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SDM-100A

Satellite Modem

Installation and Operation Manual

Part Number MN/SDM100A.IOM

Revision 0

Summary of content (212 pages)

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SDM-100A Satellite Modem Installation and Operation Manual Part Number MN/SDM100A.
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EFData Corporation is an ISO 9001 Registered Company SDM-100A Satellite Modem Installation and Operation Manual Part Number MN/SDM100A.IOM Revision 0 November 27, 1996 Special Instructions: This is the first edition of the manual. Copyright © EFData Corporation, 1996. All rights reserved. Printed in the USA. EFData Corporation, 2105 West 5th Place, Tempe, Arizona 85281 USA, (602) 968-0447, FAX: (602) 921-9012.
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Warranty Policy This EFData Corporation product is warranted against defects in material and workmanship for a period of one year from the date of shipment. During the warranty period, EFData will, at its option, repair or replace products that prove to be defective. For equipment under warranty, the customer is responsible for freight to EFData and all related custom, taxes, tariffs, insurance, etc.
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Preface About this Manual This manual provides installation and operation information for the EFData SDM-100A satellite modem. This is a technical document intended for earth station engineers, technicians, and operators responsible for the operation and maintenance of the SDM-100A. Conventions and References Used in this Manual Cautions and Warnings CAUTION CAUTION indicates a hazardous situation that, if not avoided, may result in minor or moderate injury.
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Preface SDM-100A Satellite Modem Military Standards References to “MIL-STD-188” apply to the 114A series (i.e., MIL-STD-188-114A), which provides electrical and functional characteristics of the unbalanced and balanced voltage digital interface circuits applicable to both long haul and tactical communications. Specifically, these references apply to the MIL-STD-188-114A electrical characteristics for a balanced voltage digital interface circuit, Type 1 generator, for the full range of data rates.
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SDM-100A Satellite Modem Preface European EMC Directive In order to meet the European Electro-Magnetic Compatibility (EMC) Directive (EN55022, EN50082-1), properly shielded cables for DATA I/O are required. More specifically, these cables must be double-shielded from end-to-end, ensuring a continuous ground shield. The following information is applicable for the European Low Voltage Directive (EN60950): ! Type of power cord required for use in the European Community.
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Preface SDM-100A Satellite Modem Customer Support Contact the EFData Customer Support Department for: • • • • • Product support Information on returning a product Information on upgrading a product Product training Reporting comments or suggestions concerning manuals An EFData Customer Support representative may be reached at: EFData Corporation Attention: Customer Support Department 2105 West 5th Place Tempe, Arizona 85281 USA (602) 968-0447 (Main EFData Number) (602) 517-2444 (Customer Support Desk) (
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Table of Contents CHAPTER 1. INTRODUCTION.................................................................................. 1–1 1.1 Purpose and Function ..................................................................................................................................1–2 1.2 Description ....................................................................................................................................................1–3 1.3 Options ............................................
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Table of Contents SDM-100A Satellite Modem CHAPTER 3. OPERATION........................................................................................ 3–1 3.1 Front Panel ...................................................................................................................................................3–1 3.1.1 Front Panel Keypad Option ....................................................................................................................3–2 3.1.2 LED Indicators...............
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SDM-100A Satellite Modem Table of Contents CHAPTER 4. THEORY OF OPERATION.................................................................. 4–1 4.1 Modulator .....................................................................................................................................................4–1 4.1.1 Theory of Operation ...............................................................................................................................4–1 4.1.2 Specifications......................
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Table of Contents SDM-100A Satellite Modem A.2.2 Device Address ..................................................................................................................................... A–2 A.2.3 Command/Response ............................................................................................................................. A–3 A.2.4 End Character .......................................................................................................................................
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SDM-100A Satellite Modem Table of Contents B.2.2.2 Modulator Configuration ............................................................................................................. B–16 B.2.2.3 Demodulator Configuration......................................................................................................... B–16 B.2.2.4 Utility/Interface............................................................................................................................ B–17 B.2.2.
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Table of Contents SDM-100A Satellite Modem Figures Figure 1-1. SDM-100A....................................................................................................................................1–1 Figure 1-2. SDM-100A Block Diagram ..........................................................................................................1–2 Figure 1-3. Dimensional Drawing ...................................................................................................................
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SDM-100A Satellite Modem Figure 5-4. Figure B-1. Figure B-2. Figure B-3. Figure B-4. Figure B-5. Figure B-6. Figure B-7. Table of Contents Fault Tree ......................................................................................................................................5–8 ASYNC/AUPC Block Diagram .................................................................................................. B–2 System Interface Diagram ....................................................................
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Chapter 1. INTRODUCTION This chapter provides the description, options, and specifications for the SDM-100A satellite modem, referred to in this manual as “the modem” (Figure 1-1). Figure 1-1. SDM-100A Rev.
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Introduction SDM-100A Satellite Modem 1.1 Purpose and Function The modem is ideally suited for networks implemented with digitized voice compressors. These types of circuits require the minimum processing delay provided by the modem’s Viterbi decoder. A system block diagram is shown in Figure 1-2. The modem is also employed in transportable applications, where small size and low power consumption are important. ADPCM RS-232, RS-422, V.
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SDM-100A Satellite Modem Introduction The modem interfaces with IF converter equipment operating in a 50 to 180 MHz band. The data interface options consist of RS-449/422, V.35, RS-232-C, ASYNC, and Adaptive Differential Pulse Code Modulation (ADPCM) voice. Changes in connectors for the various interfaces are accomplished by small, field-changeable connector modules. Recent advances in Digital Signal Processing (DSP) have been incorporated into the modem’s design.
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Introduction SDM-100A Satellite Modem Figure 1-3. Dimensional Drawing 1.3 Options For more information on the following options, refer to Appendix B. 1.3.1 ASYNC/AUPC Interface The ASYNC interface board provides the interface for terrestrial data and a single ASYNC overhead channel, along with an AUPC feature. 1.3.2 ADPCM Voice The ADPCM voice interface is capable of providing a single, duplex voice channel and Ear and Mouth (E&M) signaling data transmission. 1–4 Rev.
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SDM-100A Satellite Modem Introduction 1.4 Modem Specifications Table 1-1 lists the operating specifications of the modem. Table 1-1. SDM-100A Specifications Modem Specifications 50 to 180 MHz, synthesized in 2.5 kHz steps. Quadrature Phase Shift Keying (QPSK), or Bi-Phase Shift Keying (BPSK). Operating Channel Spacing Less than 0.5 dB degradation operating with 2 adjacent-like channels, each 10 dB higher at 1.3 times the symbol rate, or a minimum of 1.2 times the specified acquisition range.
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Introduction SDM-100A Satellite Modem Additional Modulator Specifications Output Power -5 to -30 dBm, adjustable in 0.1 dB steps. Output Spurious and Harmonics -55 dBc in 4 kHz BW in-band (50 to 180 MHz). -55 dBc in 4 kHz BW out-of-band (0 to 500 MHz). Output Impedance 75Ω standard, or 50Ω optional. Output Return Loss 20 dB. Output Frequency Stability ± 10 PPM. Data Clock Source Internal or external. External clock, ± 100 PPM and < 5% jitter. Internal Data Clock Stability ± 10 PPM.
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SDM-100A Satellite Modem Introduction 1.5 BER Performance The bit energy-to-noise ratio (Eb/N0) required to achieve 10-5 to 10-7 bit error rates is listed in Table 1-2. Table 1-2. BER Performance Specification BER 10-5 10-7 Viterbi K = 7 1/2 Rate 3/4 Rate 5.5 dB 6.8 dB 6.7 dB 8.3 dB 7/8 Rate 8.1 dB 9.4 dB The Bit Error Rate (BER) performance of the modem with a Viterbi decoder is shown in Figure 1-4. The BER performance of the modem with a sequential decoder is shown in Figure 1-5.
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Introduction SDM-100A Satellite Modem 10-2 10-3 10-4 10-5 10-6 BER 10-7 10-8 1/2 RATE 3/4 RATE 7/8 RATE 10-9 10-10 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0 Eb/N0 (dB) Figure 1-4. Viterbi Bit Error Rate Performance 1–8 Rev.
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SDM-100A Satellite Modem Introduction 10-2 10-3 10-4 10-5 10-6 BER 10-7 10-8 1/2 RATE 3/4 RATE 7/8 RATE 10-9 10-10 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0 Eb/N0 (dB) Figure 1-5. Sequential Bit Error Rate Performance Rev.
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Introduction SDM-100A Satellite Modem RL -10.00 dBm *ATTEN 0 dB 10.00 dB/DIV SDM 100 64 kbit/s, 1/2 RATE QPSK VITERBI TYPICAL SDM-100A OUTPUT SPECTRUM CENTER 70.000 0 MHz 1 00 k 30 0 SPAN 500.0 kHz ST 50 00 Figure 1-6. Typical Output Spectrum 1–10 Rev.
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Chapter 2. INSTALLATION This chapter provides unpacking instructions, system requirements, and external connections for the modem. 2.1 Unpacking The modem and manual are packaged in pre-formed, reusable cardboard cartons that contain foam spacing for maximum shipping protection. The circuit cards are contained in the modem chassis. To remove the modem: Do not use any cutting tool that will extend more than 1” into the container and cause damage to the modem. CAUTION 1.
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Installation SDM-100A Satellite Modem 6. Check the equipment against the packing list shipped with the equipment to ensure that the shipment is complete. 7. Refer to Section 2.2 for further system installation instructions. 2.2 System Installation Install the modem as follows: 1. Mount the modem chassis in the assigned position in the equipment rack. Refer to Figure 2-1 for an illustration of a typical rack elevation for an M:N system. 2. Connect the cables to the appropriate locations on the rear panel.
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SDM-100A Satellite Modem Installation 2.3 System Requirements The standard modem with all the cards installed is a full-duplex QPSK satellite modem. The system can also be configured for TX-only or RX-only. • For a TX-only system, enter the UTILITY SYSTEM menu under FUNCTION SELECT UTILITY on the front panel. Select OPERATION MODE. Enter the menu and select Transmit Only. This will mask all receive faults and receive stored faults in the Faults menu.
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Installation SDM-100A Satellite Modem $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ Figure 2-1. Typical Rack Elevation 2–4 Rev.
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SDM-100A Satellite Modem Installation 2.4 External Connections Connections between the modem and other equipment are made through five connectors. These connectors are listed in Table 2-1, and their locations are shown in Figure 2-2. The use of each connector is described in the following paragraphs. Table 2-1.
