MI7-IPM800Mobile Radio

I I P P S S e e r r i i e e s s I I P P M M 8 8 M M o o b b i i l l e e R R a a d d i i o o P P r r o o d d u u c c t t O O w w n n e e r r ’ ’ s s M M a a n n u u a a l l Revision Date: September 29, 2003 Document #: 516-80511-POM Revision: A Copyright 2003 IPMobileNet, Inc. 16842 Von Karman Avenue, Suite 200  Irvine, CA 92606 Voice: (949) 417-4590 Fax: (949) 417-4591 IPM8-FCCRpt.doc Page ii The term “IC”: before the radio certification number only signifies that Industry of Canada technical specifications were met. Operation is subject to the following two (2) conditions: (1) this devise may not cause interference, and (2) this device must accept any interference, including interference that may cause undesired operation of this device. The following U.S. Patents apply to this product: U.S. Patent numbers 5,640,695,6,018,647,6,243,393 Information contained in this document is subject to change without notice. All rights reserved. Reproductions, adaptations, or translation without prior written permission is prohibited, except as allowed under copyright laws. TABLE OF CONTENTS IPM8-FCCRpt.doc Page 2 SECTION 1: THEORY OF OPERATION................................................................................. 3 General Block Diagram................................................................................................ 3 General Block Diagram Definitions ..................................................................... 3 IPM8 Mobile Radio Section Descriptions................................................................... 5 Microcontroller .................................................................................................... 5 Support Circuitry ................................................................................... 5 Inputs/Outputs .................................................................................................... 5 Modem .............................................................................................................. 6 VLogic and Digital Ground ................................................................................. 6 Receiver 1 Front-End ......................................................................................... 7 Receiver 1 IF ...................................................................................................... 7 Transmit Modulation ........................................................................................... 7 Injection Synthesizer .......................................................................................... 8 Transmitter/TR Switch ........................................................................................ 8 Power and Analog Ground ................................................................................. 8 SECTION 2: FACTORY TEST PROCEDURE......................................................................... 9 Equipment List............................................................................................................. 9 Programming and Configuring Mobile Radio.......................................................... 10 Adjustment / Alignment Procedures........................................................................ 11 Receiver Injection ............................................................................................. 11 Receiver 1 ........................................................................................................ 11 Receiver 2 ........................................................................................................ 12 Transmit Data ................................................................................................... 12 Transmit Power Control .................................................................................... 13 Receive Data .................................................................................................... 13 Final Test .......................................................................................................... 13 Uplink Hardware Timing Verification ................................................................ 15 Downlink Hardware Timing Verification ............................................................ 