Tait TB7100 User Manual

TB7100 bas e station

Installation and

Operation Ma nu a l

MBB-00001-02

Issue 2

December 2005

Tait Contact Information

Tait Radio Communications
Corporate Head Office

Tait Electronics Ltd
P.O. Box 1645
Christchurch
New Zeala n d

For the address and telephone number of
regiona l of f ices, refer to th e TaitWorld
website:

Website: http://www.taitworld.com

Technical Support

For assistance with specific technical issues,
contact Technical Support:

E-mail: [e-mail]
Website: http://support.taitworld.com

To our European customers:

Tait Electronics Limited is an environmentally responsible company which
supports waste minimi zation and ma terial reco very. 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 enviro nmentally responsible and dispose
through the original supplier, your local municipal waste “separate
collection” service, or contact Tait Electronics Limited.

2 TB7100 Installation and Operation Manual

© Tait Electronics Limited December 2005

Contents

Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Scope of Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Enquiries and Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Updates of Manual and Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Copyright . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Disclaimer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Document Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

Associated Documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Publication Record . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

1.1 Frequency Bands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

1.2 RF Output Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

1.3 Power Supply Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

1.4 Mechanical Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

1.5 Product Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

2 Mechanical Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

2.1 Tray. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

2.2 UI Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

2.3 Receiver Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

2.4 Transmitter Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

2.5 SI Board. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

2.6 AC Power Supply Unit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

3 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

3.1 Receiver Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

3.1.1 RF Hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

3.1.2 Digital Baseband Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

3.1.3 Audio Processing and Signalling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

3.2 Transmitter Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

3.2.1 Audio Processing and Signalling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

3.2.2 Frequency Synthesizer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

3.2.3 RF Power Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

3.3 User Interface Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

3.4 System Interface Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

3.4.1 Internal Power Distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

3.4.2 Serial Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

3.4.3 General Purpose IO. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

3.4.4 Receiver Audio Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

3.4.5 Tone On Idle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

3.4.6 Transmitter Audio Processing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

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3.4.7 Opto Isolated Keying . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

3.4.8 Relay Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

3.4.9 Fan Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

3.4.10 RSSI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

3.4.11 Receiver Gate. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

3.4.12 Receiver Inhibit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

3.5 Fan Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

4 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

4.1 Personal Safety. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

4.1.1 Lethal Voltages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

4.1.2 Explosive Environments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

4.1.3 Proximity to RF Transmissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

4.1.4 High Temperatures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

4.2 Equipment Safety. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

4.2.1 ESD Precautions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

4.2.2 Antenna Load. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

4.2.3 Equipment Grounding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

4.2.4 Installation and Servicing Personnel . . . . . . . . . . . . . . . . . . . . . . . . . . 43

4.3 Regulatory Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

4.3.1 Distress Frequencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

4.3.2 FCC Compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

4.3.3 Unauthorised Modifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

4.3.4 Health, Safety and Electromagnetic Compatibility in Europe. . . . . . . . 44

4.4 Environmental Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

4.4.1 Operating Temperature Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

4.4.2 Humidity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

4.4.3 Dust and Dirt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

4.5 Grounding and Lightning Protection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

4.5.1 Electrical Ground . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

4.5.2 Lightning Ground. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

4.6 Recommended Tools. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

4.7 Ventilation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

4.7.1 Cabinet and Rack Ventilation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

4.8 Installing the Base Station . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

4.8.1 Unpacking the Equipment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

4.8.2 Identifying the Mechanical Configuration . . . . . . . . . . . . . . . . . . . . . 49

4.8.3 Power Supply Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

4.8.4 Setting the AC Mains Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . 50

4.8.5 Mounting the Base Station . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

4.8.6 Cabling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

4.8.7 Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

5 Replacing Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

5.1 Removing the Base Station and Opening the Tray. . . . . . . . . . . . . . . . . . . . . . . 54

5.2 Replacing the UI Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

5.3 Replacing the Receiver Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

5.4 Replacing the Transmitter Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

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5.5 Replacing the SI Board. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