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Installation SDM-100A Satellite Modem 2.4.1 DATA I/O Interface (J8) The DATA I/O interface connector is used to interface data input and output signals to and from the modem. The DATA I/O connects to the customer terrestrial equipment directly or through a protection switch. The DATA I/O interface can be MIL-STD-188, RS-422/449, V.35, or RS-232-C. The interface module of the modem is mounted directly on the modulator board. The modem operates with a single interface configuration.
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SDM-100A Satellite Modem Installation 2.4.3 Faults (J7) The Fault connector on the modem is used to interface FORM-C contact closures for the purpose of fault reporting. There are three FORM-C summary fault contacts: • • • Modulator Demodulator Common equipment For further discussion on the monitored faults, refer to Chapter 3. To obtain a system summary fault, connect all FORM-C contacts in parallel. The fault interface is provided on a 9-pin female D connector.
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Installation SDM-100A Satellite Modem 2.4.5 RX IF Input (CP2) This is the receive IF connector. The input impedance is 75Ω (50Ω optional). For normal operation, the desired carrier signal level should be between -30 and -55 dBm. Signals between 50 and 180 MHz are selected and demodulated to produce clock and data at the DATA I/O connector. 2.4.6 AC Power The AC power is supplied to the modem by a standard detachable, non-locking, 3-prong power cord. Normal input voltage is 90 to 264 VAC, 47 to 63 Hz.
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Chapter 3. OPERATION This chapter describes the front panel operation and clocking configurations of the modem. For remote control operation information, refer to Appendix A. 3.1 Front Panel The front panel of the modem (Figure 3-1) provides the local user interface, which is necessary to configure and monitor status of the modem. Figure 3-1.
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Operation SDM-100A Satellite Modem 3.1.1 Front Panel Keypad Option This feature is a future option which will allow the user to plug in a hand-held keypad, and will allow access to all programming capabilities. 3.1.2 LED Indicators General modem status and summary faults are indicated by 10 LEDs on the front panel.
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SDM-100A Satellite Modem Operation 3.1.3 Front Panel Controls The modem is locally operated by using the front panel keypad (Figure 3-1), which consists of the following keys: [ENTER] [CLEAR] [←] and [→] [↑] and [↓] This key is used to select a displayed function, or to execute a change to the modem’s configuration. This key is used to back out of a selection, or to cancel a configuration change which has not been executed using [ENTER].
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Operation SDM-100A Satellite Modem 3.2 Menu System In order to access and execute all functions, refer to the menus in Figures 3-2 through 3-25. Use the main menu in Figure 3-2 as a quick reference for accessing all modem functions. For further configuration details, refer to Section 3.3. The base level of this structure is the sign-on message, which is displayed on the front panel upon modem power up.
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SDM-100A Satellite Modem Operation 3.2.1 Standard SDM-100 Menus SDM-100 "TYPE" VER: 14.7.
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SDM-100A Satellite Modem Operation 3.2.1.1 Configuration Modem configuration may be viewed or changed by entering the “CONFIGURATION” level from the “FUNCTION SELECT” menu on the front panel. After entering the “CONFIGURATION” menu, press [←] or [→] to select “MODULATOR,” “DEMODULATOR,” “INTERFACE,” or “LOCAL AUPC” (if that option is installed). Enter the selected configuration menu by pressing [ENTER]. Press [←] or [→] to view the selected configuration parameters.
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Operation SDM-100A Satellite Modem SDM-100 "TYPE" VER: 14.7.4 FUNCTION SELECT CONFIGURATION TX-X CODE_RATE/ TYPE x = A, B, C, D, or V CONFIGURATION MODULATOR TX-IF FREQUENCY TX-IF OUTPUT TX POWER LEVEL (Fixed or Adj.) 50 to 180 MHz in 2.5 kHz steps. OFF ON -5 to -30 dBm in 0.1dBm steps. TX-A QPSK 1/2 64.000 kbit/s TX-B QPSK 1/2 96.000 kbit/s TX-C QPSK 1/2 128.000 kbit/s TX-D QPSK 1/2 38.400 kbit/s TX-V QPSK 1/2 19.200 kbit/s SCRAMBLER ON OFF DIFF.
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SDM-100A Satellite Modem Operation 3.2.1.1.1 Configuration Modulator TX-X Code_Rate/Type Transmitter Rate selection. One of four predefined transmitter code/data rate combinations may be selected: A, B, C, or D, or a variable rate selection (V). These selections must first be set up in the Utility menu. On entry, the current transmitter rate is displayed with the flashing cursor on the first character of the code rate on line 1. The data rate is displayed on line 2.
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Operation SDM-100A Satellite Modem TX Power Level Programs the modulator output power level from -5 to -30 dBm, in 0.1 dBm steps. The high power option operates from + 5 to -20 dBm. On entry, the current transmitter power level is displayed with the flashing cursor on the first character. Press [↑] or [↓] to increase or decrease the output power level in 0.1 dB steps. Press [ENTER] to execute the change.
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Operation SDM-100A Satellite Modem SDM-100 "TYPE" VER: 14.7.4 FUNCTION SELECT CONFIGURATION RX-X CODE_RATE/ TYPE x = A, B, C, D, or V CONFIGURATION DEMODULATOR RX-IF FREQUENCY DESCRAMBLER 50 to 180 MHz In 2.5 kHz steps. ON OFF TX-A QPSK 1/2 64.000 kbit/s TX-B QPSK 1/2 96.000 kbit/s TX-C QPSK 1/2 128.000 kbit/s TX-D QPSK 1/2 38.400 kbit/s TX-V QPSK 1/2 19.200 kbit/s DIFF. DECODER ON OFF RF LOOP BACK IF LOOP BACK BER THRESHOLD SWEEP CENTER OFF ON OFF ON 1.0 E-3 to 1.
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SDM-100A Satellite Modem Operation 3.2.1.1.2 Configuration Demodulator RX-X Code_Rate/Type Receiver rate selection. One of four predefined receiver decoder/data rate combinations (A, B, C, or D) or a variable rate selection (V) may be selected. These selections must first be set up in the Utility menu. On entry, the current receiver rate is displayed with the flashing cursor on the first character of the code rate on line 1. The data rate is displayed on line 2.
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Operation SDM-100A Satellite Modem IF Loop Back Programs the modem for IF loopback operation (test mode). When IF loopback is turned on, the demodulator input is connected to the modulator output through an internal attenuator, and the demodulator is programmed to the same frequency as the modulator. An attenuator within the modem connects the IF out to the IF in. When IF loopback is turned off, the demodulator is tuned to its previous frequency, and is reconnected to the IF input.
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Operation SDM-100A Satellite Modem SDM-100 "TYPE" VER: 14.7.4 FUNCTION SELECT CONFIGURATION TX CLOCK SOURCE TX TERRESTRIAL RX (SATELLITE) SCT (INTERNAL) B-BAND LOOP BACK OFF ON CONFIGURATION INTERFACE TX CLOCK PHASE AUTO NORMAL INVERT BUFFER SIZE BUFFER CLOCK RX CLOCK PHASE RX (SATELLITE) SCT (INTERNAL) EXT. REFERENCE TX TERRESTRIAL NORMAL INVERT BUFFER CENTER LOOP TIMING YES/NO ON OFF (ASYNC only) 64 to 65536 Bits in 16-bit steps or Bypass = 0 bits.
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SDM-100A Satellite Modem B Operation ASYNC TX STOP ADPCM INTF CIRCUIT TYPE 1 or 2 bits (ASYNC only) ON/OFF (ADPCM only) TRUNK SUBSCRIBER (ADPCM only) EM CIRCUIT ENCODING TYPE ON HOOK/ OFF HOOK 1, 2, 3, or 4 (ADPCM only) A-LAW µ-LAW (ADPCM only) ON HOOK OFF FOOK (ADPCM only) TX CHANNEL LEVEL= X RX CHANNEL LEVEL= X -20 to +10 in 1 dBm steps (ADPCM only) -20 to +10 in 1 dBm steps (ADPCM only) Key: ACCESS TO SUBMENU CONDITIONAL OR OPTION-DEPENDENT Parameter Information Figure 3-5.
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Operation SDM-100A Satellite Modem 3.2.1.1.3 Configuration Interface TX Clock Source Programs the clock source for the modem transmitter clock. “TX Terrestrial” sets the TX clock to recover timing from the incoming clock/data. “RX (Satellite)” sets the TX clock to operate from the satellite clock. “SCT (Internal)” sets the TX clock to operate from the modem internal clock. This is also the fallback clock. TX Clock Phase On entry, the current transmit clock setting is displayed.
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SDM-100A Satellite Modem B-Band Loop Back Operation Programs the modem for baseband loopback operation (test mode). When baseband loopback is turned on, the data and timing signals are hard-wired (via relays) from the demodulator to the modulator on the modem side of the interface. The Data Terminal Equipment (DTE) baseband signals are also looped back from the transmitter data and clock to the receiver data and clock on the customer side of the interface.
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Operation SDM-100A Satellite Modem ADPCM Intf Circuit Type E&M Circuit Encoding Type On Hook/Off Hook TX Channel Level RX Channel Level 3–20 ADPCM interface ON/OFF selection. If ADPCM is set ON, the ADPCM operation is selected. If ADPCM is set OFF, then the standard RS-422 interface option is selected. Available only with the ADPCM option installed. This refers to the emulation mode of the modem ADPCM interface.
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Operation SDM-100A Satellite Modem SDM-100 "TYPE" VER: 14.7.4 FUNCTION SELECT CONFIGURATION CONFIGURATION LOCAL AUPC (AUPC only) AUPC ENABLE NOMINAL POWER MINIMUM POWER MAXIMUM POWER ON/OFF -30 to -5 dBm -30 to -5 dBm -30 to -5 dBm TARGET NOISE TRACKING RATE 3.2 to 9.7 dB in 0.1 dB increments 0.5 to 6.
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SDM-100A Satellite Modem Operation 3.2.1.1.4 Configuration Local AUPC AUPC Enable This option turns the local modem’s AUPC ON or OFF. Nominal Power This option programs the nominal power set point for AUPC from -30 to -5 dBm. This option programs the minimum power set point for AUPC from 30 to -5 dBm. This option programs the maximum power set point for AUPC from 30 to -5 dBm. This option programs the target Eb/N0 setpoint. The Eb/N0 setpoint can range from 3.2 to 9.7 dB, in 0.1 dB increments.