17 SECTION 3: FCC LABEL...................................................................................................... 19 IPM8 Data Transceiver FCC Label Placement......................................................... 19 IPM8 Data Transceiver FCC Label............................................................................ 19 APPENDIX A: IPM8 CIRCUIT BOARD DIAGRAMS............................................................. 21 APPENDIX B: IPM8 TEST DATA SHEET............................................................................. 23 SECTION 1: THEORY OF OEPRATION IPM8-FCCRpt.doc Page 3  General Block Diagram General Block Diagram Definitions For increased data security, the modem supports the Federal Government developed Digital Encryption Standard (DES) data encryption and decryption protocols. This capability requires installation of third party, Internet Protocol (IP) compliant DES encryption and decryption software on the system. The IPM8 mobile radio is comprised of two (2) circuit boards, the digital board and the RF board. The digital circuit board contains the following sections: Input/Output Circuitry associated with the radio’s DB9 data connector providing all the RS232 data and handshake functions, including the necessary level changes. Microcontroller Manages the operation of the radio, the modem, and determines which receiver provides a better signal from a given transmission. Also provides transmit time-out protection in the event a fault causes the radio to halt in the transmit mode. Modem Converts serial data into an analog audio waveform for transmission and analog audio from the receiver to serial data. Within a single chip it provides forward e…

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Crystal LAN TM Ethernet Controller 1 Cirrus Logic, Inc.Copyright © Cirrus Logic, Inc. 2000 P.O. Box 17847, Austin, Texas 78760(All Rights Reserved) (512) 445 7222 FAX: (512) 445 7851 http://www.cirrus.com CS8900A OVERVIEW FEATURES •Single-Chip IEEE 802.3 Ethernet Controller •Maximum Current Consumption = 55 mA (5V Supply) •3 V Operation •Industrial Temperature Range •Comprehensive Suite of Software Drivers Available •Efficient PacketPage™ Architecture Operates in I/O and Memory Space and as DMA Slave •Direct Bus Interface •Full Duplex Operation •On-Chip RAM Buffers Transmit and Receive Frames •10BASE-T Port with Analog Filters, Provides: — Automatic Polarity Detection and Correction • AUI Port for 10BASE2, 10BASE5, and 10BASE-F •Programmable Transmit Features: — Automatic Re-transmission on Collision — Automatic Padding and CRC Generation The CS8900A is a true single-chip, full-duplex, Ethernet solution, incorporating all of the analog and digital circuitry needed for a complete Ethernet circuit. Major functional blocks include: a direct bus interface; an 802.3 MAC engine; integrated buffer memory; a serial EEPROM interface; and a com- plete analog front end with both 10BASE-T and AUI. The CS8900A is a low-cost Ethernet LAN Control- ler optimized for embedded applications and Per- Functional Block Diagram EEPROM RJ-45 10BASE- T Attachment Unit Interface (AUI) 20 MHz XTA L RAM Bus Logic Memory Manager 802.3 MAC Engine EEPROM Control Encoder/ Decoder & PL L 10BASE-T RX Filters & Receiver 10BASE-T TX Filters & Transmitter AUI Transmitter AUI Collision AUI Receive r Cloc k Power Manage r Boundary Scan Test Logic LED Contro l CS8900A Ethernet Controller Bus (cont.)(cont.) NOV ‘01 PI271PP2 Product Bulletin CS8900A Crystal LAN TM Ethernet Controller 2PI271PP2 OVERVIEW(Continued from Page 1) sonal Computers. Its highly-integrated design eliminates the need for costly external components required by other Ethernet controllers. The CS8900A includes on-chip RAM, 10BASE-T trans- mit and receive filters, and a direct Bus interface with 24 mA Drivers. In addition to high integration, the CS8900A offers a broad range of performance features and config- uration options. Its unique PacketPage architec- ture automatically adapts to changing network traffic patterns and available system resources. The result is increased system efficiency. The CS8900A is available in a 100-pin TQFP package ideally suited for small form-factor, cost-sensitive Ethernet applications. With the CS8900A, system engineers can design a complete Ethernet circuit