5.6 Replacing the Transmitter and Receiver Fans . . . . . . . . . . . . . . . . . . . . . . . . . . 59

5.7 Replacing the Fan Power Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60

5.8 Replacing the Temperature Sensor Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

5.9 Replacing the AC Power Supply Unit, Fan and Filter Module . . . . . . . . . . . . . .61

5.10 Replacing the Speaker . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

5.11 Final Reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

6 Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

6.1 External Connectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

6.2 Internal Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

6.2.1 Transmitter and Receiver Connectors . . . . . . . . . . . . . . . . . . . . . . . . 71

6.2.2 SI Board Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

6.2.3 UI Board Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

7 Preparation for Operat ion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

7.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

7.2 Mode of Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

7.3 Line-controlled Base. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

7.3.1 Test Equipment Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

7.3.2 Test Equipment Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

7.3.3 Link Settings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

7.3.4 Applying Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

7.3.5 Programming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

7.3.6 Receiver Audio Level Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

7.3.7 Receiver Functional Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

7.3.8 Transmitter Audio Level Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . 85

7.3.9 Transmitter Functional Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86

7.4 Talk Through Repeater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

7.4.1 Test Equipment Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

7.4.2 Test Equipment Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

7.4.3 Link Settings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

7.4.4 Applying Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

7.4.5 Programming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

7.4.6 Audio Level Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

7.4.7 Talk Through Repeater Functional Testing . . . . . . . . . . . . . . . . . . . . 91

7.4.8 Alternate Talk Through Repeater Configuration . . . . . . . . . . . . . . . . 92

7.5 RF Modem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

7.5.1 Test Equipment Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

7.5.2 Test Equipment Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

7.5.3 Link Settings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

7.5.4 Applying Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

7.5.5 Programming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

7.5.6 Audio Level Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

7.5.7 Programming for FFSK Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

7.5.8 Programming for THSD Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 98

7.5.9 Verification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

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7.6 Data Repeater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

7.6.1 Link Settings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

7.6.2 Applying Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

7.6.3 Programming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

7.6.4 Audio Level Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

7.6.5 Data Repeater Functional Testing . . . . . . . . . . . . . . . . . . . . . . . . . . 104

7.7 TaitNet Trunking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

7.8 Programmable Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

7.8.1 Connecting to the PC. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

7.8.2 TB7100 Programming Application . . . . . . . . . . . . . . . . . . . . . . . . . 105

7.8.3 Mandatory Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

7.8.4 User-defined Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

7.8.5 Recommended Settings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112

7.8.6 Function Keys. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

7.9 Additional Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

7.10 Adding Subaudible Signalling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

7.10.1 Enabling Subaudible Signalling . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

7.10.2 Testing Subaudible Signalling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116

7.10.3 Multiple Subaudible Tones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117

7.11 Soft Off (Tx Tail Time) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118

7.11.1 Link Settings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118

7.12 Tone On Idle (TOI). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118

7.12.1 Link Settings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119

7.13 Fan Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120

7.13.1 Link Settings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120

7.14 Channel ID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122

7.14.1 Link Settings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122

7.15 Relay Polarity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

7.15.1 Link Settings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

7.16 Channel Increment and Decrement by Function Keys . . . . . . . . . . . . . . . . . . . 123

7.17 Carrier Wave Identification (CWID). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124

7.17.1 Station ID. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124

7.17.2 Station ID 2/Message . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124

7.17.3 Tone Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124

7.17.4 ID Repeat Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124

7.17.5 Speed (Words per Minute) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124

7.17.6 Wait Period after Loss of COR/COS/CTCSS Input Before IDing. . 124

7.17.7 Transmit Key-Up Delay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124

7.17.8 Transmit Time Out Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

7.17.9 Transmit PTT Drop Out Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

7.17.10Output Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

8 Maintenance Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .127

Glossary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .129

Directive 1999/5/EC Declaration of Co nformity . . . . . . . . . . . . . . . . . . . . . . . .141

6 TB7100 Installation and Operation Manual

© Tait Electronics Limited May 2005

Preface

Scope of Manual

Welcome to the TB7100 Installation and Operation Manual. This manual
provides information on installing and operating the TB7100 base station.
Also included in this manual are a high-lev el cir cuit description, a functional
description and a maintenance guide.

Enquiries and Comments

If you have any enquiries regarding this manual, or any comments,
suggestions and notifications of errors, please contact Technical Support
(refer to “Tai t Contact Information” on page 2).

Updates of Manual and Equipment

In the interests of i mpr oving the performance, r eliability or servicing of the
equipment, Tait Electronics Limited reserves the right to update the
equipment or this manual or bot h without prior notice.

Copyright

All information contained in this manual is the property of
Tait Electronics Limited. All rights are reserved. This manual may not, in
whole or in part, be copied, photocop ied, repr oduced, tra nslated, stor ed, or
reduced to any electronic medium or machine-r eadable form, without prior
written permission from Tait Electronics Limited.

Disclaimer

There are no warranties extended or gr a nted 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 softwar e complies with the la ws, rules and
regulations of the applicab le jurisdictions.

TB7100 Installation and Operation Manual 7
© Tait Electronics Limited December 2005

Document Conventions

“File > Open” means “click File on the menu bar, then click Open on the
list of commands that pops up”. “Channel Setup > Channels > Detailed”
means “in the navigation pane find the Channel Setup group, and select
Channels from it, on the Cha nnels page select the Detailed tab”.