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Operation SDM-100A Satellite Modem SDM-100 "TYPE" VER: 14.7.4 FUNCTION SELECT MONITOR RAW BER CORRECTED BER CURRENT RAW BER NO DATA (if carrier not locked) CURRENT CORRECTED BER NO DATA (if carrier not locked) Low limit: based on performance. High limit: based on data/code rate. Low limit: based on performance. High limit: 1.0 E-12. SWEEP FREQUENCY RECEIVE SIGNAL EB/N0 CURRENT Eb/N0 NO DATA (if carrier not locked) Low limit: based on data rate. High limit: 16.0 dB. CURRENT RECEIVE LEVEL ( 25.
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SDM-100A Satellite Modem Operation 3.2.1.2 Monitor When the “MONITOR” level is entered, press [←] or [→] to select the desired monitor function. Each monitor function is displayed in real time as long as it is selected. Raw BER Corrected BER Eb/N0 Receive Signal Sweep Frequency Buffer Fill Raw Bit Error Rate Corrected Bit Error Rate Energy bit/Noise Ratio Receive Signal Level Sweep Monitor Range Current Buffer Fill Status Range: m.m E-e Range: m.m E-e Range: mm.
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Operation SDM-100A Satellite Modem 3.2.1.3 Faults/Alarms The “FAULTS/ALARMS” level is accessible from the “FUNCTION SELECT” menu. These are similar to monitor functions, as the current status is displayed. Press [←] or [→] to move between the Fault/Alarm groups: • • • • • Modulator faults Demodulator faults Transmit Interface faults Receive Interface faults Common Equipment faults The current Faults/Alarms status is displayed on line 2 of the display in real time.
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Operation SDM-100A Satellite Modem SDM-100 "TYPE" VER: 14.7.4 FUNCTION SELECT FAULTS/ALARMS MODULATOR DEMODULATOR IF SYNTHESIZER DATA CLOCK SYN I CHANNEL Q CHANNEL AGC LEVEL MODULE See notes. CARRIER DETECT IF SYNTHESIZER I CHANNEL Q CHANNEL DESCRAMBLER BER THRESHOLD MODULE See notes.
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SDM-100A Satellite Modem Operation 3.2.1.3.1 Modulator Faults Fault/Alarm IF Synthesizer Possible Problem and Action Modulator IF synthesizer is faulted. Data Clock Syn This is considered a major alarm and will turn off the modulator output. Return the modem for repair. Transmit data clock synthesizer fault. This fault is an indication that the internal clock VCO has not locked to the incoming data clock, or the internal clock synthesizer has not locked to the internal reference.
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Operation SDM-100A Satellite Modem 3.2.1.3.2 Demodulator Faults Fault/Alarm Carrier Detect Possible Problem and Action Carrier detect fault. Indicates the decoder is not locked. This is the most common fault displayed in the modem. Any problem from the input data on the modulator end of the circuit to the output of the decoder can cause this alarm. IF Synthesizer I Channel Q Channel First, check to see that the demodulator has an RF input at the proper frequency and power level.
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SDM-100A Satellite Modem Operation 3.2.1.3.3 TX Interface Faults Fault/Alarm TX Clock Activity TX Audio Clip Possible Problem and Action Activity detector alarm of selected interface transmit clock. Indicates the selected TX clock is not being detected. Check the signal of the selected TX clock source to verify the signal is present. The interface will fall back to the internal clock when this alarm is active. With ADPCM option on, excessive input sensed on TX+ and TX- interface lines. 3.2.1.3.
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Operation SDM-100A Satellite Modem 3.2.1.3.5 Common Equipment Faults Fault/Alarm Battery/Clock -12 Volt Supply Possible Problem and Action M&C battery voltage or clock fault. Indicates a low voltage in the memory battery. Typically will be active when a modem has been Hard Reset, or the firmware has been changed. When a Hard Reset has been executed or the firmware has been changed, this fault will typically be active when the modem is first turned on.
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Operation SDM-100A Satellite Modem SDM-100 "TYPE" VER: 14.7.
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SDM-100A Satellite Modem Operation 3.2.1.4 Stored Faults/Alarms The modem stores the first 10 (Flt0 through Flt9) occurrences of fault status changes in each of the seven major fault categories. Each fault status change is stored with the time and date of the occurrence. Stored faults may be viewed by entering the “Stored Faults” level from the “FUNCTION SELECT” menu. All stored faults may be cleared by executing the “CLEAR Stored Faults?” command from the “Stored Faults” level.
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Operation SDM-100A Satellite Modem SDM-100 "TYPE" VER: 14.7.4 FUNCTION SELECT REMOTE AUPC REMOTE AUPC STATUS: BB LOOP BACK STATUS: ON OFF ON OFF Key: ACCESS TO SUBMENU CONDITIONAL OR OPTION-DEPENDENT Parameter Information Figure 3-10. Remote AUPC (SDM-100 Operation) 3.2.1.5 Remote AUPC Remote AUPC Status: BB Loop Back Status: Programs the modem for remote AUPC. On entry, the current status is displayed. Press [↑] or [↓] to select ON or OFF. Press [ENTER] to execute the change.
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SDM-100A Satellite Modem Operation 3.2.1.6 Utility The utility functions are divided into five user categories, and provide access to the following Utility menus: • • • • • MODULATOR DEMODULATOR INTERFACE SYSTEM MODEM TYPE These menus provide a means to: • Set the time and date of the modem real time clock. • Test the front panel optical indicators. • Choose filtering types, code rates, decoder types, TX and RX fault enables, modem type, and overhead type.
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Operation SDM-100A Satellite Modem SDM-100 "TYPE" VER: 14.7.4 ASSIGN TRANSMIT FILTERS x = FILTER A, B, C, D, or V TX-A QPSK 1/2 19.200 kbit/s TX-B QPSK 1/2 38.400 kbit/s TX-C QPSK 1/2 19.200 kbit/s TX-D QPSK 1/2 38.400 kbit/s TX-V QPSK 1/2 19.200 kbit/s FUNCTION SELECT UTILITY UTILITY MODULATOR MOD POWER OFFSET MOD POWER FIXED OFFSET +0.0 dBm Fixed Status only. -99.9 to +99.9 dB, +/-nn.
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SDM-100A Satellite Modem Operation 3.2.1.6.1 Utility Modulator Assign Transmit Filters Transmit filter display/assignment utility. Used to make filter rate reassignments. The modulator has five symbol rate filter presets. Filters are designated as A, B, C, D, and V. Note: Switching between Modem types will reset the Filter presets to their factory-defined values.
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Operation SDM-100A Satellite Modem Modulator Type Transmit Filter Type Select. Encoder Type Allows operator to select INTELSAT Open, CSC Closed, FDC Closed, or EFD Closed network filtering. Select Viterbi or Sequential encoder type. TX BPSK Ordering If the Sequential encoder firmware is not installed, the modem will double beep, and not allow the selection change. Select Standard or Non-standard TX BPSK ordering. Mod Spectrum The normal operation is Standard TX BPSK ordering.
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Operation SDM-100A Satellite Modem SDM-100 "TYPE" VER: 14.7.4 FUNCTION SELECT UTILITY ASSIGN RECEIVE FILTERS DEMODULATOR TYPE A, B, C, D, or V INTELSAT OPEN CSC CLOSED FDC CLOSED EFD CLOSED RX-A QPSK 1/2 RX-B QPSK 1/2 RX-C QPSK 1/2 TX-D QPSK 1/2 RX-V QPSK 1/2 64.000 kbit/s 96.000 kbit/s 128.000 kbit/s 38.400 kbit/s 19.
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SDM-100A Satellite Modem Operation 3.2.1.6.2 Utility Demodulator Assign Receive Filters Receive filter display/assignment utility. Used to view current filter rate assignments and to make filter rate reassignments. Demodulator Type Refer to the previous text under “Assign TX_Filters.” The receive filters assignments are basically identical. Receive Filter Type Select. Decoder Type Allows the operator to select Open, Closed, or Comstream compatible network receive filtering.
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Operation SDM-100A Satellite Modem SDM-100 "TYPE" VER: 14.7.4 FUNCTION SELECT UTILITY UTILITY INTERFACE INTERFACE TYPE BUFFER PROGRAM RTS TX-IF CONTROL TERRESTRIAL INTERFACE Status Only BITS MILLI-SECONDS ON OFF RS-422 V.
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SDM-100A Satellite Modem Operation 3.2.1.6.3 Utility Interface Interface Type Buffer Program Displays the interface type installed in modem (RS-422, V.35, RS-232-C, ASYNC, or ADPCM). This is a status window only, and no changes can be made from this menu. Sets the size of the buffer. On entry, the current buffer length is displayed. Press [↑] or [↓] to select the desired buffer size. The buffer size is displayed in seconds or bits.
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Operation SDM-100A Satellite Modem DM Signal Inverts the polarity of the DM signal. RS Signal Select either NORMAL or INVERT (inverted) signal poarity. Available only with the ASYNC or ADPCM options. Inverts the polarity of the RS signal. CS Signal Select either NORMAL or INVERT (inverted) signal poarity. Available only with the ASYNC option. Inverts the polarity of the CS signal. MC Signal Select either NORMAL or INVERT (inverted) signal poarity. Available only with the ASYNC option.
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Operation SDM-100A Satellite Modem FUNCTION SELECT UTILITY SDM-100 "TYPE" VER: 14.7.4 TIME: HH:MM:SS AM/PM DATE: MM/DD/YY UTILITY SYSTEM REMOTE BAUD RATE 110 150 300 600 1200 2400 Current time and date.
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SDM-100A Satellite Modem Operation 3.2.1.6.4 Utility System Time/Date Remote Baud Rate Remote Address Operation Mode Time of day and Date set/display function. The current time and date in the modem memory are displayed when selected. To set the modem time and/or date, press [ENTER]. Press [←] or [→] to position the flashing cursor over the parameter to be changed. Press [↑] or [↓] to change the parameter to the desired value.
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Operation SDM-100A Satellite Modem M&C Module Firmware FPGA Firmware DSP Firmware Master Reset Displays M&C module firmware version. Upon entry, the date of release of this firmware will be displayed. This is a status window only. Displays firmware version of the Field Programmable Gate Array. Upon entry, the date of release of this firmware will be displayed. This is a status window only. Displays the firmware version installed in the Digital Signal Processor (DSP).
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SDM-100A Satellite Modem SDM-100 "TYPE" VER: 14.7.4 Operation UTILITY MODEM TYPE MODEM SIMULATION SDM-100 TYPE 1(REQUIRES SEQUENTIAL DECODER) REV EMULATION CURRENT_VERSION FUNCTION 11 FUNCTION 12 FUNCTION 13 Key: ACCESS TO SUBMENU CONDITIONAL OR OPTION-DEPENDENT Parameter Information Figure 3-15. Utility Modem Type (SDM-100 and Type 1 Operation) 3.2.1.6.
