is then changed using the STarrow keys. The user should then press ENT. There is a restriction on values that can be entered here - they may only be in increments of 10.
CDM-Qx Satellite Modem Front Panel Operation 5.6.1.6 Revision 5 MN/CDMQx.IOM (ConfigInterface) – DATA INTERFACE Data interface for each card (modulator or demodulator) is auto detected. If grouped as a modem, the operating data interface will be the one installed in the demod card (interface on the modulator is not required). If a QDI interface is installed and a modem is grouped, then either it or the interface installed on the Demod can be selected.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM If HSSI is selected, the following sub menu will be displayed: HSSI Mode Select: TA to CA Loop (▲ ▼, ENT) The option is changed using the STarrow keys. The user should then press ENT. The following options are possible: TA to CA Loop TA and CA are looped, but TA does not control the ON/OFF state of the carrier.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM If Length is selected, the following sub-menu will be displayed: T1 Line Length: 000-133 feet ENT) (▲ ▼, Edit the line length using the STarrow keys, then press ENT Values will toggle between the following values: 0-133, 133-266, 266-399, 399-533, and 533-655 feet. If either E1-Balanced or E1-Unbalanced is selected, the following sub-menu will be displayed: Select HDB3 or AMI using the W Xarrow keys, then press ENT. G.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM If Insert is selected, the sub-menu will display: Port#X Rx Trib Rate:(▲▼, ENT) 01536.000kbps (24x64kbps) IMPORTANT This is similar to the drop-side. Upon setting the data rate, a sub-menu will appear as shown: Px I-CH: 1 2 3 4 5 6 ► TS: 11 02 06 04 05 03 This is similar to the drop-side except that this is done at the Rx side. Please make sure that ENT key is pressed once it’s done.
CDM-Qx Satellite Modem Front Panel Operation 5.6.1.7 Revision 5 MN/CDMQx.IOM (ConfigRef) - REFERENCE OSCILLATOR The modem can accept an externally supplied frequency reference, using the BNC connector on the rear panel. However, rather than bypassing the internal reference, and substituting the external signal, the internal reference is used in a low-bandwidth (~ 2Hz) phase-locked loop (PLL), so the modem actually phase locks to the reference external signal.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM If Transmit is selected the following sub-menu will be displayed: Tx Alarm Mask: Tx-FIFO G.703-BPV Tx-AIS (◄ ► ENT) Select Tx-FIFO, G.703-BPV, or Tx-AIS, using the ◄ ► arrow keys, then press ENT. For each of the choices a sub-menu similar to the one shown below will be shown: Tx-FIFO Alarm: Active Masked (◄ ► ENT) Select Active or Masked, using the ◄ ► arrow keys, then press ENT.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM If Reference is selected the following sub-menu will be displayed: Reference Alarm: Active Masked (◄ ► ENT) Select Active or Masked, using the ◄ ► arrow keys, then press ENT. If the user selects Active, then a unit fault will be generated whenever the unit sees: 1. External Reference is selected 2. There is no signal activity at the external reference port If the user selects Masked, no alarm will be generated.
CDM-Qx Satellite Modem Front Panel Operation 5.6.1.9 Revision 5 MN/CDMQx.IOM (ConfigODU) – OUTDOOR UNIT (for L-Band Unit Only) ODU (Outdoor Unit): BUC LNB (◄ ► ENT) The ODU (Outdoor Unit) menu permits the user to choose between controlling and monitoring either a BUC (Block Upconverter) or an LNB (Low-noise Block downconverter). Select BUC or LNB, using the ◄ ► arrow keys, then press ENT.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM (ConfigODUBUCM&C-FSK) - M&C FSK If M&C-FSK is selected, the following sub-menu is displayed: BUC M&C-FSK: Comms Address Tx-On/Off (◄ ►, ENT) Select Comms, Address, Tx-On/Off, or Pwr-Level, using the ◄ ► arrow keys, then press ENT. Comms If an FSK-capable BUC is employed, this menu turns the FSK between the modem and BUC either ON or OFF.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM (ConfigODUBUCM&C-FSKTx-On/Off) - FSK TX-ON/OFF If Tx-On/Off is selected, the following sub-menu is displayed: BUC RF Output: On Off (◄ ►,ENT) Select On or Off, using the ◄ ► arrow keys, then press ENT. (ConfigODUBUCDC-Pwr) - BUC DC POWER If DC-Pwr is selected, the following sub-menu is displayed: BUC DC Power: On Off (◄ ►,ENT) Select On or Off, using the ◄ ► arrow keys, then press ENT.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM If Upper is selected, the following sub-menu is displayed: BUC Current Alarm Upper Limit:1200mA (◄ ►,▲▼, ENT) Edit the BUC Current Alarm Upper limit. This is accomplished by selecting the digit to be edited, using the WXarrow keys. The value of the digit is then changed using the STarrow keys. The user should then press ENT. The range of current is from 500 to 4000 mA.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM (ConfigODUBUCLO) - BUC LO If LO is selected, the following sub-menu is displayed: BUC LO Frequency: 12000 MHz (◄ ► ▲ ▼ ENT) Edit the value of the BUC LO frequency. This is accomplished by selecting the digit to be edited, using the WXarrow keys. The value of the digit is then changed using the STarrow keys. The user should then press ENT. The valid range is from 0 to 35000 MHz.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM (ConfigODULNB) LNB If LNB is selected, the following sub-menu is displayed: LNB: DC-Voltage LO Mix 10MHz Alarm (◄ ►, ENT) Select Voltage, Power-On/Off, 10MHz, Alarm, LO or Mix, using the ◄ ► arrow keys, then press ENT. Voltage Selects 13 or 18 Volts as the LNB power supply output voltage. 10MHz This menu permits the user to turn the 10MHz frequency reference for the BUC ON or OFF.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM (ConfigODULNBPower-On/Off) – LNB POWER- ON/OFF If Power-On/Off is selected, the following sub-menu is displayed: LNB Power: On Off (◄ ► ENT) Select On or Off, using the ◄ ► arrow keys, then press ENT. (ConfigODULNB10MHz) - LNB 10MHz If 10MHz is selected, the following sub-menu is displayed: LNB 10MHz Reference: On Off (◄ ► ENT) Select On or Off, using the ◄ ► arrow keys, then press ENT.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM If Lower is selected, the following sub-menu is displayed: LNB Current Alarm Lower Limit: 050mA (◄ ►▲ ▼ ENT) Edit the LNB Current Alarm Lower limit. This is accomplished by selecting the digit to be edited, using the WXarrow keys. The value of the digit is then changed using the STarrow keys. The user should then press ENT. The range of current is from 10 to 400 mA.
CDM-Qx Satellite Modem Front Panel Operation 5.6.2 Revision 5 MN/CDMQx.IOM MONITOR MONITOR: Alarms Rx-Params Event-Log Stats AUPC CnC ODU Select Alarms, Rx-Params, Event-Log, Stats, AUPC, CnC or ODU using the ◄ ► arrow keys, then press ENT. The ODU menu will only appear for 70/140MHz units. If the user selects Alarms, the following sub-menu is displayed: 5.6.2.1 (MonitorAlarms) ALARMS IMPORTANT The modem uses a system of Fault Prioritization.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM (MonitorAlarmsReceive) – RECEIVE ALARMS Rx Traffic: AGC Alarm Reduce Input level (ENT) The screen will indicate if there are any Receive Traffic Faults. If not, it will display ‘None’. Pressing ENT takes the user back to the previous menu. (MonitorAlarmsTransmit) - TRANSMIT ALARMS Tx Traffic: No Tx From Terrestrial Clock (ENT) The screen will indicate if there are any Transmit Traffic Faults. If not, it will display ‘None’.
CDM-Qx Satellite Modem Front Panel Operation 5.6.2.2 Revision 5 MN/CDMQx.IOM (MonitorRx-Params) – RECEIVE-PARAMETERS If the user selects Rx-Params, the following sub-menu is displayed: EbNo=05.7dB BER=3.4E-9 UF=+11.7k Buf=50% RSL=-24dBm If the demodulator is locked, this screen shows the following: Eb/No This shows the value of Eb/No calculated by the demodulator. The value referred to here is the energy per information bit (Ebi), divided by the noise spectral density (No).
