Tait TM8235, TM8250, TM8255, TM8252, TM8115 Service Manual

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Page 1

TM8100 mobiles TM8200 mobiles

Service Manual

MMA-00005-04

Issue 4

June 2006

Page 2

Contact Information

Tait Radio Communications Corporate Head Office

Tait Electronics Limited P.O. Box 1645 Christchurch New Zealand

For the address and telephone number of regional offices, refer to the TaitWorld website:

We b s it e : http://www.taitworld.com

Technical Support

For assistance with specific technical issues, contact Technical Support:

E-mail: support@taitworld.com We b s it e : http://support.taitworld.com

Intellectual Property Rights

This product may be protected by one or more patents of Tait Electronics Limited together with their international equivalents, pending patent applications and registered trade marks: NZ338097, NZ 508054, NZ508340, NZ508806, NZ 508807, NZ 509242, NZ509640, NZ509959, NZ 510496, NZ 511155, NZ511421, NZ516280/519742, NZ 519118, NZ519344, NZ520650/537902, NZ 521450, NZ524509, NZ524537, NZ 524630, NZ 530819, NZ534475, NZ534692, NZ 535471, NZ 536945, NZ537434, NZ534369, NZ 522236, NZ 524378, AU2003281447, AU2002235062, AU2004216984, CA2439018, EU03784706.8, EU 02701829.0, EU04714053.8, GB23865476, GB 2386010, GB0516094.0, GB0516092.4, US 09/847322, US60/ 613748, US60/539617, US 10/520827, US10/468740, US5,745,840, US 10/520827.

All information contained in this manual is the property of Tait Electronics Limited. All rights reserved. This manual may not, in whole or in part, be copied, photocopied, reproduced, translated, stored, or reduced to any electronic medium or machine-readable form, without prior written permission from Tait Electronics Limited.

The word TAIT and the TAIT logo are trademarks of Tait Electronics Limited.

All trade names referenced are the service mark, trademark or registered trademark of the respective manufacturers.

Disclaimer

There are no warranties extended or granted by this manual. Tait Electronics Limited accepts no responsibility for damage arising from use of the information contained in the manual or of the equipment and software it describes. It is the responsibility of the user to ensure that use of such information, equipment and software complies with the laws, rules and regulations of the applicable jurisdictions.

Enquiries and Comments

If you have any enquiries regarding this manual, or any comments, suggestions and notifications of errors, please contact Technical Support.

To Our European Customers

Tait Electronics Limited is an environmentally responsible company which supports waste minimization and material recovery. The European Union’s

Waste Electrical and Electronic Equipment Directive requires that this product be disposed of separately from the general waste stream when its service life is over. Please be environmentally responsible and dispose through the original supplier, your local municipal waste “separate collection” service, or contact Tait Electronics Limited.

Updates of Manual and Equipment

In the interests of improving the performance, reliability or servicing of the equipment, Tait Electronics Limited reserves the right to update the equipment or this manual or both without prior notice.

2 TM8100/TM8200 Service Manual

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Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Scope of Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Hardware and Software Versions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Associated Documentation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Publication Record . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Alert Notices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Chapter 1 Description of the Radio . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

2 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

3 Circuit Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Chapter 2 Servicing the Radio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

4 General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

5 Disassembly and Reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129

6 Servicing Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149

7 Power Supply Fault Finding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163

8 Interface Fault Finding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173

9 Frequency Synthesizer Fault Finding . . . . . . . . . . . . . . . . . . . . . . . . 179

10 Receiver Fault Finding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239

11 Transmitter Fault Finding (40W/50W) . . . . . . . . . . . . . . . . . . . . . 259

12 Transmitter Fault Finding (25W) . . . . . . . . . . . . . . . . . . . . . . . . . . 323

13 CODEC and Audio Fault Finding. . . . . . . . . . . . . . . . . . . . . . . . . . 381

14 Fault Finding of Control Head with Graphical Display . . . . . . . . . . . 405

15 Fault Finding of Control Head with 1- 2- or 3-Digit Display . . . . . . 429

16 Spare Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 437

Chapter 3 Accessories. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .447

17 TMAA01-01 Line-Interface Board . . . . . . . . . . . . . . . . . . . . . . . . . 451

18 TMAA01-02 RS-232 Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 471

19 TMAA01-05 Options-Extender Board . . . . . . . . . . . . . . . . . . . . . . 479

20 TMAA02-02 DTMF Microphone . . . . . . . . . . . . . . . . . . . . . . . . . 489

21 TMAA02-06 Support Kit for Concealed & Dynamic Microphones. . 493

22 TMAA02-07 Concealed Microphone . . . . . . . . . . . . . . . . . . . . . . . 501

23 TMAA02-08 Keypad Microphone . . . . . . . . . . . . . . . . . . . . . . . . . 503

24 TMAA03-02 Security Bracket . . . . . . . . . . . . . . . . . . . . . . . . . . . . 507

25 Installing a Remote Kit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 511

26 Installing an Enhanced Remote Kit . . . . . . . . . . . . . . . . . . . . . . . . . 527

27 TMAA04-04 Crossband Linking Cable . . . . . . . . . . . . . . . . . . . . . . 543

TM8100/TM8200 Service Manual 3 © Tait Electronics Limited June 2006

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28 TMAA04-05 Ignition Sense Kit . . . . . . . . . . . . . . . . . . . . . . . . . . . 549

29 TMAA10-01 Desktop Microphone . . . . . . . . . . . . . . . . . . . . . . . . 551

30 TMAA10-02 Handset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 555

31 TMAA10-03 and TMAA10-06 High-Power Remote Speakers . . . . 559

32 TMAA10-04 Remote PTT Kit and TMAA10-05 Hands-Free Kit . . 561

33 TMAA10-07 Desktop Microphone . . . . . . . . . . . . . . . . . . . . . . . . 569

34 TOPA-SV-024 Test Unit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 571

4 TM8100/TM8200 Service Manual

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Preface

Scope of Manual

This manual contains information to service technicians for carrying out level-1 and level-2 repairs of TM8100 and TM8200 radios and accessories.

Level-1 repairs entail the replacement of faulty parts and circuit boards; level-2 repairs entail the repair of circuit boards, with the exception of certain special items on the boards. The manual does not cover level-3 repairs, which entail the repair of the special items.

Hardware and Software Versions

This manual describes the following hardware and software versions. The IPNs (internal part numbers) of the boards are listed below; the last two digits in the IPN represent the issue of the board. The board information in this manual covers all production-issue boards up to the issue listed below.

■ Main board (A4 band) 25W : 220-02074-04

■ Main board (B1 band) 25W : 220-01700-11

■ Main board (B1 band) 50W : 220-01723-02

■ Main board (C0 band) 25W : 220-01742-04

■ Main board (D1 band) 25W : 220-01717-02

■ Main board (H5 and H6 bands) 25W : 220-01697-11

■ Main board (H5 and H7 bands) 40W : 220-01722-02

■ Control-head board (1-digit display) : 220-02070-01

■ Control-head board (2-digit display) : 220-01699-03

■ Control-head board (3-digit display) : 220-02151-02

■ Control-head board (graphical display) : 220-01718-01

■ Control-head board (RJ45) : 220-01720-05

■ Programming application (TM8100) : version 2.92

■ Programming application (TM8200) : version 2.1

■ Calibration application : version 2.71

TM8100/TM8200 Service Manual 5 © Tait Electronics Limited June 2006

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Associated Documentation

The following associated documentation is available for this product:

Manuals ■ MMA-00002-xx TM8100 User’s Guide

■ MMA-00003-xx TM8200 User’s Guide

■ MMA-00051-xx TM8235 User’s Guide

■ MMA-00028-xx TM8100/TM8200 Installation Guide

■ MMA-00006-xx TM8100 Operator’s Guide

■ MMA-00004-xx TM8200 Operator’s Guide

PCB Information ■ MMA-00016-xx TM8100/TM8200 Main Board (A4) 25W

■

MMAB12-B1-00-814

■ MMA-00031-xx TM8100/TM8200 Main Board (B1) 25W

■ MMA-00032-xx TM8100/TM8200 Main Board (D1) 25W

■

MMAB12-H5-00-814

■ MMA-00033-xx TM8100/TM8200 Main Board (H5/H6) 25W

■ MMA-00020-xx TM8100/TM8200 Main Board (B1) 50W

■ MMA-00021-xx TM8100/TM8200 Main Board (H5/H7) 40W

■ MMA-00035-xx TM8100 Control-Head Board (2-Digit Display)

■ MMA-00036-xx TM8100 Control-Head Board (1-Digit Display)

■ MMA-00015-xx TM8200 Control-head Board (Graphical Display)

■ MMA-00058-xx TM8200 Control-Head Board (3-Digit Display)

■ MMA-00034-xx TM8200 Control-Head Board (RJ45)

■ MMA-00037-xx TM8100/TM8200 PCB Information

The characters xx represent the issue number of the documentation.

TM8100/TM8200 Main Board (B1) 25W (board IPN 220-01700-05)

(boards after IPN 220-01700-05)

TM8100/TM8200 Main Board (H5/H6) 25W

(board IPN 220-01697-05)

(boards after IPN 220-01697-05)

(printed, pre-punched and shrink wrapped; comprises MMA-00015-xx, MMA-00016-xx, MMA-00020-xx, MMA-00021-xx, MMA-00031xx, MMA-00032-xx, MMA-00033-xx, MMA00034-xx, MMA-00035-xx, MMA-00050-xx and MMA-00058-xx).

All available documentation is provided on the TM8100/TM8200 Service CD, product code TMAA20-01. Updates may also be published on the Tait support website.

3DK Manuals The following manuals are mainly of concern to third-party developers.

The manuals are supplied on the 3DK (third-party developer’s kit) resource CD.

■ MMA-00011-xx TM8100/TM8200 3DK Hardware Developer’s

Kit Application Manual

6 TM8100/TM8200 Service Manual

Page 7

■ MMA-00014-xx TMAA30-02 TM8000 3DK Application Board

■ MMA-00013-xx TMAA30-02 TM8000 3DK Application Board

■ MMA-00038-xx TM8100/TM8200 Computer-controlled Data

Publication Record

Issue Publication Date Description

01 March 2005 first release

02 May 2005 update for 40W/50W radios

03 August 2005 update to board issue 10 (B1, H5 and H6 bands)

04 June 2006 include TM8200 3-digit-display control head, A4

Software Programmer’s Manual

Service Manual

Interface Protocol Definition

of 25W radios, incorporation of accessories manual

and C0 bands, and information on issue -05 main board for B1, H5 and H6 bands

Alert Notices

Within this manual, four types of alerts are given to the reader: warning, caution, important and note. The following paragraphs illustrate each type of alert and its associated symbol.

Warning!! This alert is used when there is a potential risk

of death or serious injury.

Caution This alert is used when there is the risk of minor or

moderate injury to people.

Important This alert is used to warn about the risk of equipment dam-

age or malfunction.

Note This alert is used to highlight information that is required to

ensure that procedures are performed correctly.

TM8100/TM8200 Service Manual 7 © Tait Electronics Limited June 2006

Page 8

Abbreviations

Abbreviation Description

ACP Adjacent Channel Power

ADC Analog-to-Digital Converter

AGC Automatic Gain Control

ALC Automatic Level Control

ASC Accredited Service Centre

C4FM Compatible Four-level Frequency Modulation

CCTM Computer-Controlled Test Mode

CODEC Coder-Decoder

CSO Customer Service Organisation

CTCSS Continuous-Tone-Controlled Subaudible Signaling

DAC Digital-to-Analog Converter

DC Direct Current

DSP Digital Signal Processor

DTMF Dual-Tone Multi-Frequency

EPTT External PTT (Press-To-Talk)

ESD Electrostatic Discharge

FCL Frequency Control Loop

FE Front-End

FEC Forward Error Correction

FPGA Field-Programmable Gate Array

GPIO General Purpose Input/Output

GPS Global Positioning System

GUI Graphical User Interface

IC Integrated Circuit

IPN Internal Part Number

IF Intermediate Frequency

IQ In-Phase and Quadrature

ISC International Service Centre

LCD Liquid-Crystal Display

8 TM8100/TM8200 Service Manual

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Abbreviation Description

LED Light-Emitting Diode

LNA Low-Noise Amplifier

LO Local Oscillator

LPF Low-Pass Filter

NPN Negative-Positive-Negative

PA Power Amplifier

PCB Printed Circuit Board

PLL Phase-Locked Loop

PNP Positive-Negative-Positive

PSU Power Supply Unit

PTT Press-To-Talk

RISC Reduced Instruction Set Computing

RSSI Received Signal Strength Indication

SFE Software Feature Enabler

SMA Sub Miniature Version A

SMD Surface-Mount Device

SMT Surface-Mount Technology

SMPS Switch-Mode Power Supply

SPI Serial Peripheral Interface

TCXO Temperature-Compensated Crystal Oscillator

TEL Tait Electronics Limited

UHF Ultra High Frequency

VCO Voltage-Controlled Oscillator

VCXO Voltage-Controlled Crystal Oscillator

VHF Very High Frequency

TM8100/TM8200 Service Manual 9 © Tait Electronics Limited June 2006

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10 TM8100/TM8200 Service Manual

Page 11

TM8100 mobiles TM8200 mobiles

Chapter 1

Description of the Radio

TM8100/TM8200 Service Manual 11 © Tait Electronics Limited June 2006

Page 12

Chapter 1 – Description of the Radio

1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

1.1 Frequency Bands. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

1.2 RF Output Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

1.3 Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

1.4 Product Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

1.5 Labels. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

1.6 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

2 Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

2.1 Mechanical Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

2.2 User Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

2.3 Connectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

2.4 Hardware and Software Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

2.5 Operation in Receive Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

2.6 Operation in Transmit Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

3 Circuit Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

3.1 Transmitter Circuitry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

3.2 Receiver Circuitry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

3.3 Frequency Synthesizer Circuitry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

3.4 Frequency Control Loop. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

3.5 CODEC and Audio Circuitry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

3.6 Power Supply Circuitry. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

3.7 Interface Circuitry. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

3.8 Digital Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

3.9 Control-Head Board with Graphical Display . . . . . . . . . . . . . . . . . . . . . 92

3.10 Control-Head Board with 1-, 2- or 3-Digit Display . . . . . . . . . . . . . . . . 95

3.11 RJ45 Control Head . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

12 TM8100/TM8200 Service Manual

Page 13

1 Introduction

The TM8100 and TM8200 series is a range of high-performance microprocessor-controlled radios for analog voice and data communication. The radios are designed for installation in vehicles but can also be used in desktop, remote-monitoring and similar applications.

This manual includes the information required for servicing the radio and its accessories.

This section describes the different options available for:

■ frequency bands

■ RF output power

■ accessories

■ product codes.

This section also gives an overview of the labels on the product and the specifications.

Figure 1.1 TM8200 mobile radios

TM8235 radio with 3-digit-display control head

TM8250 or TM8255 radio with graphical-display control head

TM8252 radio with RJ45 control head

TM8100/TM8200 Service Manual Introduction 13 © Tait Electronics Limited June 2006

Page 14

Figure 1.2 TM8100 mobile radios

TM8110 radio with 1-digit-display control head

TM8115 radio with 2-digit-display control head

rear view (25W radio)

TM8105 radio with blank control head

14 Introduction TM8100/TM8200 Service Manual

Page 15

1.1 Frequency Bands

The radios are available in the following frequency bands:

■ 66 to 88MHz (A4)

■ 136 to 174MHz (B1)

■ 174 to 225MHz (C0)

■ 216 to 266MHz (D1)

■ 400 to 470MHz (H5)

■ 450 to 530MHz (H6)

■ 450 to 520MHz (H7)

The frequency bands are implemented by different main boards in the radio body. The control heads are identical for all frequency bands.

1.2 RF Output Power

The radio bodies are available with 40W/50 W and 25W RF output power.

The two RF output power options are implemented by different main boards in the radio body, mechanically different radio bodies, and different power connectors. The control heads are identical for all RF output power options.

The 40W/50W radio is available in the following frequency bands:

■ B1 (50W)

■ H5 (40W)

■ H7 (40W)

The 25W radio is available in the following frequency bands:

■ A4

■ B1

■ C0

■ D1

■ H5

■ H6

TM8100/TM8200 Service Manual Introduction 15 © Tait Electronics Limited June 2006

Page 16

1.3 Accessories

Tait offers a large variety of audio accessories, installation kits, internal options boards and other accessories such as a desktop power supply.

For more information on these accessories refer to “Chapter 3 Accessories”

on page 447.

Audio Accessories The radios allow for the connection of a comprehensive range of audio

accessories:

■ rugged microphone (standard)

■ DTMF microphone

■ keypad microphone

■ handset

■ concealed microphone (TM8200) and concealed microphone kit

(TM8100)

■ high-power remote speaker

■ remote PTT kit and hands-free kit.

Installation Kits The radio is delivered with a vehicle installation kit, including a U-bracket.

Installation of the radio is described in the user’s guide or the installation guide.

Optional installation kits are:

■ remote control-head kit for remote installation of the control head

■ security bracket for secure and quick-release installation

■ ignition-sense kit.

Internal Options Boards

The radio provides space for an internal options board inside the radio body connecting to an internal options connector. An aperture for an external options connector is also provided.

Tait offers the following internal options boards:

■ line-interface board

■ RS-232 board

■ options-extender board.

Control-Head Options Boards

The radio provides space for a control-head options board inside the blank control head of the TM8105 and TM8252 radios.

Desktop Power Supply

16 Introduction TM8100/TM8200 Service Manual

A desktop power supply including the parts for mounting the radio is available for desktop installations.

Page 17

1.4 Product Codes

This section describes the product codes used to identify products of the TM8100 and TM8200 mobile radio product lines.

General The product codes of the TM8100 and TM8200 mobile radio product lines

have the format:

TMAabc–ddee

where:

■ a identifies the product category:

A=accessory, B =radio body, C =control head, S= software feature

■ b, c, dd and ee identify specific product features.

Radio Bodies The product codes of the radio bodies have the format:

TMABbc–ddee

where:

■ b identifies the architecture of the digital board:

1=conventional analog 2=conventional analog (dual-mode capability) 3 identifies the digital boards of the digital TM9100 product line.

■ c identifies the RF output power:

2=25W, 3=25 W (trigger-base), 4=30 to 59 W, 5=30 to 59W (trigger-base).