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Operation SDM-100A Satellite Modem SDM-100 "TYPE" VER: 14.7.4 FUNCTION SELECT UTILITY UTILITY FACTORY SETUP Key: Factory setup should not be changed by unauthorized persons. Failure to comply may cause modem failure. ACCESS TO SUBMENU CONDITIONAL OR OPTION-DEPENDENT Parameter Information Figure 3-16. Utility Factory Setup (SDM-100 and Type 1 Operation) 3.2.1.6.6 Utility Factory Set-Up This configuration is used for factory alignment and filter setup parameters.
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SDM-100A Satellite Modem Operation 3.2.2 Type 1 Operation Menus SDM-100 "TYPE" VER: 14.7.
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Operation SDM-100A Satellite Modem SDM-100A "TYPE" VER: 14.7.4 TX-X CODE_RATE/ TYPE FUNCTION SELECT CONFIGURATION RX-X CODE_RATE/ TYPE X = A, B, C, D, OR V X = A, B, C, D, OR V TX-A QPSK 1/2 [64.000 kbit/s] TX-B QPSK 1/2 [96.000 kbit/s] TX-C QPSK 1/2 [128.00 kbit/s] TX-D QPSK 1/2 [32.00 kbit/s] TX-V QPSK 1/2 [19.2 kbit/s] RX-A QPSK 1/2 [64.000 kbit/s] RX-B QPSK 1/2 [96.000 kbit/s] RX-C QPSK 1/2 [128.00 kbit/s] RX-D QPSK 1/2 [32.00 kbit/s] RX-V QPSK 1/2 [19.
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SDM-100A Satellite Modem Operation 3.2.2.1 Configuration: Type 1 Operation TX-X Code_Rate/Type Transmitter rate selection. One of four predefined transmitter code/data rate combinations may be selected: • • • • A B C D A variable rate selection (V) can also be selected. These settings must first be set up in the Utility menu. On entry, the current transmitter rate is displayed with the flashing cursor on the code rate on line 1. The data rate is displayed on line 2.
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Operation SDM-100A Satellite Modem RX-X Code_Rate/Type Receiver rate selection. Four predefined receiver decoder/data rate combinations are available: • • • • A B C D A variable rate selection (V) may also be selected. These settings must first be set up in the Utility menu. TX-IF Frequency On entry, the current receiver rate is displayed with the flashing cursor on the code rate on line 1. The data rate is displayed on line 2. Press [↑] or [↓] to select one of four predefined rates.
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SDM-100A Satellite Modem TX Power Level Operation Programs the modulator output power level from -5 to -30 dBm, in 0.1 dB steps. The high-power option operates from +5 to -20 dBm. On entry, the current transmitter power level is displayed with the flashing cursor on the first character. Press [↑] or [↓] to increase or decrease the output power level, in 0.1 dB steps. Press [ENTER] to execute the change.
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Operation SDM-100A Satellite Modem B-Band Loop Back Programs the modem for baseband loopback operation (test mode). When baseband loopback is turned on, the data and timing signals are hard-wired (via relays) from the demodulator to the modulator on the modem side of the interface. The DTE baseband signals are also looped back from the transmitter data and clock to the receiver data and clock on the customer side of the interface. This is a bi-directional loopback of the baseband data.
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SDM-100A Satellite Modem Reacquisition Operation Programs the sweep re-acquisition mode time duration. The time that is selected with this parameter is the time that the modem will remain in a narrow sweep (± 10%) after acquisition has been accomplished. After this timer runs out, the modem will return to the normal sweep. Carrier Mode On entry, the current programmed setting is displayed with a flashing cursor on the first character. Use [←] and [→] to move the flashing cursor.
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Operation SDM-100A Satellite Modem SDM-100 "TYPE" VER: 14.7.4 FUNCTION SELECT MONITOR RAW BER CORRECTED BER CURRENT RAW BER NO DATA (if carrier not locked) CURRENT CORRECTED BER NO DATA (if carrier not locked) Low limit: based on performance. High limit: based on data/code rate. Low limit: based on performance. High limit: 1.0 E-12. RECEIVE SIGNAL EB/N0 CURRENT Eb/N0 NO DATA (if carrier not locked) Low limit: based on data rate. High limit: 16.0 dB. CURRENT RECEIVE LEVEL ( 25.0 to -60.
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SDM-100A Satellite Modem Operation 3.2.2.3 Faults/Alarms: Type 1 Operation The Faults/Alarms level is accessible from the Function Select menu. Faults/Alarms are similar to Monitor functions. The Faults/Alarms level displays the current fault status of the group being displayed.
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Operation SDM-100A Satellite Modem SDM-100 "TYPE" VER: 14.7.4 FUNCTION SELECT FAULTS/ALARMS MODULATOR DEMODULATOR COMMON IF SYNTHESIZER DATA CLOCK ACT DATA CLOCK SYN I CHANNEL Q CHANNEL AGC LEVEL MODULE See notes. CARRIER DETECT IF SYNTHESIZER DATA CLOCK SYN I CHANNEL Q CHANNEL DESCRAMBLER BER THRESHOLD MODULE See notes. BATTERY/CLOCK -12 VOLT SUPPLY +12 VOLT SUPPLY +5 VOLT SUPPLY CONTROLLER INTERFACE MODULE See notes. Notes: 1. A “-” indicates that no fault or alarm exists. 2.
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SDM-100A Satellite Modem Operation 3.2.2.3.1 Modulator Faults: Type 1 Operation Fault IF Synthesizer Data Clock Act Data Clock Syn I Channel Q Channel AGC Level Module Description Modulator IF synthesizer fault. Activity detector alarm of the selected interface receive clock. The interface will fall back to the satellite clock when this fault is active. Transmit clock synthesizer fault. Indicates the internal VCO has not locked to the incoming data clock. I channel data activity fault.
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Operation SDM-100A Satellite Modem FUNCTION SELECT STORED FLTS/ALMS SDM-100 "TYPE" VER: 14.7.
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SDM-100A Satellite Modem Operation 3.2.2.4 Stored Faults/Alarms: Type 1 Operation The modem stores the first 10 (Flt0 through Flt9) occurrences of fault status changes in each of the seven major fault categories. Each fault status change is stored with the time and date of the occurrence (i.e., when a fault occurs and when it clears). Stored faults may be viewed by entering the stored faults level from the Function Select menu.
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Operation SDM-100A Satellite Modem 3.2.2.
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Operation SDM-100A Satellite Modem SDM-100 "TYPE" VER: 14.7.4 FUNCTION SELECT UTILITY ASSIGN TRANSMIT FILTERS UTILITY MODULATOR MODULATOR TYPE x = FILTER A, B, C, D, or V TX-A QPSK 1/2 [64.000 kbit/s] TX-B QPSK 1/2 [96.000 kbit/s] TX-C QPSK 1/2 [128.000 kbit/s] TX-D QPSK 1/2 [32.000 kbit/s] TX-V QPSK 1/2 [19.
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SDM-100A Satellite Modem Operation 3.2.2.5.1 Utility Modulator: Type 1 Operation Assign Transmit Filters Transmit filter display/assignment utility. Used to make filter rate reassignments. The modulator has five symbol rate filter presets. Filters are designated as A, B, C, D, and V. Note: Switching between Modem types will reset the Filter presets to their factory-defined values.
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Operation SDM-100A Satellite Modem SDM-100 "TYPE" VER: 14.7.4 FUNCTION SELECT UTILITY ASSIGN RECEIVE FILTERS x = FILTER A, B, C, D, or V RX-A QPSK 1/2 [64.000 kbit/s] RX-B QPSK 1/2 [96.000 kbit/s] RX-C QPSK 1/2 [128.000 kbit/s] RX-D QPSK 1/2 [32.000 kbit/s] RX-V QPSK 1/2 [19.200 kbit/s] code_rate = QPSK or BPSK m/n = 1/2, 3/4, 7/8 UTILITY DEMODULATOR DEMODULATOR TYPE BER THRESHOLD CSC CLOSED FDC CLOSED EFD CLOSED 1.0 E-3 to 1.
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SDM-100A Satellite Modem Operation 3.2.2.5.2 Utility Demodulator Functions: Type 1 Operation Assign Receive Filters Receive filter display/assignment utility. Used to view and change current filter rate assignments. Demodulator Type Refer to the previous text under assign transmit filters. The receive filters assignments are basically identical. Receive filter type select. BER Threshold Allows the operator to select CSC Closed, FDC Closed, or EFD Closed network receive filtering.
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Operation SDM-100A Satellite Modem SDM-100 "TYPE" VER: 14.7.4 FUNCTION SELECT UTILITY UTILITY INTERFACE INTERFACE TYPE TX CLOCK PHASE BUFFER CLOCK BUFFER SIZE RS422 V.35 RS232 ASYNC ADPCM AUTO NORMAL INVERT EXT. REFERENCE RX (SATELLITE) TX TERRESTRIAL 64 to 65536 BITS 0 BYPASS BUFFER CENTER Key: YES NO ACCESS TO SUBMENU CONDITIONAL OR OPTION-DEPENDENT Parameter Information Figure 3-24. Utility Interface (Type 1 Operation) 3–72 Rev.
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SDM-100A Satellite Modem Operation 3.2.2.5.3 Utility Interface Functions: Type 1 Operation Interface Type TX Clock Phase Displays the interface type (RS-422, V.35, RS-232-C, ASYNC, or ADPCM) installed in the modem. This is a status window only, and no changes can be made from this menu. Programs transmit clock phase to Auto, Normal or Invert. Buffer Clock On entry, the current setting for the TX clock phase is displayed. Press [↑] or [↓] to select Normal or Invert. Press [ENTER] to execute the change.
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Operation SDM-100A Satellite Modem SDM-100 "TYPE" VER: 14.7.4 TIME: HH:MM:SS AM/PM DATE: MM/DD/YY Current time and date.
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SDM-100A Satellite Modem Operation 3.2.2.5.4 Utility System Functions: Type 1 Operation Time/Date Remote Baud Rate Remote Address Lamp Test?? Display Contrast Level Time of day and date set/display function. The current time and date in the modem memory are displayed when selected. To set the modem time and/or date, press [ENTER]. Press [←] or [→] to position the flashing cursor over the parameter to be changed. Press [↑] or [↓] to change the parameter to the desired value.
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Operation SDM-100A Satellite Modem M&C Module FW FPGA Firmware DSP Firmware Master Reset Displays M&C module firmware version. Upon entry, the date of release of this firmware will be displayed. This is a status window only. Displays firmware version of the Field Programmable Gate Array (FPGA). Upon entry, the date of release of this firmware will be displayed. This is a status window only. Displays the firmware version installed in the Digital Signal Processor (DSP).