Within this manual, four types of alerts are given to the reader: Warning,
Caution, Important and Note. The follo wing paragraphs illustrate each type
of alert and its associated symbol.

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

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

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

of death or serious injury.

moderate injury to people.

age or malfunction.

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

ensure procedures are performed correctly.

Associated Documentation

The following associated documentation is available for this produc t:

■ MBB-00002-xx TB7100 Specifications Manual

■ MBB-00003-xx TB7100 Installation Guide

■ MBB-00005-xx TB7100 Service Manual

■ MBA-00013-xx TBA0STU/TBA0STP Calibration and Test Unit

The characters xx represent the issue number of the documentation.
All available documentation is provided on the CD (406-00047-xx)

supplied with the base station. Updates may also be published on the Tait
support website.

Technical notes are published from time to time to d escribe applications for
Tait products, to provide technical details not included in manuals, and to
offer solutions for any problems that arise.

Operation Manual

8 TB7100 Installation and Operation Manual

© Tait Electronics Limited December 2005

Publication Record

Issue Publication Date Description

1 May 2005 First release
2 December 2005 Internal AC power supply, A4 and D1 bands

added.

TB7100 Installation and Operation Manual 9
© Tait Electronics Limited December 2005

10 TB7100 Installation and Operation Manual

© Tait Electronics Limited December 2005

1Introduction

Figure 1.1 TB7100 base stations

Configuration with pr ovision for int ernal AC p ower supply*

Configuration without provision for internal AC power supply*

*cover removed

The TB7100 is a softw ar e and h ar dw ar e link- configur ed ba se stati on which
is designed for operation in a large variety of standard frequency ranges.
It makes extensive use of digital and DSP technology. Many operating
parameters such as channel spacing, audio bandwidth and sig na lling are
controlled by software.

This manual includes the information required for installing and operating
the base station.

This section describes the different options available for:

■ frequency bands

■ RF output power

■ power supply

■ mechanical configurations

■ product codes

For specifications, refer to the specifications manual or the area on the
Tait World website reserved for TB7100 products.

TB7100 Installation and Operation Manual Introduction 11
© Tait Electronics Limited December 2005

1.1 Frequency Bands

The base station is available in the following frequency bands:

■ 66 to 88MHz (A4)

■ 136 to 174MHz (B1)

■ 216 to 266 MHz (D1)

■ 400 to 470MHz (H5)

■ 450 to 530MHz (H6)

■ 450 to 520MHz (H7)

The RF band of the base station is implemented by the frequency band of
the transmitter and receiver modules.

1.2 RF Output Power

The base station is available with 25W and 50W/40W RF output power.
The RF output pow er options ar e implemented by d ifferent transmitter and
receiver modules.

The 25W base station is available in the following frequency bands:

■ A4

■ B1

■ D1

■ H5

■ H6

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

■ B1 (50 W)

■ H5 (40W)

■ H7 (40W)

12 Introduction TB7100 Installation and Operation Manual

© Tait Electronics Limited December 2005

1.3 Power Supply Options

The base station is available with or without an internal AC power supply.
All base stations have an external DC input power connector which is used

as main power supply when no internal AC power supply is fitted.
When the internal AC power supply is fitted, the DC input can be used as

a DC backup pow er option. In case of AC mains failure the base station will
automatically and seamlessly switch to DC power input.

If no internal AC power supply is fitted, an external Tait T809-10-87xx
power supply can be used to supply the DC voltage required.

Warning!! The internal AC power supply unit contains

voltag es that ma y be lethal. Refer to the ratings
label on the rear of the bas e station. The internal
AC power supply contains no user-servicable
parts.

Important Wrong mains v oltage! Befor e connecting to the A C po w er

connector, ensure that the internal 115V/230V voltage
mains selector switch is set to the correct mains voltage.

1.4 Mechanical Configurations

The base station is available in two different mechanical configurations—
with or without provision for an internal AC power supply unit.

The mechanical configuration with provision for an internal AC power
supply has the following distinguishing features:

■ larger air intake on the right-hand side of the front panel

■ pro vis ion for A C con nector on the left-hand side o f the r ear p anel (r efer

to Figure 1.1 on page 11)

■ ground point on the right-hand side of the rear panel rather than on the

left-hand side

■ different SI board and internal cables.

The mechanical configuration without provis ion f or an internal AC power
supply unit cannot be upgraded with an internal AC power supply unit.

The product codes of the base station (see belo w) do not distinguish
between the mechanical configurations.

TB7100 Installation and Operation Manual Introduction 13
© Tait Electronics Limited December 2005

1.5 Product Codes

This section describes the product codes used to identify products of the
TB7100 base station product line.