■ dd identifies the frequency band:

A4=66 to 88MHz, B1 =136 to 174 MHz, C0 =174 to 225MHz, D1=216 to 266MHz, H5 =400 to 470MHz, H6 =450 to 530MHz, H7=450 to 520 MHz.

■ ee identifies any radio options:

00=BNC RF connector, 01=mini-UHF RF connector

Control Heads The product code of the control heads has the format:

TMACbc–dd

where:

■ b identifies the control-head type:

1=blank control head, 2=2-digit-display control head, 3=RJ45 control head, 4=graphical-display control head, 5=1-digit-display control head, 6= 3-digit-display control head.

■ c identifies the control-head configuration:

0=no options, 4=RS-485 option 1 identifies the control-head configuration of the digital TM9100 product line.

■ dd identifies label and branding options:

0T=Tait, 0U= unbranded.

TM8100/TM8200 Service Manual Introduction 17 © Tait Electronics Limited June 2006

Page 18

1.5 Labels

Four external labels are attached to the bottom of the radio body:

■ compliance information

■ serial number and product code

■ hot surface safety warning

■ RF exposure safety warning.

Figure 1.3 Labels of the TM8100 and TM8200 product lines

Made in

TAIT

New Zealand

TMAH6C

IC: 737A-TMAH6C FCC ID: CASTMAH6C

N46

Contains intellectual property licenced by Digital Voice Systems Inc, Motorola Inc and Tait Electronics Ltd. Details in user documentation.

S/N 19061964

TMAB22-H600

450-530 MHz

Tait Electronics Ltd, NZ

1.6 Specifications

For up-to-date specifications, refer to the area on the TaitWorld website reserved for TM8100 and TM8200 products.

18 Introduction TM8100/TM8200 Service Manual

Page 19

2 Description

This section describes the mechanical design and architecture of the radio, explains the operation of the transceiver and the control head, and gives pinouts of the radio connectors.

2.1 Mechanical Design

Overview The radio consists of the following main components:

■ control head B

■ radio body C.

Figure 2.1 Components of the radio

3068z_01

The control head where a seal connects the control head to the radio body. Two dot-dash-dot marks at the bottom of the radio body indicate the positions where a screwdriver is applied to separate the control head from the radio body.

B clips firmly to the front face of the radio body C,

E provides IP54 class protection. A control-head loom D

TM8100/TM8200 Service Manual Description 19 © Tait Electronics Limited June 2006

Page 20

2.1.1 Radio Body

Overview The radio body consists of the following main components (see Figure 2.2

on page 21):

■ cover B

■ lid D

■ internal options board (optional)

■ chassis G

■ main-board assembly F.

Cover The black plastic cover B wraps over the top and sides of the radio body.

Apertures in the sides of the cover allow access to the four external screw bosses of the radio body used for mounting the radio to the U-bracket.

Lid The aluminium lid D is attached to the chassis G with four M4x16 Torx-

head screws provides for IP54 class protection. The rear of the lid has an aperture for an external options connector, which may be fitted if an internal options board is used. If no external options connector is used, the aperture is sealed with a bung for IP54 class protection. The lid contains two of the four screw bosses to attach the radio to the U-bracket of the installation kit.

C. A seal fitted inside a groove at the underside of the lid

Internal Options Board (Optional)

On the inside of the lid, nine screw points are provided for mounting an internal options board, which can be sized and shaped as required. The internal options board connects to the internal options connector of the main board. Tait offers a range of internal options board, which are described in the accessories section of this manual. For more information on how to create your own internal options board, contact Tait Electronics Limited.

Chassis The aluminium chassis g is different for the 40W/50W radio and the 25W

radio.

The chassis five screws

G houses the main-board assembly F, which is attached with

E to screw bosses inside the chassis and with two screws I

through the rear of the chassis to the heat-transfer block.

The rear of the chassis has apertures for the RF, power and auxiliary connectors of the main board. If the auxiliary connector is not used, the aperture is sealed with a rubber bung The RF connector has a rubber seal

J for IP54 class protection.

H which is fitted inside the aperture

for the RF connector.

20 Description TM8100/TM8200 Service Manual

Page 21

Figure 2.2 Components of the radio body

thermal paste

cover

screw M4x 16 (x4)

lid assembly

screw M3x 10 (x5)

main-board assembly

chassis

auxiliary connector bung

screws M4x 16 (x2)

seal

gap pad (50W/40W radio only)

3630z_01

TM8100/TM8200 Service Manual Description 21 © Tait Electronics Limited June 2006

Page 22

The front of the chassis has an aperture for the control-head connector. The control-head seal is fitted inside a groove around the flange at the front face of the chassis and provides for IP54 class protection when the control head is fitted. Two dot-dash-dot marks at the underside side of the chassis indicate the leverage points for removing the control head from the radio body.

The sides of the chassis contain two of the four screw bosses to attach the radio to the U-bracket of the installation kit.

For heat dissipation, the chassis has heat fins at the rear, grooves at the bottom, and holes in the front.

The heat fins at the rear of the 40W/50W radio are longer than those of the 25W radio. The grooves at the bottom of the 40W/50W radio are deeper than those of the 25W radio.

For additional heat dissipation, the 40W/50W radio has an additional L-shaped gap pad

1) between the chassis and the main board.

22 Description TM8100/TM8200 Service Manual

Page 23

Main-Board Assembly

The main-board assembly consists of the following components (see Figure 2.3):

■ main board 1^ with SMT components, digital board D, shielding cans,

and connectors

■ heat-transfer block H

■ mounting and sealing elements for the connectors at the rear of the

radio body.

Figure 2.3 Components of the main-board assembly

thermal paste

M3x10 screw (x3)

50W/40W radios:

M2.2x10 PT screw (x2)

25W radios: K30x8 PT screw (x2)

digital board

internal options connector

auxiliary connector

inner foam D-range seal

heat-transfer block

outer foam seal

D-range screwlock fastener (x2)

power connector seal

power connector

gap pad (50W/40W radio only)

hexagonal nut

lock washer

RF connector

main board

control-head connector

3631z_01

TM8100/TM8200 Service Manual Description 23 © Tait Electronics Limited June 2006

Page 24

The main board 1^ is attached to the heat-transfer block H with three M3x10 Torx-head screws auxiliary and RF connectors.

B and the fastening elements J, 1# and 1$ of the

The inner foam D-range seal heat-transfer block. The power connector seal against the heat-transfer block.

The power connector seal the seal of the 25W radio (black).

Main Board The main board 1^ is a printed circuit board in SMT design with

components on the top and bottom sides. A digital board soldered to the main board. Most components are shielded by metal cans.

There are different main boards for each frequency band and each RF output power configuration.

The internal options connector and the factory connector (not illustrated) for factory use are soldered to the top side of the main board. The control-head connector of the radio) and the auxiliary the rear of the radio) are located on the bottom side of the main board.

The 40W/50W radio has a black power connector has a white power connector.

G seals the auxiliary connector against the

1) seals the power connector

1) of the 40W/50W radio (blue) is different to

D is reflow-

E for connecting an internal options board

1& (facing the front

F, power 1! and RF 1% connectors (facing

1! and the 25W radio

For more information on the connectors, refer to “Connectors” on

page 36.

For heat dissipation, one of the screw bosses inside the chassis is in contact with the underside of the main board. A larger copper plate at the underside of the main board connects to the body of the heat-transfer block.

The 40W/50W radio has an additional gap pad between the heat-transfer block and the main board at the bottom side of the main board.

Heat-Transfer Block The aluminium heat-transfer block H dissipates heat from the main board

to the heat fins of the chassis. The heat-transfer block has a contact surface to the larger copper plate at the underside of the main board contact surface to the rear of the chassis. All contact surfaces are coated with thermal paste.

Two self-adhesive foam seals connector on either side of the heat-transfer block and the power connector

1) inside the aperture of the power connector are fitted to the heat-

seal transfer block.

1^ which connects to an additional copper plate

1^, and a

G and I around the aperture of the auxiliary

24 Description TM8100/TM8200 Service Manual

Page 25

2.1.2 Control Head with Graphical Display

Overview The control head can be divided into the following main areas:

■ front panel with control elements, indicators, LCD, speaker, and

concealed microphone (optional)

■ space-frame and seals

■ control-head board with SMT components, shielding cans, connectors,

and volume potentiometer

■ control-head loom with female-female adapter

■ adapter flange.

The circled numbers in this section refer to the items in Figure 2.4 on

page 27.

Front Panel Assembly

The front panel assembly 1^ consists of an injection-moulded plastic part with an integrated transparent light pipe element for the radio

STATUS LEDs,

a transparent lens which cannot be replaced, a cloth membrane which is fixed to the speaker grille, and a foam seal inside a rectangular LCD recess behind the lens. A label

1* with the radio model number is attached to the

front panel assembly with self-adhesive coating and can be replaced for rebranding purposes.

Three clips on the rear side of the front panel assembly snap onto the spaceframe to hold the keypads

1# and 1#, the LCD assembly 1@ and the speaker

1! in place. The rear side of the front panel assembly also has four screw

bosses to fasten the control-head board

Knob for Volume-Control Potentiometer

Keypads The main keypad 1# (for the function, selection, and scroll keys) and the

The knob for the volume-control potentiometer 1& is fitted to the shaft of the volume-control potentiometer, which is soldered to the control-head board

power keypad

1$ protrude through apertures in the front panel assembly 1^.

The rear sides of these keypads connect directly to the relevant contacts on the control-head board

LCD Assembly The graphical-display LCD assembly 1@ sits on a foam seal inside a

rectangular recess of the front panel assembly

1^. Another foam seal is

attached to the rear of the LCD with self-adhesive coating. The LCD assembly has a loom, which runs through a slot in the space-frame connects to a connector on the rear side of the control-head board

TM8100/TM8200 Service Manual Description 25 © Tait Electronics Limited June 2006

J and

Page 26

Speaker The speaker 1! sits inside a round recess of the front panel assembly, where

a cloth membrane is fixed to the speaker grille. The speaker clamp

1) holds

the speaker in position. The speaker cable plugs into the speaker connector on the rear side of the control-head board

Note In some configurations the speaker may be disconnected.

Concealed Microphone (Optional)

A concealed microphone 1% consisting of the microphone capsule and a rubber seal can be fitted in a round recess inside the front panel assembly

1^.

The microphone leads are soldered to two pads on the top side of the control-head board. Before the microphone is fitted, a small hole is drilled in the recess to provide an acoustic path to the microphone. The hole is covered by the rubber seal to ensure that the control head remains sealed to IP54 standards. For more information refer to “TMAA02-07 Concealed

Microphone” on page 501.

Space-Frame The aluminium space-frame J snaps into the three clips of the front panel

assembly

1^. The front side of the space-frame holds the keypads, the LCD

assembly, and the speaker in place and at the same time allows access to their electrical contacts. The rear side of the space-frame has four through-holes for the screws the adapter flange

E of the control-head board F and two screw bosses to fit

C. Two light pipes H and I are fitted in recesses in the

space-frame and direct light from LEDs on the control-head board to the front panel. A slot at the top edge of the space-frame allows the loom of the LCD assembly

Seals Two identical ring seals G fitted to grooves around the perimeter of the

1@ to run to the control-head board.

space-frame provide for IP54 class protection.

26 Description TM8100/TM8200 Service Manual

Page 27

Figure 2.4 Components of the control head with graphical display

M4 x 12 Taptite screw (x2)

adapter flange

control-head loom assembly with

female-female adapter

3 x 10 PT screw (x4)

control-head board

space-frame seal (x2)

short light pipe

long light pipe

space-frame

speaker clamp

speaker

LCD assembly

main keypad

power keypad

concealed microphone (optional)

front panel assembly

knob for volume-control potentiometer

3451z_02

TM8100/TM8200 Service Manual Description 27 © Tait Electronics Limited June 2006

Page 28

Control-Head Board The control-head board F is a printed circuit board in SMT design with

components on the top and bottom sides. Some SMT components are shielded by metal cans.

The control-head board is fitted to the front panel assembly space-frame

J with four 3x10 PT screws E.

1^ through the

The side facing the radio body has the connectors for the connection of the control-head loom, the LCD loom, the speaker, an optional control-head options board, and pads for the leads of the optional concealed microphone.

Figure 2.5 Connectors of the control-head board

pads for leads of concealed microphone

connector for loom of LCD assembly

connector for control-head options board

connector for speaker

connector for control-head loom

The side facing the front panel has the volume-control potentiometer, the microphone connector, the indicator and backlight LEDS, and the contacts for the keypads.

Control-Head Loom The control-head loom D connects the connector on the control-head

board to the control-head connector of the radio body. For more information refer to “Control-Head Connectors” on page 42.

Adapter Flange The adapter flange C is an injection-moulded plastic part, which is fitted to

the space-frame with two M4x 12 Taptite screws

28 Description TM8100/TM8200 Service Manual

Page 29

2.1.3 Control Heads with 1-, 2- or 3-Digit Display

Overview The control heads with 1-, 2- or 3-digit display can be divided into the

following main areas:

■ front panel with control elements, indicators, speaker, and optional

concealed microphone

■ space-frame

■ control-head board with SMT components, shielding cans, connectors,

and volume potentiometer

■ control-head loom with female-female adapter.

The circled numbers in this section refer to the items in Figure 2.6 on

page 31.

Front Panel Assembly

The front panel assembly H consists of an injection-moulded plastic part with an integrated transparent light pipe element for the radio

STATUS LEDs,

a transparent lens which cannot be replaced, and a cloth membrane which is fixed to the speaker grille. Depending on the type of control head, the aperture on the lens is sized to display either one, two or three characters. A label with the radio model number is attached to the front panel assembly with self-adhesive coating and can be replaced for rebranding purposes.

Six clips on the space-frame inside of the front panel assembly to hold the keypad the speaker

Knob for Volume-Control Potentiometer

Keypad The keypad 1@ protrudes through apertures in the front panel assembly H.

The knob for the volume-control potentiometer I is fitted to the shaft of the volume-control potentiometer, which is soldered to the control-head board

J in place.

G snap into corresponding locations on the

1@, the LCD 1!, and

The rear side of each key connects directly to the relevant contact on the control-head board

E. Four light pipes 1# and 1$ are fitted in the

appropriate recesses in the keypad and direct light from LEDs on the control-head board to the front panel.

LCD The LCD 1! sits inside a rectangular recess of the front panel assembly H

and is held in place by the space-frame LCD and the control-head board is ensured by two elastomeric strips

G. Electrical contact between the

held in place by the space-frame.

Speaker The speaker J sits inside a round recess of the front panel assembly, where

a cloth membrane is fixed to the speaker grille. The space-frame

G holds

the speaker in position. The speaker cable plugs into the speaker connector on the rear side of the control-head board

Note In some configurations the speaker may be disconnected.

TM8100/TM8200 Service Manual Description 29 © Tait Electronics Limited June 2006

Page 30

Concealed Microphone (Optional)

A concealed microphone 1) consisting of the microphone capsule and a rubber seal can be fitted in a round recess inside the front panel assembly The microphone leads are soldered to two pads on the top side of the control-head board

E. Before the microphone is fitted a small hole is drilled

in the recess to provide an acoustic path to the microphone. The hole is covered by the rubber seal to ensure that the control head remains sealed to IP54 standards. For more information refer to “TMAA02-06 Support Kit

for Concealed & Dynamic Microphones” on page 493.

Space-Frame The plastic space-frame G clips into the six recesses inside the front panel

assembly

H. The front side of the space-frame holds the keypad (with the

four light pipes), the LCD, and the speaker in place and at the same time allows access to their electrical contacts. The rear side of the space-frame has three holes for the screws

Control-Head Board The control-head board E is a printed circuit board in SMT design with

D of the control-head board E.

components on the top and bottom sides. There are different boards for the control heads with 1-, 2- and 3-digit display.s

The control-head board is clipped and then fitted to the space-frame three 3x8 PT screws

G with

The side facing the radio body has the connectors for the connection of the control-head loom

B, the speaker, an optional control-head options board

C, and pads for the leads of the optional concealed microphone 1).

The side facing the front panel has the volume-control potentiometer, the microphone connector, the indicator and backlight LEDs, the contacts for the keypads, and the LCD.

Control-Head Loom The control-head loom B with the female-female adapter connects the

connector on the control-head board the radio body. For more information refer to “Control-Head Connectors”

on page 42.

E to the control-head connector of

30 Description TM8100/TM8200 Service Manual

Page 31

Figure 2.6 Components of the control head (1-, 2- or 3-digit display)

3828z_01

control-head loom with female-female adapter

control-head options board (optional)

3 x 8 PT screw (x3)

control-head board

elastomeric strip (x2)

space-frame

front panel assembly

knob for volume-control potentiometer

speaker

concealed microphone (optional)

LCD

keypad

short light pipe

long light pipe

TM8100/TM8200 Service Manual Description 31 © Tait Electronics Limited June 2006

Page 32

2.1.4 RJ45 Control Head

The RJ45 control head consists of the following parts:

■ front panel

■ control-head loom with female-female adaptor

■ control-head board

■ PCB bracket.

The circled numbers in this section refer to the items in Figure 2.7 on

page 33.

Front Panel The front panel F is an injection-moulded plastic part with two apertures

for the fitted programming connector and a second optional RJ45 connector. When not in use, the apertures are sealed with two RJ45 bungs

F to ensure that the control head is sealed to IP54 standards. There is also a

hole for the

A label with the model number is attached to the front panel with selfadhesive coating and can be replaced for rebranding purposes.

The rear side of the front panel has four screw bosses to fasten the PCB bracket

POWER ON/OFF LED which illuminates through the label.

Control-Head Loom The control-head loom C with the female-female adapter connects the

connector on the control-head board

B to the control-head connector of

the radio body. For more information refer to “Control-Head Connectors”

on page 42.

Control-Head Board The control-head board B is a printed circuit board in SMT design with

some hand-soldered parts.

All components are placed on the top side, including the programming connector, the connector for the control-head loom

POWER ON/OFF LED.

C, and the

The control-head board slides into a slot in the front panel and slots in the PCB bracket

PCB Bracket The PCB bracket E is an injection-moulded plastic part which is fitted to

the front panel

E, and is held in place by two clips of the PCB bracket E.

F with four 3x8 PT screws D.