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SDM-100A Satellite Modem Operation MODEM REQUIRES AN EXTERNAL PATH TO LOCK. THIS IS DONE EITHER AT THE MODEM INPUT, OR FROM THE SATELLITE CUSTOMER DATA INTERFACE ENCODER/ MODULATOR TX = 70 MHz .
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Operation CUSTOMER DATA SDM-100A Satellite Modem INTERFACE TRANSMIT RF EQUIPMENT ENCODER/ MODULATOR ANTENNA REMOTE SERIAL INTERFACE MICROCOMPUTER FAULT INDICATORS SDM-100A SATELLITE DATA MODEM POWER SUPPLY DEMODULATOR/ DECODER AC POWER RECEIVE RF EQUIPMENT Figure 3-27. IF Loopback Note: When IF loopback is turned on, the demodulator is looped back to the modulator inside the modem, and the demodulator is programmed to the same frequency as the modulator.
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SDM-100A Satellite Modem Operation 3.3 Clocking Options Methods of clocking the data from the terrestrial equipment to the satellite (and vice versa) will depend upon the application. The two most common options and recommended configurations are described in the following paragraphs. 3.3.1 Master/Master This application is used when both earth stations have high stability clocks, and the receive data will be clocked to the local network.
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Operation SDM-100A Satellite Modem Figure 3-29. Master/Master Clocking Block Diagram 3–80 Rev.
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SDM-100A Satellite Modem Operation Figure 3-30. Master/Slave Clocking Block Diagram Rev.
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Chapter 4. THEORY OF OPERATION This chapter describes the theory of operation for the various components of the modem. 4.1 Modulator The modem modulator creates a QPSK or BPSK modulated carrier within the 50 to 180 MHz range from the digital data stream that is provided by the Interface section.
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Theory of Operation SDM-100A Satellite Modem Fault information from the modulator is sent to the host M&C, and includes: • • • • • • Synthesizers out-of-lock RF output leveled Input data clock activity I channel digital filter activity Q channel digital filter activity AGC level faults MPC MPC RF SYNTH 0 90 VCO IF OUTPUT 50 TO 180 MHz -5 TO -30 dBm VARIABLE ATTENUATOR IF FILTER IF LOOPBACK ATTENUATOR REF OSC DDS MPC RX SAT CLK EXT.
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SDM-100A Satellite Modem Theory of Operation The data signal passes to the convolutional encoder. • For Viterbi codes, the convolutional encoder encodes the data at rate 1/2. If the selected code rate is 3/4, then two of every six symbols are punctured out. For every three data bits in, there are four bits out. • For sequential encoding, the convolutional encoder generates the parity bits from the input data stream that allows for error correction at the far end of the link.
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Theory of Operation SDM-100A Satellite Modem In the normal (or “Standard”) operation, the I channel data is output from the MUX first, followed by Q channel data. If this order of data does not match the receive BPSK ordering, the modem will not lock. The TX and RX BPSK ordering must be the same in order to get the receiver to lock.
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SDM-100A Satellite Modem Theory of Operation 4.1.2 Specifications Modulation Type Data Rate Range Symbol Rate Range Test Modes Frequency Range Frequency Select Method Frequency Step Size Frequency Stability (RF) Frequency Stability (SCT) Phase Error Filtering Type Spectral Occupancy Spurious and Harmonics Output Power Level Range Output Stability Output Power Adjustment Output Impedance Output Return Loss Scrambling FEC Encoding Decoding Reported Faults Rev. 0 QPSK or BPSK 19.
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Theory of Operation SDM-100A Satellite Modem 4.2 Demodulator The modem demodulator converts a QPSK or BPSK modulated signal of 50 to 180 MHz to a demodulated baseband data stream. The demodulator then performs error correction on the data stream, using a Viterbi decoding algorithm or a sequential decoder. There also is a summary fault relay that provides a Form-C output located on the demodulator board. Refer to Figure 4-3 for a block diagram of the demodulator. 4.2.
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SDM-100A Satellite Modem Theory of Operation RF IF INPUT 50 TO 180 MHz -55 TO -30 dBm ALIAS FILTER A/D DIGITAL NYQUIST ALIAS FILTER A/D DIGITAL NYQUIST I IF FILTER AGC IF LOOPBACK MPC RF SYNTH 90 0 BB VCO MICROPROCESSOR RX DATA Q DIGITAL COSTAS LOOP DDS MPC SYNCHRONOUS DESCRAMBLER VITERBI SOFT DECISION MAPPING UNIQUE WORD DETECTOR MPC MPC RX CLOCK DDS DELAY DIGITAL CLOCK LOOP RR Figure 4-3. Demodulator Block Diagram 4.2.
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Theory of Operation SDM-100A Satellite Modem A set of “branch metric” values is then computed for each of the received symbol pairs, related to the probability that the received symbol pair was actually transmitted as one of the four possible symbol pairs. The “branch metrics” are then processed by the Add-Select-Compare (ASC) computer.
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SDM-100A Satellite Modem Theory of Operation 4.2.4 Sequential Decoding Theory The sequential decoder is used in closed network applications, typically in Frequency Division Multiple Access (FDMA) satellite communications systems. The sequential decoder is optional firmware that plugs onto the demodulator/M&C/interface board. When not installed, sequential encoding and decoding types may not be selected. Refer to Figure 4-5 for a block diagram of the sequential decoder.
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Theory of Operation SDM-100A Satellite Modem The syndrome input generator converts the 2-bit soft decision data into a single bit per channel, and simultaneously corrects some isolated bit errors. The data is then shifted through the syndrome shift registers, which allows the parity generator to detect bit errors. The resulting error signal provides the feedback to the timing and control circuitry to allow it to direct the data along the path of the highest cumulative metric.
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SDM-100A Satellite Modem Theory of Operation 4.3 Monitor and Control A sophisticated microcontroller module is used to perform the monitor and control functions of the modem. This module is located on the demodulator board, and is referred to as the Monitor and Control (M&C). The M&C monitors the modem, and provides configuration updates to other modules within the modem when necessary. Extensive fault monitoring and status gathering are provided.
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Theory of Operation SDM-100A Satellite Modem 4.3.4 Remote Interface Configuration All modem functions can be remotely controlled and monitored via an RS-485 (or optional RS-232-C) communications link. The 2- or 4-wire, half-duplex RS-485 interface makes it possible to operate up to 255 modems and other units on a common communications link. The RS-232-C interface is used to communicate with a single modem.
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SDM-100A Satellite Modem Theory of Operation 4.3.5 Modem Defaults The M&C has default settings that are loaded into the modem at power-up. These default settings are also loaded each time the modem has been Hard Reset. The following table lists the defaults settings for each modem configuration parameter.
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Theory of Operation SDM-100A Satellite Modem 4.4 Digital Interfaces The modem interface module is a daughter card that plugs onto the demodulator board. It provides the interface for terrestrial data and overhead signals, and provides the fault reporting output of the modem. RS-422/449, V.35, RS-232-C, and ASYNC interfaces are available for input and output of terrestrial data. Both baseband and interface loopbacks are provided. Terrestrial data rates from 19.2 to 128 kbit/s are supported. 4.4.
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SDM-100A Satellite Modem Theory of Operation P1 J1 +TT -TT 35 17 +S -SD 22 4 5 TT 31,32 -5V 6 SD 37,38 +5V 13 MC +MC -MC 34 16 15 16 14 7 DF MF CS RS DEMOD FAULT MOD FAULT +C +R 21 3 27 25 8 ST +ST -ST 23 5 33,34 +12V 10 RT +RT -RT 26 8 35,36 -12V 11 12 9 RD RR DM +RD -RD 24 6 1,2 39,40 3 4 GND GND INTF0 INTF1 +RR -RR 31 13 +DM -DM 29 11 GND 1,19,20,37 Figure 4-6. RS-422 Block Diagram Table 4-1.
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Theory of Operation SDM-100A Satellite Modem Data received by the modem is output on the Receive Data (RD) lines, while the recovered clock is output on the Receive Timing (RT) lines. • Receive Clock NORMAL mode should be selected for applications that require the rising edge of the clock to occur in the middle of the data bit time. • INVERT mode puts the falling edge of RT in the middle of the data bit.
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SDM-100A Satellite Modem Theory of Operation Fault indicators are also provided on TTL open collector drivers on the RS-422 connector. • The TTL MOD fault indicates one of the following: • MODULATOR fault COMMON EQUIPMENT fault The TTL DEMOD fault indicates one of the following: DEMOD fault COMMON EQUIPMENT fault 4.4.1.1 Connector Pinouts The RS-422 interface is provided on a 37-pin female D connector accessible from the rear panel of the modem.
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Theory of Operation SDM-100A Satellite Modem 4.4.1.2 Specification Circuit Supported Amplitude (RD, RT, ST, DM, RR) DC Offset (RD, RT, ST, DM, RR) Impedance (RD, RT, ST, DM, RR) Impedance (SD, TT, MC) Polarity Phasing (RD, RT) Symmetry (ST, TT, RT) Frequency Stability (ST) Modulator Fault Demodulator Fault SD, ST, TT, RD, RT, DM, RR, MC, MOD FAULT, DEMOD FAULT 4, ± 2V differential into 100Ω 0.0, ± 0.
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SDM-100A Satellite Modem Theory of Operation J1 J2 5 31,32 3 6 TT +TT 11 -TT 24 -5V INTF0 SD +S 14 -SD 2 37,38 +5V 13 MC 15 DF DEMOD FAULT 21 16 MF MOD FAULT 25 14 CS CS 7 RS RS 4 +ST 12 -ST 15 8 ST 33,34 +12V 10 RT 35,36 -12V 11 RD 12 RR 9 DM 1,2 GND 39,40 GND +MC 23 -MC 20 +RT 9 -RT 17 +RD 16 -RD 3 -RR -DM 4 5 8 6 INTF1 GND 1, 7 Figure 4-7. V.
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Theory of Operation SDM-100A Satellite Modem The Request to Send (RTS) line is hard-wired to the Clear to Send (CTS) line by JP11, pins 5 and 6, on the Demodulator/M&C card (AS/4973), since the modem does not support polled operation. Data Set Ready (DSR) indicates that the modem is powered up. Receive Line Signal Detect (RLSD) indicates that an RF carrier is being received and demodulated with a sufficiently low error rate for the decoder to remain locked. The V.