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM Log 023: 30/11/02 10:37:32 Fault - Demod Lock (3) (▲▼,ENT) In this example, the demodulator installed in slot #3 is faulted on Nov. 30, 2002 at 10:37:32 with log number 23. (MonitorEvent-LogView) – VIEW STORED EVENTS The user may scroll backwards or forwards through the entries in the event log, using the STarrow keys. Pressing ENT or CLR will take the user back to the previous menu. The event log can store up to 255 events.
CDM-Qx Satellite Modem Front Panel Operation 5.6.2.4 Revision 5 MN/CDMQx.IOM (MonitorStats) – LINK STATISTICS (for grouped as modem only) If the user selects Stats, the following sub-menu is displayed: Link Statistics: View Clear-All Config (◄ ►,ENT) Select View, Clear-All, or Config, using the ◄ ► arrow keys, then press ENT. (MonitorStatsView) – VIEW LINK STATISTICS If the user selects VIEW, the following screen is displayed: Sta198: 02/11/02 10:37:32 16.0, 16.0, 9.0, 9.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM If the measured values are greater than, or equal to 16.0 dB, the display will show 16.0 dB. If AUPC is not enabled, the values of maximum and average TPLI will both show ‘Off'. Examples: 08.0, 13.5, 2.5, 1.8 means: Minimum Eb/No observed in the measurement interval = 8.0 dB Average Eb/No observed in the measurement interval = 13.5 dB Maximum TPLI observed in the measurement interval = 2.
CDM-Qx Satellite Modem Front Panel Operation 5.6.2.5 Revision 5 MN/CDMQx.IOM (MonitorAUPC) – MONITOR AUPC(for grouped as modem only) If AUPC is selected, and the modem is not in Framed mode, the following sub-menu is displayed: Framing is required for AUPC Monitor (ENT or CLR) If AUPC is selected, and the modem is in Framed mode, the following sub-menu is displayed: AUPC:Remote EbNo = 14.0dB TX Power Increase = 2.
CDM-Qx Satellite Modem Front Panel Operation 5.6.2.7 Revision 5 MN/CDMQx.IOM (MonitorODU) – MONITOR ODU (for L-Band Unit only) If ODU is selected, the following sub-menu is displayed: Outdoor Unit Monitor: ODU LNB (◄ ►, ENT) If BUC is selected, the following menu is displayed: BUC: DC=47.8V,3.2A T=38oC SW=1.1 PLL=Flt Pwr=02.
CDM-Qx Satellite Modem Front Panel Operation 5.6.3 Revision 5 MN/CDMQx.IOM TEST: Selecting Test will display this sub-menu: TEST: Mode BIST (◄ ►, ENT) Spec-Analyzer Select Mode, BIST, or Spec-Analyzer using the ◄ ► arrow keys, then press ENT. Note that BIST stands for built-in system test. Selecting Mode will display this submenu: Mode: Norm IF2 Dig2 I/O2 RF2 Tx-CW Tx1-0 (◄ ►, ENT) All the modes are available if grouped as modem.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM This sub-menu permits the user to select the following test modes: Norm IF Loop Dig Loop I/O Loop RF Loop TX-CW TX-1,0 (Normal) This clears any test modes or loopbacks, and places the unit back into an operational state. (IF Loopback) This test mode invokes an internal IF loop. This is a particularly useful feature, as it permits the user to perform a quick diagnostic test without having to disturb external cabling.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM If BIST is selected, the display will show: BIST: BERT-Config BERT-Control BERT-Mon (◄ ►, ENT) The Built-In System Test (BIST) specifically refers to the built-in BERT (BER Tester). If BERT-Config is selected: BERT Config: Tx=ON Rx=ON Tx-Pat=2047 Rx-Pat=2047 If the selected slot is Tx, the Rx parameters are not selectable, and vice-versa. Note the BERT generator resides at the Tx side while the BERT monitor resides at the Rx side.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM If Spec-Analyzer is selected: Spectrum Analyzer: Mode Config (◄ ►, ENT) Selecting Mode will display: Spectrum Analyzer Mode: Off On (◄ ►, ENT) This menu allows the user to turn ON or OFF the engine of the spectrum analyzer. If spectrum analyzer mode is ON, the user can use Comtech’s application software (Windows) to view the spectrum, or use the Web browser.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM IF LOOPBACK DIGITAL LOOPBACK I/O LOOPBACK Figure 5-4.
CDM-Qx Satellite Modem Front Panel Operation 5.6.4 Revision 5 MN/CDMQx.IOM INFO (Information) Select Rem, Tx, Rx, Buf, Frame, Interface, Mask, Ref, or ID using the ◄ ► arrow keys, then press ENTER. INFO: Rem Tx Rx Buffer Frame Interface Mask Ref ID These screens display information on the current configuration of the unit. Depending on the choice selected, one of the following screens will be displayed: using the ◄ ► arrow keys, then press ENT. 5.6.4.
CDM-Qx Satellite Modem Front Panel Operation 5.6.4.2 Revision 5 MN/CDMQx.IOM (InfoTx) - TX INFORMATION The information displayed here is as follows: Tx: 1140.000 05000.000 TUR 8P 17/18 S EXT -20.
CDM-Qx Satellite Modem Front Panel Operation 5.6.4.3 Revision 5 MN/CDMQx.IOM (InfoRx) – RX INFORMATION The information displayed here is as follows: Rx: 1140.000 05000.
CDM-Qx Satellite Modem Front Panel Operation 5.6.4.4 Revision 5 MN/CDMQx.IOM (InfoBuffer) - BUFFER INFORMATION Buffer: Enabled (Tx=Rx) (ENT) This displays if the buffer is enabled or disabled, shows the exact clocking mode (TX=RX, or TX<> RX), and the buffer size. Pressing ENT takes the user back to the previous menu. 5.6.4.
CDM-Qx Satellite Modem Front Panel Operation 5.6.4.7 Revision 5 MN/CDMQx.IOM (InfoMask) – ALARM MASK INFORMATION This shows, in the same format as the CONFIG, MASK sub menu, which alarms are currently masked. If an alarm is not masked, a blank is displayed in the relevant screen position. Mask: FIFO BPV TAIS AGC EbNo BUF Ref 5.6.4.8 RAIS (InfoRef) - FREQUENCY REFERENCE Frequency Reference: Internal 10 MHz (ENT) This shows the source of the frequency reference for the CDM-QX. 5.6.4.
CDM-Qx Satellite Modem Front Panel Operation 5.6.5.1 Revision 5 MN/CDMQx.IOM (Save/LoadSave) – SAVE CONFIGURATION Selecting Save will display the following screen, if the selected location is empty: Save Config to Location: 9 Empty (▲ ▼ ENT) However, if the location already contains data, the following screen will be displayed: Save Config to Location: 9 11:10:29 23/12/03 (▲ ▼ ENT) The user is shown the time and date stamp of the previously stored configuration, for identification purposes.
CDM-Qx Satellite Modem Front Panel Operation 5.6.5.2 Revision 5 MN/CDMQx.IOM (Save/LoadLoad) – LOAD CONFIGURATION Having selected Load, if there is a configuration stored at the selected location the following screen will be displayed: Load Config from Location: 9 11:10:29 23/12/03 (▲ ▼ ENT) Note the data and time stamp identifying the stored configuration.
CDM-Qx Satellite Modem Front Panel Operation 5.6.6 Revision 5 MN/CDMQx.IOM UTILITY UTILITY: RxBuffer Clock Ref ID Display Firmware FAST Select RxBuffer, Clock, Ref, ID, Display, Firmware or FAST using the ◄ ► arrow keys then press ENT. According to the selection, the following sub-menus are displayed: 5.6.6.1 (UtilityRxBuffer) - BUFFER RECENTER Press ENT to Re-Center the Receive Buffer Pressing ENT will cause a forced re-centering of the Plesiochronous/Doppler buffer. 5.6.6.
CDM-Qx Satellite Modem Front Panel Operation 5.6.6.3 Revision 5 MN/CDMQx.IOM (UtilityRef) - REFERENCE ADJUST Internal Freq Ref: Adjust Warm-up delay (▲▼, ENT) Fine adjustment of the Internal 10 MHz reference oscillator is possible through this menu. Use the STarrow keys to edit the value, then press ENT. The range of values is from –2048 to +2047. Note: The numbers displayed here do not correspond to an exact frequency increment.