32 Description TM8100/TM8200 Service Manual

Page 33

Figure 2.7 Components of the RJ45 control head

control-head board

control-head loom with female-female adapter

3 x 8 PT screw (x4)

PCB bracket

front panel

RJ45 bung (x2)

TM8100/TM8200 Service Manual Description 33 © Tait Electronics Limited June 2006

Page 34

2.1.5 Blank Control Head

The blank control head consists of the following parts:

■ front panel

■ control-head loom with programming connector

■ seals.

The circled numbers in this section refer to the items in Figure 2.8 on

page 34.

Front Panel The front panel E is an injection-moulded plastic part with an aperture for

fitting the programming connector, which is part of the control-head loom

G. A label with the model number is attached to the front panel with self-

adhesive coating and can be replaced for rebranding purposes.

Control-Head Loom The programming connector at one end of the control-head loom and a

foam seal When the programming connector is not in use, the seal two screws

The control-head loom with the female-female adapter connects to the control-head connector of the radio body. For more information refer to

“Control-Head Connectors” on page 42.

F are screwed to the front panel with a pair of lock-nuts D.

C is fitted with

B to ensure that the control head is sealed to IP54 standards.

There is provision in the blank control head for the fitting of a custom circuit board.

Figure 2.8 Components of the blank control head

3/16 inch (5mm)

4lb·in (0.45 N·m)

3829z_01

UNX 4-40 x 3/16-inch pan Pozi screw (x2)

cover seal

lock-nut (pair)

front panel

foam seal

control-head loom with female-female adapter

34 Description TM8100/TM8200 Service Manual

Page 35

2.2 User Interfaces

Figure 2.9 shows the controls and indicators of the user interfaces. For more

information refer to the following user’s guides:

■ TM8100 (1-digit and 2-digit-display control head)

■ TM8250/TM8255 (graphical-display control head)

■ TM8235 (3-digit-display control head).

Some keys have functions assigned to both short and long key presses. A short key press is less than one second, and a long key press is more than one second.

Figure 2.9 User interfaces

press-to-talk

(PTT) key

microphone

display

radio status LEDs

green

red

amber

speaker

on/off key

volume

control

microphone

socket

function keys

1 to 4

on/off key

volume

control

microphone

socket

1- and 2-digit-display

control head:

function keys 1to 4

left selection key

scroll keys

display

scroll keys

right selection key

radio status LEDs

green

red

amber

speaker

3-digit-display

control head:

function key 1

clear key shift key

function key 2

TM8100/TM8200 Service Manual Description 35 © Tait Electronics Limited June 2006

Page 36

2.3 Connectors

Overview This section describes the specifications and pinouts of the connectors of the

radio body and the control head.

Figure 2.10 provides an overview of the connectors:

Figure 2.10 Connectors (radio with graphical-display control head)

Volume Control

Microphone

Connector

Keys

LCD

LEDs

Speaker

Control-Head

Options Connector

Control-Head

Options Board

Control-Head

Board

Pads for Concealed Microphone

Speaker

Connector

Speaker Leads

Control-Head

Loom

Control-Head Connector

Factory Connector (Factory Only)

Internal Options

Loom

Main Board

Internal

Options

Connector

Internal Options

Board

RF Connector

Power

Connector

Auxiliary

Connector

External

Options

Connector

Figure 2.11 shows the connectors of the radio body. Figure 2.12 shows the connectors of the control head.

For information on the factory connector of the main board and the internal connectors of the control head, refer to the PCB information of the main boards and the control-head board.

36 Description TM8100/TM8200 Service Manual

Page 37

Figure 2.11 Connectors of the radio body (25W radio)

control-head

connector

front view

provision for

external options

connector

auxiliary

connector

provision for

additional

connector

power

connector

rear view

connector

internal options

connector

top view

TM8100/TM8200 Service Manual Description 37 © Tait Electronics Limited June 2006

Page 38

Figure 2.12 Connectors of the control head with graphical display

microphone

connector

rear view without adapter flange

front view

control-head

connector

Figure 2.13 Connectors of the control head with 1-, 2- or 3-digit display

microphone

connector

connector for speaker

pads for leads of concealed microphone

control-head

connector

connectors for optional circuit board

front view

rear view

38 Description TM8100/TM8200 Service Manual

Page 39

2.3.1 RF Connector

The RF connector is the primary RF interface to the antenna. The RF connector is a BNC connector or a mini-UHF connector with an impedance of 50Ω.

Important The maximum RF input level is +27dBm. Higher levels

may damage the radio.

Table 2.1 RF connector - pins and signals

Pinout Pin Signal Name Signal Type

1 RF RF analog

rear view

2 GND RF ground

2.3.2 Power Connector

The power connector is the interface for the primary 13.8 V power source and the external speaker. The primary power source can be the vehicle battery or a mains-fed DC power supply. There are different power connectors for the 40W/50W and 25 W radios.

Important The speaker load configuration is balanced; the speaker

output lines must not be connected to ground. Connecting a speaker output line to ground will cause audio power amplifier shutdown

Table 2.2 Power connector (radio) – pins and signals

Pinout Pin Signal name Description Signal type

50W/40W radio

rear view

25W radio

1 2 3 4

rear view

1 AGND Earth return for radio body power

source.

2 SPK– External speaker output. Balanced load

configuration.

3 SPK+ External speaker output. Balanced load

configuration.

4 13V8_BATT DC power input for radio body and

control head.

Ground

Analog

Power

TM8100/TM8200 Service Manual Description 39 © Tait Electronics Limited June 2006

Page 40

2.3.3 Auxiliary Connector

The auxiliary connector is the standard interface for external devices that are typically connected to a radio. The auxiliary connector is a 15-way standard-density D-range socket. The auxiliary connector provides a serial port, three programmable input lines, four programmable digital I/O lines and audio I/O.

The I/O lines can be programmed for a variety of functions, logic levels, and in some cases, direction. Audio lines can also be programmed to tap into, or out of, different points in the audio processing chain. For more information refer to the online help of the programming application.

Table 2.3 Auxiliary connector – pins and signals

Pinout Pin Signal name Description Signal type

12 AUX_GPI1 General purpose digital input.

Programmable function.

rear view

a. For more information on hardware links refer to “Power-Sense Options” on page 83. b. Can be switched or unswitched. For more information refer to “Connector Power Supply Options” on page 86.

5 AUX_GPI2 General purpose digital input.

Programmable function. With LK3 fitted, GPI2 is an emergency power sense input.

4 AUX_GPI3 General purpose digital input.

Programmable function. With LK2 fitted, GPI3 is a power sense input.

10 AUX_GPIO4 Programmable function and

2 AUX_GPIO5

9 AUX_GPIO6

1 AUX_GPIO7

11 AUX_TXD Asynchronous serial port -

3 AUX_RXD Asynchronous serial port -

7 AUD_TAP_IN Programmable tap point into the Rx

13 AUD_TAP_OUT Programmable tap point out of the

14 AUX_MIC_AUD Auxiliary microphone input.

6 RSSI Analog RSSI output. Analog

8 +13V8_SW

15 AGND Analog ground Ground

direction. Pads available to fit a higher power driver transistor on GPIO4 line

Tran sm it d at a

Receive data

or Tx audio chain. DC-coupled.

Rx or Tx audio chain. DC-coupled.

Electret microphone biasing provided. Dynamic microphones are not supported.

Switched 13.8V supply. Supply is switched off when radio body is switched off.

Digital, 3V3 CMOS

Digital, 3V3 CMOS input; open collector output with pullup

Digital, 3V3 CMOS

Analog

Power

40 Description TM8100/TM8200 Service Manual

Page 41

2.3.4 Internal Options Connector

When installing an internal options board, the internal options connector is the electrical interface to the main board of the radio body. The internal options connector provides similar I/O to the auxiliary connector. The internal options connector is an 18-pin 0.1 inch pitch Micro-MaTch connector.

Important The digital I/O signals are intended to interface directly

with compatible logic signals only. Do not connect these signals to external devices without appropriate signal conditioning and ESD protection.

Table 2.4 Internal options connector – pins and signals

Pinout Pin Signal Description Signal type

1 13V8_SW

1) 1!

top view

a. Can be switched or unswitched. For more information refer to “Connector Power Supply Options” on page 86. b. For more information on hardware links refer to“Power-Sense Options” on page 83.

2 AUD_TAP_OUT Programmable tap point out of the Rx or

3 AGND Analog ground. Ground

4 AUX_MIC_AUD Auxiliary microphone input.

5 RX_BEEP_IN Receive sidetone input. AC-coupled. Analog

6 AUD_TAP_IN Programmable tap point into the Rx or Tx

7 RX_AUD Receive audio output. Post volume

8 RSSI Analog RSSI output. Analog

9…15 IOP_GPIO1…7 General-purpose port for input and

16 DGND Digital ground. Ground

17 IOP_RXD Asynchronous serial port - Receive data. Digital.

18 IOP_TXD Asynchronous serial port - Transmit data. Digital.

Switched 13V8 supply. Supply is switched off when the Radio Body is switched off.

Tx audio chain. DC-coupled.

Electret microphone biasing provided. Dynamic microphones are not supported.

audio chain. DC-coupled.

control. AC-coupled.

output of data. Programmable function and direction. With LK4 fitted, GPIO7 is a power sense input

Power

Analog

Digital. 3V3 CMOS

3V3 CMOS

2.3.5 Provision for External Options Connector

The radio has a mechanical interface for the external connector of an internal options board. This external options connector can be a 9-way standard-density or 15-way high-density D-range connector. If no internal options board is installed (standard configuration), the hole for the external options connector is sealed by a bung.

TM8100/TM8200 Service Manual Description 41 © Tait Electronics Limited June 2006

Page 42

2.3.6 Control-Head Connectors

The control-head loom connects the connector on the front of the radio body to the connector on the rear of the control head.

The connector on the front of the radio body is an 18-way two-row rightangled IDC (insulation displacement connector) SMD header socket.

The connector on the rear of the control head is an 18-way 0.1 inch pitch Micro-MaTch SMD socket.

Table 2.5 Control-head connectors – pins and signals

Pinout Pin Signal Description Signal type

1 RX_AUD Receive audio output. Post volume

CEGI1)1@1$1^1* BDFHJ1!1#1%1&

front view

of radio body

1) 1!

top view of

control-head

board

a. Can be switched or unswitched. For more information refer to “Connector Power Supply Options” on page 86.

2+13V8

3 CH_TXD Asynchronous serial port -

4 CH_PTT PTT input from microphone.

5 CH_MIC_AUD Fist microphone audio input. Analog

6 AGND Analog ground. Ground

7 CH_RXD Asynchronous serial port - Receive data. Digital. 3V3 CMOS.

8 DGND Digital ground. Ground

9 CH_ON_OFF Hardware power on/software-

10 VOL_WIP_DC DC signal from volume pot wiper

11 CH_SPI_DO Data output signal to control head. Digital. 3V3 CMOS.

12 CH_LE Latch enable output to control head. Digital. 3V3 CMOS.

13 CH_GPIO1 General purpose digital input/output. Digital. 3V3 CMOS

14 +3V3 Power supply to control head digital

15 CH_SPI_DI Data input from control head. Digital. 3V3 CMOS.

16 CH_SPI_CLK Clock output to control head. Digital. 3V3 CMOS.

17 SPK– Speaker audio output for non-remote

18 SPK+ Speaker audio output for non-remote

control. AC-coupled.

Power supply output from radio body power source.

Transmit data.

Also carries the hookswitch signal.

controlled power off input. Active low.

(grounded for graphical display).

circuits.

control head. Balanced load configuration.

Analog

Power

Digital. 3V3 CMOS.

Digital

Analog

input. Open collector output with pullup.

Power

Analog

42 Description TM8100/TM8200 Service Manual

Page 43

2.3.7 Microphone Connector

The microphone connector of the control head is an RJ45 socket.

When the control head is connected to the control-head connector of the radio body using the loom provided, the microphone connector uses the following eight control-head connector signals:

Table 2.6 Microphone connector – pins and signals

Pinout Pin Signal name Description Signal type

1 MIC_RX_AUD Receive audio output. Analog

front view

a. Can be switched or unswitched. For more information refer to “Connector Power Supply Options” on page 86.

2+13V8

3 MIC_TXD Asynchronous serial port -

4 MIC_PTT PTT input from microphone. Also carries

5 MIC_AUD Fist microphone audio input. Analog

6 AGND Analog ground. Analog ground

7 MIC_RXD Asynchronous serial port - Receive data. 3.3 V CMOS

8 MIC_GPIO1 General purpose digital input/output. Open collector out

Power supply output. Switched off when radio body is switched off.

Tran sm it d at a.

hookswitch signal.

Power

3.3V CMOS

Digital

3.3V CMOS in

2.3.8 Programming Connector (RJ45 Control Head)

The programming connector of the RJ45 control head is an RJ45 socket.

When the RJ45 control head is connected to the radio body, the programming connector uses the following signals.

Table 2.7 Programming connector – pins and signals

Pinout Pin Signal name Description Signal type

1 PRG_RX_AUD Receive audio output. Analog

2 +13V8

3 PRG_TXD Asynchronous serial port -

front view

a. Can be switched or unswitched. For more information refer to “Connector Power Supply Options” on page 86.

4 PRG_PTT PTT input from microphone.

5 PRG_MIC_AUD Fist microphone audio input. Analog

6 AGND Analog ground Ground

7 PRG_RXD Asynchronous serial port -

8 PRG_ON_OFF Hardware power on/software-power

Power supply output. Switched off when radio body is switched off.

Transmit data.

Also carries hookswitch signal.

Receive data.

off input. Active low.

Power

3.3V CMOS

Digital

3.3V CMOS

Digital

TM8100/TM8200 Service Manual Description 43 © Tait Electronics Limited June 2006

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2.3.9 Programming Connector (Blank Control Head)

The programming connector of the blank control head is a 9-way standarddensity D-range plug.

When the blank control head is connected to the radio body, the programming connector uses the following signals.

Table 2.8 Programming connector – pins and signals

Pinout Pin Signal name Description Signal type

1 PRG_RX_AUD Receive audio output. Analog

2 PRG_TXD Asynchronous serial port -

Transmit data.

3 PRG_MIC_AUD Fist microphone audio input. Analog

4 PRG_RXD Asynchronous serial port -

Receive data.

5 PRG_ON_OFF Hardware power on/software-power

off input. Active low.

front view

a. Can be switched or unswitched. For more information refer to “Connector Power Supply Options” on page 86.

6+13V8

7 PRG_PTT PTT input from microphone.

8 AGND Analog ground Ground

9 DGND Digital ground Ground

Power supply output. Switched off when radio body is switched off.

Also carries hookswitch signal.

3.3V CMOS

Digital

Power

Digital

44 Description TM8100/TM8200 Service Manual

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2.4 Hardware and Software Architecture

Overview This section describes the hardware and software modules of the radio and

their interaction in the functioning of the radio.

2.4.1 Hardware Architecture

The electrical hardware of the radio is implemented on a main board inside the radio body and a control-head board inside the control head.

For a detailed description and block diagrams of individual circuits, refer to

“Circuit Descriptions” on page 19.

Main Board The main board inside the radio body includes the following circuitry:

■ transmitter

■ receiver

■ frequency synthesizer

■ digital board with a RISC processor and custom logic (implemented on

an FPGA), memory, and a DSP

■ CODEC and audio

■ interface

■ power supply.

The main board has an internal options connector which allows internal options boards to access a variety of discrete and programmable signals. For more information refer to “Internal Options Connector” on page 41.

For a basic block diagram of the main board, refer to Figure 2.14 on

page 46.

For a more detailed block diagram of the transceiver, refer to Figure 2.16 on

page 51.

Control-Head Board The control-head board of the control head with graphical display includes:

■ the circuitry needed for the controls and indicators on the front panel

■ with a RISC processor and custom logic (implemented on an FPGA),

and memory.

For a block diagram of this control-head board, refer to Figure 3.14 on

page 93.

The control head with graphical display may have a concealed microphone inside the control head and also has provision for a separate circuit board that may be designed to perform a variety of tasks including—but not limited to—Bluetooth connectivity. No separate circuit board is required for a dynamic microphone.

TM8100/TM8200 Service Manual Description 45 © Tait Electronics Limited June 2006

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Figure 2.14 Hardware architecture of the main board

Power

Connector

Control-Head

Connector

Interface

CODEC

and Audio

Auxiliary

Connector

Internal Options

Connector

Power Supply

Main Board

Logic

Custom

Synthesizer

DSP

Transmitter

digital

analog

asynchronous serial data

synchronous serial data

part of transmitter circuitry

analog-to-digital converter

digital-to-analog converter

part of CODEC and audio circuitry2)

Flash

Serial

Digital Board

FPGA

RISC

Proc.

SRAM

Flash

Memory

Frequency

Receiver

Switch

LPF

RF Connector

46 Description TM8100/TM8200 Service Manual

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2.4.2 Software Architecture

Overview Software plays an important role in the functioning of the radio. Some radio

functions such as the graphical user interface, processing of the analog and digital signals, and the implementation of radio applications are completely implemented by software.

For a block diagram of the software architecture, refer to Figure 2.15 on

page 48.

Software Modules The following software modules are stored on the digital board of the main

board:

■ FPGA image, which includes the software-implemented RISC processor

and the custom logic (the custom logic executes additional digital signal processing)

■ boot code

■ radio application code

■ digital signal processing

■ radio application database and radio calibration database.

The following software modules are stored on the control-head board with graphical display:

■ FPGA image, which includes the software-implemented RISC processor

■ boot code

■ control-head application code

■ control-head application database.

Hardware and interface drivers are part of the boot code, the RISC code, and—in the case of the main board—the DSP code.

TM8100/TM8200 Service Manual Description 47 © Tait Electronics Limited June 2006

Page 48

Figure 2.15 Software architecture (radio with graphical-display control head shown)

Serial

Flash

FPGA Image

RISC Proc.

FPGA Image

FPGA

Flash

Memory

Boot Code

Application Code

Boot Code

Control-Head Application Code

Database

FPGA

FPGA Image

RISC Processor

Boot Code

Radio Application

Code

Custom Logic

Additional Digital Signal Processing

Serial Flash

FPGA Image

Flash Memory

Boot Code

Radio Application Code

Database

DSP Code

DSP

DSP Code

SRAM

Dynamic Memory

SRAM

Software Start-Up

When the radio is turned on, the following processes are carried out on the main board:

Note This process describes the software start-up into normal radio

operation mode.