The product codes of the TB7100 base station product line has the format:

TBBaabb-cde-ff

where:

■ aa identifies the frequency band of the receiver:

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

■ bb identifies the frequency band of the transmitter:

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

■ c identifies the RF output power and digital architecture:

A=25W, level-1 digital architecture
B=35W to 50W, level-1 digital architecture
C=25W, level-2 digital architecture
D=35W to 50W, level-2 digital architecture
E=25W, level-3 digital architecture
F=35W to 50W, level-3 digital architecture

■ d identifies the power supply option:

0=DC only
1=internal AC power supply unit, factory preset to 115VAC
2=internal AC power supply unit, factory preset to 230VAC

■ e identifies the AC power cable:

1 = Australia/New Zealand
2 = United Kingdom
3 = Europe
4 = USA

■ ff identifies base station options:

00=no options

14 Introduction TB7100 Installation and Operation Manual

© Tait Electronics Limited December 2005

2 Mechanical Description

Overview The base station consists of the follo wing main modules:

■ tray b

■ UI board (user interface) d

■ receiver module h

■ transmitter module i

■ SI board (system interface) 1)

■ internal AC power supply unit 1@ (if fitted).

Figure 2.1 P arts of the base station (configuration with internal AC power supply unit shown)

b

1#

c

1@

f

g

h

e

d

i

j

1!

All modules and boards are mounted from above into the 1U tray
The modules are secured by scr ews or clips into s tandoffs on the tray chassis,
and are easily removed for replacement.

1)

b.

The base station includes two cooling fans
the receiver and transmitter modules, a speaker
panel, a fan power board
sensor board

If the internal AC po wer su pply unit
additional fan

The modules and components are interconnected by looms and cables.

TB7100 Installation and Operation Manual Mechanical Description 15
© Tait Electronics Limited December 2005

j mounted on the heatsink of the transmitter module i.

1# and an AC filter module 1!.

g mounted on the fan duct, and a temperature

f and a fan duct e in front of

c mounted behind the fr ont

1@ is fitted, the base station includes an

2.1 Tray

The 1U tray consists of a mild steel folded chassis and a flat cover (not
shown) which is fastened to the chassis with 15 Torx T10 screws. The tray
can be fitted into a standard 19 inch rack or cabinet using the two rack
mounting brackets.

The front panel ha s holes to accommodate the controls and the
microphone/programming connector of the UI board.
The rear panel has holes to accommodate the connectors and the fuse holder
of the SI board, the antenna connectors, and a gr ound terminal.

For more information on the connections, refer to “Connections” on

page 65.

2.2 UI Board

The UI board is mounted behind the front panel with three Torx T10
screws
transmitter and receiver modules via the two Micro-MaTch connectors
and the two UI cables (not shown). The UI board also has a speaker
connector

c and two spring clips D. The UI board is connected to the

e

b.

Figure 2.2 UI board

b

Cables not shown.

A volume knob is fitted to the shaft of the volume-control potentiometer.

c

e

d

16 Mechanical Description TB7100 Installation and Operation Manual

© Tait Electronics Limited December 2005

2.3 Receiver Module

The receiver module is mounted in the front left of the tra y with five Torx
T10 screws

The receiver module is a printed circuit board in SMT design with
components on the top and bottom sides. A digital board is reflo w-sol dered
to the receiver. Most components are shielded by metal cans.

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

g.

The RF
located on the bottom side of the boar d. The internal options connector
and a factory connector (not shown) for factory use are located on the top
side of the board.

For compliance reasons, there are different variants of the receiver module
for use in the 25W and 50W/40W base stations. The 25W version has a
white DC power connector
power connector.

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

page 65.

Figure 2.3 Receiver module

b

b, D C po w er c, auxiliary d, and user interface f connectors are

e

C and the 50W/40W version has a black DC

cd

e

g

g

g

TB7100 Installation and Operation Manual Mechanical Description 17
© Tait Electronics Limited December 2005

f

2.4 Transmitter Module

The transmitter module consisting of a transmitter board f mounted o n a
purpose-designed heatsink
four Torx T10 screws (not shown).

The transmitter board is a printed circuit board in SMT design with
components on the top and bottom sides. A digital board is r eflo w-soldered
to the board. Most components are shielded by metal cans. There are
different boards for each frequency band and each RF output power
configuration.

1) is mounted in the left rear of the tray with

The RF
located on the bottom side of the boar d. The internal options connector
and a factory connector (not shown) for factory use are located on the top
side of the board.

The 50W/40W version has a bla ck DC power connector
version has a white DC power connector. For more information on the
connectors, refer to “Connections” on page 65.