CDM-Qx Satellite Modem Front Panel Operation 5.6.6.5 Revision 5 MN/CDMQx.IOM (UtilityDisplay) - DISPLAY BRIGHTNESS Edit Display Brightness: 100% (▲▼, ENT) Edit the display brightness, using the STarrow keys. The user should then press ENT. 5.6.6.6 (UtilityFirmware) - FIRMWARE This series of sub-menus permits the user to view information about the CDM-Qx internal firmware.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM If the user selects Select, the following sub-menu is displayed: Current Active Image: #1 Next Reboot Image: #1 #2 The top line shows the current active image. On the bottom line the user may select, using the ◄ ► arrow keys and ENT key, the image that will be active the next time the unit is re-booted.
CDM-Qx Satellite Modem Front Panel Operation 5.6.7 Revision 5 MN/CDMQx.IOM (UtilityFAST) - FAST Code Options FAST is the way to enable new options in the modem. Obtain the FAST code for the new option from Comtech EF Data. FAST – Select the module: Base Slot1 Slot2 Slot3 Slot4 The Base refers to the base unit where you can view the redundancy option as well as the CnC option. The Slot# refers to the cards where it is installed.
CDM-Qx Satellite Modem Front Panel Operation Revision 5 MN/CDMQx.IOM User can either select Edit Code or Demo Mode. If Edit Code is selected, the following menu is displayed: Edit 20 digit FAST Code: 00000000000000000000 ENT Enter the code carefully. Use the WXarrow keys to move the cursor to each character. Use the STarrow keys to edit the character, then press ENT. The modem will respond with “Configured Successfully” if the new FAST option has been accepted as shown below.
Chapter 6. FORWARD ERROR CORRECTION OPTIONS 6.1 Introduction As standard, the Modem is equipped with three Forward Error Correction encoders/decoders – Viterbi, concatenated Reed-Solomon and Trellis (which is available with the 8-PSK FAST option). The constraint lengths and encoding polynomials are not only Open Network compatible (IESS-315), but are also Closed Network compatible with the vast majority of existing modems from other manufacturers.
CDM-Qx Satellite Modem Forward Error Correction Options 6.2 Revision 5 MN/CDMQx.IOM Viterbi The combination of convolutional coding and Viterbi decoding has become an almost universal standard for satellite communications. The Modem complies with the Intelsat standards for Viterbi decoding with a constraint length of seven. This is a de facto standard, even in a closed network environment, which means almost guaranteed interoperability with other manufacturer’s equipment.
CDM-Qx Satellite Modem Forward Error Correction Options 6.3 Revision 5 MN/CDMQx.IOM Reed-Solomon Outer Codec IMPORTANT It cannot be emphasized strongly enough that the purpose of the concatenated Reed-Solomon is to dramatically improve the BER performance of a link under given noise conditions. It should NOT be considered as a method to reduce the link EIRP requirement to produce a given BER.
CDM-Qx Satellite Modem Forward Error Correction Options 6.3.1 Revision 5 MN/CDMQx.IOM Closed Network Modes A 220,200 code is used in transparent closed network modes, and a 200, 180 code is used in framed (EDMAC) modes. (220, 200 means that data is put into blocks of 220 bytes, of which 200 bytes are data, and 20 bytes are FEC overhead.) These two codes were chosen because they fit well into Comtech EF Data’s clock generation scheme, and they have almost identical coding gain.
CDM-Qx Satellite Modem Forward Error Correction Options 6.4 Revision 5 MN/CDMQx.IOM Trellis Coding In the other FEC methods described here, the processes of coding and modulation are independent - the FEC codec has no knowledge of, or interaction with the modulator. However, there are schemes in which the coding and modulation are combined together, where the encoder places FEC symbols in a precise manner into the signal constellation.
CDM-Qx Satellite Modem Forward Error Correction Options Revision 5 MN/CDMQx.IOM 6.5 Turbo Product Codec (Hardware Option) 6.5.1 Introduction Turbo coding is an FEC technique developed within the last few years, which delivers significant performance improvements compared to more traditional techniques. Two general classes of Turbo Codes have been developed, Turbo Convolutional Codes (TCC), and Turbo Product Codes (TPC, a block coding technique).
CDM-Qx Satellite Modem Forward Error Correction Options Revision 5 MN/CDMQx.IOM Table 6-4. Available TPC Modes 6.5.3 Code Rate/Modulation Rate 21/44 BPSK Rate 5/16 BPSK Rate 21/44 QPSK Rate 3/4 QPSK Rate 3/4 8-PSK Rate 3/4 16-QAM Rate 7/8 QPSK Rate 7/8 8-PSK Rate 7/8 16-QAM Rate 17/18 QPSK 32 kbps to 4.772 Mbps 32 kbps to 3.125 Mbps 32 kbps to 10 Mbps 32 kbps to 15 Mbps 288 kbps to 20 Mbps 384 kbps to 20 Mbps 32 kbps to 17.5 Mbps 336 kbps to 20 Mbps 448 kbps to 20 Mbps 32 kbps to 18.
CDM-Qx Satellite Modem Forward Error Correction Options 6.5.4 Revision 5 MN/CDMQx.IOM Comparison of all TPC Modes Eb/No at BER = 10-6 Guaranteed (Typical in parentheses) Eb/No at BER = 10-8 Guaranteed (Typical in parentheses) Spectral Efficiency Symbol Rate Occupied * Bandwidth for 1 Mbps Carrier QPSK Rate 1/2 Viterbi * 6.0 dB (5.5 dB) 7.3 dB (6.8 dB) 1.00 bits/Hz 1.0 x bit rate 1190 kHz BPSK Rate 21/44 Turbo 2.9 dB (2.6 dB) 3.3 dB (3.0 dB) 0.48 bits/Hz 2.
CDM-Qx Satellite Modem Forward Error Correction Options Revision 5 MN/CDMQx.IOM It can be seen that the 8-PSK Rate 3/4 Turbo performance closely approaches that of the Rate 2/3 TCM/Reed-Solomon case – the BER performance is within approximately 0.4 dB. However, it should be noted that the Rate 3/4 Turbo mode is 20% more bandwidth efficient than the TCM case. The additional advantages of Turbo (lower delay, performance during fades etc) should also be considered. Table 6-6.
CDM-Qx Satellite Modem Forward Error Correction Options Revision 5 MN/CDMQx.IOM Eb/No in dB 1 2 3 4 5 6 7 8 9 10 11 12 1E-1 Uncoded BPSK/QPSK Viterbi Decoding 1E-2 Typical Performance 1E-3 1E-4 1E-5 1E-6 Specification limit, Rate 7/8 Coding 1E-7 1E-8 Specification limit, Rate 3/4 Coding Specification limit Rate 1/2 Coding 1E-9 BER 1 2 3 4 5 6 7 Figure 6-1.
CDM-Qx Satellite Modem Forward Error Correction Options Revision 5 MN/CDMQx.
CDM-Qx Satellite Modem Forward Error Correction Options Revision 5 MN/CDMQx.IOM Eb/No in dB 1 2 3 4 5 6 7 8 9 10 11 12 1E-1 8-PSK/TCM Rate 2/3 Decoding, with and without 219, 201 RS Outer Code Uncoded BPSK/QPSK 1E-2 Performance with CDM-Qx 1E-3 1E-4 Typical Performance 1E-5 1E-6 1E-7 1E-8 Specification limit Rate 2/3 Coding and 219, 201 RS Outer Code 1E-9 BER 1 2 3 4 5 Specification limit, Rate 2/3 Coding 6 7 8 9 10 11 12 Figure 6-3.
CDM-Qx Satellite Modem Forward Error Correction Options Revision 5 MN/CDMQx.IOM Eb/No in dB 1E-1 1 12 2 3 4 5 6 7 8 9 10 11 Comtech Turbo Product Codec Rate 3/4 QPSK, 8-PSK and 16-QAM Uncoded BPSK/QPSK 1E-2 Performance with CDM-Qx Uncoded 16-QAM 1E-3 Spec limit Rate 3/4 8-PSK Uncoded 8-PSK 1E-4 Spec Speclimit limit Rate Rate3/4 3/4 QPSK/OQPSK QPSK 1E-5 1E-6 1E-7 Spec limit Rate 3/4 16-QAM 1E-8 Typical performance 1E-9 BER 1 12 2 3 4 5 6 7 8 9 10 Figure 6-4.