1. The FPGA image, which includes the RISC processor and the custom logic, is loaded from the serial flash to the FPGA.

2. The RISC processor executes the boot code, which carries out an initialization and auto-calibration, and—in the case of a fault— generates an error code for display on the control head.

3. Normal radio operation starts with:

■ the RISC processor executing the radio application code,

including application software

■ the DSP executing the DSP code for processing of digital signals

■ the custom logic executing additional digital signal processing.

48 Description TM8100/TM8200 Service Manual

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When the radio is turned on, the following processes are carried out on the control-head board of the control head with graphical display:

1. The FPGA image, which includes the RISC processor, is loaded from

the serial flash to the FPGA.

2. The RISC processor executes the boot code, which carries out an

initialization, and—in the case of a fault—generates an error code for display on the control head.

3. Normal radio operation starts with the RISC processor executing

■ the graphical user interface

■ the I/O processing

■ the user interface processing.

During normal radio operation the radio body and control head communicate via interface software, which is part of the radio and controlhead application software.

Software Shutdown On shutdown, the programming and calibration data is stored in the

database, and power is removed from the radio.

Important On power loss, any changes made to the programming or

calibration data may be lost.

Programming and Calibration Files

One of the servicing tasks is the downloading and uploading of programming and calibration files to the database. For more information, refer to “Servicing Procedures” on page 149 and the online help of the programming and calibration applications.

Software Upgrades During servicing it may become necessary to upload software to a

replacement main board, control head, or control head board using the Tools>Options> Download command of the programming application. For more information, refer to the online help of the programming application and to the technical notes accompanying the software files.

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2.5 Operation in Receive Mode

Overview This section describes the functioning of the transceiver in receive mode.

The operation of the transceiver is illustrated in Figure 2.16 on page 51.

These block diagrams show the hardware modules integrated with the software modules:

■ hardware (transmitter, receiver, CODEC and audio)

■ RISC processor (on FPGA of digital board)

■ custom logic (on FPGA of digital board)

■ DSP (on digital board).

The receive path consists of three major functional parts:

■ RF hardware

■ digital baseband processing

■ audio processing and signalling.

50 Description TM8100/TM8200 Service Manual

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Figure 2.16 Transceiver operation

Interface

RSSI

Power

Audio

Volume

Secondary

Primary

Volume

Optional

Processing

De-

emphasis

Audio

Filtering

Control

Head

Side

Tones

Decoders

Data and Signaling

Squelch

Hardware

DSP

Auxiliary

Head

Control

Mic

FGA

Mic

PGA

ALC

Optional

Processing

Pre-

emphasis

Audio

Filtering

Encoders

Data and Signaling

Interface

RISC Processor

For UHF there are separate VCOs for RX and TX

(1) Noise blanker not shown

(2) VHF configuration shown*

Analog-to-digital conversion

Digital-to-analog conversion

System interface

Key Notes

RISC Processor

Channel

UHF: 45.1 MHz

VHF: 21.4 MHz

LPF

Digital

Down-

Quad

1st

Front

Antenna

Demod

converter

Demod

End

LPF

Channel

2nd IF:

64 kHz

Second LO

UHF: 90.328 MHz

Phase

locked to

Logic

Custom

VHF: 42.928 MHz

TCXO

VCO*

Control

Triple-point

Equalization

Loop

Filter

PLL

/Ex

Drv

Fin

Bias

Dir.

Coup.

Frequency

Loop

VCXO

TCXO:

Filter

13.000 MHz

Ramp

Control

Hardware

Ctrl

Pwr

Mag.

AGC

IF:

TM8100/TM8200 Service Manual Description 51 © Tait Electronics Limited June 2006

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2.5.1 RF Hardware

PIN Switch The RF PIN switch circuitry selects the RF path to and from the antenna

to either the Tx or Rx circuitry of the radio. In addition to the switching functionality, the PIN switch is used to provide attenuation to the Rx front end in high signal-strength locations.

Front End and First IF

Quadrature Demodulator

Automatic Gain Control

The front-end hardware amplifies and image-filters the received RF spectrum, then down-converts the desired channel frequency to a first intermediate frequency (IF1) of 21.4MHz (VHF) or 45.1 MHz (UHF) where coarse channel filtering is performed. The first LO signal is obtained from the frequency synthesizer and is injected on the low side of the desired channel frequency for all bands. In receive mode, the modulation to the frequency synthesizer is muted. See “Frequency Synthesizer” on page 57 for a description of the frequency synthesizer. The output of the first IF is then down-converted using an image-reject mixer to a low IF of 64kHz.

The LO for the image-reject mixer (quadrature demodulator) is synthesized and uses the TCXO as a reference. This ensures good centring of the IF filters and more consistent group-delay performance. The quadrature demodulator device has an internal frequency division of 2 so the second LO operates at 2 x (IF1+64kHz). The quadrature output from this mixer is fed to a pair of ADCs with high dynamic range where it is oversampled at 256kHz and fed to the custom logic device.

The AGC is used to limit the maximum signal level applied to the imagereject mixer and ADCs in order to meet the requirements for intermodulation and selectivity performance. Hardware gain control is performed by a variable gain amplifier within the quadrature demodulator device driven by a 10-bit DAC. Information about the signal level is obtained from the IQ data output stream from the ADCs. The control loop is completed within the custom logic. The AGC will begin to reduce gain when the combined signal power of the wanted signal and first adjacent channels is greater than about -70dBm. In the presence of a strong adjacentchannel signal it is therefore possible that the AGC may start acting when the wanted signal is well below -70dBm.

Noise Blanking (A4, B1 bands only)

With frequency bands between 66 and 174MHz, a noise blanker can be selected to remove common sources of electrical interference such as vehicle ignition noise. The noise blanker functions by sampling the RF input to the receiver for impulse noise and momentarily disconnecting the first LO for the duration of the impulse. The response time of the noise blanker is very fast (tens of nanoseconds) and is quicker than the time taken for the RF signal to pass through the front-end hardware, so that the LO is disabled before the impulse reaches the IF stage where it could cause crystal filter ring.

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2.5.2 Digital Baseband Processing

Custom Logic The remainder of the receiver processing up to demodulation is performed

by custom logic. The digitized quadrature signal from the RF hardware is digitally down-converted to a zero IF and channel filtering is performed at baseband. Different filter shapes are possible to accommodate the various channel spacings and data requirements. These filters provide the bulk of adjacent channel selectivity for narrow-band operation. The filters have linear phase response so that good group-delay performance for data is achieved. The filters also decimate the sample rate down to 48kHz. Custom logic also performs demodulation, which is multiplexed along with AGC and amplitude data and fed via a single synchronous serial port to the DSP. The stream is demultiplexed and the demodulation data used as an input for further audio processing.

Noise Squelch The noise squelch process resides in the DSP. The noise content above and

adjacent to the voice band is measured and compared with a preset threshold. When a wanted signal is present, out-of-band noise content is reduced and, if below the preset threshold, is indicated as a valid wanted signal.

RSSI Receive signal strength is measured by a process resident in the DSP.

This process obtains its input from the demodulator (RF signal magnitude value) and from the AGC (present gain value). With these two inputs and a calibration factor, the RF signal strength at the antenna can be accurately calculated.

Calibration The following items within the receiver path are factory-calibrated:

■ front-end tuning

■ AGC

■ noise squelch

■ RSSI.

Information on the calibration of these items is given in the on-line help facility of the calibration application.

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2.5.3 Audio Processing and Signalling

Audio Processing Raw demodulated data from the receiver is processed within the DSP.

The sample rate at this point is 48kHz with signal bandwidth limited only by the IF filtering. Scaling (dependent on the bandwidth of the RF channel) is then applied to normalize the signal level for the remaining audio processing. The sample rate is decimated to 8 kHz and 0.3 to 3kHz bandpass audio filtering is applied. De-emphasis is then applied to cancel out the receive signals pre-emphasized response and improve signal to noise performance. Optional processing such as decryption or companding is then applied if applicable.

Data and Signalling Decoders

The data and signalling decoders obtain their signals from various points within the audio processing chain. The point used depends on the decoders’ bandwidth and whether de-emphasis is required. Several decoders may be active simultaneously.

Side Tones Side tones are summed in at the end of the audio processing chain. These are

tones that provide some form of alert or give the user confidence an action has been performed. The confidence tones may be generated in receive or transmit mode. The sidetone level is a fixed proportion (in the order of

-10dB) relative to full scale in the receive path.

CODEC The combined audio and side-tone signal is converted to analog form by a

16-bit DAC with integral anti-alias filtering. This is followed by a programmable-gain amplifier with 45dB range in 1.5 dB steps, that performs primary volume control and muting. The DAC and primary volume control are part of the same CODEC device (AD6521).

Output to Speakers The output of the CODEC is fed to an audio power amplifier via a

secondary volume control (not TM8100 radios) and to the control head via a buffer amplifier. The output configuration of the audio power amplifier is balanced and drives an internal speaker in non-remote control-head configuration and, optionally, an external speaker. The speaker loads are connected in parallel rather than being switched. The power delivered to each speaker is limited by its impedance. The internal speaker has 16Ω impedance whereas the external speaker can be as low as 4Ω.

Volume Control Configurations

There are two volume controls in the TM8200 radio but only one is active at any time when audio is being output to the speaker(s). The inactive volume control is set to maximum. For non-remote control-head configuration, the primary volume control is active. For remote controlhead configuration, the secondary volume control is active. This enables fixed level audio feed to the remote control head, and independent volume control of the external speaker and the speaker of the remote control head.

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2.6 Operation in Transmit Mode

Overview This section describes the functioning of the transceiver in transmit mode.

The operation of the transceiver is illustrated in Figure 2.16 on page 51.

These block diagrams show the hardware modules integrated with the software modules:

■ hardware (transmitter, receiver, CODEC and audio)

■ RISC processor (on FPGA of digital board)

■ custom logic (on FPGA of digital board)

■ DSP block (on digital board).

The transmit path consists of three major functional parts:

■ audio processing and signalling

■ frequency synthesizer

■ RF transmitter.

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2.6.1 Audio Processing and Signalling

Microphone Input The input to the transmitter path begins at the microphone input. There are

two microphone sources: a fist microphone connected to the control head and an auxiliary microphone connected via the auxiliary or external options connector. Only electret-type microphones are supported. Support for optional dynamic fist microphones is facilitated by a hardware amplifier and filter in the control head, and must be activated in the programming software.

Analog Processing of the Microphone Input

Automatic Level Control

DSP Audio Processing

The CODEC (AD6521) performs microphone selection and amplification. The microphone amplifier consists of a fixed gain amplifier of 16dB followed by a programmable-gain amplifier with 0 to 22dB gain. The amplified microphone signal is converted to a digital stream by a 16-bit ADC with integral anti-alias filtering (0.1 to 3.2 kHz). The digital stream is transported to the DSP for further audio processing.

The ALC follows and is used to effectively increase dynamic range by boosting the gain of the microphone pre-amplifier under quiet conditions and reducing the gain under noisy acoustic conditions. The ALC function resides in the DSP and controls the microphone-programmable gain amplifier in the CODEC. The ALC has a fast-attack (about 10ms) and slow-decay (up to 2 s) gain characteristic. This characteristic ensures that the peak signal level is regulated near full scale to maximize dynamic range.

The output of the automatic level control provides the input to the DSP audio processing chain at a sample rate of 8kHz. Optional processing such as encryption or companding is done first if applicable. Pre-emphasis, if required, is then applied. The pre-emphasized signal is hard limited to prevent overdeviation and filtered to remove high frequency components. The sample rate is then interpolated up to 48 kHz and scaled to be suitable for the frequency synthesizer.

Data and Signalling Encoders

The data and signalling encoders inject their signals into various points within the audio processing chain. The injection point depends on the encoders bandwidth and whether pre-emphasis is required.

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2.6.2 Frequency Synthesizer

Introduction As shown in Figure 2.16, the frequency synthesizer consists of two main

parts:

■ FCL (frequency control loop)

■ RF PLL, comprising RF PLL device, loop filter, VCO, and VCO output

switch.

Frequency Control Loop

The FCL consists of the following:

■ TCXO

■ mixer

■ loop filter

■ VCXO

■ frequency control block.

The FCL provides the reference frequency for the RF PLL. The FCL generates a high-stability reference frequency that can be both modulated and offset in fine resolution steps.

RF PLL ■ The RF PLL consists of the following:

■ RF PLL device

■ loop filter

■ VCO

■ VCO output switch.

The RF PLL has fast-locking capability but coarse frequency resolution. This combination of control loops creates improved frequency generation and acquisition capabilities.

Note that patents are pending for several aspects of the synthesizer design.

Operation of Control Loop

The RF PLL is a conventional integer-N-type design with frequency resolution of 25kHz. In transmit mode, the loop locks to the transmit frequency, whereas in receive mode, it locks to the receive frequency minus the first IF frequency.

Initially, the VCO generates an unregulated frequency in the required range. This is fed to the PLL device (ADF4111) and divided down by a programmed ratio to approximately 25 kHz. The reference frequency input from the FCL is also divided down to approximately 25kHz. The phase of the two signals is compared and the error translated into a DC voltage by a programmable charge pump and dual-bandwidth loop filter. This DC signal is used to control the VCO frequency and reduce the initial error. The loop eventually settles to a point that minimizes the phase error between divided down reference and VCO frequencies. The net result is that the loop “locks” to a programmed multiple of the reference frequency.

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The FCL generates an output of 13.012 MHz±4kHz. Initially, a VCXO (voltage controlled crystal oscillator) produces a quasi-regulated frequency in the required range. The VCXO output is fed to a mixer where it is mixed with the 13.000MHz TCXO frequency. The mixer, after low-pass filtering to remove unwanted products, produces a frequency of 12kHz nominally. This is converted to digital form and transported to the frequency control block in the custom logic.

The frequency control block compares the mixer output frequency to a reference generated by the digital clock and creates a DC error signal. A programmed offset is also added. This error signal is converted to analog form and used to control the VCXO frequency and reduce the initial error. Once settled, the loop “locks” to the TCXO frequency with a programmed offset frequency. The FCL output therefore acquires the TCXO's frequency stability.

Modulation The full bandwidth modulation signal is obtained from the DSP in digital

form at a sample rate of 48kHz. In traditional dual-point modulation systems the modulation is applied, in analog form, to both the frequency reference and the VCO in the RF PLL, combining to produce a flat modulation response down to DC. Reference modulation is usually applied directly to the TCXO.

Frequency Generation

Fast Frequency Settling

In the system employed in the radio, the frequency reference is generated by the FCL, which itself requires dual-point modulation injection to allow modulation down to DC. With another modulation point required in the RF PLL, this system therefore requires triple-point modulation. The modulation signals applied to the FCL are in digital form while for the RF PLL (VCO) the modulation signal is applied in analog form. The modulation cross-over points occur at approximately 30 and 300Hz as determined by the closed loop bandwidths of the FCL and RF PLL respectively.

The RF PLL has a frequency resolution of 25kHz. Higher resolution cannot be achieved owing to acquisition-time requirements and so for any given frequency the error could be as high as ±12.5kHz. This error is corrected by altering the reference frequency to the RF PLL. The FCL supplies the reference frequency and is able to adjust it up to ± 300 ppm with better than 0.1ppm resolution (equivalent to better than 50 Hz resolution at the RF frequency). The FCL offset will usually be different for receive and transmit modes.

Both the FCL and RF PLL employ frequency-acquisition speed-up techniques to achieve fast frequency settling. The frequency-acquisition process of the FCL and RF PLL is able to occur concurrently with minimal loop interaction owing to the very large difference in frequency step size between the loops.

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Frequency Acquisition of RF PLL

In the RF PLL the loop bandwidth is initially set to high by increasing the charge-pump current and reducing time constants in the loop filter. As a result, settling to within 1kHz of the final value occurs in under 4 ms. In order to meet noise performance requirements the loop parameters are then switched to reduce the loop bandwidth. There is a small frequency kick as the loop bandwidth is reduced. Total settling time is under 4.5ms.

Frequency Acquisition of FCL

The FCL utilizes self-calibration techniques that enable it to rapidly settle close to the final value while the loop is open. The loop is then closed and settling to the final value occurs with an associated reduction in noise. The total settling time is typically less than 4ms.

Calibration The following items are calibrated in the frequency synthesizer:

■ nominal frequency

■ KVCO

■ KVCXO

■ VCO deviation.

Calibration of the nominal frequency is achieved by adding a fixed offset to the FCL nominal frequency; the TCXO frequency itself is not adjusted. The items KVCO and KVCXO are the control sensitivities of the RF VCO (in MHz/V) and VCXO (in kHz/V) respectively. The latter has temperature compensation.

2.6.3 RF Transmitter

RF Power Amplifier and Switching (50W/40W Radio)

The RF power amplifier and exciter of the 40W/50 W radio is a five-stage line-up with approximately 40dB of power gain. The output of the frequency synthesizer is first buffered to reduce kick during power ramping. The buffer output goes to a discrete exciter that produces approximately 300 to 400mW output. This is followed by an LDMOS driver producing up to 8W output that is power-controlled. The final stage consists of two parallel LDMOS devices producing enough power to provide 40 to 50W at the antenna.

RF Power Amplifier and Switching (25W Radio)

The RF power amplifier of the 25W radio is a four-stage line-up with approximately 37dB of power gain. The output of the frequency synthesizer is first buffered to reduce kick during power ramping. The buffer output goes to a broad-band exciter IC that produces approximately 200mW output. This is followed by an LDMOS driver producing up to 2W output that is power-controlled. The final stage consists of two parallel LDMOS devices producing enough power to provide 25W at the antenna.

Output of RF Power Amplifier

The output of the RF power amplifier passes through a dual-directional coupler, used for power control and monitoring, to the PIN switch. The PIN switch toggles the antenna path between the receiver and transmitter in receive and transmit modes respectively. Finally, the output is low-pass-filtered to bring harmonic levels within specification.

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Power Control The steady-state power output of the transmitter is regulated using a

hardware control loop. With the 40 W/50 W radio, the sum of the forward power output from the RF power amplifier and reverse power reflected from the load is sensed by the directional coupler and fed back to the power control loop. With the 25W radio, the forward power output from the RF power amplifier is sensed by the directional coupler and fed back to the power control loop. The PA output power is controlled by varying driver gate bias voltage that has a calibrated maximum limit to prevent overdrive. The power control signal is supplied by a 13-bit DAC driven by custom logic.