that occupies less than 1.5 square inches (10 sq. cm)ofboardspace. Contacting Cirrus Logic Support For a complete listing of Direct Sales, Distributor, and Sales Representative contacts, visit the Cirrus Logic web site at: http://www.cirrus.com/corporate/contacts/ Preliminary product information describes products which are in production, but for which full characterization data is not yet available. Advanceproduct infor- mation describes products which are in development and subject to development changes. Cirrus Logic, Inc. has made best efforts to ensure that the information contained in this document is accurate and reliable. However, the information is subject to change without notice and is provided “AS IS” without warranty of any kind (express or implied). No responsibility is assumed by CirrusLogic, Inc. for the use of this information, nor for infringements of patents or other rights of third parties. This document is the property of Cirrus Logic, Inc. and implies no license under patents, copyrights, trademarks, or trade secrets. No part of this publi- cation may be copied, reproduced, stored in a retrieval system, or transmitted, in any form or by any means (electronic, mechanical, photographic, orotherwise) without the prior written consent of Cirrus Logic, Inc. Items from any Cirrus Logic website or disk may be printed for use by the user. However, no part ofthe printout or electronic files may be copied, reproduced, stored in a retrieval system, or transmitted, in any form or by any means (electronic, mechanical, photo- graphic, or otherwise) without the prior written consent of Cirrus Logic, Inc.Furthermore, no part of this publication may be used as a basis for manufacture or sale of any items without the prior written consent of Cirrus Logic, Inc. The names of products of Cirrus Logic, Inc. or other vendors and suppliers appearing in this document may be trademarks or service marks of their respective owners which may be registered in some jurisdictions. A list of Cirrus Logic, Inc.trade- marks and service marks can be found at http://www.cirrus.com. FEATURES(Continued from Page 1) •Programmable Receive Features: — Stream Transfer™ for Reduced CPU Overhead — Auto-Switch Between DMA and On-Chip Memory — Early Interrupts for Frame Pre-Processing — Automatic Rejection of Erroneous Packets • EEPROM Support for Jumperless Configuration •Boot PROM Support for Diskless Systems •Boundary Scan and Loopback Test •LED Drivers for Link Status and LAN Activity •Standby and Suspend Sleep Modes •All the most popular drivers are available, including: — LINUX —Microsoft •NDIS2DOSdriver • NDIS 2 OS/2 driver • NDIS 3 drivers for Windows NT, Windows for Work- groups, Windows 95, and Windows CE • Novell •ODI DOS driver •ODI OS/2 driver •ODI Server •Packet Driver (TCP/IP) •pSOS •Real-time OS drivers •RIPL (Remote Initial Program Load) for ODI and NDIS 2 •RTOS/NCOS (ARM and Oracle) - In development •SCO •Setup/installation Utility: EEPROG Utility (EEPROM programming utility) •UNIX •VxWorks NOTE:To inquire about additional drivers, see“Order- ing Information” on page 3 CONFIDENTIAL DRAFT CS8900A Crystal LAN TM Ethernet Controller 3PI271PP2 OVERVIEW(cont.) CONFIDENTIAL DRAFT Key Benefits Very Low Cost The CS8900A is designed to provide the lowest- cost Ethernet solution available for embedded applications, portable motherboards, and adapter cards. Cost-saving features include: •Int…

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Trimble Key Features and Benefits • 3.3 V for battery powered applications • Programmable power management • Sized for portable devices Lassen LP GPS Low power module for portable applications Trimble’s new Lassen ™ LP GPS is a low power miniature GPS receiver module that is ideal for power-conscious portable appli- cations. It is intended specifically for system designers and integra- tors who are developing the next generation of portable devices. This embedded technology gives the system developer the programming flexibility to achieve a significant reduction in power consumption. Power management The Lassen LP GPS features a new set of power management tools that puts the power budget decision in the developer’s hands. The developer now can deter- mine the best balance between operational frequency and power