CDM-Qx Satellite Modem Forward Error Correction Options Revision 5 MN/CDMQx.IOM Eb/No in dB 1 2 3 4 5 6 7 8 9 10 11 12 1E-1 Comtech Turbo Product Codec Rate 7/8 QPSK, 8-PSK and 16-QAM Uncoded BPSK/QPSK 1E-2 Performance with CDM-Qx Uncoded 16-QAM 1E-3 Spec limit Rate 7/8 8-PSK Spec limit Rate 7/8 QPSK/OQPSK QPSK Uncoded 8-PSK 1E-4 1E-5 1E-6 1E-7 Spec limit Rate 7/8 16-QAM 1E-8 Typical performance 1E-9 BER 1 2 3 4 5 6 7 8 9 10 Figure 6-5.
CDM-Qx Satellite Modem Forward Error Correction Options Revision 5 MN/CDMQx.
CDM-Qx Satellite Modem Forward Error Correction Options Revision 5 MN/CDMQx.IOM Eb/No in dB 1 2 3 4 5 6 7 8 9 10 11 12 1E-1 Comtech Turbo Product Codec Rate 21/44 BPSK Rate 5/16 BPSK 1E-2 1E-3 Spec limit Rate 5/16 BPSK Spec limit Rate 21/44 BPSK 1E-4 Uncoded BPSK/QPSK 1E-5 1E-6 1E-7 1E-8 Typical performance 1E-9 BER 1 2 3 4 5 6 7 8 9 Figure 6-7.
CDM-Qx Satellite Modem Forward Error Correction Options Revision 5 MN/CDMQx.IOM Eb/No in dB 1 2 3 4 5 6 7 8 9 10 11 12 1E-1 16-QAM Viterbi, Rate 3/4 and Rate 7/8 with 220,200 RS Outer Code Uncoded BPSK/QPSK 1E-2 Uncoded 16-QAM 1E-3 1E-4 Specification limit Rate 7/8 Viterbi and 220,200 RS Outer Code 1E-5 Typical Performance 1E-6 1E-7 1E-8 Specification limit Rate 3/4 Viterbi and 220,200 RS Outer Code 1E-9 BER 1 2 3 4 5 6 7 8 9 10 11 Figure 6-8.
CDM-Qx Satellite Modem Forward Error Correction Options Revision 5 MN/CDMQx.
Chapter 7. EDMAC CHANNEL 7.1 Theory Of Operation As explained earlier, EDMAC is an acronym for Embedded Distant-end Monitor And Control. This is a feature, which permits the user to access the M&C features of modems that are at the distant-end of a satellite link. This is accomplished by adding extra information to the user’s data, but in a manner, which is completely transparent to the user.
CDM-Qx Satellite Modem EDMAC Channel Revision 5 MN/CDMQx.IOM When framing is used, the normal V.35 scrambler is no longer used. This V.35 approach is called ‘self synchronizing’, because in the receiver, no external information is required in order for the de-scrambling process to recover the original data. The disadvantage of this method is that it multiplies errors. On average, if one bit error is present at the input of the descrambler, 3 output errors are generated.
CDM-Qx Satellite Modem EDMAC Channel Revision 5 MN/CDMQx.IOM Now, a unit that has been designated an EDMAC master not only responds to its own unique bus address, but it will also be configured to listen for the address, which corresponds to its EDMAC Slave. When a complete message packet has been received by the EDMAC Master, it will begin to transmit this packet over the satellite channel, using the overhead bytes, which become available.
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Chapter 8. AUTOMATIC UPLINK POWER CONTROL 8.1 Introduction Automatic Uplink Power Control (AUPC) is a feature whereby a local modem is permitted to adjust its own output power level in order to attempt to maintain the Eb/No at the remote modem. The user SHALL obtain permission from the Satellite Operator to use this feature. WARNING Improper use of this feature could result in a transmitting terminal seriously exceeding its allocated flux density on the Operator’s satellite.
CDM-Qx Satellite Modem Automatic Uplink Power Control (AUPC) Revision 5 MN/CDMQx.IOM There are several important parameters associated with this mode of operation, and the user needs to understand how the AUPC feature works, and the implications of setting these parameters. 8.2 Setting AUPC Parameters 1. The user, under the menu (CONFIG, MODE) first ensures that EDMAC is selected. EDMAC may be selected as IDLE, or the unit may be defined as an EDMAC Master or Slave.
CDM-Qx Satellite Modem Automatic Uplink Power Control (AUPC) 8.2.3 Revision 5 MN/CDMQx.IOM Alarm This parameter defines how the user wants the modem to act if, under AUPC control, the maximum power limit is reached. The two choices are: • NONE (no action) • TX ALARM (generate a Tx alarm) The default setting is NONE. 8.2.4 Demod Unlock This defines the action the modem will take if the remote demodulator loses lock.
CDM-Qx Satellite Modem Automatic Uplink Power Control (AUPC) 8.4 Revision 5 MN/CDMQx.IOM Monitoring The remote demodulator’s value of Eb/No can be monitored at all times, either from the front panel (MONITOR, AUPC) or via the remote control interface. The resolution of the reading is 0.2 dB. For all values greater than or equal to 16 dB, the value 16.0 dB will be displayed. As long as framing is enabled, the value will still be available, even though AUPC may be disabled.
Chapter 9. DoubleTalk™ Carrier-in-Carrier® OPERATION The Modem optionally incorporates a proprietary technology licensed from Applied Signal Technology, Inc. called DoubleTalk™, hereafter referred to as DoubleTalk Carrier-In-Carrier (CnC) when implemented in Comtech EF Data modems. CnC essentially allows two carriers to share the same channel. Traditional full-duplex links utilize frequency division multiplexing to allow communications in two directions.
CDM-Qx Satellite Modem Carrier-in-Carrier Operation Revision 5 MN/CDMQx.IOM copy of the outbound modulators signal in time and frequency within the composite signal received by the demodulator. When the search algorithm has found the carrier, the modem front panel will report search successful! It will also display an accurate value for the delay of the signal.
CDM-Qx Satellite Modem Carrier-in-Carrier Operation Revision 5 MN/CDMQx.IOM Traditional FDMA System Without CnC A B A B Uplink Transponder Downlink Transponder CDM-Qx System With CnC A Uplink Transponder B A Downlink Transponder B Figure 10-1.
CDM-Qx Satellite Modem Carrier-in-Carrier Operation Revision 5 MN/CDMQx.
Chapter 10. REDUNDANCY Redundancy is built into the modem and can be enabled using the FAST optioning.
CDM-Qx Satellite Modem Redundancy Revision 5 MN/CDMQx.
Chapter 11. ETHERNET MANAGEMENT 11.1 Introduction The base modem is equipped with an RJ-45, 10/100BaseT Ethernet management interface used for monitor and control purposes. This chapter of the manual will provide a high-level overview of the functionality provided by this interface. 11.
CDM-Qx Satellite Modem Ethernet Management (Base Modem) 11.3 Revision 5 MN/CDMQx.IOM Web Server (HTTP) Interface The embedded Web Server application provides the user with an easy to use interface to configure and monitor all aspects of the Base Modem. These web pages have been designed for optimal performance when using Microsoft’s Internet Explorer 5.5 or higher. By typing http://xxx.xxx.xxx.xxx” (where xxx.xxx.xxx.xxx =Base Modem IP address) on your browser, the Login prompt will appear.
CDM-Qx Satellite Modem Ethernet Management (Base Modem) 11.3.1 Revision 5 MN/CDMQx.IOM Web Server Menu Tree Table 12-1. Web Server Menu Tree Level 2 Level 1 Home Home Contact Support Admin Access Remote Config Mdm Quick View Unit Status Maint Unit Info Please make sure that the web browser does not use the old cached web page once you visited the same page.
CDM-Qx Satellite Modem Ethernet Management (Base Modem) Revision 5 MN/CDMQx.IOM To see the installed cards in the chassis, click Quick View under Config Mdm. It should be noted that the user needs to wait for the whole page to display, that is, the left-hand side of the page should display at least the word Base.
CDM-Qx Satellite Modem Ethernet Management (Base Modem) Revision 5 MN/CDMQx.IOM As you can see the MD icon is highlighted as well as the Config. In this case, both the modulator and demodulator parameters are accessible. If TX icon is selected, only the modulator parameters will be displayed and accessible. If RX icon is selected, only the demodulator parameters will be displayed and accessible.