Ramping Power ramp-up consists of two stages:

■ bias

■ power ramping.

The timing between these two stages is critical to achieving the correct overall wave shape in order to meet the specification for transient ACP (adjacent channel power). A typical ramping waveform is shown in

Figure 2.17.

Figure 2.17 Typical ramping waveforms

Power

Bias

Power

ramp

High power

powerLow

Bias Ramp-Up The steady-state final-stage bias level is supplied by an 8-bit DAC

ramp

Bias

ramp

Time

programmed prior to ramp-up but held to zero by a switch on the DAC output under the control of a release by the

TX INHIBIT signal with the ramping shape being determined by

TX INHIBIT signal. Bias ramp-up begins upon

a low-pass filter. Owing to power leakage through the PA chain, ramping the bias takes the PA output power from less than –20dBm for the 40W/50W or –10dBm for the 25 W radio to approximately 25dB below steady-state power.

Power Ramp-Up The power ramp signal is supplied by a 13-bit DAC that is controlled by

custom logic. The ramp is generated using a look-up table in custom logic memory that is played back at the correct rate to the DAC to produce the desired waveform. The ramp-up and ramp-down waveforms are produced by playing back the look-up table in forward and reverse order respectively. For a given power level the look-up table values are scaled by a steady-state

60 Description TM8100/TM8200 Service Manual

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power constant so that the ramp waveform shape remains the same for all power levels.

PIN Switch The RF PIN switch circuitry selects the RF path to and from the antenna

to either the Tx or Rx circuitry of the radio. In addition to the switching functionality, the PIN switch is used to provide attenuation to the Rx front end in high signal-strength locations.

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3 Circuit Descriptions

Introduction This section describes and illustrates the circuitry of the main board and the

control-head boards.

The main board is divided into the following circuitry modules:

■ transmitter

■ receiver

■ frequency synthesizer (including FCL)

■ CODEC and audio

■ power supply

■ interface

■ digital board.

Figure 3.1 gives an overview of the of the circuitry modules of the main

board and shows how they are interconnected.

Sample Schematics For up-to-date schematics refer to the relevant PCB information (refer to

“Associated Documentation” on page 6).

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Figure 3.1 Main board hardware architecture

Power

Connector

Control-Head

Connector

Interface

CODEC

and Audio

Auxiliary

Connector

Internal Options

Connector

Power Supply

Main Board

Logic

Custom

Synthesizer

DSP

Transmitter

digital

analog

asynchronous serial data

synchronous serial data

part of transmitter circuitry

analog-to-digital converter

digital-to-analog converter

part of CODEC and audio circuitry2)

Flash

Serial

Digital Board

FPGA

RISC

Proc.

SRAM

Flash

Memory

Frequency

Receiver

Switch

LPF

RF Connector

64 Circuit Descriptions TM8100/TM8200 Service Manual

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3.1 Transmitter Circuitry

Introduction For a block diagram of the transmitter circuitry, refer to Figure 3.2.

The transmitter circuitry is different for the 40W/50W radios and the 25 W radios, and the different bands.

Exciter With the 40 W/50 W radio, the discrete-component exciter is designed for

specific bands (UHF or VHF). It is made up of Q3501, Q3502, and Q3505, which amplify the signal provided by the frequency synthesizer from its level of 7 to 10dBm up to 24dBm for the frequency bands 136 to 174MHz and 400 to 520MHz.

With the 25W radio, the broadband exciter is a common element in all the bands, as it operates across all frequencies from 66 to 530MHz. It is made up of Q300 and Q303, which amplify the signal provided by the frequency synthesizer from its level of 7 to 10dBm up to 24.5dBm for the frequency band from 66 to 530MHz.

The exciter operates in full saturation, thereby maintaining a constant output power independent of the varying input power level supplied by the synthesizer.

Power Amplifier The power amplifier comprises the driver amplifier Q306 and two paralleled

final devices Q309 and Q310.

With the 40W/50W radio, the signal from the exciter is amplified by Q306 to a power level of approximately 2W (VHF) using a PD55003 and about 3W (UHF) using a PD55008. The resulting signal is then amplified by Q309 and Q310 to produce a typical output power of 90W at 155 MHz and 65W across the UHF band, when measured after the series capacitors (C348, C349, C350) at the start of the directional coupler.

With the 25W radio, the 24.5dBm signal from the exciter is reduced by a band-dependent pi-attenuator and is amplified by Q306. The resulting signal is then amplified a second time by Q309 and Q310 to produce a typical output power of 40W when measured after the series capacitors (C348, C349, C350) at the start of the directional coupler.

The high-level RF signal passes via the directional coupler, the transmitreceive PIN switch, and the LPF, through to the antenna. The LPF is used to attenuate unwanted harmonic frequencies.

Power Control Loop Calibration is used to adjust the power control loop, thus setting the output

of the transmitter to one of four preferred power levels:

■ 10, 15, 25, and 50 watts (VHF), and

10, 15, 20, and 40 watts (UHF) for 40W/50W radios

■ 1, 5, 12 and 25 watts (all bands) for 25W radios.

TM8100/TM8200 Service Manual Circuit Descriptions 65 © Tait Electronics Limited June 2006

Page 66

Figure 3.2 Block diagram of the transmitter circuitry

and

CODEC

CDC TX PWR CTL

Shaping

Audio

Filter

TX TEMP

TX FWD PWR

TX REV PWR

DIG TX INH

Board

Digital

DIG SYN EN

SYN LOCK

Frequency

Synthesizer

SYN TX LO

CDC TX DRV BIAS

CDC TX FIN BIAS1

CDC TX FIN BIAS2

Power

Supply

+9V0 TX

+13V8 BATT

OR Gate

Switch

TX INH

Crowbar

Bias

Limiter

Shaper

and Level

Shifter

Shaper

and Level

Shifter

Driver Exciter

AGND

Transmitter

Power

Control

Thermal

Coupling

ture

Sensor

Tempera-

Buffer Amplifier

Reverse Power

Buffer Amplifier

Forward Power

Buffer Amplifier

Coupler

Directional

Switch

LPF

TX RX RF

(40W/50W only)

Signal Types:

analog

clock

digital

asynchronous serial data

synchronous serial data

Interface

Connector

Receiver

66 Circuit Descriptions TM8100/TM8200 Service Manual

Page 67

The loop maintains these power settings under changing environmental conditions. The control mechanism for this loop is via the DAC IC204 and one of the operational amplifiers making up IC301. The power control loop will be inhibited if for any reason an out-of-lock signal is detected from the synthesizer. This ensures that no erroneous signals are transmitted at any time.

With the 40W/50W radio, the power control loop processes the voltages from the forward and reverse power sensors in the directional coupler. This signal is fed to the buffer and a band-limited operational amplifier back to the gate of Q306. In this way, the transmitter is protected against bad mismatches.

With the 25W radio, the power control loop senses the forward power by means of the diode D304. This signal is fed to the buffer and a band-limited operational amplifier back to the gate of Q306.

A voltage clamp (one of the operational amplifiers of IC301) for Q306 limits the maximum control-loop voltage applied to its gate.

Directional Coupler

With the 40W/50W radio, the directional coupler actively senses the forward power and the reverse power, and feeds them back to the powercontrol circuit.

With the 25W radio, the directional coupler actively senses the forward power and feeds it back to the power-control circuit. If the directional coupler detects too much reverse power, indicating a badly matched antenna, the transmitter will be reduced to the lowest power setting.

Temperature Sensor For added protection, a temperature sensor ensures that the transmitter

power is reduced to very low levels should a temperature threshold be exceeded. If the temperature does not decrease, the transmitter is switched off.

TM8100/TM8200 Service Manual Circuit Descriptions 67 © Tait Electronics Limited June 2006

Page 68

3.2 Receiver Circuitry

Introduction For a block diagram of the receiver circuitry, refer to Figure 3.3 (B1, H5,

H6 bands, 05 issue PCBs) and Figure 3.4 (other bands and later issue PCBs).

The receiver is of the triple-conversion superheterodyne type. The first two IF stages are implemented in hardware; the third stage is implemented in the FPGA (Field-Programmable Gate Array) of the digital board. The FPGA also carries out the demodulation of the received signals.

Front-End Circuitry The front-end circuitry is a standard varicap-tuned singlet (band-pass filter),

followed by an LNA (low-noise amplifier), and then a varicap-tuned doublet (image filter). The varicap tuning voltage by a DAC, with voltages calculated from a calibration table stored in nonvolatile memory. The two varicap-tuned filters need to be calibrated to ensure that maximum sensitivity is achieved.

First Mixer The first mixer is a standard diode-ring mixer with SMD (surface-mount

device) baluns and a quadruple SMD diode. For the bands between 66 and 174MHz, the receiver includes a circuit for suppressing ignition noise. This circuit momentarily removes the LO signal from the mixer when an ignition noise pulse is detected. The ignition-noise suppressor is selectable on a per-channel basis when the radio is programmed.

CDC RX FE TUNE is provided

First IF Stage and Second Mixer

The first IF stage consists of a crystal channel filter (BPF1), followed by an IF amplifier, and then another crystal filter (BPF2). The second mixer is an IC quadrature mixer with an internal AGC amplifier. This IC has a divideby-two function on the LO input in order to provide the quadrature LO frequencies required internally. The second LO frequency is synthesized by an integer PLL (IC403), which uses the TCXO frequency

SYN RX OSC

(13.0000 MHz) as its reference.

Frequencies of IF Stages

The frequency of the first IF stage depends as follows on the frequency band of the radio:

■ VHF bands: 21.400029MHz

■ UHF bands: 45.100134MHz.

The above are nominal values; the actual frequency will differ by a small amount depending on the exact initial frequency of the TCXO. The frequency of the second IF stage will always be precisely 64.000kHz once the TCXO calibration has been completed. (The TCXO calibration does not adjust the TCXO frequency, but instead adjusts the VCXO frequency, which in turn adjusts the VCO or first LO frequency as well as the frequency of the first IF stage. The second LO frequency remains fixed.) The third IF stage is completely within the FPGA and is not accessible.

Demodulation Demodulation takes place within the FPGA. Demodulated audio is passed

to the DSP of the digital board for processing of the receiver audio signal. Raw demodulated audio can be tapped out from the DSP for use with an external modem. The modem may be connected to the auxiliary connector or to the external options connector when an internal options board is fitted.

68 Circuit Descriptions TM8100/TM8200 Service Manual

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Figure 3.3 Block diagram of the receiver circuitry (05 issue boards, B1, H5, H6 bands)

CODEC

CIRCUITRY

POWER SUPPLY

AND AUDIO

CIRCUITRY

INTERFACE

DIGITAL BOARD

+3V0 RX

+3V0 AN

CDC RX VREF

RX CDC IN

RX CDC IP

FIRST IF STAGE

RX CDC QN

RX CDC QP

BIAS NETWORK

QUADRATURE

DEMODULATOR

BPF 2

IF AMPLIFIER

BPF 1

CDC RX FE TUNE

CDC RX AGC

AGND

DIG RX EN

DIG RX LE

RX DIG LD

DIG SYN SPI DO

DIG SYN SPI CLK

DIG RX NB EN

(NOT USED)

VCO

LOOP FILTER

PLL

SYN RX OSC

SYN RX LO1

TX RX RF

FREQUENCY SYNTHESIZER

TRANSMITTER

RECEIVER

ANALOGUE

CLOCK

SIGNALTYPES

DIGITAL

ASYNCHRONOUS

SERIAL DATA

SYNCHRONOUS

SERIAL DATA

MIXER

IMAGE FILTER

LNA

BPF

TM8100/TM8200 Service Manual Circuit Descriptions 69 © Tait Electronics Limited June 2006

Page 70

Figure 3.4 Block diagram of the receiver circuitry (B1, H5, H6 bands after PCB issue 05 & other bands)

and

Power

Supply

CODEC

Audio

Interface

Board

Digital

+3V0 RX

+3V0 AN

CDC RX VREF

RX CDC IN

RX CDC IP

RX CDC QP

Bias

Network

Quadrature

BPF 2

First IF

IF Amplifier

BPF 1

First IF

CDC RX AGC

RX CDC QN

Demodulator

CDC RX FE TUNE

CDC RX PIN AGC

AGND

DIG RX EN

DIG RX LE

RX DIG LD

DIG SYN SPI DO

DIG SYN SPI CLK

DIG RX NB EN

VCO

Loop Filter

PLL

SYN RX OSC

Frequency

Mixer

Switch

(66-225 MHz

only)

SYN RX LO1

Synthesizer

Receiver

Image Filter

Noise

LNA

analog

clock

digital

asynchronous serial data

synchronous serial data

Image Filter

Blanker

(66-174 MHz only)

Attenuator

TX RX RF

Transmitter

Signal Types:

70 Circuit Descriptions TM8100/TM8200 Service Manual

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Automatic Gain Control

The receiver has an AGC circuit to enable it to cover a large signal range. Most of the circuit functions are implemented in the FPGA. The FPGA passes the AGC signal to the CODEC IC204 for output from pin 14 (

IDACOUT) and then via IC201 as the signal CDC RX AGC to pin 23 of the

quadrature mixer IC400. As the antenna signal increases, the AGC voltage decreases.

Channel Filtering The channel filtering is split between the first and third IF stages.

The channel filtering circuit in the first IF stage comprises a pair of two-pole crystal filters. The first filter has a 3dB bandwidth of 12kHz, and the second a 3dB bandwidth of 15kHz. Most of the channel filtering, however, is implemented in the FPGA. When the radio is programmed, the different filters are selected as assigned by the channel programming. The selectable filters plus the fixed crystal filters result in the following total IF 3dB bandwidths:

■ wide channel spacing : 12.6 kHz

■ medium channel spacing: 12.0kHz

■ narrow channel spacing : 7.8 kHz.

(The FPGA runs from the

DIG SYS CLK signal, which has a frequency of

12.288MHz.) The receiver requires the TCXO calibration to be completed to ensure that the channel filtering is centred, thereby minimizing distortion.

Received Signal Strength Indication

Front-End AGC Control

Noise Blanker (A4, B1 bands only)

The RSSI is calculated in the FPGA and DSP, and can be passed as an analog voltage to the internal options interface and the external auxiliary interface. To obtain an accurate estimate of the RSSI (over the signal level and frequency), it is necessary to calibrate the AGC characteristic of the receiver and the front-end gain versus the receive frequency.

The receiver has a front-end AGC circuit to enable it to handle large receiver signals with minimal receiver distortion. This is very important for the correct operation of the THSD modem (Tait High-Speed Data). It enables THSD to maintain residual BER of < 10

-4

. The front-end AGC is controlled by an algorithm which monitors the RSSI and configures the DAC to turn on the front-end attenuation via the receive pin diode of the PIN switch.

If the frequency band is between 66 and 174MHz, a noise blanker can be selected to remove common sources of electrical interference such as vehicle ignition noise. The noise blanker functions by sampling the RF input to the receiver for impulse noise and momentarily disconnecting the first LO for the duration of the impulse. The response time of the noise blanker is very fast (tens of nanoseconds) and is quicker than the time taken for the RF signal to pass through the front-end hardware, so that the LO is disabled before the impulse reaches the IF stage where it could cause crystal filter ring.

TM8100/TM8200 Service Manual Circuit Descriptions 71 © Tait Electronics Limited June 2006

Page 72

3.3 Frequency Synthesizer Circuitry

Introduction For a block diagram of the frequency synthesizer circuitry, refer to

Figure 3.5 and Figure 3.6 (FCL for the A4 band).

The frequency synthesizer includes an active loop filter, one or two VCOs and buffer amplifiers, and a PLL IC. The last-named uses conventional integer-N frequency division and includes a built-in charge pump. Speedup techniques ensure a transmit-receive settling time of less than 4.5ms while retaining low noise characteristics in static operation.

Power Supplies Several power supplies are used by the frequency synthesizer owing to a

combination of performance requirements and the availability of suitable components. The PLL IC includes analog and digital circuitry and uses separate power supplies for each section. The digital section is run on 3V, while the analog section is run on approximately 5V. The VCOs and buffer amplifiers run off a supply of about 5.3V. The active loop filter requires a supply of 14 to 15V, and a reference voltage of approximately 2.5V.

Performance Requirements

Effect of Tuning Range

Switch-mode Power Supply

Low noise and good regulation of the power supply are essential to the performance of the synthesizer. A 6V regulator IC provides good line regulation of the 9V supply and good load regulation. Good regulation of the power-supply line and load is essential for meeting the transient ACP requirements. The regulator output voltage is electrically noisy, however, and filtering is essential. Filtering of the power supply is achieved with two capacitance multipliers (Q508 and C585 for the VCO supply, and Q512 and C579 for the PLL and loop-filter supply). The VCO (or VCOs) use a separate capacitance multiplier because these multipliers have poor load regulation and the VCOs impart sufficient load transients to warrant a separate supply.

For reasons of noise performance, the VCOs are designed to be tuned within a range of 2 to 12V. Active tuning circuitry is required. An active loop filter incorporating an IC operational amplifier achieves this range with a suitable power supply voltage. Normal synthesizer switching behaviour involves overshoot, which dictates that the tuning voltage range must extend above and below the range of 2 to 12V. The 14V limit is a result of limits on the working supply voltage of the IC operational amplifier.

The power supply VCL SUPPLY for the active loop filter is provided by a SMPS, which is in turn powered by 9V. The SMPS consists of an oscillator (switching circuit) and a detector. The output voltage is monitored by a feedback circuit that controls the DC bias of the switching circuit to maintain a constant output voltage.

Synthesizer Circuitry

The essential function of the PLL frequency synthesizer is to multiply a 25kHz reference frequency (30kHz for A4 band) to give any desired frequency that is an integer multiple of 25 kHz (30 kHz for A4 band). There are some constraints imposed by the capabilities of the synthesizer hardware, especially the tuning range of the VCOs.