The board

b, DC po w er c, auxiliary d, and user interface f connectors are

e

C and the 2 5W

f is mounted to the heatsink 1) with seven Torx T10 screws

f and g.

An L-shaped gap pad
pad

j are fitted between the board f and the heatsink 1) to improve h eat

transfer.

Figure 2.4 Transmitter module

i and (with the 50W/40W version) a r ectangular gap

g

f

h

g

e

b

c

i

D

j

1)

18 Mechanical Description TB7100 Installation and Operation Manual

© Tait Electronics Limited December 2005

2.5 SI Board

The SI board is mounted in the rear right of the tray with two Torx T10
screws

The SI board has the follo wing external connectors:

■ 13.8 V DC power connector (labelled 12V DC) b

■ system connector (labelled SYSTEM) c

■ serial data connector (labelled IOIOI) D.

The SI board has the following internal connectors:

■ two syst em interface connectors e (to transmitter and receiver)

■ one DC input connector h, if fitted (from internal AC power supply)

■ one DC output connector i (to transmitter and receiver)

■ fan control connector f (to fan power board on fan duct)

■ temperature control connecto r g (to temperature sensor on transmitter

1), one Pozidriv scr ew j, an d two spring cli ps 1!.

heatsink).

Figure 2.5 SI board

1)

i

h

g

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

page 65.

b

c d

1)

j

1!1! ef

TB7100 Installation and Operation Manual Mechanical Description 19
© Tait Electronics Limited December 2005

2.6 AC Power Supply Unit

The base station ma y be fitt ed with an int ernal AC po w er supply unit f, an
AC filter module

The AC filter module has a stan dard A C connector that fit s into a pr o vision
on the rear of the tra y. The AC filter module slides into securing tabs on the
tray floor and is held in place by the AC power supply unit.

Note Mechanical configurations without the provision for a standard

AC connector cannot be upgraded with the internal AC power
supply unit.

d, and an additional fan g.

The AC power supply unit is held in place by two screws
attached to the AC power supply unit by two screws

The AC po w er supply unit is connected to the A C filter module via a cable
connector (not shown).

The DC output of the AC power supply unit is connected to the SI board

b. The AC pow er supp ly unit al so has a cable to provide a mains failure

signal to the SI board
power circuitry on the SI board to switch to DC external input.

Figure 2.6 AC power supply unit, filter module and fan

c. In case of a mains failure, this signal will cause the

e. The fan is

h.

bc

h

g

20 Mechanical Description TB7100 Installation and Operation Manual

e dfe

© Tait Electronics Limited December 2005

3 Functional Description

This section describes some principles of the base station operation.

Figure 3.1 shows the high-level block diagram of the base station.

Figure 3.1 Base station high-level block diagram

Ground

Point

Transmitter

Module

Receiver

Module

Fan Power

Board

Tx/Ant

Connector

RF

Temperature

Sensor

Internal power

Transmitter/SI

RF

Internal power

Receiver/SI

Rx

Connector

Fuse

DC Input

Connector

System

Connector

SI Board

Mains fail signal

Serial Data

Connector

Internal power

AC

Power Supply

Unit

115V/230V

Selector

Switch

AC Input

Connector

Module

AC Input Filter

FanFan

Internal power

UI/Receiver

UI/Transmitter

Prog/Mic

Connector

UI Board

Speaker

Fan

TB7100 Installation and Operation Manual Functional Description 21
© Tait Electronics Limited December 2005

The block diagram illustrates the main inputs and outputs for power, RF
and control signals, as well as the interconnection between modules:

■ pro gram data and audio fr om the PROG/MIC sock et on the UI boar d to and

from the transmitter and recei ver modules

■ audio and signalling from the SYSTEM connector to and from the

transmitter and receiver modules

■ RS-232 data from the serial data connector (IOIOI) to and from the

transmitter and receiver modules

■ fan power and control from the SI board

■ power distribution fr om the AC and DC power in put connecto rs to the

transmitter and receiver modules, and from the recei ver module to the
UI board.

The circuitry of the individual modules that make up the base station is
described in more detail in the following sections.

Frequency Bands
and Sub-bands

The circuitry of the transmitter and receiver modules is similar for all
frequency bands and is therefore covered by a single description in this
manual. Where the circuitry differs between bands, separate descriptions are
provided for each frequency band. For more information on frequency
bands, refer to the specifications man ual.

RS-232 Signals External data communications all occur directly between the connected

computer (or other electrical equipment) and the transmitter and receiver
modules over the RS-232 serial lines.

Fan Signals The power and ground signals for the fans are routed from the SI board to

the fans behind the front panel. These signals are electrically isolated from
all other system signals to ensur e fan noise is not transferred to other sensitiv e
system components.