CDM-Qx Satellite Modem Ethernet Management (Base Modem) Revision 5 MN/CDMQx.IOM Using the web browser, the user can view the constellation of the demodulated signal as shown below: In this example, the CDM-Qx has four (4) Rx cards installed. Clicking the Base and then Test, will allow the user to view all the constellations of all the demodulators at once. The user can also view one constellation at a time by just selecting one RX only.
CDM-Qx Satellite Modem Ethernet Management (Base Modem) Revision 5 MN/CDMQx.IOM Since the introduction of the spectrum analyzer feature in the CDM-Qx, the user can view the spectrum of the signal as shown below: When the spectrum analyzer feature is turned ON, the demodulator handling this will not be allowed to receive traffic and built-in BERT monitor is ignored. It should be noted the web page only captures the spectrum.
CDM-Qx Satellite Modem Ethernet Management (Base Modem) 11.4 Revision 5 MN/CDMQx.IOM SNMP Interface The Simple Network Management Protocol (SNMP) is an application-layer protocol designed to facilitate the exchange of management information between network devices. The CDM-Qx SNMP agent supports both SNMPv1 and v2c. IMPORTANT 11.4.1 For proper SNMP operation, the CDM-Qx MIB files must be used with the associated version of the CDM-Qx base modem M&C.
CDM-Qx Satellite Modem Ethernet Management (Base Modem) 11.4.2 Revision 5 MN/CDMQx.IOM SNMP Community Strings The modem uses community strings as a password scheme that provides authentication before gaining access to the modem agent’s MIBs. In “SNMP v1/v2c”, the community string is sent unencrypted in the SNMP packets. Caution must be taken by the network administrator to ensure that SNMP packets travel only over a secure and private network if security is a concern.
CDM-Qx Satellite Modem Ethernet Management (Base Modem) Revision 5 MN/CDMQx.IOM The following tables are the Alarms and Faults v1 traps / v2 notifications that the modem supports. Alarms and Faults SNMPv1 traps:\ CdmQxTxTrafficAlarmV2 6247272 CdmQxUnitAlarmV2 6247271 CdmQxRxTrafficAlarmV2 6247273 Alarms and Faults SNMPv2 notifications: 11.5 CdmQxUnitAlarmV2 1.3.6.1.4.1.6247.27.2.0.1 CdmQxTxTrafficAlarmV2 1.3.6.1.4.1.6247.27.2.0.2 CdmQxRxTrafficAlarmV2 1.3.6.1.4.1.6247.27.2.0.
CDM-Qx Satellite Modem Ethernet Management (Base Modem) Revision 5 MN/CDMQx.
CDM-Qx Satellite Modem Ethernet Management (Base Modem) Revision 5 MN/CDMQx.IOM There is a disadvantage when using Windows DOS as Telnet Client. Since Windows DOS cannot translate a ‘\r’ to a ‘\r\n’ for the messages coming from Telnet Server, the multi-line command response (for example, FRW? Response) will be displayed as one line, with the latter lines overwrite the previous lines. In order to view the full response messages, we recommend using HyperTerminal configured as Telnet Client.
CDM-Qx Satellite Modem Ethernet Management (Base Modem) Revision 5 MN/CDMQx.
CDM-Qx Satellite Modem Ethernet Management (Base Modem) Revision 5 MN/CDMQx.
Appendix A. SUMMARY OF SPECIFICATIONS A.1 Modulator Note: Features not in the initial product release are identified in parentheses. Modulation Symbol rate range Data rate range Operating modes FEC Transmit filtering Scrambling Output frequency External Reference Harmonics and spurious Transmit On/Off Ratio Output phase noise Output power Power accuracy See Table A-5 Up to 10 Msps (lower end is modulation and FEC rate dependant) Refer to Figure A-1.
CDM-Qx Satellite Modem Summary of Specifications Output Connector Output Return Loss Clocking Options External TX Carrier Off 0.00 0.10 Revision 5 MN/CDMQx.IOM Type BNC Female (70/140MHz IF) Type N Female (L-Band) ≥ 19 dB (70/140MHz IF) ≥ 10 dB (L-Band) Internal, ±1ppm or 0.1 ppm (SCT) External, locking over a ±100 ppm range (TT) Loop timing (Rx satellite clock) - supports asymmetric operation - Rx and Tx data rates do not need to be identical External Clock at transmit data rate.
CDM-Qx Satellite Modem Summary of Specifications A.2 Revision 5 MN/CDMQx.
CDM-Qx Satellite Modem Summary of Specifications (With two adjacent carriers, each 7 dB higher than the desired carrier) TURBO PRODUCT CODEC Rate 3/4 QPSK Rate 3/4 8-PSK Rate 3/4 16-QAM BER (With two adjacent carriers, each 7 dB higher than the desired carrier) TURBO PRODUCT CODEC Rate 7/8 QPSK Rate 7/8 8-PSK Rate 7/8 16-QAM BER (With two adjacent carriers, each 7 dB higher than the desired carrier) TURBO PRODUCT CODEC Rate 17/18 QPSK Rate 17/18 8-PSK BER (With two adjacent carriers, each 7 dB higher than
CDM-Qx Satellite Modem Summary of Specifications A.3 Revision 5 MN/CDMQx.IOM Data Interfaces Note: Features not in the initial product release are identified in parentheses. EIA-530 Synchronous RS-232 EIA-530 (3 selectable modes) EIA-422/EIA-530 DCE (Rates up to 12 Mbps) Also supports X.21 V.35 DCE (Rates up to 12 Mbps) Synchronous RS-232 (Rates up to 300 kbps) 25-pin D-sub (female) G.703 (Balanced) 1.544 Mbps T1 (Balanced 100 Ω) 2.048 Mbps E1 (balanced 120 Ω) 15-pin D-sub (female) G.
CDM-Qx Satellite Modem Summary of Specifications A.5 Revision 5 MN/CDMQx.
CDM-Qx Satellite Modem Summary of Specifications A.6 Revision 5 MN/CDMQx.IOM Framing Summary (Future) Overhead added Transparent None Available data rates and format Overhead components All rates and formats Additional ReedSolomon Overhead Scrambling (see Note 1 ) 220/200 225/205 219/201 for IESS-310 mode Basic ITU V.35 (Intelsat) None EDMAC (Future) 5% to 2 Mbps 1.5% (see Note 2) All rates and formats Remote control link between modems’ processor 200/180 Proprietary scrambler Notes: 1.
CDM-Qx Satellite Modem Summary of Specifications Revision 5 MN/CDMQx.
Appendix B. FLASH UPGRADING The modem eliminates the need for updating firmware by physically replacing EPROMs. Instead, the modem uses ‘flash memory’ technology internally, and new firmware can be uploaded to the unit from an external PC, as follows: Go to: www.comtechefdata.com Click on: downloads Click on: flash upgrades This makes software upgrading very simple, and updates can now be sent via the Internet, E-mail, or on disk.
CDM-Qx Satellite Modem Flash Upgrading Revision 5 MN/CDMQx.IOM Alternate Method: CMD Prompt: At the command prompt (c:\>) type "MD temp" without quotes (MD stands for make directory). This is the same as creating a new folder from Windows. You should now have a "c:\temp" subdirectory created where c: is the drive letter used in the example. 3. Download the correct firmware file to this temporary folder. (Procedure is Under Construction.
CDM-Qx Satellite Modem Flash Upgrading Revision 5 MN/CDMQx.IOM Verify the communication and connection by issuing a "ping" command to the modem. You can find the IP address of the modem either remotely using the <0/IPA? command or from the front panel with the menus. To PING and FTP from DOS, press the “Start” button on the Windows toolbar, and select the “Run...” option. • From Win95 or Win98, type “command”. • From WinNT, Win2K or WinXP, type “cmd”.
CDM-Qx Satellite Modem Flash Upgrading Revision 5 MN/CDMQx.IOM 10. Verify the new software versions are booting by observing the following messages on the modem display: Comtech CDM-Qx Modem Firmware Version: 1.1.
Appendix C. REMOTE CONTROL This section describes the protocol and message command set for remote monitor and control of the CDM-QX Satellite Modem. The protocol is based on the CDM-570L, but is modified to add the new features and to separately address the four plug-in slots. The electrical interface is either an RS-485 multi-drop bus (for the control of many devices) or an RS-232 connection (for the control of a single device), and data is transmitted in asynchronous serial form, using ASCII characters.