72 Circuit Descriptions TM8100/TM8200 Service Manual

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Figure 3.5 Block diagram of the frequency synthesizer circuitry

and

Power

Supply

CODEC

Audio

Interface

+6V0

+9V0

Frequency Synthesizer

14 V

VP SUPPLY

SMPS

+3V0 AN

Modulator

+5 V

CDC VCXO MOD

Buffer Amplifier

VCXO

SYN CDC FCL

Mixer

SYN CDC LFV

CDC VCO MOD

LPF

(FCL)

Frequency Control Loop

Buffer Amplifier

TCXO

Buffer Amplifier

PLL

AGND

Inverter

Loop

Filter

Signal Types:

PLL

Coupler

TR SWITCH

SYN TX LO

analog

VCO

Filter

Supply

SYN RX LO1

clock

digital

asynchronous serial data

+5 V DEC VCL SUPPLY

MOD

5 V SWITCH

DIG SYN TR SW

VCO (VHF only)

synchronous serial data

Summer

5 V SwitchTR Switch

PLL

MOD

VCO 2

VCO 1

and

Buffer

Coupler

SYN TX LO

Trans-

Amplifiers

mitter

VCO (UHF only)

SYN RX LO1

Receiver

SYN RX OSC

DIG SYN SPI DO

DIG SYN SPI CLK

DIG SYN TR SW

DIG SYN EN

DIG SYN FAST

Digital

DIG SYN LATCH

Board

SYN LOCK

SYN DIG FREF

TM8100/TM8200 Service Manual Circuit Descriptions 73 © Tait Electronics Limited June 2006

Page 74

Figure 3.6 Block diagram of the frequency control loop circuitry—A4 band

÷ 4

Buffer

Buffer Amplifier

Amplifier

÷ 4

FCL

Reference Frequency

The approximately 25kHz (30kHz for A4) reference is obtained by dividing the approximately 13MHz (2.612 kHz for A4) output of the FCL. Any error in the FCL output frequency will be multiplied by the synthesizer. Therefore, if the synthesizer is locked but not the FCL, then the synthesizer output frequency will be wrong. The FCL frequency division is performed by a digital counter inside the PLL IC. The divider setting is constant.

VCO Frequency and Output Power

The output frequency from the synthesizer is generated by a VCO. The VCO frequency is tuned across the frequency range of the radio by means of a DC control voltage, typically between 2V and 12V. The VCO output power is amplified by a buffer amplifier. The power is low and varies from band to band. The buffer output power depends on which mode— receive or transmit—is used. In receive mode the output power should be about 7dBm, whereas in transmit mode it should be about 9 dBm.

Dual VCOs Some variants of the synthesizer use two VCOs: one for receive and one for

transmit. Synthesizers with two VCOs share the same tuning signal. Only one VCO is switched on at a time, and so the PLL IC will see only one output frequency to tune. A portion of the RF output from the VCOs is fed to the RF input of the PLL IC. The RF signal is divided by an integer that gives 25kHz (30kHz for A4) if the output frequency is correct.

Phase-locked Loop The PLL IC compares the 25kHz reference (30kHz for A4) and the divided

VCO signal, and the error is used to control the internal charge pump. The charge pump is a current source that can sink or source current in proportion to the frequency or phase error. The output is a series of 25kHz pulses (30kHz for A4) with a width that is dependent on the phase error. When the output frequency of the synthesizer is correct, there is no error and the charge pump output will become open circuit.

74 Circuit Descriptions TM8100/TM8200 Service Manual

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Active Loop Filter The loop filter continuously integrates the current pulses from the charge

pump and produces a steady DC output voltage that tunes the VCO (or VCOs). When the VCO frequency is correct, there is no frequency error and therefore no charge-pump output, and so the loop filter’s output voltage remains constant. If the frequency is too high or too low, the error will result in the output of charge-pump current pulses (negative or positive depending on the sign of the error). The loop filter’s output voltage will change accordingly, causing the VCO frequency to change in proportion. The synthesizer design is such that normally the VCO frequency will be automatically corrected.

Re-tuning of VCO Frequency

Speed-up Te ch n iq ue s

When the radio changes channels or switches between receive and transmit, the VCO frequency must be changed. The rate at which the VCO is retuned is dependent on many factors, of which the loop filter is the main factor. The loop filter is an integrator built around an operational amplifier. The resistors and capacitors of the filter affect both the switching time and the stability of the synthesizer; the values of these components have been carefully selected to give optimum control characteristics.

To reduce the change-over time between transmit and receive, part-time speed-up techniques have been implemented. Speed-up involves changing some resistor values while simultaneously changing the PLL IC settings. This process is implemented in hardware under software control in conjunction with use of the synthesized reference input. The result is a transmit-receive settling time of less than 4.5ms. (The switching time is measured for a frequency change equal to the first IF plus 10MHz or 1MHz, depending on the repeater offsets used for the band. This implies a synthesizer transmit-receive change-over plus an offset of 1MHz or 10 MHz in less than 4.5ms. The ramp-up and ramp-down of the transmitter, which totals 1ms, extends this change-over time to 5.5ms.)

TM8100/TM8200 Service Manual Circuit Descriptions 75 © Tait Electronics Limited June 2006

Page 76

3.4 Frequency Control Loop

Introduction The FCL is included in the block diagram of the frequency synthesizer

(see Figure 3.5 and Figure 3.6).

The FCL forms part of the frequency-synthesizer module. The basis of the FCL is a VCXO, which generates the reference frequency required by the main PLL of the synthesizer.

Elements of FCL Circuitry

The FCL is a simple frequency-locked loop. The circuitry consists of the following elements:

■ VCXO (XL501, Q501, Q503)

■ TCXO (XL500)

■ buffer amplifier (IC500)

■ mixer (IC501)

■ low-pass filter (IC502, pins 5 to 7)

■ modulator buffer amplifier (IC502, pins 1 to 3).

The A4 band has additional circuitry:

■ 2.612MHz mixer (IC506)

■ amplifiers (Q504, IC509)

■ TCXO divide by 4 (IC508)

The TCXO supplies a reference frequency of 13.0000MHz (10.4MHz for the A4 band), which is extremely stable, regardless of the temperature. The VCXO runs at a nominal frequency of 13.0120MHz, and is frequencylocked to the TCXO reference frequency.

Circuit Operation The VCXO is mixed with the TCXO output to create a nominal difference

(or offset) frequency of 12kHz

SYN CDC FCL. In A4 band radios, there is

additional circuitry and the VCXO is mixed with the TCXO to produce

2.612MHz. This is then mixed with 2.6MHz (TCXO divided by 4) to produce the 12kHz

SYN CDC FCL.

The signal

SYN CDC FCL is fed via the CODEC IC502 in the CODEC

circuitry to the FPGA on the digital board. The FPGA detects the offset frequency, compares it with the programmed offset frequency, and outputs a corresponding feedback signal

CDC VCXO MOD via IC205. The feedback

signal is amplified and inverted by the modulator buffer amplifier and output as the loop voltage for the VCXO. With this design the VCXO frequency can be adjusted by very small precise amounts, and because the loop is locked, the VCXO inherits the temperature stability of the TCXO.

Modulation The FCL modulation is implemented within the FPGA and appears at the

output of IC205, and therefore on the VCXO loop voltage. Consequently, the VCXO is frequency modulated directly by the relevant modulation information. The latter may be the microphone audio, an audio tap-in signal, internal modem signals, or any combination of these.

76 Circuit Descriptions TM8100/TM8200 Service Manual

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3.5 CODEC and Audio Circuitry

Introduction For a block diagram of the CODEC and audio circuitry, refer to Figure 3.7.

A/D and D/A Conversion

Device IC203 IC203 is an eight-channel DAC that provides control of transmitter biasing,

The analog-to-digital conversion and digital-to-analog conversion is performed by the devices IC203, IC204 and IC205.

front-end AGC, front-end tuning, and the output of analog RSSI signals. The digital input data are fed to IC203 in synchronous serial form. Three of the DAC channels are not used.

Device IC205 IC205 contains two CODECs. One is used by the FCL. The second is used

for auxiliary audio (input) and VCO modulation (output). The digital section communicates with this device via a four-wire synchronous serial interface.

Device IC204 IC204 contains base-band, voice-band and auxiliary CODECs and some

analog signal conditioning. The reference voltage (nominally 1.2V) for these CODECs is provided internally by IC204 but is decoupled externally by C228.

Base-band CODEC The base-band CODEC handles the I and Q outputs (IRXP, IRXN, QRXP and

QRXN balls) of the receiver’s second IF stage. The analog signals are

differential and biased at 1.2V nominally. The digital section communicates with this CODEC via a two-wire synchronous serial interface (

BSOFS balls). The digital-to-analog conversion section of the base-band

BSDO and

CODEC is not used.

Voice-band CODEC The voice-band CODEC handles the microphone and speaker signals.

The digital section communicates with this CODEC via a three-wire synchronous serial interface (

VSFS, VSDO and VSDI balls). IC204 also contains

voice-band filtering, pre-amplification and volume control.

Auxiliary CODEC The auxiliary CODEC handles transmitter power control, receiver gain

control, auxiliary audio output and general analog monitoring functions. The digital section communicates with this CODEC via a three-wire synchronous serial interface ( receiver gain control (

IDACOUT ball) is a current output type. Current-to-

ASFS, ASDI and ASDO balls). The DAC used for

voltage conversion is performed by R238. The full-scale output of 1.2 V is amplified by IC201 to approximately 3V as required by the receiver.

Audio Circuitry The audio circuitry performs four functions:

■ output of audio signal for speaker

■ input of microphone audio signal

■ input of auxiliary audio signal

■ output of auxiliary audio signal.

TM8100/TM8200 Service Manual Circuit Descriptions 77 © Tait Electronics Limited June 2006

Page 78

Figure 3.7 Block diagram of the CODEC and audio circuitry

Power

Supply

Interface

DIG RX EN

PSU SYS RST

+13V8 BATT

+2V5 CDC

+9V0

+3V3

+3V0 AN

CDC RX AUD

AUD ITF SPK+

AUD ITF SPK–

ITF RX BEEP IN

ITF CH MIC AUD

ITF AUX MICAUD

ITF VOLWIP DC

CDC AUDTAP OUT

CDC RSSI

AGND

ITF AUDTAP IN

DIG AUD PA EN2

DIG AUD PA EN1

digital

asynchronous serial data

analog

Signal Types:

synchronous serial data

clock

Audio PA

CODEC and Audio

Voltage

Divider

Buffer

Amplifier

Volume

Control

Buffer

Amplifier

DIG AUD UD

DIG AUD CS

Summer

2V3

Supply

Bias

Network

LPF

+2V3 FIL

PSU SYS RST

CDC DIG ASDO

DIG CDC ASDI

DIG CDC ASFS

CDC DIG BSDO

+1V8

CDC DIG BSOFS

DIG CDC VSDI

CDC DIG VSDO

CDC DIG VSFS

DIG CDC ARSM

Digital Board

CODEC 1

DIG DAC SPI CLK

DIG DAC SPI DO

DIG DAC LATCH

DIG SYS CLK

DIG CDC2 LRCK

DIG CDC2 SCLK

DIG CDC2 SDTI

CDC2 DIG SDTO

DIG RX EN

CDC RX VREF

RX CDC IP

RX CDC IN

RX CDC QP

RX CDC QN

Receiver

DIG RX EN

Level

Shifter

DAC

CDC RX AGC

CDC RX FE TUNE

CDC TX FIN BIAS1

CDC TX FIN BIAS2

CDC TX DRV BIAS

CDC TX PWR CTL

TX TEMP

TX FWD PWR

Trans-

TX REV PWR

mitter

CDC RX PIN AGC

SYN CDC LFV

CDC VCO MOD

CODEC 2

CDC VCXO MOD

SYN CDC FCL

Frequency

Synthesizer

78 Circuit Descriptions TM8100/TM8200 Service Manual

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The sections of the circuitry concerned with these functions are described below.

Audio Signal for Speaker

The audio signal for the speaker is generated by IC204 (VOUTAUXP ball). This signal is post-volume-control and has a pre-emphasized frequency response. The signal is then processed by R218, R217 and C231 (C205) to restore a flat frequency response and reduce the signal level to that required by the audio power amplifier.

Summing Circuit The top of C231 (C205) is where side tones are summed in and the CDC RX

AUD signal is obtained. C201 and R211 pre-emphasize and attenuate the

side-tone signal to give a flat side-tone frequency response and reduce the input to an appropriate level.

Buffer Amplifier IC201 (pins 8 to 10) amplifies the signal at the top of C231 (C205) by 19dB

and drives the

CDC RX AUD system interface line via C212 and R225.

The capacitor C212 provides AC output coupling and R225 ensures stability. The DC bias for this amplifier is derived from IC204.

Audio Power Amplifier

The signal at the top of C231 (C205) is fed via C204 to the audio power amplifier IC202. IC202 has 46dB of gain and a differential output configuration. C209, C211, R252 and R253 ensure stability of the amplifier at high frequencies. When operational, the output bias voltage for IC202 is approximately half the radio supply voltage. When not operational, the output becomes high impedance.

Control of Audio Power Amplifier

Power up, power down, and muting of IC202 is controlled by two signals from the digital section,

DIG AUD PA EN1 and DIG AUD PA EN2. The network

consisting of Q200, Q201, R200 to R206, R210 and R250 converts the two digital signals to the single three-level analog signal required by IC202.

Microphone Signals There are two microphone source signals:

■ ITF AUX MIC AUD from auxiliary or internal options connector

■ ITF CH MIC AUD from control head.

The biasing for electret microphones is provided by a filtered 3.0V supply via R226 and R227. The components R209 and C202 provide the supply filtering. The microphone inputs to IC204 (

VINNORN balls) are differential. The negative inputs are decoupled to the

filtered 3.0V supply by C215 and C216. The positive inputs are biased to approximately 1.5 V by R229, R232, R230 and R233. AC coupling and DC input protection is provided by C213 and C214.

Auxiliary Audio Input

The auxiliary audio input signal ITF AUD TAP IN is DC-coupled to the ADC input of IC205. R241 combined with internal clamping diodes in IC205 provide DC protection for the ADC input. IC205 provides the input biasing of approximately 1.5V.

VINAUXP, VINAUXN, VINNORP, and

TM8100/TM8200 Service Manual Circuit Descriptions 79 © Tait Electronics Limited June 2006

Page 80

Auxiliary Audio Output

The source for the auxiliary audio output signal CDC AUD TAP OUT is provided by IC204 (

RAMPDAC ball). The DAC output of IC204 is low-pass filtered to

remove high-frequency artefacts. The low-pass filter, formed by IC201 (pins 1 to 3), R219, R220, R221, R224, C206, C208 and C210, is a thirdorder Butterworth type with a cut frequency of approximately 12kHz. The output of the low-pass filter is amplified by 6dB by a buffer amplifier, IC201 (pins 5 to 7), and fed via R207 and R208 to drive the

OUT interf ace line. The DC bias for this signal pa th is provided by IC204 and

is approximately 1.2V when operational. The offset at

CDC AUD TAP OUT is

CDC AUD TAP

approximately 2.4V owing to the gain of the buffer amplifier.

80 Circuit Descriptions TM8100/TM8200 Service Manual

Page 81

3.6 Power Supply Circuitry

Introduction For a block diagram of the power supply circuitry, refer to Figure 3.8.

The power-supply circuitry consists of the following main sections:

■ supply protection

■ supervisory circuit

■ internal power supplies

■ control of internal power supplies

■ control of external power supply.

Supply Protection Electrical protection to the radio is provided by the clamping diode D600

and by 20A fuses (for the 40W/50 W radios) and 10A fuses (for the 25W radios) in the positive and negative leads of the power cable. This provides protection from reverse voltages, positive transients greater than 30V, and all negative transients. An ADC monitors the supply and is responsible for the protection of internal devices, which have an operating voltage of less than 30V. The ADC also ensures protection if the radio operates outside its specified voltage range of 10.8V to 16 V.

Supervisory Circuit The supervisory circuit comprises a reset and watchdog timer. The circuit

PSU SYS RST to the digital section, which in turn

DIG WD KICK required by the supervisory circuit.

V8 BATT.

Internal Power Supplies

provides the reset signal provides the watchdog signal

There are eight internal power supplies:

■ one SMPS (+3V3)

■ four linear regulators (+9V0, +6V0, +3V0 AN, +2V5 CDC)

■ three switched supplies (+9V0 TX, +3V0 RX, +13V8 SW).

The SMPS is used to regulate to 3.3V from the external supply +13 The four lower voltages required are then further stepped down with linear regulators. These all take advantage of the efficiency gain of the SMPS. The 9V regulator and the 13.8V switched supply are connected to +13

BATT. The two remaining switched supplies (9V and 3V) use P-channel

MOSFETs.

Control of Internal Power Supplies

The radio can be switched on using the ON/OFF key on the control head or by means of external signals. For the latter case hardware links are required and there are several power-sense options; these are discussed below. Some internal power supplies can be controlled by means of digital lines depending on the mode in which the radio is operating.

TM8100/TM8200 Service Manual Circuit Descriptions 81 © Tait Electronics Limited June 2006

Page 82

Figure 3.8 Block diagram of the power supply circuitry

SMPS

Power Supply

+3V3

Regulator

2V5

Regulator

6V0

Regulator

+9V0

9 V Tx Switch

3 V Rx Switch

+13V8 BATT

+9V0 TX

+9V0

+3V0 AN

+6V0

+13V8 BATT

+3V0 AN

+9V0

+3V3

+2V5 CDC

+3V0 AN

+3V0 RX

DIG RX EN DIG TX EN DIG SLP EN +3V3 DIG PSU LATCH

Transmitter

Frequency

Synthesizer

CODEC

and

Audio

Receiver

OR Gate

Super-

visor

Signal Types:

analog

clock

digital

asynchronous serial data

synchronous serial data

PSU

13V8 PWR

SENSE

IOP PWR SENSE

IGNITION SENSE

EMERGENCY

Hardware

Links

13V8 Switch

Reverse

Polarity

Protection

DIG WD KICK PSU SYS RST

+3V3

AGND

CH ON OFF ITF IOP GPIO7 AUX GPI3 AUX GPI2 +3V3

+13V8 SW

+13V8 BATT

Digital

Board

Debug

Connector

Interface

82 Circuit Descriptions TM8100/TM8200 Service Manual

Page 83

Power-Sense Options

The radio allows the configuration of different power-sense options to control how the radio is powered up and down:

■ battery power sense

■ auxiliary power sense (ignition sense)

■ internal-options power sense

■ no power sense

■ emergency power sense.