conservation for a particular application. In Schedule Track ™ operat- ing mode, the developer can program the unit to power up, quickly acquire satellites and out- put position to a schedule. After gathering satellite data and com- puting its location, the receiver may be directed to power down to a minimal mode of operation for a programmed interval or until awakened by a hardware interruption. Schedule Track provides hot start performance at a programmed interval or in response to a hardware event. Schedule Track mode provides an advantage over normal battery-backed fast start modes with automatic wakeup to maintain current satellite data for fastest possible acquisition. Schedule Track offers the lowest power consumption in a deep sleep mode but provides position data as quickly as possible when needed. Ease of integration Lassen LP GPS provides a choice of data protocols for maximum flexibility. The TSIP binary data protocol incorporates new power management features and provides maximum control over system operation. The TAIP and NMEA protocols are available where ASCII data is preferred. A secondary serial input port is available for RTCM SC-104 differential correction data for high accuracy applications. The Lassen LP GPS also incorporates Trimble’s antenna detection and protection circuit to monitor the condition of the antenna system. And a new high performance, miniature 3.3 V antenna is available for the Lassen LP GPS. Getting started The Starter Kit makes it easy to evaluate the Lassen LP GPS and begin development. Actual size Lassen LP GPS Low power module for portable applications PHYSICAL CHARACTERISTICS Dimensions2.605′′L×1.250′′W×0.475′′H (66.167 mm×31.750 mm×12 mm) Weight0.4 oz. (12.5 grams) ConnectorsRF:right angle MCX Power, I/O:8-pin (2×4), 2 mm header ACCESSORIES GPS antennaCompact, 3.3 V active micropatch antenna with 5-meter cable and magnetic mount. 1.65′′×1.99′′×0.55′′high (42 mm×50.5 mm×13.8 mm) ORDERING INFORMATION Module Lassen LP GPS Module, Extended Temperature, TSIP (binary) protocol, NMEA 0183 (ASCII) protocol and TAIP (ASCII) protocol, DGPS ready Antennas 3.3 V antenna, 5-meter cable with MCX connector Starter Kit Includes Lassen LP GPS module mounted on interface motherboard in a durable metal enclosure with dual DB9, RS232 interface, AC/DC power converter, magnetic-mount 3 V antenna, TSIP, NMEA and TAIP protocols, software toolkit for TSIP, interface cable and manual. Manual Lassen LP GPS Module System Designer Reference Guide © Copyright 1999, Trimble Navigation Limited. All rights reserved. The Trimble logo with Trimble is a trademark of Trimble Navi gation Limited registered in the United States Patent and Trademark Office. Lassen and Schedule Track are trademarks of Trimble Navigation Limited. All other marks are the property of their respective own ers. TID11547C (11/99) PERFORMANCE SPECIFICATIONS GeneralL1 frequency, C/A code (SPS), 8-channel, continuous tracking receiver, 32 correlators Update rateTSIP @ 1 Hz NMEA @ 1 Hz TAIP @ 1 Hz Accuracy Position 25 m CEP (50%) w/o SA Velocity0.1 m/sec without SA Time±95 nano-seconds (over-determined clock mode) DGPS accuracy Position 2 m CEP (50%) Velocity0.05 m/sec Acquisition (typical)Cold start*:< 130 seconds (90%) Warm start**:< 45 seconds (90%) Hot start***:< 20 seconds (90%) Reacquisition after signal loss< 2 seconds (90%) Dynamics Acceleration 4 g (39.2 m/sec 2 ) Motional Jerk20 m/sec 3 Operational limitsAltitude <18,000 m or velocity < 515 m/sec either limit may be exceeded but not both ENVIRONMENTAL SPECIFICATIONS Operating temp–40°C to +85°C (standard) Storage temp–55°C to +100°C Vibration0.008 g 2 /Hz5 Hz to 20 Hz 0.05 g 2 /Hz20 Hz to 100 Hz –3 dB/octave100 Hz to 900 Hz Operating humidity5% to 95% R.H. non-condensing, + 60°C Altitude–400 m to +18,000 m TECHNICAL SPECIFICATIONS Prime power+3.3 V DC, ± 0.3 V Power consumption Normal operation GPS board only: 55 mA, 0.182 W with antenna: 67 mA, 0.221 W Deep sleep8 mA, board only Backup power+3.0 to +3.6 V DC 2–5 μA at +25°C (nominal) Serial ports/1PPSCMOS TTL levels I/O ProtocolsTSIP (binary data) NMEA 0183 v2.1 (ASCII data) TAIP (ASCII data) NMEA messagesGGA, VTG, GLL, ZDA, GSA, GSV and RMC messages selectable by TSIP command; selection stored in non-volatile memory. Antenna power3.3 V at 12 mA, feedline