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SDM-100A Satellite Modem Theory of Operation 4.4.2.1 Connector Pinouts The V.35 interface is provided on the industry standard 34-pin block or 25-pin D connector accessible from the rear panel of the modem. Screw locks are provided for mechanical security of the mating connector.
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Theory of Operation SDM-100A Satellite Modem 4.4.2.2 Specification Circuit Supported Amplitude (RD, SCR, SCT, SD, SCTE) Amplitude (CTS, DSR, RLSD) Impedance (RD, SCR, SCT) Impedance (SD, SCTE) Impedance (RTS) DC Offset (RD, SCR, SCT) Polarity (SD, SCT, SCTE, RD, SCR) Polarity (RTS, CTS, DSR, RLSD) Phasing (SCTE, SCR) Symmetry (SCT, SCTE, SCR) Frequency Stability (SCT) Modulator Fault Demodulator Fault SD, SCT, SCTE, RD, SCR, DSR, RLSD, MC, MOD FAULT, DEMOD FAULT 0.
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SDM-100A Satellite Modem Theory of Operation TT DA SD BA P5 RS 5 6 7 13 15 16 10 8 9 14 11 12 30 33,34 35,36 37,38 4 1,2 39,40 3 TT SD RS MC DF MF RT ST DM CS RD RR -CP +12V -12V +5V INF1 GND GND INF0 J1 CA MC DF DA (TT) BA (SD) CA (RS) -MC DEMOD FAULT MOD FAULT DD (RT) DB (ST) CC (DM) CB (CS) BB (RD) CF (RR) CP GND -MC DF MF MF RT DD ST DB DM CC CS CB RD 24 2 4 9 11 25 17 15 6 5 3 8 18 1,7 BB RR CF CP - CP Figure 4-8. RS-232-C Interface 4.4.3.
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Theory of Operation SDM-100A Satellite Modem The TX clock phasing choice is made from the front panel in the Interface Configuration menu. • The AUTO setting is used when there is no jitter on the clock source. • The NORMAL setting is used when standard clock and data relationships exist. • The INVERT mode is used when the incoming clock is inverted from the standard clock and data relationship.
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SDM-100A Satellite Modem Theory of Operation Two fault outputs are provided on dry contact Form-C relays on the Demodulator/M&C card, and are sent to the interface card. The signals are buffered and output for use in monitoring fault status, and are available on the FAULT connector on the modem rear panel. These are: • • MODULATOR faults DEMODULATOR faults Generation of these fault conditions is described in Chapter 3. 4.4.3.
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Theory of Operation SDM-100A Satellite Modem 4.4.4 Asynchronous Interface Refer to Appendix B. 4.4.5 Terrestrial Interface Change The modem comes configured for one specific type of interface. To convert to another interface type, a field change is required. Since the modem interface module is a daughter card that plugs onto the demodulator board, it will be necessary to remove the top cover of the modem to make an interface change. The interface daughter cards are as follows: Interface RS-422 V.
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Chapter 5. MAINTENANCE This chapter describes system checkout, maintenance, and troubleshooting procedures for the modem. 5.1 System Checkout The system checkout section is to be used as an aid in setting up a modem within the earth station. There are tables for use in checking to see if the Eb/N0 is correct, a typical output spectrum, and typical eye pattern and constellation pictures. 5.1.1 Interface Checkout 1. Set modem to IF Loopback (Configuration Interface menu). 2.
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Maintenance SDM-100A Satellite Modem 5.1.2 Modulator Checkout The first step in turning up a carrier is to set the output frequency. This is done in the CONFIGURATION menu on the front panel (refer to Chapter 3). The CONFIGURATION menu also allows the operator to set the output level, turn the output on or off, set the scrambler, differential encoder, clock source, and gives access to the test modes for system check-out. Available test modes are RF loopback, IF loopback, Baseband loopback, and CW mode.
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SDM-100A Satellite Modem Maintenance Figure 5-1. Typical Output Spectrum RL -53.0 dBm ATTEN 10 dB 1 dB/DIV 5 dB Eb/N0 of Noise 64 kbit/s 1/2 Rate QPSK CENTER 70.0000 MHz *RBW 3.0 kHz *VBW 3.0 Hz SPAN 200.0 kHz SWP 56.0 sec Figure 5-2. Typical Output Spectrum With Noise Rev.
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Maintenance SDM-100A Satellite Modem Table 5-1. EFData Conversion of (S+N)/N to S/N and Eb/N0 for Various Code Rates (dB) (S+N)/N 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 9.5 10.0 10.5 11.0 11.5 12.0 12.5 13.0 13.5 14.0 14.5 15.0 15.5 16.0 16.5 17.0 17.5 18.0 18.5 19.0 19.5 20.0 5–4 Code Rate 1/2 S/N Eb/N0 Code Rate 3/4 S/N Eb/N0 Code Rate 7/8 S/N Eb/N0 1.8 2.6 3.3 4.1 4.7 5.4 6.0 6.6 7.3 7.8 8.4 9.0 9.5 10.1 10.6 11.2 11.7 12.2 12.8 13.3 13.8 14.3 14.9 15.4 15.9 16.4 16.9 17.4 17.9 18.4 18.9 19.
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SDM-100A Satellite Modem Maintenance WITH NOISE WITHOUT NOISE Figure 5-3. Typical Eye Constellations Rev.
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Maintenance SDM-100A Satellite Modem 5.1.4 Test Points The modem does not have accessible test points. When troubleshooting is required at board level, the cover must be removed. The following is a list of test points located on the PCB, and a description of the signal that is to be present under normal operation. 5.1.4.
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SDM-100A Satellite Modem Maintenance 5.1.4.2 Modulator Test Points TP 1 DATA CLOCK TP 2 SYMBOL CLOCK TTL level clock that is locked to the incoming data to the interface card. TTL level clock that is locked to the incoming clock at the interface card. This clock is running at the symbol frequency and not at the data rate. The frequency is equal to: Rev.
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Maintenance SDM-100A Satellite Modem 5.2 Fault Isolation The modem has been designed so that a competent technician can isolate fault conditions without removing the modem from its location. The fault monitoring capability of the modem is designed to aid the operator in determining the cause of a failure. System faults are reported in the Faults menu, and stored faults are reported in the StFaults menu. Refer to Figure 5-4 for an illustration of the modem fault tree. Refer to Section 3.2.1.3.
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SDM-100A Satellite Modem Maintenance 5.3 Module Identification The modem PCBs each have an assembly number that is marked on the board. The latest revision is stamped on the board along with the serial number. EFData tracks the hardware by the assembly number, revision, and serial number. When replacing a plug-on module, care must be taken to ensure the proper orientation of the card. Refer to the individual sections on each module for the location of the configuration identification.
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Maintenance SDM-100A Satellite Modem This page is intentionally left blank. 5–10 Rev.
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Appendix A. REMOTE CONTROL OPERATION This appendix describes the remote control operation of the SDM-100, -100A, -150, and -150A. • • Firmware number: Software version: FW/4969-1C and FW/4969-2C 14.7.4 The -2 version is the PLCC (Plastic Leadless Chip Carrier) version, applicable to the SDM-100A and 150A. The -1 version is the 28-pin DIP version, applicable to the SDM-100 and -150. A.
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Remote Control Operation SDM-100A Satellite Modem A.2 Message Structure The ASCII character format used requires 11 bits/character: • • • • 1 start bit 7 information bits 1 parity bit 2 stop bits Messages on the remote link fall into the categories of commands and responses. Commands are messages which are transmitted to a satellite modem, while responses are messages returned by a satellite modem in response to a command.
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SDM-100A Satellite Modem Remote Control Operation A.2.3 Command/Response The command/response portion of the message contains a variable-length character sequence which conveys command and response data. If a satellite modem receives a message addressed to it which does not match the established protocol or cannot be implemented, a negative acknowledgment message is sent in response.
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Remote Control Operation SDM-100A Satellite Modem A.3 Configuration Commands/Responses A.3.1 Modulator Modulator Frequency RF Output (IF Output) Modulator Rate Preset Assignment Command: Response: add/MF_nnn.nnnn'cr' RF_OFF'cr''lf'] Status: Response: add/MF_nnn.nnnn'cr''lf'] Command: Response: add/RF_xxx'cr''lf'] Status: Response: add/RF_xxx'cr''lf'] Command: Response add/AMRx_nnnn_mmm.
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SDM-100A Satellite Modem Remote Control Operation Set Modulator Output Power Level Command: Response: add/MOP_snn.n'cr''lf'] Where: snn.n = -30.0 to -5.0, in 0.1 steps (nominal range in dBm). Status: Response: add/MOP_snn.n'cr''lf'] Notes: 1. The nominal power range is modified relative to the value specified by the modulator power offset (MPO_). 2. The MOP_ command will return status only when local AUPC is enabled.
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Remote Control Operation SDM-100A Satellite Modem A.3.2 Demodulator Set Demod Frequency Demod Rate Preset Assignment Command: Response: add/DF_nnn.nnnn'cr''lf'] Status: Response: add/DF_nn.nnnn'cr''lf'] Command: Response add/ADRx_nnnn_mmm.mmm'cr''lf'] Status: Response: add/ADRx_nnnn_mmm.mmm'cr''lf'] Where: nnn.nnnn = Frequency in MHz, 50.0000 to 180.0000, in 2.5 kHz steps.
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SDM-100A Satellite Modem Sweep Center Frequency Sweep Width Range Bit Error Rate Threshold Demod Type Demod Decoder Type Receive BPSK Data Ordering Demod Spectrum Rotation ReedSolomon Decoder Enable Rev.
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Remote Control Operation SDM-100A Satellite Modem A.3.
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SDM-100A Satellite Modem Interface Subscriber/ Trunk Emulation Command: Response: add/SBTR_xxx'cr''lf'] Status: Response: add/SBTR_xxx'cr''lf'] E&M Signal Type Command: Response: add/EMS_n'cr''lf'] Status: Response: add/EMS_n'cr''lf'] Command: Response: add/LAW_y'cr''lf'] Status: Response: add/LAW_y'cr''lf'] Command: Response: add/HOOK_xxx'cr''lf'] Status: Response:
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Remote Control Operation SDM-100A Satellite Modem ASYNC Receive Overhead Baud Rate Command: Response: add/ROBR_nnnnn'cr''lf'] Status: Response: add/ROBR_nnnnn'cr''lf'] ASYNC Transmit Channel Character Length Command: Response: add/TCCL_n'cr''lf'] Status: Response: add/TCCL_n'cr''lf'] ASYNC Receive Channel Character Length Command: Response: add/RCCL_n'cr''lf'] Status: Response: add/RCCL_n'c
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SDM-100A Satellite Modem Interface MC Signal Command Command: Response: Interface TT Signal Command Command: Response: Interface RD Signal Command Command: Response: Interface RR Signal Command Command: Response: Interface DM Signal Command Command: Response: Interface CS Signal Command Command: Response: Interface RT Signal Command Command: Response: Interface ST Signal Command Command: Response: Rev.