The emergency power-sense option can be used in conjunction with any of the other four options.

The different power-sense options have to be facilitated by hardware means, as the software cannot act before it is powered up. The radio provides four hardware links (LK1 to LK4) on the top-side of the main board which can be configured to attain the power-sense option desired.

Figure 3.9 shows a block diagram of the hardware links LK1 to LK4.

Figure 3.9 Block diagram of hardware links LK1 to LK4

ON/OFF Key

13V8 BATT

LK1

13.8V Battery Power Sense

LK2

AUX GPI3

Auxiliary Power Sense

(Ignition Sense)

13V8 BATT

Power-up

Circuit

LK3

AUX GPI2

Emergency

Sense

LK4

IOP GPIO7

Internal Options

Power Sense

The radio can be programmed to be either on, or to return to its previous state when the power sense signal is removed. For information on programming the power-on mode refer to the online help of the programming software.

The

ON/OFF key can be used with any of the of the power-sense options to

turn the radio on and off.

Page 84

Table 3.1 shows the configuration of the hardware links LK1, LK2 and LK4

for the individual power-sense options. It also lists the dependence of the power-sense options with respect to the GPI lines, which can or cannot be used.

Table 3.1 Configuration of hardware links and GPI lines for power-sense options

Power-sense option

13.8V battery power sense

Links required

LK1 in LK2 in:

Configuration of remaining links and use of AUX GPI3 and IOP GPIO7

AUX GPI3 must be left floating.

LK2 out: AUX GPI3 can be used as GPI

Voltages required

≤ supply≤ 16V

10.8V

LK4 out IOP GPIO7 can be used as GPIO.

auxiliary power sense (ignition sense)

LK2 in LK1 in:

Input line must sink >1mA from AUX GPI3 (which is pulled to 13.8V by a

Ω resistor). The impedance between

33k

AUX GPI3 AUX GPI3 ignition-sense tolerant to

3.3V, 5 V and 12 V

≤0.7V off ≥2.6V high (active)

the vehicle ignition signal and ground must be ≤1k

LK1 out: Input line must be active high

Ω.

LK4 out IOP GPIO7 can be used as GPIO.

internal power sense LK1 out IOP GPIO7

LK2 out AUX GPI3 can be used as GPI.

LK4 in With LK4 in, the input line must be active

high

IOP GPIO7≥ 2.6V high (active) ignition-sense tolerant to

3.3V and 5V only

≤0.7V off

no power sense LK1 out 10.8V ≤ supply ≤16V

LK2 out AUX GPI3 can be used as GPI.

LK4 out IOP GPIO7 can be used as GPIO.

a. If LK2 is out and AUX GPIO is not used, R775 (33k) should be placed to ensure that AUX GPI3 does not float

(R775 is not placed by factory default). b. If LK1 is out and R775 is placed, AUX GPI3 should be driven low as well. c. If LK 4 is in and R723 is placed, IOP GPIO7 should be driven low as well. (R723 is placed by factory default.)

Table 3.2 shows the configuration of ‘emergency power sense’. ‘Emergency

power sense’ can be configured with any of the above power sense options.

Table 3.2 Configuration of hardware link LK3 and AUX GPI2 for ‘emergency power sense’

External push-button or toggle switch required to enter emergency mode

Yes LK3 in AUX GPI2 must be connected to an

No LK3 in AUX GPI2 must be left floating

84 Circuit Descriptions TM8100/TM8200 Service Manual

Links required

Implications on AUX GPI2 Voltages required

external (hidden) push-button or toggle switch, which connects it to ground.

LK3 out AUX GPI2 can be used as GPI.

≤0.7V active,

floating inactive

Page 85

Battery Power Sense

With this option, link LK1 connects +13V8 BATT of the power connector to the power-up circuitry. With this option, when a 13.8 V supply is connected to the radio, the radio enters the programmed power-on mode. The

ON/OFF

key can then be used to switch the radio on and off. This option has the disadvantage that the radio still draws about 50mA after being switched off using the

ON/OFF key. The reason is that the radio enters the stand-by mode

and does not shut down completely.

Auxiliary Power Sense (Ignition Sense)

This option uses the digital input line AUX GPI3 of the auxiliary connector to power the radio up and down. Link LK2 is required to connect the line to the power-up circuitry. The line is active high; it is on when the level exceeds 2.6V and off when the level falls below 0.7V; the line tolerates maximum inputs equal to the radio supply voltage. When the line becomes active, the radio enters the programmed power-on mode. The

ON/OFF key

can then be used to switch the radio on and off. With the radio off and the line active, the radio draws about 50mA. When the line becomes inactive, the radio is shut down completely regardless of whether it was on or in stand-by mode. With the line inactive the radio draws less than 1mA. In a vehicle installation this avoids flattening the battery when the ignition key is off.

Internal-Options Power Sense

This option is similar to the auxiliary power-sense option, except that the

IOP GPIO7 line of the internal options connector is used. Link LK4 is required

to connect the line to the power-up circuitry. This line is active high; it is on when the level exceeds 2.6V and off when the level falls below 0.7V; the line tolerates maximum inputs of 5V. The behaviour of the

ON/OFF key

is the same as with the auxiliary power-sense option.

No Power Sense If no power-sense option is selected, the radio can only be powered up and

powered down by means of the

ON/OFF key. For this option, the links LK1,

LK2 and LK4 must be removed. The advantage of this option over the battery power-sense option is that the radio draws less than 1 mA when it is switched off.

Emergency Power Sense

This option uses the AUX GPI2 line of the auxiliary connector. Externally, this line is typically connected to a hidden switch. Internally, link LK3 is required to connect the line to the power-up circuitry. The line is active low and has an internal pull-up resistor to the external supply voltage. The line is on when the level falls below 0.7V. When the line becomes active (when the hidden switch is pressed for two seconds) the radio enters the emergency mode. This mode can also be activated by making an emergency call or by pressing a key that has been programmed appropriately. The concealed microphone is typically fitted when the emergency power-sense option is selected.

Page 86

Operation in Emergency Mode

If the radio is off when the emergency mode is activated, the radio is powered up but the display on the control head is not switched on. If the radio is on when the mode is activated, the display is frozen. In the latter case, if the

ON/OFF key is pressed, the display is switched off but the radio

remains in the emergency mode. While in this mode the radio cycles between transmit and receive. To exit the emergency mode, the

ON/OFF key

needs to be pressed again.

Connector Power Supply Options

Power from the radio’s primary power source is fed to the auxiliary, internal options, control head and microphone connectors. Whether power to these connectors is unswitched, switched or not supplied is determined by hardware links LK5 to LK8 on the top side of the main board, as shown in

Figure 3.10 and Table 3.3.

Unswitched power means that power will always be supplied to the connector while the primary power source is connected to the radio and is alive. The supply to the connector is not affected by the state of the radio.

Switched power means that when the radio is off or in standby mode, the power to the connector is switched off. The power will also be switched off if the primary power source voltage is outside the radio’s operating range. The combined switched current drawn by the internal options connector, the auxiliary connector and the control-head connector must not exceed 1A.

Note The switched output is protected. Short-circuiting the switched

power on any connector will not damage the radio. In the event of a short circuit, the current folds back to protect the switch device and connectors.

Figure 3.10 Connector power supply options

Internal Options

Connector

LK7 (R787)

LK5

LK6

+13V8

Auxiliary

Connector

Control-

Connector

Head

Microphone

Connector

Primary

Power

Source

Power

Connector

LK8 (R786)

+13V8 BATT

Note The links LK7 and LK8 have the alternative designations R787

and R786 respectively. The factory-default setting is with LK5 and LK7 inserted and LK6 and LK8 omitted.

86 Circuit Descriptions TM8100/TM8200 Service Manual

Page 87

Table 3.3 Connector power supply options

Link state Connector power state

LK5 LK6

out out out out switched no power no power no power

in out in out switched switched switched switched

out in in out switched switched unswitched unswitched

in out out in switched unswitched switched switched

out in out in switched unswitched unswitched unswitched

in in/out in in unswitched unswitched unswitched unswitched

LK7 (R787)

LK8 (R786)

Auxiliary

Internal options

Control head Microphone

3.7 Interface Circuitry

Introduction For a block diagram of the interfaces circuitry, refer to Figure 3.11.

For more on the connector pinouts, refer to “Connectors” on page 36.

Bi-directional Lines Bi-directional lines are provided on four pins of the auxiliary connector,

AUX GPIO4 to AUX GPIO7) one on the control-head connector (CH GPIO1), and

( seven on the internal options connector ( the auxiliary and control-head connectors are formed by combining two uni-directional lines. For example, the line auxiliary connector is formed from The circuitry is the same in all five cases and is explained below for the case

AUX GPIO4.

IOP GPIO1 to IOP GPIO7). Those on

AUX GPIO4 at pin 10 of the

ITF AUX GPI4 and DIG AUX GPO4.

Output Signals (e.g. AUX GPIO4)

An output on the line AUX GPIO4 originates as the 3.3V signal DIG AUX GPO4 from the digital section. The signal is first inverted by Q703 (pins 3 to 5) and the output divided down to 1.6V by R748 and R753 to drive the base of Q703 (pins 1, 2 and 6). When the latter’s collector current is low, the base current is a maximum and creates a small voltage drop across R761, causing the collector emitter to saturate. As the collector current increases, the base current decreases proportionally until the voltage across R761 reaches 1V. At this point the base-emitter begins to turn off and the base current diminishes rapidly. The net effect is a current-limiting action. The current limit value is approximately 18mA (the inverse of the value of R761). The output configuration is open-collector with a pull-up to 3.3 V by default. Pull-up options to 5V and 13.8 V are also available. On

AUX GPIO4

only, the optional MOSFET Q707, which has a high current drive, may be fitted. If Q707 is fitted, R768 must be removed.

5-Volt Regulator The 5V supply mentioned above is provided by a simple buffered zener

regulator formed by Q702, D721, R721 and R722. The resistor R722 limits the current to about 25 mA under short-circuit conditions.

Page 88

Figure 3.11 Block diagram of the interface circuitry

Power

Supply

CODEC

and

Audio

+13V8 BATT AGND

+3V3 +13V8 SW AUX GPI2 AUX GPI3 CH ON OFF ITF IOP GPIO7

AUD ITF SPK+ AUD ITF SPKITF VOLWIP DC AGND

ITF CH MIC AUD CDC RX AUD ITF RX BEEP IN CDCAUD TAPOUT ITF AUDTAP IN ITF AUX MICAUD CDC RSSI

ITF ON OFF ITF CH RXD DIG CH TXD

ITF CH HOOK

ITF CH PTT

ITF CH GPI1 DIG CH GPO1

ITF CH SPI DI DIG CH SPI DO DIG CH SPI CLK DIG CH LE

Interface

Hookswitch

PTT and

Decode

I/O

Combine

EMC

Filters

EMC

Filters

ESD and

EMC

Filters

ESD and

EMC

Filters

EMC

Filters

+13V8 BATT

AGND SPK+ SPK–

+13V8 BATT +3V3

AGND DGND

SPK+ SPK– VOL WIP DC

CH MIC AUD

RX AUD

CH ON OFF CH RXD CH TXD

CH PTT

CH GPIO1

CH SPI DI CH SPI DO CH SPI CLK CH LE

Power

Connector

Control-

Head

Connector

Digital

Board

Debug

Connector

Frequency

Synthesizer

Receiver

and

Transmitter

ITF IOP GPIO1-6

ITF IOP GPIO7

ITF IOP RXD

DIG IOP TXD

ITF AUX RXD DIG AUXTXD ITF AUX GPI1 ITF AUX GPI2 ITF AUX GPI3

DGND

ITF AUX GPI4-7 DIG AUX GPO4-7

AGND

Signal Types:

analog

clock

+3V3 CL

+3V3 Clamp

I/O

Combine

and

Pull-up

Resistors

+5V

Regulator

digital

asynchronous serial data

synchronous serial data

Clamps

and

Pull-up

Resistors

Clamps,

ESD

Filters,

and

EMC

Filters

RX AUD RX BEEP IN AUD TAP OUT AUD TAP IN AUX MIC AUD RSSI +13V8 SW

IOP GPIO1-6 IOP GPIO7 IOP RXD IOP TXD AGND DGND

AUX RXD AUX TXD AUX GPI1 AUX GPI2 AUX GPI3

AGND +13V8 SW

AUX GPIO4-7

AUD TAP OUT AUD TAP IN AUX MIC AUD RSSI

Internal Options

Connector

Auxiliary

Connector

88 Circuit Descriptions TM8100/TM8200 Service Manual

Page 89

Input Signals (e.g. AUX GPIO4)

An input signal applied to AUX GPIO4 is coupled via R757 to ITF AUX GPI4 and fed to the digital section. As the input signal may exceed the maximum allowed by the digital section, it is clamped by D711 and a shunt regulator. The shunt regulator consists of Q708, R719 and R720 and begins to turn on at approximately 2.7V. In combination with D711, the input to

ITF AUX GPI4 is therefore clamped to 3.3V nominally. The value of R757 is

made large to minimize the loading effect on the output pull-up resistors.

Input Signals (AUX GPI1 to AUX GPI3)

Dedicated inputs are provided on three pins of the auxiliary connector

AUX GPI1 to AUX GPI3). AUX GPI1 is a general-purpose input with strong

( protection of the same type used for

AUX GPIO4. AUX GPI2 is normally a

dedicated emergency input but can be made a general-purpose input like

AUX GPI1 by removing the link LK3 in the power supply area. AUX GPI3 is

normally a dedicated ignition-sense input but can be made a generalpurpose input like

AUX GPI1 by removing the link LK2 in the power supply

area and fitting the 33kΩ resistor R775.

ESD Protection On exposed inputs of the auxiliary and control-head connectors ESD

(electrostatic discharge) protection is provided by a 470pF capacitor and by clamping diodes to ground and to 13.8V. For example, on consists of D713 and C725. The lines

IOP GPIO1 to IOP GPIO7 are intended for

AUX GPIO4 this

connection to internal digital devices and so these have relatively light protection.

Hookswitch Detection

Hookswitch detection is performed by Q700, R709, R706 and R712. When the resistance to ground on the PTT line is less than 13.2kΩ, Q700 will turn on and drive the

ITF CH HOOK line high; this indicates either that the

microphone is on hook or that the PTT (press-to-talk) switch is pressed.

3.8 Digital Board

Introduction Different digital boards are used for the TM8200 and TM8100 radios.

For a block diagram of the digital board of the TM8200 radios, refer to

Figure 3.12. For a block diagram of the digital board of the TM8100 radios,

refer to Figure 3.13.

The digital board is not serviceable at level-2 and is not described in this manual.

Page 90

Figure 3.12 Block diagram of the digital board (TM8200 radios)

Trans-

mitter

Frequency

Synthesizer

Receiver

CODEC

and

Audio

DIG TX INH

DIG SYN EN

SYN LOCK

DIG SYN TR SW

DIG SYN FAST

DIG SYN LATCH

SYN DIG FREF

DIG SYN SPI DO

DIG SYN SPI CLK

DIG RX LE

RX DIG LD

DIG RX NB EN

DIG RX EN

CDC2 DIG SDTO

DIG CDC2 SDTI

DIG CDC2 CLK

DIG CDC2 LRCK

DIG DAC SPI DO

DIG DAC SPI CLK

DIG DAC LATCH

DIG CDC ARSM

CDC DIG VSFS

CDC DIG VSDO

DIG CDC VSDI

CDC DIG BSOFS

CDC DIG BSDO

DIG CDC ASFS

DIG CDC ASDI

CDC DIG ASDO

DIG AUD PA EN1

DIG AUD PA EN2

DIG SYS CLK

DIG CDC RST

FPGA

+1V8+3V3

Serial Flash

DGND

AGND

DIG CH SPI CLK

DIG CH SPI DO

ITF CH SPI DI

DIG CH LE

ITF CH GPI1

DIG CH GPO1

ITF CH PTT

ITF CH HOOK

ITF ON OFF

ITF IOP GPIO1-7

DIG IOP TXD

ITF IOP RXD

ITF AUX GPI1-7

DIG AUX GPO4-7

DIG AUXTXD

ITF AUX RXD

DIG CH TXD

ITF CH RXD

Interface

Digital Board

DIG PSU LATCH

DIG WD KICK

DIG TX EN

DIG SLP EN

SRAM

DATA

ADDRESS

CONTROL

PSU SYS RST

Flash

Memory

+1V8+3V3

RESET IO

McBSP0

McBSP1

BIRDIE

FPGA CLOCK

System

Clock

DSP

Power

Supply

+1V8

Signal Types:

analog

clock

digital

asynchronous serial data

+1V5

FPGA JTAG Signals:

JTAG TCKFPGA JTAG TMSFPGA FPGA JTAGTDO

FPGA JTAG (x4)

JTAG FPGATDI

Factory Connector

+1V5

Regulator

+1V8

Regulator

DSP JTAG Signals:

JTAG TCKDSP JTAG TMSDSP

DSP JTAG (x7)

DSP JTAGTDO JTAG DSPTDI

+3V3

AGND

1V5

1V8

+3V3

PSU SYS RST

DIG RX EN

JTAG TRSTDSP DSP JTAG EMU0 DSP JTAG EMU1

synchronous serial data

90 Circuit Descriptions TM8100/TM8200 Service Manual

Page 91

Figure 3.13 Block diagram of the digital board (TM8100 radios)

Trans-

mitter

Fre-

quency

Synthe-

sizer

Receiver

CODEC

and

Audio

DIG TX INH

DIG SYN EN

SYN LOCK

DIG SYN TR SW

DIG SYN FAST

DIG SYN LATCH

SYN DIG FREF

DIG SYN SPI DO

DIG SYN SPI CLK

DIG RX LE

RX DIG LD

DIG RX NB EN

DIG RX EN

CDC2 DIG SDTO

DIG CDC2 SDTI

DIG CDC2 SCLK

DIG CDC2 LRCK

DIG DAC SPI DO

DIG DAC SPI CLK

DIG DAC LATCH

DIG CDC ARSM

CDC DIG VSFS

CDC DIG VSDO

DIG CDC VSDI

CDC DIG BSOFS

CDC DIG BSDO

DIG CDC ASFS

DIG CDC ASDI

CDC DIG ASDO

FPGA

DIG EE CS

EE DIG SPI DI

CONTROL

McBSP0 (x4)

McBSP1 (x4)

BIRDIE

FPGA CLK

+1V5

ADDRESS

1V5

Regulator

Digital Board

DATA

System

Clock

Serial

EEPROM

RAM

Flash

Memory

DSP and

Address Decoder

ITF CH RXD

DIG CH TXD

PSU SYS RST

DGND

AGND

DIG CH SPI CLK

DIG CH SPI DO

ITF CH SPI DI

DIG CH LE

ITF CH GPI1

DIG CH GPO1

ITF CH PTT

ITF CH HOOK

ITF ON OFF

ITF IOP GPIO1-7

DIG IOP TXD

ITF IOP RXD

ITF AUX GPI1-7

DIG AUX GPO4-7

DIG AUXTXD

ITF AUX RXD

DIG CH TXD

ITF CH RXD

DIG TX EN

DIG PSU LATCH

DIG WD KICK

DIG SLP ENDIG CDC RST

Interface

Power Supply

DIG SYS CLK

Signal Types:

analog

clock

digital

asynchronous serial data

DIG AUD PA EN1

DIG AUD PA EN2

+1V8

PSU SYS RST

FPGA JTAG Signals:

FPGA JTAGTCK FPGA JTAGTMS FPGA JTAGTDO

FPGA JTAG (x4)

JTAG FPGATDI

DSP JTAG (x7)

Factory Connector

1V8

Regulator

+1V8

DSP JTAG Signals:

DSP JTAGTCK DSP JTAGTMS DSP JTAGTDO JTAG DSPTDI

+3V3

AGND

DSP JTAGTRST DSP JTAG EMU0 DSP JTAG EMU1

+3V3

PSU SYS RST

DIG RX EN

synchronous serial data

Page 92

3.9 Control-Head Board with Graphical Display

Introduction This section describes the control-head board for the control head with

graphical display.