fault detect/protect * Cold start requires no initialization ** Warm start implies last position, time and almanac are saved in battery-backed memory *** Hot start implies ephemeris also saved. All GPS receivers are subject to degradation of position and velocity accuracies under Department of Defense imposed Selective Availability (SA). Visit our website at www.trimble.com/oem Specifications subject to change without notice. Trimble Navigation Limited Corporate Headquarters 645 North Mary Avenue Sunnyvale, CA 94086 +1-408-481-8940 +1-408-481-7744 Fax www.trimble.com Trimble Navigation Europe Limited Trimble House Meridian Office Park Osborne Way Hook, Hampshire RG27 9HX U.K. +44 1256-760-150 +44 1256-760-148 Fax Trimble Navigation Singapore PTE Limited 79 Anson Road #05-02 Singapore 079906 SINGAPORE +65-325-5668 +65-225-9989 Fax

~\Technical Documentation\Install_Guides\MR-Guide\29-Oct-03 Page 1 of 16 INSTALLATION GUIDE IP SERIES MOBILE RADIO SYSTEM INSTALLATION GUIDE CONTENTS: Section Title Page ƒ IP Series Mobile Radio Illustration .......................................2 ƒ Installation Overview and Safety Reminder.........................2 ƒ Installation Requirements ....................................................3 ƒ Pre-Installation Guidelines ...................................................5 ƒ Mounting the Mobile Radio ..................................................5 ƒ Serial Cable Connection and Routing..................................5 ƒ EMI Filter Installation ...........................................................6 ƒ Power Supply Installations...................................................6 ƒ Switch Installation ................................................................7 ƒ Delay Timer Installation .......................................................7 ƒ Antenna Installation .............................................................8 ƒ VIU (Vehicle Interface Unit) Connections ............................9 ƒ Testing and Installation Checklist ......................................10 ƒ Vehicle Unit Wiring Interconnection Layout .......................11 ƒ Diversity Antenna Vehicle Installation Detail Diagram.......12 ƒ Mobile Antenna Distance Matrix ........................................13 ƒ Vehicle Unit Wiring Interconnection Layout with VIU (Voice Interface Unit)..........................................................14 ƒ Vehicle Unit Wiring Interconnection Layout with Data911 and VIU (Voice Interface Unit).............................15 ƒ Vehicle Unit Wiring Interconnection Layout with Litton Computer and RF Filters....................................................16 IPMN p/n: 516-80307 Document Control #: DC-10 Version: C-3 11909 East Telegraph Road, Santa Fe Springs, CA 90670-3785 Voice: (562) 946-9493 Fax: (562) 949-0223 Copyright 2001-2002 IPMobileNet, Inc. Notice: While reasonable efforts were made to ensure that the information in this document was complete and accurate at the time of printing, IPMobileNet, Inc. can assume no responsibility for any inaccuracies. Changes and corrections to the inforrmation within this document may be incorporated into future releases. IP Series Mobile Radio ~\Technical Documentation\Install_Guides\MR-Guide\29-Oct-03 Page 2 of 16 IP Series Mobile Radio Illustration Installation Overview This guide will provide standard steps involved in the installation process of an IP Series Mobile Radio. This guide includes wire routing and connections between the radio, other components, and the vehicle’s power. Safety Reminder 1. To prevent personal injury and vehicle damage, exercise extreme caution throughout this installation process. ‰ Follow safety precautions for handling wiring, tools, and a vehicle’s engine. ‰ Handle the vehicle’s battery with extreme caution to avoid burns. ‰ Do not alter the components listed in the Installation Requirements on page 3 unless substitutions are noted within this document. ‰ Once the antennas are installed, as directed within this guide on page 8 of 15, all persons must maintain a distance of no less than 39 inches from the antennas. Black Red TX/RX1 RX2 Serial Cable DB9 Power Cable Mounting Bracket TX FCC ID M17-EC8DT450TX xxxxxxxxxxx xxxxwweddd xxxxxxxx xxxxwweddd ~\Technical Documentation\Install_Guides\MR-Guide\29-Oct-03 Page 3 