If there is a fault in the fan circuitry , the transmitter module is protected fr om
overheating by its internal foldback circuitry.

Speaker Signal Received audio is sen t from the receiver module to the UI board.

The volume is controlled by the volume potentiometer on the UI board.
The audio signal is routed through the UI board to the speaker for
monitoring purposes.

Power and Ground The SI board provides power to the transmitter and receiver modules.

The receiver modules provides power to the UI board.

22 Functional Description TB7100 Installation and Operation Manual

© Tait Electronics Limited December 2005

3.1 Receiver Operation

Parts of Receiver
Board

The main circuit parts of the receiver modules are:

■ receiver

■ frequency synthesizer

■ CODEC (coder-decoder) and audio circuitry

■ power supply

■ interface circuitry

Software plays a prominent role in the functioning of the radio.
When describing the operation of the radio the software m ust be included
with the above. This is considered further below.

These functional parts are described in detail below.

Figure 3.2 Receiver high-level block diagram

RX

2nd IF:
64 kHz

Second LO
UHF: 90.328 MHz
VHF: 42.928 MHz

AGC

Digital
down-

converter

IF:

UHF: 45.1 MHz

ANT

LPF

Front

end

VHF: 21.4 MHz

1st

IF

Phase

locked to

TCXO

Quad

Demod

VCO

Channel

LPF

Channel

LPF

CUSTOM-

LOGIC

BLOCK

Mag.

Demod

FM

RSSI

Audio

filtering

emphasis

Data and signalling

decoders

Squelch

De-

BLOCK

Optional

processing

DSP

Side

tones

System Interface
or User Interface

HARDWARE BLOCK

3.1.1 RF Hardware

Front End Circuitry
and First IF

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 45.1MHz (UHF) or 21.4MHz (VHF) where
coarse channel filtering is performed. The first LO (local oscillator) signal is
obtained from the frequency synthesizer and is injected on the low side of
the desired channel frequen cy for all bands except A4. When r eceiving the
modulation to the freque ncy synthesizer is muted. The ou tput of the first IF
(intermediate frequency) stage is then down-converted using an image­reject mixer to a low IF of 64kH z.

TCXO:

13.000 MHz

PLL

VCXO

Loop

filter

Loop
filter

Triple-point

Equalisation

Frequency

control

KEY

Analogue-to-digital conversion

Digital-to-analogue conversion

NOTES

(1) Noise blanker not shown

TB7100 Installation and Operation Manual Functional Description 23
© Tait Electronics Limited December 2005

Quadrature
Demodulator

Automatic Gain
Control

The LO for the image-reject mixer (quadratur e demodulator) is synthesized
and uses the TCXO (temperature-compensated crystal oscillator) 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 a t
2 x (IF1 + 64kHz). The quadrature output from this mixer is fed to a pair
of ADCs (analog-to-digital con v erters) with high dynamic range where it is
oversampled at 256kHz and fed to the custom logic device.

The AGC (automatic gain contr ol) is used to limit the maximum signal lev el
applied to the image-reject mixer and ADCs in order to meet the
requirements for intermodulation and selectivity performance. Hardware
gain control is perfo rmed by a variable-gain amplifier within the quadrature
demodulator device driven by a 10-bit DAC (digital-to-analog converter).
Information about the signal level is obtained from the IQ (in-phase and
quadrature) data out put stream from the ADCs. The control loop is
completed within custom logic. The A GC will begin to reduce gain when
the combined signal power of the wanted signal and first adjac ent channels
is greater than about –70dBm. In the presence of a str ong adjacent-channel
signal it is therefore possib le that the AGC may st art acting when the wanted
signal is well below –70dBm .

3.1.2 Digital Baseband Processing

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

by custom logic. The digitised quadrature signal from the RF hardware is
digitally down-converted to a zero IF, and channel filtering is performed at
base-band. 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
achiev ed. The filters also decimate the sample rate do wn to 48kHz. Custom
logic also performs demodulation, which is multiplexed along with A GC
and amplitude data, and fed via a s ingle synchronous serial port to the DSP.
The stream is demultiplex ed a nd the demodulation data used a s 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 presen t, out-of-band noise content is
reduced and, if below the preset threshold, is indicated as a valid wanted
signal.

Received Signal
Strength Indication

Received signal strength is measured by a process resident in the DSP.
This process obtains its input from the demodulator (value of RF signal
magnitude) and from the AGC (value of present gain). With these two
inputs and a calibration factor , t he RF sign al strength at the antenna can be
accurately calculated.