CDM-Qx Satellite Modem Remote Control Revision 4 MN/CDMQx.IOM Each target has a unique address, and each time the controller transmits, in a framed ‘packet’ of data, the address of the intended recipient target is included. All of the targets receive the packet, but only one (the intended) will reply. The target enables its output line driver, and transmits its return data packet back to the controller, in the other direction, on the physically separate pair.
CDM-Qx Satellite Modem Remote Control C.4 Revision 4 MN/CDMQx.IOM Packet Structure Controller-to-target: Start of Packet < ASCII code 60 Target Address (4 characters) (1 character) Address De-limiter / ASCII code 47 Instruction Code (3 characters) (1 character) Example: Code Qualifier = or ? ASCII code 61 or 63 (1 character) Optional Arguments (n characters) End of Packet Carriage Return ASCII code 13 (1 character) <0135/TRQ=70.
CDM-Qx Satellite Modem Remote Control C.4.2 Revision 4 MN/CDMQx.IOM Address Up to 9999 devices can be uniquely addressed. The RS-485 base address is set by the front panel; the RS-232 base address is always zero. Each plug-in slot (as viewed from the back of the chassis) has its own address. Slot Upper Left Lower Left Upper Right Lower Right Address Base Base + 1 Base + 2 Base + 3 Common functions can be accessed through any of the four addresses.
CDM-Qx Satellite Modem Remote Control C.4.4 Revision 4 MN/CDMQx.IOM Instruction Code Qualifier This is a single character that further qualifies the preceding instruction code. Code Qualifiers obey the following rules: 1.
CDM-Qx Satellite Modem Remote Control Revision 4 MN/CDMQx.IOM First, if the controller has sent a query code to a target (for example TFQ?, meaning ‘what’s the Transmit frequency?’), the target would respond with TFQ=xxxx.xxxx, where xxxx.xxxx represents the frequency in question.
CDM-Qx Satellite Modem Remote Control Revision 4 MN/CDMQx.IOM The target acknowledges the message indicating that the unit is in Ethernet mode. While in Ethernet mode, the unit cannot be serially queried for modem parameters. This mode will allow the user to access the Web server, SNMP, or Telnet. C.4.5 Message Arguments Arguments are not required for all messages.
CDM-Qx Satellite Modem Remote Control Revision 4 MN/CDMQx.
C.5.1 Parameter Type TX Frequency TX Remote Commands Command (Instruction Code and Qualifier) TFQ= Arguments for Command or Response to Query 9 bytes Description of Arguments Command or Query TX Frequency, 950 to 1950 MHz (L-Band units) 50 to 90 and 100 to 180 MHz (70/140 MHz units) Resolution=100 Hz Example: TFQ=0950.
CDM-Qx Satellite Modem Remote Control Parameter Type TX FEC Code Rate Command (Instruction Code and Qualifier) TCR= Revision 4 MN/CDMQx.
CDM-Qx Satellite Modem Remote Control Parameter Type TX Spectrum Invert Command (Instruction Code and Qualifier) TSI= Revision 4 MN/CDMQx.
CDM-Qx Satellite Modem Remote Control Parameter Type TX Clock Source TX Data Invert Revision 4 MN/CDMQx.IOM Command (Instruction Code and Qualifier) TCK= Arguments for Command or Response to Query 1 byte, value 0 1, 2 TDI= 1 byte, value 0,1 Description of Arguments Command or Query TX Clock Source, where: 0=Internal 1=TX Terrestrial 2=Loop-Timed 3=Ext loop (G.
CDM-Qx Satellite Modem Remote Control C.5.2 Parameter Type RX Frequency Revision 4 MN/CDMQx.IOM RX Remote Commands Command (Instruction Code and qualifier) RFQ= Arguments for Command or Response to Query 9 bytes Description of Arguments Command or Query Tx Frequency, 950 to 1950 MHz (L-Band units) 50 to 90/100 and 180 MHz (70/140 MHz units) Resolution = 100 Hz Example: RFQ=0950.
CDM-Qx Satellite Modem Remote Control Parameter Type RX Demod Type Command (Instruction Code and qualifier) RMD= Revision 4 MN/CDMQx.
CDM-Qx Satellite Modem Remote Control Parameter Type RX Data Rate Command (Instruction Code and qualifier) RDR= Revision 4 MN/CDMQx.IOM Arguments for Command or Response to Query 9 bytes Description of Arguments Command or Query RX Data Rate, in kbps, between 32 kbps and 20 Mbps Resolution = 1 bps. (See Chapter 5 for valid rates) Query ONLY if Interface Type is Quad Drop & Insert (ITF=D). RX Spectrum Invert RSI= 1 byte, value of 0, 1 Example: RDR=02047.
CDM-Qx Satellite Modem Remote Control Parameter Type RX Demod Acquisition Sweep Width Command (Instruction Code and qualifier) RSW= Revision 4 MN/CDMQx.IOM Arguments for Command or Response to Query 3 bytes Description of Arguments Command or Query RX acquisition sweep range of demodulator, in kHz, ranging from 1 to 32 kHz .
CDM-Qx Satellite Modem Remote Control Parameter Type Eb/No Alarm Point Command (Instruction Code and qualifier) EBA= Revision 4 MN/CDMQx.IOM Arguments for Command or Response to Query 4 bytes Description of Arguments Command or Query Eb/No alarm point in dB, with a range between 0.1 and 16 dB. Resolution = 0.1 dB Example: EBA=12.3 C.5.
CDM-Qx Satellite Modem Remote Control Parameter Type Card Interface Type Framing Mode (Modem only) Revision 4 MN/CDMQx.IOM Command (Instruction Code and qualifier) ITF= Arguments for Command or Response to Query 1 byte FRM= 1 byte, value of 0, 1, 2 Description of Arguments Command or Query. Terrestrial interface type, where: 0=RS422/EIA530 DCE (Command or Query) 1=V.35 DCE (Command or Query) 2=RS232 (SYNC) (Command or Query) 3=G.703 TI Bal AMI (Command or Query) 4=G.
CDM-Qx Satellite Modem Remote Control Parameter Type EDMAC Slave Address Range (Modem only) Command (Instruction Code and qualifier) ESA= Revision 4 MN/CDMQx.IOM Arguments for Command or Response to Query 4 bytes Description of Arguments Command or Query EDMAC Slave Address Range – sets the range of addresses of distant-end units (modems or transceivers), which this unit, as the Master, will forward, messages for.
CDM-Qx Satellite Modem Remote Control Parameter Type Test Mode (Modem or Tx only) Command (Instruction Code and qualifier) TST= Revision 4 MN/CDMQx.
CDM-Qx Satellite Modem Remote Control Parameter Type AUPC Enabled (Modem only) Command (Instruction Code and qualifier) AUP= Revision 4 MN/CDMQx.
CDM-Qx Satellite Modem Remote Control Parameter Type T1 Line Build-Out Command (Instruction Code and qualifier) LBO= Revision 4 MN/CDMQx.IOM Arguments for Command or Response to Query 1 byte, value of 0 though 4 Description of Arguments Command or Query.
CDM-Qx Satellite Modem Remote Control Parameter Type HSSI handshake control (valid only for HSSI interface) Circuit ID String Revision 4 MN/CDMQx.IOM Command (Instruction Code and qualifier) HHC= Arguments for Command or Response to Query 1 byte, value of 0,1 CID= 28 bytes Description of Arguments Command or Query. Defines how TA/CA control the HSSI interface. 0 = TA to CA loop (default) 1 = RR control CA, TA control Tx output.
CDM-Qx Satellite Modem Remote Control Parameter Type Quad Drop & Insert (applies to cards grouped as modem) Command (Instruction Code and qualifier) QDI= Revision 4 MN/CDMQx.IOM Arguments for Command or Response to Query 77 bytes Description of Arguments Quad Drop & Insert Commands (E1 CCS Only) Command or query. QDI=pccdddddddddddddddddddddddddddddddtCCiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiTLMrrr rrr p = Port number 1 thru 4 cc = Number of Drop Channels, 0-31.
CDM-Qx Satellite Modem Remote Control Parameter Type Configuration Save Revision 4 MN/CDMQx.
CDM-Qx Satellite Modem Remote Control Parameter Type RTC Time Command (Instruction Code and qualifier) TIM= Revision 4 MN/CDMQx.
CDM-Qx Satellite Modem Remote Control Parameter Type Internal Redundancy Mode Command (Instruction Code and qualifier) IRM= Revision 4 MN/CDMQx.