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Remote Control Operation SDM-100A Satellite Modem A.3.4 System Time Of Day Command: Response: add/TIME_hh:mmxx'cr''lf'] Status: Response: add/TIME_hh:mmxx'cr''lf'] Command: Response: add/DATE_mm/dd/yy'cr''lf'] Status: Response: add/DATE_mm/dd/yy'cr''lf'] Remote Command: Response: add/REM_'cr''lf'] This command configures the modem for remote operation.
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SDM-100A Satellite Modem AUPC Minimum Power Limit Remote Control Operation Command: Response: add/MINP_snn.n'cr''lf'] Where: snn.n = -30.0 to -5.0, in 0.1 steps (nominal range in dBm). Status: Response: add/MINP_snn.n'cr''lf'] Note: The nominal power range is modified relative to the value specified by the modulator power offset (MPO_). Command: Response: add/ENSP_nn.n'cr''lf'] Where: nn.n = 3.2 to 16.0, in 0.1 increments (Eb/N0 in dB).
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Remote Control Operation SDM-100A Satellite Modem A.4 Status Commands/Responses A.4.1 Configuration Modulator Config Status Command: Response: add/MCS_'cr' RF_xxx'cr' MF_nnn.nnnn'cr' MR_nnnn_mmm.mmm'cr' AMRA_nnnn_mmm.mmm'cr' AMRB_nnnn_mmm.mmm'cr' AMRC_nnnn_mmm.mmm'cr' AMRD_nnnn_mmm.mmm'cr' AMRV_nnnn.mmm.mmm'cr' MPO_snn.n'cr' MOP_snn.
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SDM-100A Satellite Modem Modulator/ Coder Config Program Status Command: Response: add/MCP_'cr' MOM_xxxxxxx'cr' MT_xxxx'cr' MET_xxx'cr' MF_nnn.nnnn'cr' MR_nnnn_mmm.mmm'cr' MPO_snn.n'cr' MOP_snn.
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Remote Control Operation Demodulato r Config Status Command: Response: SDM-100A Satellite Modem add/DCS_'cr' DF_nnn.nnnn'cr' DR_nnnn_mmm.mmm'cr' ADRA_nnnn_mmm.mmm'cr' ADRB_nnnn_mmm.mmm'cr' ADRC_nnnn_mmm.mmm'cr' ADRD_nnnn_mmm.mmm'cr' ADRV_nnnn.mmm.
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SDM-100A Satellite Modem Demod/ Decoder Config Program Status Command: Response: add/DCP_'cr' MOM_xxxxxxx'cr' BERT_xxxx'cr' DT_xxxx'cr' DDT_xxx'cr' DF_nnn.nnnn'cr' DR_nnnn_mmm.
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Remote Control Operation Interface Config Status Command: Response: SDM-100A Satellite Modem add/ICS_'cr' TC_xxx'cr' TCP_xxxx'cr' RCP_xxxx'cr' BBL_xxx'cr' BC_xxx'cr' IBP_xxx'cr' IBS_nnnnn'cr' ADP_xxx'cr' SBTR_xxx'cr' EMS_x'cr' LAW_y'cr' HOOK_xxx'cr' ISCL_TX_nnn'cr' ISCL_RX_nnn'cr' RD_xxx'cr' SD_xxx'cr' RR_xxx'cr' DM_xxx'cr' ALBJ_xxx'cr' RTSM_xxx'cr' TOBR_nnnnn'cr' TCCL_n'cr' TCSB_n'cr' TOCP_xxxx'cr' ROBR_nnnnn'cr' RCCL_n'cr' ROCP_xxxx'cr' LPC_xxx'cr' NOMP_snn.n'cr' MINP_snn.
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SDM-100A Satellite Modem Automatic Uplink Power Control (AUPC) Config Status Command: Response: Remote Control Operation add/ACS_'cr' LPC_xxx'cr' NOMP_-nn.n'cr' MINP_-nn.n'cr' MAXP_-nn.n'cr' ENSP_n.n'cr' MAXT_n.n'cr' LCL_xxxx'cr' RCL_xxxx'cr' Local AUPC Enable (ON/OFF) Nominal Power Value (-5.0 to -30.0) Minimum Power Limit (-5.0 to -30.0) Maximum Power Value (-5.0 to -30.0) Eb/N0 Target Set Point (3.2 to 9.7) Max. Tracking Rate (0.5 to 6.
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Remote Control Operation Common Equipment Status Command: Response: SDM-100A Satellite Modem add/CES_'cr' M&C_xxx'cr' INT_xxx'cr' BAT_xxx'cr' +5_xxx'cr' +12_xxx'cr' -12_xxx'cr' MODE_xxxxxx'cr' SFLT_xx'cr''lf'] Monitor & Control Module (OK/FLT) Data Interface Module (OK/FLT) Battery/Clock (OK/FLT) +5V Power Supply (OK/FLT) +12V Power Supply (OK/FLT) -12V Power Supply (OK/FLT) Mode (LOCAL or REMOTE) Number of Stored Faults Logged (0 to 10) The common equipment status command causes a block
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SDM-100A Satellite Modem Current Sweep Value Command: Response: add/CSV_snnnnn'cr''lf'] Remote Control Operation Where: x = < or > (data modifier to indicate that the sweep offset value is less than or greater than the returned value). s = + or - (sweep offset from center). nnnnn = 0 to 35000. Notes: 1. This command returns the current sweep offset value. 2. The 'x' (< or >) parameter is only returned if the level has exceeded the computational resolution of the system. 3.
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Remote Control Operation Bulk Consol Status Command: Response: SDM-100A Satellite Modem add/BCS_p1,p2,p3, . . . pn'cr''lf'] This command causes bulk modem status to be returned. To reduce the length of the response, message parameter data are returned without identifiers. However, parameter identification can be determined by order of return.
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SDM-100A Satellite Modem Remote Control Operation Parameter 20 (p20): Demodulator preset B assignment (ref. "ADRB_" command). p20 = nnnn_mmm.mmm, code rate/data rate in kbit/s. Parameter 21 (p21): Demodulator preset C assignment (ref. "ADRC_" command). p21 = nnnn_mmm.mmm, code rate/data rate in kbit/s. Parameter 22 (p22): Demodulator preset D assignment (ref. "ADRD_" command). p22 = nnnn_mmm.mmm, code rate/data rate in kbit/s. Parameter 23 (p23): Demodulator preset V assignment (ref. "ADRV_" command).
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Remote Control Operation SDM-100A Satellite Modem "APD_" command). (Note 1) p43 = n, where 'n' is '0' (off) or '1' (on). Parameter 44 (p44): ADPCM Subscriber/Trunk Emulation (ref. "SBTR_" command). (Note 1) p44 = n, where 'n' is '0' (Subscriber) or '1' (Trunk). Parameter 45 (p45): ADPCM E & M Signal Type (ref. "EMS_" command). (Note 1) p45 = n, where 'n' is '1', '2', '3', '4', or '5' (signal type). Parameter 46 (p46): ADPCM Encoding Law (ref. "LAW_" command).
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SDM-100A Satellite Modem Remote Control Operation p64 = xxxx, where 'xxxx' is the currently programmed parity. Parameter 65 (p65): ASYNC Overhead Communications Type (ref. "OCT_" command). (Note 2) p65 = n, where 'n' is '0' (RS232) or '1' (RS485). Parameter 66 (p66): Interface Wire Type (ref. "IWt_" command). (Note 2) p66 = n, where 'n' is '2' (2-Wire) or '4' (4-Wire). Parameter 67 (p67): Terrestrial Communications Type (ref. "TCT_" command). (Note 2) p67 = n, where 'n' is '0' (RS422) or '1' (V.35).
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Remote Control Operation Change Status Command: Response: SDM-100A Satellite Modem add/CS_x'cr''lf'] Where: The 'x' character is defined as follows: '@' = no change since last BCS_ and BCSF_ polls. 'A' = BCS_ response has changed since last BCS_ poll. 'B' = BCSF_ response has changed since last BCSF_ poll. 'C' = Both responses have changed since last BCS_ and BCSF_ polls.
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SDM-100A Satellite Modem Remote Control Operation A.4.2 Error Performance Raw BER Command: Response: add/RBER_xm.mE-ee'cr''lf'] Where: x = < or > (data modifier to indicate that the error rate is less than or greater than the returned value). m.m = 1.0 to 9.9 (error rate mantissa). ee = 1 to 99 (error rate exponent). Notes: 1. The 'x' (< or >) parameter is only returned if the error rate has exceeded the computational resolution of the system. 2.
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Remote Control Operation SDM-100A Satellite Modem A.5 Stored Faults Information on stored faults is returned when requested. If no stored fault exists for a given fault number, the words “NO Fault” will be returned instead of the normal time/date status information.
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SDM-100A Satellite Modem ReedSolomon Unavailable Seconds Command: Response: Bulk Consol Status Faults Command: Response: add/RSSF_# hh:mm:ss MM/DD/YY'cr' UNASEC_xxx'cr''lf'] add/BCSF_abcdefghijkl'cr''lf'] Remote Control Operation Unavailable Seconds (FLT/OK) This command causes all modem fault status to be returned. To reduce the length of the response, fault status is embedded into the bit structure of the characters that are returned.
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Remote Control Operation SDM-100A Satellite Modem Character 'h': Interface transmit side faults character 2. Bit 6 = 1 always. Bit 5 = Selected Transmit Clock Activity. Bit 4 = ADPCM Transmit Audio Clip. (See Note) Bit 3 = reserved. Bit 2 = reserved. Bit 1 = reserved. Bit 0 = reserved. Note: This bit will only be set if ADPCM is installed. Character 'i': Interface receive side faults character 1. Bit 6 = 1 always. Bit 5 = reserved. Bit 4 = reserved.
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Appendix B. OPTIONS This appendix provides information about the following options: • • • Asynchronous/Automatic Uplink Power Control (AUPC Interface) ADPCM Voice Interface Reed-Solomon Codec B.1 AUPC Interface The asynchronous (ASYNC) interface board provides the interface for terrestrial data and a single ASYNC overhead channel. Refer to Figure B-1 for a modem block diagram with the ASYNC/AUPC interface option. RS-422 or V.35 interfaces are also available for terrestrial data input and output.