24 Functional Description TB7100 Installation and Operation Manual

© Tait Electronics Limited December 2005

Calibration

The following items within the receiver path are calibrated in the Factory:

■ front-en d tuning

■ AGC

■ noise squelch

■ RSSI (received signal strength indication)

Information o n th e c al i b ration of these items is given in the on-line help
facility of the calibration application.

3.1.3 Audio Processing and Signalling

Audio Processing Raw demodulated data from the r eceiver 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 normalise the signal level for the remaining audio pr ocessing.
The sample rate is decimated to 8kHz and bandpass audio filtering (0.3 to
3kHz) is applied. The base station takes the audio from the receiver mode
at Tap R4 by default; this point has no de-emphasis. This tap point can be
changed if required, for example, for trunking applications.

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
bandwidth of the decoders and whether de-emphasis is required. Se veral
decoders may be active simultaneously.

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

These are tones that pro vide some form of alert or giv e the user confidence
an action has been performed. The confidence tones may be generated in
the receiver. The side-tone level is a fixed proportion (in the order of
–10dB) relative to full scale in the receive path. By default, all audible
indicators are turned off.

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

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

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

UI board via a buffer amplifier. The output configu ration of the audio
power amplifier is balanced and drives an internal speaker. The power
delivered to the speake r is limited by its impedance. The speaker has 16Ω
impedance.

TB7100 Installation and Operation Manual Functional Description 25
© Tait Electronics Limited December 2005

3.2 Transmitter Operation

Parts of T ransmitter
Board

The main circuit parts of the transmitter board are:

■ transmitter

■ frequency synthesizer

■ CODEC (coder-decoder) and audio circuitry

■ power supply

■ interface circuitry

Software plays a prominent role in the functioning of the board.
When describing the operation of the radio the software must be included
with the above. This is considered further below.

These functional parts are described in detail below.

Figure 3.3 Transmitter high-level block diagram

ANT

LPF

HARDWARE BLOCK

Dir.

Coup.

Drv

Fin

/Ex

Bias

Pwr
Crtl

TCXO:

13.000 MHz

VCO

Loop

PLL

filter

VCXO

Loop

filter

CUSTOM

LOGIC

BLOCK

Triple-point

Equalisation

Frequency

control

Ramp

control

Tap pointT8

Audio

filtering

emphasis

Data and signalling

encoders

KEY

Analog-to-digital conversion

Digital-to-analog conversion

DSP

BLOCK

Pre-

Optional

processing

ALC

HARDWARE

BLOCK

Mic

PGA

SYSTEM connector

PROG/MIC connector

3.2.1 Audio Processing and Signalling

Microphone Input The input to the transmitter path begins at either the SI board or the

PROG/MIC connector of the UI board. Only electret-type microphones are

supported. The audio input is then applied to tap point T8 on the
transmitter board (the tap point is user-selectable).

Analog Processing
of Microphone
Signal

26 Functional Description TB7100 Installation and Operation Manual

The CODEC (AD6521) performs microphone selection and ampli fication.
The microphone amplifier consi sts of an amplifier with a fix ed gain of 16dB
followed by a programmable-gain amplifier with 0dB to 22dB gain.
The amplified microphone signal is conv erted to a digital stream by a 16-bit
ADC with integral anti-alias filtering (0.1 to 3.2kHz). The digital stream is
transported to the DSP for further audio processing.

© Tait Electronics Limited December 2005

Automatic Level
Control

DSP Audio
Processing

Data and Signalling
Encoders

The ALC (automatic lev el control) follo ws, and is used to effectiv ely increase
dynamic range by boosting the gain o f the micro phone 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 2s) characteristic. This characteristic
ensures that the peak signal level is regulated near full scale to maximise
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-emphasised signal is har d limited to
prev ent o v er deviation , and filtered to r emov e high -frequency components.
The sample rate is then interpolated up to 48kHz and scaled to be suitable
for the frequency synthesizer.

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

3.2.2 Frequency Synthesizer

Main Parts of
Synthesizer

Frequency Control
Loop

The frequency synthesizer consists of two main parts:

■ FCL (frequency control loop)

■ RF PLL (phase-locked loop)

The FCL and RF PLL are described br iefly below. Note that patents are
pending for several aspects of the synthesizer desi gn.

The FCL consists of the following:

■ TCXO

■ mixer

■ loop filter

■ VCXO (voltage-controlled crystal oscillator)

■ frequency control block

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

TB7100 Installation and Operation Manual Functional Description 27
© Tait Electronics Limited December 2005

RF PLL

Operation of
Control Loop

The RF PLL consists of the following:

■ RF PLL device

■ loop filter

■ VCO (voltage-cont rolled oscillator)

■ VCO output switc h

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

The RF PLL is a conventional integer-N design with frequency resolution
of 25 kH z. In transmit mode the loop locks to the transmit frequency.