CDM-Qx Satellite Modem Remote Control Parameter Type Forced Back-up in redundancy Online status for Internal Redundancy Command (Instruction Code and qualifier) Revision 4 MN/CDMQx.IOM Arguments for Command or Response to Query FBU= 1 byte N/A 4 bytes Carrier-inCarrier (CnC) Mode CNM= 1 byte, value of 0,1,2 Carrier-inCarrier (CnC) Frequency Offset CCF= 9 bytes Description of arguments Command or Query Valid only if redundancy is enabled (see IRM command).
CDM-Qx Satellite Modem Remote Control Parameter Type Command (Instruction Code and qualifier) Revision 4 MN/CDMQx.IOM Arguments for Command or Response to Query Carrier-inCarrier (CnC) Min/Max Search Delay CSD= 7 bytes CnC ReAcquisition Time CRA= 3 bytes Description of arguments Command or Query CnC min/max delay value in milliseconds. Maximum allowable value is 330ms. Syntax: CSD=xxx,yyy Where: xxx=min, yyy-max Example: 010,325 Command or Query CnC re-Acquisition time in seconds.
CDM-Qx Satellite Modem Remote Control C.5.4 Parameter Type Equipment ID Revision 4 MN/CDMQx.
CDM-Qx Satellite Modem Remote Control Parameter Type Unit ID Command (Instruction Code and qualifier) N/A Revision 4 MN/CDMQx.IOM Arguments for Command or Response to Query 7 bytes Description of Arguments Query only Unit returns information concerning the base unit identification and the option field in the form: abcdefg a=Redundancy option: 0=None, 1=1:1 mode, 2=1:2 mode, 3=1:3 mode. Note: if a=3, capable of supporting also1:2 and 1:1. If a=2, capable of supporting 1:1 as well.
CDM-Qx Satellite Modem Remote Control Parameter Type Faults and Status Command (Instruction Code and qualifier) N/A Revision 4 MN/CDMQx.
CDM-Qx Satellite Modem Remote Control Parameter Type Unit Type Revision 4 MN/CDMQx.IOM Command (Instruction Code and qualifier) Arguments for Command or Response to Query N/A 11 bytes Description of Arguments Query only. Syntax: Who=aw,bx,cy,dz Type of plug-in: Where: Response to Command (Target to Controller) N/A Query (Instruction Code and Qualifier) Response to query (Target to Controller) WHO? WHO=aw,bx,cy,dz (see description of arguments) N/A REB? REB=xx.
CDM-Qx Satellite Modem Remote Control Parameter Type Number of Unread Stored Events Revision 4 MN/CDMQx.IOM Command (Instruction Code and qualifier) Arguments for Command or Response to Query N/A 3 bytes Description of Arguments Query only Unit returns the number of stored Events, which remain Unread, in the form of xxx.
CDM-Qx Satellite Modem Remote Control Parameter Type Number of Unread stored Statistics (Modem Only) Retrieved next 5 unread Stored Statistics (Modem Only) RX Eb/No Command (Instruction Code and qualifier) Revision 4 MN/CDMQx.IOM Arguments for Command or Response to Query Description of Arguments Response to Command (Target to Controller) N/A N/A 3 bytes Query only Unit returns the number of stored Statistics, which remain Unread, in the form xxx.
CDM-Qx Satellite Modem Remote Control Parameter Type Command (Instruction Code and qualifier) RX Signal Level N/A Revision 4 MN/CDMQx.
CDM-Qx Satellite Modem Remote Control Parameter Type CnC Freq Offset Monitor Command (Instruction Code and qualifier) N/A Revision 4 MN/CDMQx.IOM Arguments for Command or Response to Query 6 bytes Software Revision N/A 34-37 bytes Software Information N/A variable Description of Arguments Query only When CnC is enabled, an estimated frequency offset between desired and interferer will be calculated. Unit is in kilohertz ( kHz). Example 1: CFM=+001.0 (1 kHz) Example 2: CFM=9999.
CDM-Qx Satellite Modem Remote Control Revision 4 MN/CDMQx.IOM Parameter Type Command (Instruction Code and qualifier) Arguments for Command or Response to Query Software Image IMG= 1 byte, value of 1 or 2 Command or Query. Current active software image, where: 1=Bulk Image #1 currently active 2=Bulk Image #2 currently active Serial Number of Modulator or Demodulator N/A 9 bytes Query only Used to query the modulator or demodulator card 9-digit serial number.
CDM-Qx Satellite Modem Remote Control Parameter Type Temperature of the Base Unit Command (Instruction Code and qualifier) N/A Revision 4 MN/CDMQx.
CDM-Qx Satellite Modem Remote Control C.5.5 Revision 4 MN/CDMQx.IOM Bulk Commands Parameter Type Command (Instruction Code and qualifier) Global Configuration MGC= Argument s for Command or Response to Query 138 bytes, with numerical entries, fixed values and delimiters Description of arguments Command or Query Global Configuration of CDM-QX on a card slot basis if not grouped as a modem or on a modem basis if grouped.
CDM-Qx Satellite Modem Remote Control Parameter Type OGC Outdoor Unit Global Configuration (L-Band Unit only) Command (Instruction Code and qualifier) OGC= Arguments for Command or Response to Query 50 bytes Revision 4 MN/CDMQx.
CDM-Qx Satellite Modem Remote Control C.5.6 Parameter Type BUC Address (L-Band Unit only) Revision 4 MN/CDMQx.IOM BUC Commands Command (Instruction Code and qualifier) BAD= Arguments for Command or Response to Query 2 bytes, value of 01 to 15 Description of arguments Command or Query Indicates the Block Up Converter (BUC) Address, in the form: xx, where xx is between 01 and 15 Example: BAD=03 Note: This command is only valid when the FSK and BUC power are enabled.
CDM-Qx Satellite Modem Remote Control Parameter Type BUC Output Enable (L-Band Unit only) Command (Instruction Code and qualifier) BOE= Arguments for Command or Response to Query 1 byte, value of 0,1 Revision 4 MN/CDMQx.
CDM-Qx Satellite Modem Remote Control Parameter Type BUC Temperature (L-Band Unit only) Command (Instruction Code and qualifier) N/A Arguments for Command or Response to Query 4 bytes Revision 4 MN/CDMQx.
CDM-Qx Satellite Modem Remote Control Parameter Type Command (Instruction Code and qualifier) BUC Voltage (L-Band Unit only) N/A Arguments for Command or Response to Query 4 bytes Revision 4 MN/CDMQx.IOM Description of arguments Query only Indicates the value of the BUC voltage, in the form: xx.x Where: xx.x is between 0 and 64.0 If not available, response is 00.
CDM-Qx Satellite Modem Remote Control Revision 4 MN/CDMQx.IOM LNB Low Current Limit (L-Band Unit only) LCL= Arguments for Command or Response to Query 3 bytes LNB High Current Limit (L-Band Unit only) LCH= 3 bytes Command or Query LNB higher alarm limit for current, in the form of xxx, where xxx is the current value between 50 and 600 mA.
CDM-Qx Satellite Modem Remote Control C.5.8 Parameter Type Revision 4 MN/CDMQx.
CDM-Qx Satellite Modem Remote Control Parameter Type BERT Config Sync Loss Threshold (applies to Rx card) BERT Result in bit errors (applies to Rx card) BERT Result in average BER Command (Instruction Code and Qualifier) BCT= Arguments for Command or Response to Query 1 byte, value of 0 to 3 N/A 7 bytes, numeric N/A 5 bytes Revision 4 MN/CDMQx.
CDM-Qx Satellite Modem Remote Control C.5.9 Spectrum Analyzer Commands Spectrum Analyzer Mode (applies to Rx card) SPM= Arguments for Command or Response to Query 1 byte Spectrum Analyzer Center Frequency (applies to Rx card) SPF= 9 bytes Parameter Type Revision 4 MN/CDMQx.
CDM-Qx Satellite Modem Remote Control C.5.10 Parameter Type Drop & Insert (applies to cards grouped as modem) Revision 4 MN/CDMQx.IOM Drop & Insert Commands (E1 CCS Only) for D&I++ Command (Instruction Code and qualifier) DNI= Arguments for Command or Response to Query 65 bytes Description of arguments Command or query.