of 16 INSTALLATION REQUIREMENTS PL502-82019-51 - MOBILE ACCESSORY KIT -- A Mobile Radio includes the following components (part of mobile top assembly): Qty Description IPMN Part Number 1 Cable, Power Extension 502-82020-53 2 ‘L’ Brackets 50026749 2 Screws Skt Cap Button Head 10-32 X 5/8 37081032-10 6 Washers Split Lock #10 271-0062-010 2 Washers Fender 1” O.D. X .28 I.D. X .05 THK 271-0059-001 4 Washers Rubber 1” O.D. X .65 I.D. X .12 THK 36040001 2 Hoses, Rubber Black .380 O.D. X .191 I.D. X .3 34010295 4 Screws Self-Tapping #10 X 5/8 37040010-10 0 Installation Manual 516-80307 0 Technical Manual 516-82025 PL502-80208-51 - INSTALLATION KIT – The following components are required for a Mobile Radio Installation and are available for purchase through IPMobileNet, Inc. Qty Description IPMN Part Number 1 EMI Filter 127-0020-001 1 Timer, 2 hours 150-0127-001 1 Relay 128-0117-001 1 Relay Socket 128-0116-001 2 Butt Connectors #8 AWG 120-0256-001 1 Terminal, Ring #8 AWG, #10 Screw Insulated 120-0127-001 4 Terminal, Ring #18-22 AWG, #10 Screws Insulated 120-0250-004 4 Terminal, Ring #10-12 AWG, #10 Screws Insulated 120-0250-005 4 Terminal, Disconnect #14-16 F 120-0244-002 18 Terminal, Disconnect #10-12 F 120-0244-003 2 Disconnect Tab, Quad Male 200-1377-001 1 Wire, 12 AWG Black, order 5 ft. 156-0242-001 1 Wire, 12 AWG Red, order 44 ft. 156-0242-003 1 Fuse, 30 AMPS ATO 122-0042-001 1 Fuse Holder, 30 AMPS 120-0253-001 1 Switch, Toggle DPST 144-0136-001 1 Diagram, Mobile Installation without VIU 502-80259 1 Diagram, Mobile Installation with VIU 502-80260 1 Diagram, Mobile Installation with Data 911 and VIU 502-80306 1 Diagram, Litton Interconnection with RF Filters VEH-01-0503 ~\Technical Documentation\Install_Guides\MR-Guide\29-Oct-03 Page 4 of 16 OPTIONAL INSTALLATION SUPPLIES – Order each item individually: Qty Description IPMN Part Number 1 Serial Cable (DB9MF), 20 ft. 156-0245-020 1 Wire, 8 (133/29) AWG VW-1 Red, by foot, order 19.5 ft. 156-0243-003 1 Wire, 8 (133/29) AWG VW-1 Black, by foot, order 19.5 ft. 156-0243-001 2 RG58U Cable and Mount, VHF, 17 ft. (incl ¾” Brass Mount and N Male Crimp) 102-0200-001 2 RG8X Cable and Mount, UHF & 800 MHz, 17 ft. (incl ¾“ Brass Mount & N Male Crimp) 102-0200-002 2 Antenna, Radome Type, 142-164 MHz, Unity Gain (requires 1 MB8UN for ea antenna) 102-0205-001 2 Antenna, Radome Type, 150-174 MHz, Unity Gain (requires 1 MB8UN for ea antenna) 102-0205-002 2 Antenna, Radome Type, 410-430 MHz, 3dB Gain (requires 1 MB8XN for ea antenna) 102-0206-001 …

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IPM8 Data Transceiver FCC Label Placement

Interior Overall Front PCB Component Side Front PCB Back Side Back PCB Component Side Back PCB Back Side

SECTION 1: THEORY OF OPERATION IPM8 Mobile Radio Section Descriptions  The IPM8 Mobile Radio works within a frequency range of 806 to 821 MHz and requires a 1/4-wavelength antenna. This section provides detailed descriptions of each of the sections within the IPM8 Mobile Radio. Refer to Appendix A to view the IPM8 Mobile Radio Circuit Board Diagram. Microcontroller The microcontroller (U30) is a major component of the radio as it manages the operation of the radio. It also controls the operation of the modem, and determines which receiver provides a better signal from a given transmission. It provides transmit time-out protection in the event a fault causes the radio to halt in the transmit mode. It utilizes a reduced instruction set computer (RISC) architecture which provides low power operation and a powerful instruction set. Other features include a watchdog timer, serial universal asynchronous receiver/transmitter (UART), two 8-bit timers, and 2 KB of electrically erasable programmable read only memory (EEPROM) storage. NOTE : The EEPROM Random Access Memory (RAM) stores the setup data entered by the technician even if there is a loss of power. Support circuitry The support circuitry consists of the following: ƒ A Supervisor Control Chip (U25) provides power-on reset. ƒ The clock controls microcontroller operation and is generated by crystal Y3 and a Pierce oscillator circuit (inside the U30-microcontroller). ƒ The latch (U28) decodes low order address bits (A0-A7) from the address/data bits (AD0- AD7). It is controlled by Address Latch Enable (ALE) output of U30 and