Initially , the VCO generates an unr egulated frequency in the requir ed range.
This is fed to the PLL device (ADF4111) and divided down by a
programmed ratio to appr oximately 25kHz. 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 an d dual-bandwidth loop filter . This DC signal
is used to control the VCO frequency and reduce the init ial error. The loop
even tually settles to a point that minimises the phas e error between divided­down reference and VCO frequencies. The net result is that the loop locks
to a programmed multiple of the reference frequency.

The FCL generates an output of 13.012±0.004MHz. Initially a VCXO
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, a fter low-pass filtering to remov e unwant ed products,
produces a nominal frequency of 12kHz. This is converted to digital form
and transported to the frequency-control block in custom logic.

The frequency-contr ol block compares the mixer output frequency with 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 fr equency and r educe the i nitial error .
Once settled, the loop locks to the TCXO frequency with a programmed
offset frequency. The FCL output therefore acquir es 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 respon se dow n to DC. Reference m odulation is usually a pplied
directly to the TCXO.

28 Functional Description TB7100 Installation and Operation Manual

© Tait Electronics Limited December 2005

In the system employ ed in th e transmitter boar d, the fr equency r efer ence is
generated by the FCL, which itself r equires dual-point modulation injection
to allow modu lation do wn to DC. W ith another modulati on point requi red
in the RF PLL, this system therefore requires triple-point modulation.
The modulation signals applied to the FCL are in digital form, whereas for
the RF PLL (VCO) the modulation signal is applied in analog form.
The modulation cross-over points occur at appro ximately 30 and 300Hz as
determined by the closed loop bandwidths of the FCL and RF PLL
respectively.

Frequency
Generation

Fast Frequency
Settling

Frequency
Acquisition
of RF PLL

The RF PLL has a fr equency 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 fr equency and is able to adjust it up to ±300ppm with better than

0.1ppm resolution (equi valent to better than 50Hz resolution at the RF
frequency).

Both the FCL and RF PLL employ frequency-acquisition speed-up
techniques to achieve fast frequency settling. The frequency-acqui sition
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.

In the RF PLL the loop bandwidth is initially set 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 4ms. In
order to meet noise performance requir ements 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 utilises self-calibration techniques that enable it to rapidl y 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 no ise.
The total settling time is typically less than 4 ms.

Calibration The following items are calibrated in the frequency synthesizer:

■ nominal frequency

■ KVCO

■ KVCXO

■ VCO deviation

Calibration of the nominal freq uency is achi e v ed b y addi ng a fixed offset to
the FCL nominal frequency; the TCXO frequency itself is not adjusted.
The items KVCO and KVCXO are the control s ensitivities of the RF VCO
(in MHz/V) and VCXO (in kHz/V) res pectively. The latter has temperature
compensation.

TB7100 Installation and Operation Manual Functional Description 29
© Tait Electronics Limited December 2005

3.2.3 RF Power A mplifier

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

RF Power Amplifier
and Switching
(25W Version)

Output of RF
Power Amplifier

The RF power amplifier and exciter of the 50W/40W radio is a five-st age
line-up with approximately 40dB of power gain. The output of the
frequency synthesizer is first buffer ed to reduce kick during pow er ramping.
The buffer output goes to a discrete exciter that pr oduces appro ximately 300
to 400mW output. This is follo w ed b y an LDMOS driv er pr odu cing up to
8W output that is power-controlled. The final stage consists of two parallel
LDMOS devices pr oducing enoug h pow er to pro vi de 40 to 50W at the RF
connector.

The RF power amplifier of the 25 W version is a four-stage line-up with
appro ximately 37dB of power gain. The output of the frequency syn thesizer
is first buffered to reduce kick during power ramping. The b uffer output
goes to a broad-band exciter IC that produces appro ximately 200mW
output. This is follo wed by an LDMOS driver pr oducing up to 2W output
that is power-contro lled. The final stage consists of two parallel LDMOS
devices pro ducing enough power to provide 25W at the RF connector.

The output of the RF P A passes thr ough a dual-directiona l coupler, used for
power control and monitoring. Finally, the output is low-pass-filtered to
bring harmonic levels within specification.

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

hardwar e contr ol loop . The forw ard po w er output fr om the RF PA is sensed
by the directional coupler and fed back to the power control loop. The PA
output power is controlled by v arying the driv er gate bias voltage that has a
calibrated maximum limit to pre vent over drive. 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 AC P
(adjacent channel power). A typical ramping waveform is shown in

Figure 3.4.

30 Functional Description TB7100 Installation and Operation Manual

© Tait Electronics Limited December 2005