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Options SDM-100A Satellite Modem Figure B-1. ASYNC/AUPC Block Diagram B–2 Rev.
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SDM-100A Satellite Modem Options The ASYNC interface PCB also provides its own Doppler buffer, which has a maximum depth of 32 ms at the highest terrestrial data rate. Buffer fill status can be checked in the monitor menu on the front panel of the modem. Depth selection and centering of the buffer are provided in the CONFIG INTERFACE menu. The AUPC function allows each of two modems that are in a closed link to control the output of the other modem.
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Options SDM-100A Satellite Modem 4. Once modem A has re-acquired the carrier, it will start sending commands to modem B to achieve the desired Eb/N0. During this time, modem B will be sending commands to modem A to either increase or decrease power to maintain modem B’s target Eb/N0. Notes: 1. Local carrier loss will always take priority over remote carrier loss. 2. The RX AUPC link is dead when carrier is lost. B.1.1 Theory of Operation B.1.1.
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SDM-100A Satellite Modem Options B.1.1.4 Demultiplexer Operation The operation of the DEMUX section is similar to the operation of the MUX side. Data, including overhead, is received from the Demodulator card in the modem at the overhead rate. The DEMUX locates the framing in the overhead and locks to the frame sync pattern generated by the multiplexer on the transmitting end. Once locked to the framing, the terrestrial data is clocked into the Doppler buffer with the overhead clock and an enable line.
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Options SDM-100A Satellite Modem B.1.1.6 Loop Timing Operation A loop timing option is provided. When loop timing is selected, the Doppler buffer output clock is forced to the RX clock by the M&C. An M&C-controlled MUX switches the Send Timing (ST) pin to output the RX clock. The RX clock is sent out the ST pin to the appropriate interface drivers and on to the user.
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SDM-100A Satellite Modem Options B.1.1.10 Valid ASYNC Baud Rates The ASYNC baud rates are limited by the terrestrial data rates. The following tables show the relationships between data and baud rates. If DR <= 15.999K If DR <= 31.999K If DR <= 63.999K If DR <= 127.999K If DR <= 255.999K If DR <= 511.999K If DR <= 1023.999K If DR <= 2047.999K If DR <= 2048.999K If DR = 8.000K If DR = 16.000K If DR = 32.000K If DR = 64.000K If DR = 128.000K If DR = 512.000K If DR = 256.000K If DR = 1024.
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Options SDM-100A Satellite Modem B.1.2.1 Top Cover Removal The following 16 screws must be removed from the modem in order to take off the top cover: • • • Five screws located on each side Three screws at the front Three screws at the back Once the screws are removed, the top cover can be lifted and slid toward the rear of the modem. B.1.2.2 Interface Mounting Bracket Removal To remove the interface: 1. Take out the six mounting screws which secure the interface. 2.
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SDM-100A Satellite Modem Options B.1.3 Front Panel Operation The following sections describe the additional front panel operations that are specific to the ASYNC interface. These options are shown in the menu tables in Chapter 3, along with the standard menu windows. B.1.3.
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Options SDM-100A Satellite Modem B.1.3.2 Modulation Configuration TX Rate and Type This option allows the user to chose from a 9.6 to 224 kHz mode of operation with the ASYNC overhead enabled. BPSK 1/2, QPSK 1/2, 3/4, and 7/8 are also supported. With the ASYNC set to OFF, this option works in the standard SDM-100A mode. B.1.3.3 Demodulation RX Rate and Type This option allows the user to chose from a 9.6 to 224 kHz mode of operation with the ASYNC overhead enabled.
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SDM-100A Satellite Modem Options B.1.3.5 Specifications Terrestrial Interface 9.6 to 224 kHz 1/16 overhead BPSK 1/2, QPSK 1/2, 3/4, 7/8 ASYNC Interface ASYNC Interface Types RS-485 or RS-232-C 2-wire or 4-wire Channel Formats Data bits 5 to 8 Parity = odd, even, or none Stop bits = 1 and 2, 150 to 2400 baud Data Rate Overhead Coding B.1.3.6 Mechanical Specifications for Connector J1 Pin # 37 38 35 19 39 40 4 5 21 22 23 24 6 7 41 32 12 13 45 29 46 30 47 31 49 33 Rev.
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Options SDM-100A Satellite Modem B.2 ADPCM Voice Interface The ADPCM voice interface is capable of providing a single duplex voice channel and Ear and Mouth (E&M) signaling data transmission. The interface also provides an EIA STD RS-422 interface which is user selectable. This optional interface replaces the RS422, RS-232, or V.35 interfaces. B.2.1 Theory of Operation The ADPCM interface is designed to simulate either a trunk or a subscriber circuit. (Refer to Figure B-2.
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SDM-100A Satellite Modem Options T E R R E S T R I A L M O D E M Figure B-3. ADPCM Block Diagram Rev.
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Options SDM-100A Satellite Modem B.2.1.1 Multiplexer The ADPCM interface provides a 6-wire, RJ11 phone connector on the back panel for the analog input. The input is a full-duplex four-wire input, with two additional pins for E&M signaling (Refer to Section B.2.3 for the RJ11 pinout specifications). The audio input is transformer-coupled with a 600Ω input load. The signal then passes to a programmable input level control circuit. The audio input level is user selectable in 1 dB steps, from -20 to +10 dBm.
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SDM-100A Satellite Modem Options The analog signal from the PCM decoder then passes through a programmable level control circuit (user selectable from the front panel). An RX Clip detect indicator in the FAULT RX menu is provided, which indicates a reception of an excessive signal. The audio output level is user-selectable from -20 to 10 dBm, in 1 dB steps. The output signal is transformer-coupled on the RJ11 connector. B.2.1.
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Options SDM-100A Satellite Modem B.2.2 Front Panel Operation The following sections describe the additional front panel operations that are specific to the ADPCM interface. These options are shown in the front panel menu tables (Chapter 3). B.2.2.1 Interface ADPCM ON/OFF Circuit Type E&M Signaling Encoding Type TX Channel Level RX Channel Level ADPCM interface ON/OFF selection. If ADPCM is set ON, the ADPCM operation is selected.
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SDM-100A Satellite Modem Options B.2.2.4 Utility/Interface With ADPCM turned off, the RS-422 signals SD, RD, RR, and DM can be inverted, if desired. B.2.2.5 TX Alarm Indication With the ADPCM option turned on, the TX alarm LED will come on if an excessive input level is sensed on the TX+ and TX- lines of the interface. B.2.2.6 RX Alarm Indication With the ADPCM option turned on, the RX alarm LED will come on if an excessive input level is received by the DEMUX. B.2.2.
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Options SDM-100A Satellite Modem B.2.3 Specifications Audio Encoding Audio Encoding Rate Audio Encoding Type Audio Interface Type E&M Signaling Audio Input Level Audio Output Level Filtering RJ11 Signal Function SIGNAL GROUND SEND DATA SEND TIMING RECEIVE DATA REQUEST TO SEND RECEIVER TIMING CLEAR TO SEND DATA MODE RECEIVER READY TERMINAL TIMING MOD FAULT DEMOD FAULT MASTER CLOCK Voice Encoding CCITT G.711 and G.721 PCM or ADPCM 64, 32, or 16 kbit/s (user-selectable) CCITT G.
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SDM-100A Satellite Modem Options B.3 Reed-Solomon Codec The Reed-Solomon Codec firmware works in conjunction with the interface card to provide concatenated, convolutional encoding and decoding. Refer to Figure B-4 for a block diagram of the Reed-Solomon Codec. The two main sections of the Codec that will be included in the theory of operation are the Reed-Solomon encoder (Section B.3.2.1) and the Reed-Solomon decoder (Section B.3.2.2).
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Options MUXDATA (SERIAL) MUXCLK SDM-100A Satellite Modem JP2 JP2 SYNCHRONOUS SCRAMBLER U3 SERIAL TO PARALLEL CONVERTER U3 SYNCHRONOUS FIFO U6 RS CODEC (ENCODER SECTION) UNIQUE WORD INSERTION RAM INTERLEAVER U4 U3 U2 PARALLEL TO SERIAL U3 JP2 JP2 TXSATDAT TXSATCLK INTERLEAVER ADDRESS GENERATOR U3 RS TIMING CONTROLLER U3 Figure B-5.
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SDM-100A Satellite Modem Options Since errors from the Viterbi decoder usually occur in bursts, a block-interleaver with a depth of 4 is used in accordance with the INTELSAT-308 Rev. 6B specification. The interleaver has the effect of spreading out the errors across blocks of data, instead of concentrating the errors in a single block of data.
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Options SDM-100A Satellite Modem B.3.2 Reed-Solomon Decoder Refer to Figure B-7 for a block diagram of the Reed-Solomon decoder section.
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SDM-100A Satellite Modem Options Refer to Figure B-6 for the Reed-Solomon code page format. The outer Codec reads the data in blocks of n bytes and recalculates the check bytes that were appended by the encoder. If the recalculated data bytes do not match the check bytes received, the Codec makes the necessary corrections to the data within the data block. The letter k represents the total number of bytes in a given block of data out of the Codec.
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Glossary The following is a list of acronyms and abbreviations that may be found in this manual. Acronym/ Abbreviation Ω A AC ADJ ADPCM AGC AOC ASC ASYNC AUPC BB BER bit/s BPSK C CCITT CL COM CPU cr CRT CS CSC CTS CW D/A dB dBc dBm DC Rev.
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Glossary SDM-100A Satellite Modem DCE DDS Demod DEMUX DM DSP DSR DTE E&M Eb/N0 EFD EIA EMC EXT FDC FDMA FEC FIFO Flt FPGA GND Hz I&Q I/O IBS IDR IESS IF kbit/s kHz Ks/s LCD LED lf LSI M&C mA Max MC MHz Min MOP MPC MS MUX NC NO PCB PCM pF PK PPM QPSK RAM RD RLSD g–2 Data Circuit Terminating Equipment Direct Digital Synthesis Demodulator Demultiplexer Data Mode Digital Signal Processing Data Signal Rate Data Terminal Equipment Ear and Mouth Bit Energy-to-Noise Ratio EFData Compatible Electronic Industries
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SDM-100A Satellite Modem Glossary RMA ROM RR RS RT RTS RX SCR SCT SCTE SD SN ST TP TT TTL TX UART UNK US V VAC VCO VDC W Rev.
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Glossary SDM-100A Satellite Modem This page is intentionally left blank. g–4 Rev.
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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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2114 WEST 7TH STREET TEMPE ARIZONA 85281 USA 480 • 333 • 2200 PHONE 480 • 333 • 2161 FAX