For a block diagram of the digital circuitry, refer to Figure 3.14.

Most signals (except power on/off, speaker and microphone) to and from the radio body are processed by a RISC processor, which is implemented on an FPGA on the control-head board. For more information on the RISC processor and the FPGA, refer to “Software Architecture” on page 47.

User Interface The control-head board includes the circuitry for the following control

elements:

■ ON/OFF key

■ volume potentiometer

■ main keypad (with four functions keys, two scroll keys and

two selection keys)

■ LCD module (with backlighting and optional heating element)

■ three status LEDs

■ two function key LEDs (for function keys F1 and F4)

■ keypad backlighting LEDs

■ speaker.

Connectors The control-head board includes the circuitry for the following connectors:

■ microphone connector (RJ45 socket)

■ control-head connector (18-way MicroMaTch socket)

■ LCD connector (for internal connection of LCD module)

■ speaker connector (2 leads)

■ soldering pads (2 leads) for an optional concealed microphone

■ control-head options connector (for optional circuit board).

Protection circuitry is provided for the microphone connector. For pinouts of the control-head connector and the microphone connector, refer to

“Connectors” on page 36. For more information on the control-head

options connector, please contact Tait Electronics Limited.

ON/OFF Key When battery power (13.8V) is applied to the radio, a press of the ON/OFF key

will create an active low signal (

CH ON OFF) back to the radio body to initiate

the power-on or power-off sequence. This key-press will also be detected by the FPGA of the control head through Q611 as an active high signal. For more information on the start-up process, refer to “Software

Architecture” on page 47.

92 Circuit Descriptions TM8100/TM8200 Service Manual

Page 93

Figure 3.14 Block diagram of the control-head board with graphical display

Contact made

On/Off Key

LCD

LED

Lenses

Function/

Selection

Contact made

Scroll/

Keys

FPGA JTAG Signals:

FPGA JTAGTCK FPGA JTAGTMS FPGA JTAGTDO JTAG FPGATDI

when key

pressed

LCD Loom

Light Pipes

when key

pressed

On/Off

Keypad

Volume

Potentio-

meter

LCD

Connector

Function Key and

Status LEDs

Keypad

Backlighting

LEDs

Main

Keypad

Control-

Head

Options

Connector

CH ON OFF

+13V8

POWER ON/OFF SENSE

+3V3

VOL WIP DC

AGND

+3V3

TEMP SENSOR

DISPLAY CONTROL

BACKLIGHT

HEATER

AGND

BRIGHT

ROW

COL

+3V3 +13V8

ASYNC UART

DEBUG

JTAG

DGND

AGND

Analog/

Digital

Converter

Power

Switches

Constant-

Current

Drivers

BACKLIGHT

HEATER

ENABLE

BRIGHT

FPGA

+3V3+1V5

WATCHDOGTRIGGER

RESET

BIRDIE

FPGA CLOCK

ADDRESS

CONTROL

+1V5

+3V3

DATA

System

Clock

+13V8

Power Supply

SRAM

Flash

Memory

Boot

Flash

CH ON OFF

+13V8

RESET

DGND

AGND

CH SPI DO

Control-

Head

Connector

Signal Types:

analog

clock

digital

asynchronous serial data synchronous serial data

Concealed

Microphone

Leads

Speaker Leads

Microphone

Connector

Soldering

Pads

Speaker

Connector

+13.8 V

MIC RXD

MIC TXD

MIC GPIO1

MIC PTT

MIC RX AUD

MIC AUD IN

AGND

MIC+

MIC–

SPK+

SPK–

Protection

Circuitry

Microphone

Pre-amplifier

and Audio

Switching

CONTROL

Control-Head Board

+3V3 SENSE

CH RXD

CH TXD

CH GPIO1

CH PTT

CH RX AUD

CH MIC AUD

SPK+

SPK–

Speaker

Page 94

Power Supply A 3.3V regulator (U1) converts the switched 13.8V supply from the radio

body to 3.3V. A 1.5V regulator (U203) converts the 3.3V to 1.5V. A power-sense module (U202) verifies the outputs of the voltage regulators and—in the case of a fault—creates a power reset signal which is processed by the FPGA.

Volume Control The voltage level of the volume control potentiometer is converted to a

digital signal by an analog/digital converter (U601), processed by the FPGA and transmitted to the radio body.

Main Keypad The eight keys of the main keypad (function, scroll and selection keys) are

connected to the FPGA by an array of 3 columns and 3 rows. During idle operation, the

KEY ROW signals are driven low by the FPGA and the KEY COL

signals (pulled high by an external resistor) are monitored for activity by the FPGA. A key-press will generate a high-to-low transition on the associated column levels on the

LCD Module The LCD module is connected to the control-head board via the LCD

KEY COL signal. This, in turn, will initiate a sequence of high output

KEY ROW signals to identify which key was pressed.

connector. The LCD module display is contro lled by a se r ial data link to the FPGA. The backlighting and the optional heating element incorporated in the LCD module are controlled by a data line each from the FPGA, which switch two transistors on MOSFET Q102. A temperature signal from the LCD module is converted to a digital signal by an analog/digital converter (U601) and processed by the FPGA.

Function Key LEDs and Status LEDs

The function key LEDs (F1 and F4) and the red, green and amber status LEDs each are controlled by an FPGA signal and a transistor (Q604 to Q608). The brightness level is controlled by two FPGA signals, resulting in four intensity levels (off, low, medium and high).

Keypad Backlighting

The keypad backlighting LEDs are controlled by two FPGA signals and two transistors (Q2), resulting in four intensity levels (off, low, medium and high). The keypad backlighting LEDs are arranged in two groups for the main keypad and one group for the power button keypad, each group consisting of three LEDs.

Speaker The two speaker lines (SPK+ and SPK–) are connected to the speaker

connector (J104) which is joined to the control-head connector (J103) through two ferrite beads (L105 and L106).

Microphone and Concealed Microphone (Optional)

The audio signals from the microphone connector or the soldering pads of the optional concealed microphone are routed to a switching and preamplifier circuit. If a dynamic microphone is required, the pre-amplifier is engaged. The switching logic is used to select either the standard microphone input or the concealed microphone signal. The dynamic microphone must be activated in the programming software.

PTT The PTT signal from the microphone connector is connected to the FPGA

via a resistor (R25) and relayed to the radio as a digital command.

94 Circuit Descriptions TM8100/TM8200 Service Manual

Page 95

3.10 Control-Head Board with 1-, 2- or 3-Digit Display

Introduction This section describes the circuitry of the control-head boards for the

control heads with 1-, 2- or 3-digit display. The boards differ in their layouts but the components are virtually identical. The circuit description given below is sufficiently general to be applicable to all boards.

User Interface The control-head board includes the circuitry for the following control

elements:

■ ON/OFF key

■ volume potentiometer

■ keypad (with four functions keys and two scroll keys)

■ LCD

■ three status LEDs

■ four function key LEDs (for function keys F1 to F4)

■ keypad backlighting LEDs

■ speaker.

Connectors The control-head board includes the circuitry for the following connectors:

■ microphone connector (RJ45 socket)

■ control-head connector (18-way MicroMaTch socket)

■ speaker connector (2 leads)

■ soldering pads (2 leads) for an optional concealed microphone

■ two control-head options connectors (for optional circuit board).

Protection circuitry is provided for the microphone connector. For pinouts of the control-head connector and the microphone connector, refer to

“Connectors” on page 36. For more information on the control-head

options connector, please contact Tait Electronics Limited.

The optional circuit board is installed when a dynamic microphone is used or a concealed microphone is fitted.

Basic Circuitry The LCD driver is based on IC2, IC5 and IC7. Electrical contact between

the control head and the LCD itself is via two elastomeric strips as described in “Control Heads with 1-, 2- or 3-Digit Display” on page 29. There are pads on the board for the seven keys—four function keys, two channelselection keys, and the

ON/OFF key. The device IC4 reads the status of the

function and channel-selection keys. Of the 18 LEDs, there are red, orange and green

STATUS LEDs, and four green LEDs for the function keys, as well

as 11 green LEDs for back-lighting—one for each key and four for the LCD. The four dual switching transistors Q1 to Q4 control the switching of the LEDs; the transistors are driven by IC3.

Page 96

Figure 3.15 Block diagram of the control-head board with 1-, 2- or 3-digit display

Signal Types:

analog

clock

digital

asynchronous serial data synchronous serial data

LCD LCD Driver

LED Lenses LEDs LED Drivers

Control-

Options

Board

(optional)

Head

Control-head

options board

attached via

Elastomeric Strips

Light Pipes

connector

Microphone

Connector

Control-

Head

Options

Connector

Soldering

Concealed Microphone (optional)

Volume Control

RXD

TXD

CH GPIO1

PTT

RX AUD

MIC AUD IN

+13V8 SW

GND GND

D2 D3

RST

CH LE

CH SPI CLK

+3V3

+13V8 SW

MIC AUD IN P1

MIC AUD OUT

DGND

AGND

MIC+

AGND

Pads

VOL WIP DC

+3V3

AGND

Protection

Circuitry

D1 D2

CH SPI DO

+3V3

CH SPI CLK

CH LE

RST

DGND

RST

CH LE

CH SPI CLK

+3V3

+13V8 SW

DGND

R52

MIC AUD OUT

R11

Control-Head

Board

VOL WIP DC

CH RXD

CH TXD

CH GPIO1

CH PTT

RX AUD

CH SPI DO

Control-

Head

Connector

+13V8 SW

CH ON OFF

DGND

SPK+

SPK–

(not implemented)

R50

R51

LINK

Key Drivers

CH SPI DI

CH LE

CH SPI CLK

+3V3

DGND

+13V8 SW

CH ON OFF

DGND

CH SPI DI

CH LE

CH SPI CLK

+3V3

AGND

C50

R53

(not implemented)

SPK+

SPK–

On/Off Key

Function

Keys

ChannelSelection

Keys

Contact made

when key

pressed

Contact made

when key

pressed

Contact made

when key

pressed

Speaker Leads

Switch Pads

Speaker

Connector

Speaker

96 Circuit Descriptions TM8100/TM8200 Service Manual

Page 97

Serial Peripheral Interface

The control-head board uses an SPI (serial peripheral interface) to control the display on the LCD, turn back-lighting on and off, control the

STATUS

LEDs, and read the status of the keys. The interface consists of the following four lines at the control-head connector:

■ pin 11: data out CH SPI DO

■ pin 12: latch line CH LE

■ pin 15: data in CH SPI DI

■ pin 16: clock CH SPI CLK.

Data Input and Output

Data that are input to the control head are clocked through the LCD driver and daisy-chained to a shift register. Once all the data have been clocked in, the latch line is driven low. On this falling edge all the outputs (LEDs and LCD segments) are driven to their new state. When the latch line is driven high, the state of each key is latched into another shift register. The data are then clocked out back to the radio body so that the radio can respond accordingly.

LCD Driver An oscillator is used to run the LCD. It oscillates at about 60Hz and employs

a Schmitt trigger and D flip-flop to ensure a 50% duty cycle to the LCD. A reset circuit is required because the reset from the main board is not routed to the control head. The reset circuit also employs a Schmitt trigger.

Volume Control The volume-control potentiometer is linear and passes the DC voltage signal

VOL WIP DC to the radio body. The signal is read by an ADC on the main

board, and the volume is adjusted accordingly.

Page 98

3.11 RJ45 Control Head

Introduction This section describes the circuitry of the control-head board for the RJ45

control head.

User Interface The control-head board includes a POWER ON/OFF LED which indicates

whether the radio is switched on or off

Connectors The control-head board includes the circuitry for the following connectors:

■ programming connector (RJ45 socket)

■ control-head connector (18-way MicroMaTch socket).

For pinouts of the connectors, refer to “Connectors” on page 36.

Basic Circuitry The signals of the control-head connector are directly connected to the

telemetry connector. The

POWER ON/OFF LED is supplied by the +13V8

voltage.

Figure 3.16 Block diagram of the control-head board of the RJ45 control-head

Programming

Connector

PRG ON OFF

+13V8

PRG TXD

PRG RXD

PRG RX AUD

PRG MIC AUD

PRG PTT

AGND

CH ON OFF

+13V8

CH TXD

CH RXD

CH RX AUD

CH MIC AUD

CH PTT

AGND

Control-Head

Connector

Signal types:

analog

Power On/Off

LED

+13V8

digital asynchronous

serial data

Control-Head Board of

RJ45 Control Head

1. The signal supplying the LED can be switched or unswitched. For more information refer to

“Connector Power Supply Options” on page 86.

98 Circuit Descriptions TM8100/TM8200 Service Manual

Page 99

TM8100 mobiles TM8200 mobiles

Chapter 2

Servicing the Radio

Page 100

Chapter 2 – Servicing the Radio

4 General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .103

4.1 Repair Levels and Website Access . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

4.2 Tools, Equipment and Spares. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

4.3 Servicing Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

4.4 Test Equipment Setup. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

4.5 Replacing Board Components. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

4.6 Shielding Cans and Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

4.7 SMT Repair Techniques. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116

4.8 Computer-Controlled Test Mode (CCTM) . . . . . . . . . . . . . . . . . . . . . 118

4.9 Defining Frequency Bands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

4.10 Visual and Audible Indications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

5 Disassembly and Reassembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .129

5.1 Removing and Mounting the Control Head . . . . . . . . . . . . . . . . . . . . 130

5.2 Disassembling the Radio Body . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131

5.3 Reassembling the Radio Body. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137

5.4 Disassembling and Reassembling the Control Head . . . . . . . . . . . . . . . 141

6 Servicing Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .149

6.1 Initial Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149

6.2 Final Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157

7 Power Supply Fault Finding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .163

8 Interface Fault Finding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .173

9 Frequency Synthesizer Fault Finding . . . . . . . . . . . . . . . . . . . . . . . . .179

9.1 Initial Checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180

9.2 Power Supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183

9.3 Phase-locked Loop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192

9.4 Loop Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198

9.5 Receive VCO and Related Circuitry (UHF Radios) . . . . . . . . . . . . . . 203

9.6 Transmit VCO and Related Circuitry (UHF Radios) . . . . . . . . . . . . . . 212

9.7 VCO and Related Circuitry (VHF Radios) . . . . . . . . . . . . . . . . . . . . . 217

9.8 Power Supply for FCL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227

9.9 VCXO and TCXO Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230

9.10 Signals at TP501 and TP502 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233

9.11 VCXO and CODEC Circuitry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237

100 TM8100/TM8200 Service Manual

Tait TM8235, TM8250, TM8255, TM8252, TM8115 Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

Service Manual

Contents

Preface

Scope of Manual

Hardware and Software Versions

Associated Documentation

Publication Record

Alert Notices

Abbreviations

Chapter 1 – Description of the Radio

1 Introduction

1.1 Frequency Bands

1.2 RF Output Power

1.3 Accessories

1.4 Product Codes

1.5 Labels

1.6 Specifications

2 Description

2.1 Mechanical Design

2.1.1 Radio Body

2.1.2 Control Head with Graphical Display

2.1.3 Control Heads with 1-, 2- or 3-Digit Display

2.1.4 RJ45 Control Head

2.1.5 Blank Control Head

2.2 User Interfaces

2.3 Connectors

2.3.1 RF Connector

2.3.2 Power Connector

2.3.3 Auxiliary Connector

2.3.4 Internal Options Connector

2.3.5 Provision for External Options Connector

2.3.6 Control-Head Connectors

2.3.7 Microphone Connector

2.3.8 Programming Connector (RJ45 Control Head)

2.3.9 Programming Connector (Blank Control Head)

2.4 Hardware and Software Architecture

2.4.1 Hardware Architecture

2.4.2 Software Architecture

2.5 Operation in Receive Mode

2.5.1 RF Hardware

2.5.2 Digital Baseband Processing

2.5.3 Audio Processing and Signalling

2.6 Operation in Transmit Mode

2.6.1 Audio Processing and Signalling

2.6.2 Frequency Synthesizer

2.6.3 RF Transmitter

3 Circuit Descriptions

3.1 Transmitter Circuitry

3.2 Receiver Circuitry

3.3 Frequency Synthesizer Circuitry

3.4 Frequency Control Loop

3.5 CODEC and Audio Circuitry

3.6 Power Supply Circuitry

3.7 Interface Circuitry

3.8 Digital Board

3.9 Control-Head Board with Graphical Display

3.10 Control-Head Board with 1-, 2- or 3-Digit Display

3.11 RJ45 Control Head

Chapter 2 – Servicing the Radio