CDM-Qx Satellite Modem Remote Control Parameter Type Drop Timeslot (applies to cards grouped as modem) Command (Instruction Code and qualifier) DTS= Arguments for Command or Response to Query 3 bytes for command, 31 bytes for query Revision 4 MN/CDMQx.IOM Description of arguments Command or query. (Note different format between command and query.
CDM-Qx Satellite Modem Remote Control Revision 4 MN/CDMQx.
Appendix D. Carrier-in-Carrier® PERFORMANCE CHARACTERIZATION D.1 Carrier-in-Carrier® Description DoubleTalk™ Carrier-in-Carrier® (CnC) is an adaptive cancellation technology that significantly reduces bandwidth occupancy by allowing two carriers to simultaneously occupy the same spectral location, a practice that is disastrous for normal carriers. By comparison, standard carriers must occupy non-overlapping spectral segments with no more than one carrier in the same space.
CDM-Qx Satellite Modem CnCPerformance Characterization Revision 5 MN/CDMQx.IOM Nominally, these effects are treated independently so it is possible to add them together to estimate the total degradation. Initially, degradation due to carrier spacing is examined to characterize the adjacent carrier performance. Next, the CnC ratio is evaluated to estimate its impact. The symbol rate ratio of CnC carriers and the allowable carrier offset are discussed followed by some CnC examples.
CDM-Qx Satellite Modem CnCPerformance Characterization Revision 5 MN/CDMQx.IOM The results are plotted for two equally spaced adjacent carriers each at -3 dB, 0 dB, +3 dB, and +6 dB relative to the desired carrier to produce a family of operating curves. Figure D-2, through Figure D-4 plot the results for the QPSK, 8-PSK and 16-QAM cases.
CDM-Qx Satellite Modem CnCPerformance Characterization Revision 5 MN/CDMQx.IOM Eb/No Degradation Versus Carrier Spacing QPSK 3/4 Turbo α = 20% Eb/No Degradation Versus Carrier Spacing QPSK 3/4 Turbo, α = 35% 0 -0.5 Eb/No Degradation -1 -3 dB -1.5 0 dB -2 3 dB 6 dB -2.5 For Two Equally Space Carriers Each With Level Relative To Desired -3 -3.5 -4 0.70 0.90 1.10 Eb/No Degradation 0 -0.5 -1 -3 dB -1.5 0 dB -2 3 dB 6 dB -2.
CDM-Qx Satellite Modem CnCPerformance Characterization Revision 5 MN/CDMQx.IOM Other QPSK turbo code rates have similar performance and the QPSK plots above are used to estimate their performance. The degradation plots above are also used for other turbo 8-PSK and 16-QAM code rates. A good practice for carrier spacing is to operate the links with sufficient spacing so there is no degradation. D.
CDM-Qx Satellite Modem CnCPerformance Characterization Revision 5 MN/CDMQx.IOM Case D shows two desired CnC carriers accompanied by a CnC carrier on each side. Again, it does not matter whether the adjacent carriers are CnC or conventional carriers, just the total power. This situation is equivalent to adjacent carriers each 6 dB greater than the one desired CnC carrier.
CDM-Qx Satellite Modem CnCPerformance Characterization Revision 5 MN/CDMQx.IOM The following CDM-Qx configurations were tested for Eb/No degradation as a function of CnC ratio: Modulation Forward Error Correction 21/44 Turbo 3/4 Turbo 7/8 Turbo 17/18 Turbo 2/3 TCM 3/4 Turbo 7/8 Turbo 17/18 Turbo 3/4 Turbo 7/8 Turbo QPSK QPSK QPSK QPSK 8-PSK 8-PSK 8-PSK 8-PSK 16-QAM 16-QAM Reference Eb/No At BER ≈ 10-6 2.6 dB 3.7 dB 4.3 dB 6.5 dB 5.3 dB 6.1 dB 7.1 dB 9.0 dB 7.2 dB 8.1 dB C/N 2.4 dB 5.5 dB 6.7 dB 9.
CDM-Qx Satellite Modem CnCPerformance Characterization Revision 5 MN/CDMQx.IOM Eb/No Degradation (vs) CnC Ratio (16-QAM) 0.0 Eb/No Degradation (dB) -0.2 -0.4 -0.6 -0.8 -1.0 -1.2 -1.4 16-QAM 3/4 Turbo -1.6 16-QAM 7/8 Turbo -1.8 -2.0 -10 -5 0 5 10 CnC Ratio (dB) Figure D-8. CnC Ratio For 16-QAM D.5 Symbol Rate Ratio CnC operation is restricted to a maximum symbol rate ratio ≤3. This is the ratio of the larger carrier to the smaller one.
CDM-Qx Satellite Modem CnCPerformance Characterization Revision 5 MN/CDMQx.IOM Referring back to Error! Reference source not found., the degradation due to adjacent carrier spacing is negligible when spacing is 1.3 x Symbol Rate and 0 db is allocated for adjacent carrier degradation. Desired Carrier(s) Carrier Spacing Figure D-9. CnC Example Initially the CnC ratio is 0 dB, and the desired and interfering carriers are operating at the same power level.
CDM-Qx Satellite Modem CnCPerformance Characterization Revision 5 MN/CDMQx.IOM Notice from the table, the CnC change is proportional to the uplink fade. The CnC ratio decreases by the amount of the uplink fade at the near end while the CnC ratio increases by the amount of uplink fade at the distant end. Also, the CnC ratio at opposite ends of the link has the same magnitude but opposite sine. Uplink Fade -6 dB Rain Rain Fade Fade Downlink Fade -4 dB -6 dB 0 dB Site A Site B Figure D-10.
CDM-Qx Satellite Modem CnCPerformance Characterization D.8 Revision 5 MN/CDMQx.IOM 2nd CnC Example: CnC Ratio With Asymmetric Links Networks with asymmetric antennas are common with a larger antenna at one site (hub) and smaller ones at the other sites (remotes) and often have asymmetric data rates. In a number of links even a significant rain fade is not a big factor in CnC performance.
CDM-Qx Satellite Modem CnCPerformance Characterization Revision 5 MN/CDMQx.IOM The link parameters and results are summarized in the table: Parameters Satellite EIRP (dBW) Satellite BOo (dB) Satellite BOi (dB) Satellite SFD (dbW/m2) Satellite G/T (dB/K) Site A 37 6 10 -78 0 Site B 37 6 10 -78 0 4.5 192 1.3 2.4 192 1.3 Conventional Link Occupied BW1 for 2 Carriers (kHz) % of Transponder Power 8PSK 2/3 TCM 274.6 0.55 8PSK 2/3 TCM 274.6 0.
CDM-Qx Satellite Modem CnCPerformance Characterization D.9 Revision 5 MN/CDMQx.IOM 3rd CnC Example: Asymmetric Link With Rain Fade A reasonable question to ask about the previous example is the impact rain fade has on the link. This example combines parts of the previous two examples using the same symbol rates and asymmetric antennas and adds in fade at Site A, with the larger antenna and examines the CnC ratio at both sites. The impact on both sites is also estimated due to a fade at Site B.
CDM-Qx Satellite Modem CnCPerformance Characterization Revision 5 MN/CDMQx.IOM Eb/No Degradation At Site B Due To Fade At Due To Fade At Parameter B (dB) A (dB) CnC Ratio @ Site B -5.3 -5.3 Uplink Fade @ Site B 3 Uplink Fade @ Site A 6 Faded CnC @ Site B -8.3 +0.7 Eb/No Degradation (dB) @ Site B 0.0 -0.1 Per Figure D- QPSK D.10 Conclusion There are several conclusions for operation with CnC: • • • • • • • Operate adjacent carriers with sufficient spacing so there is no degradation.
Metric Conversions Units of Length Unit Centimeter Inch Foot Yard Mile Meter Kilometer Millimeter 1 centimeter — 0.3937 0.03281 0.01094 6.214 x 10-6 0.01 — — 1 inch 2.540 — 0.08333 0.2778 1.578 x 10-5 0.254 — 25.4 1 foot 30.480 12.0 — 0.3333 1.893 x 10-4 0.3048 — — 1 yard 91.44 36.0 3.0 — 5.679 x 10-4 0.9144 — — 1 meter 100.0 39.37 3.281 1.094 6.214 x 10-4 — — — 1 mile 1.609 x 105 6.336 x 104 5.280 x 103 1.760 x 103 — 1.609 x 103 1.
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