the bits are used by the modem. ƒ A 512Kx8 Static RAM Chip (U31) provides temporary storage of the radio’s configuration data facilitating the technician with access to make changes. ƒ Control logic is also an important part in the microcontroller section. The RAM chip select (RAMCS*) and modem chip select (MODEMCS*) command lines are created by U26A, U27BCD, and U44ABC. These gates decode four (4) high order address bits (A11-A15). The RAM is addressed by five (5) memory addresses (MA14-MA18) bits decoded by U26D, U27A, and U24. This logic decodes port address bits (PA14-PA18) to produce memory address bits (MA14-MA18) for the RAM chip. Input/Output Input/output components convert serial and handshake data from the modem section to RS232 levels, and vice-versa. Chip U22 is an RS232 transmitter and receiver. It converts data in 5-volt logic form to data in +/-12-volt form, as required by the RS232 standard. A charge pump power supply on the chip converts the +5-volt DC logic power on pin 26 to the +12-volt and –12-volt SECTION 1: THEORY OF OPERATION levels required. Capacitors C106-C109 generate these voltages by a charge pump. These values determine the operating voltages. SECTION 1: THEORY OF OPERATION Modem The single-chip modem circuit converts parallel data to an analog audio waveform for transmission and analog audio from a receiver to parallel data. In addition to the modem functions, the chip provides forward error detection and correction (FEC), bit interleaving and Viterbi Soft Decision Algorithms for more robust data communications. The microcontroller section controls the modem operation. Address bus, address/data bus, and control lines operate the modem chip. The modem circuitry is also run by a crystal-controlled clock, which consists of crystal Y1 and an internal Pierce oscillator. The received audio signal is demodulated into digital data appearing on the AD0-AD07 lines when the MODEMCS* and RD* lines are low. The data goes to the microcontroller section for futher processing, and then to the input/output section for conversion to RS232 or Ethernet signal levels. During a transmission, outgoing data appearing on the AD0-AD07 lines is converted into a 4-level FSK analog signal by the modem chip. This operation takes place when the MODEMCS* and WR* lines are low. Data from the user’s MDC or VIU passes through the input/output section and microcontroller section to the AD0-AD07 bus. After processing, data passes through a root raised cosine filter and is output to TXMOD. This modem supports 115.2 KBPS (serial port), 19.2 KBPS and 32 KBPS (over-the-air) data transmission rates. VLogic and Digital Ground The VLogic and Digital Ground section consists of a pulse-width modulation (PWM) step-down DC-DC converter (U20) that provides an adjustable output. It also reduces noise in sensitive communications applications and minimizes drop out voltage. An external Schottky diode (D2) is required as an output rectifier to pass inductor current during the second half of each cycle to prevent the slow internal diode of the N-channel MOSFET from turning on. This diode operates in pulse-frequency modulation (PFM) mode and during transition periods while the synchronous rectifier is off. SECTION 1: THEORY OF OPERATION Receiver 1 Front-End This section contains components that include several RF Bandpass filters, a low-noise amplifier, and a MMIC mixer. Incoming signals pass through one (1) pre-selector band pass filter (FL3) that selectively provides a high degree of out-of-band signal rejection. An RF amplifier (U35) amplifies the selected signals and is followed by a SAW filter (FL4). The output from FL4 passes through a mixer (U4). U4 is a MMIC mixer which mixes the receive injection (RXINJ1) signal from the synthesizer and the RF signal from the antenna to produce a 45 MHz IF signal. This 45 MHz signal passes through a matched pair of monolithic filters (FLT3 and FLT4) to the Receiver 1 IF section to provide the bulk of the Receiver’s selectivity.  Receiver 2 Front-End operates identical to Receiver 1 Front-End. Receiver 1 IF The major contributor of the IF subsystem (U34) a complete 45 MHz superheterodyne receiver chip incorporating a mixer/oscillator, two limiting intermediate frequen…

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