Nova PR400 Service Manual
PR400
™
Commercial Series
Portable Radio
Detailed Service Manual
PR400 Portable Radio
Detailed Service Manual
VHF 136-162 MHz
VHF 146-174 MHz
UHF 403-440 MHz
UHF 438-470 MHz
UHF 465-495 MHz
Motorola, Inc.
1301 E. Algonquin Road
Schaumburg, IL 60196
6881096C25-B
ii
Foreword
This manual is intended for use by service technicians familiar with portable two-way radios. It contains
service information required for the equipment de scribed and is current as of the printing date. Changes which
occur after the printing date may be incorporated by a com p let e Ma n ua l rev i sion or alt erna tively as additions
Product Safety and RF Exposure Compliance
ATTENTION!
This radio is restricted to occupational use only to satisfy FCC RF energy exposure requirements.
Before using this product, read the RF energy awareness information and operating instructions in the
Product Safety and RF Exposure booklet enclosed with your radio (Motorola Publication part numbe r
68P81095C98) to ensure compliance with RF energy exposure limits.
For a list of Motorola-approved antennas, batteries, and other accessories, visit the following web site which
lists approved accessories: http://www.motorola.com/cgiss/index.shtml.
Computer Software Copyrights
The Motorola products described in this manu al may include copyrigh ted Motorola compu ter programs stored
in semiconductor memories or other media. Laws in the United States and other countries preserve for
Motorola certain exclusive rights for co pyrighted computer programs, including, but not limited to, the
exclusive right to copy or reproduce in any form the copyrighted computer program. Accordingly, any
copyrighted Motorola computer programs contained in the Motorola products described in this manual may
not be copied, reproduced, modified, reverse-engineered, or distributed in any manner without the express
written permission of Motorola. Furthermore, the purchase of Motorola products shall not be deemed to grant
either directly or by implication, estoppel, or otherwise, any license under the copyrights, patents or patent
applications of Motorola, except for the normal non-exclusive license to use that arises by opera tion of law in
the sale of a product.
Document Copyrights
No duplication or distribution of this document or any portion thereof shall take place without the express
written permission of Motorola. No part of this manual may be reproduced, distributed, or transmitted in any
form or by any means, electronic or mechanical, for any purpose without the express written permission of
Motorola.
Disclaimer
The information in this document is carefully examined, and is believed to be entirely reliable. However, no
responsibility is assumed for inaccuracies. Furthermore, Motorola reserves the right to make changes to any
products herein to improve readability, function, or design. Motorola does not assume any liability arising out
of the applications or use of any product or circuit described herein; nor does it cover any license under its
patent rights nor the rights of others.
MOTOROLA and The Stylized M logo are trademarks of Motorola, Inc.
All other product or service names are the property of their respective owners.
© 2005 Motorola, Inc. All rights reserved. Printed in U.S.A.
Note:
Before using this product, read the operating instructions for safe usage contained in the
Product Safety and RF Exposure booklet enclosed with your radio.
!
C a u t i o n
Table of Contents iii
6881096C25-B June, 2005
Table of Contents
Foreword .....................................................................................................................................................ii
Computer Software Copyrights ........................................ .... ... ... ... .... ... ... ... ... .... ... ... ... .... ... ... .......................ii
Document Copyrights..................................................................................................................................ii
Disclaimer....................................................................................................................................................ii
List of Figures ................................................................................................x
List of Tables ................................................................................................xii
Related Publications...................................................................................xiii
Chapter 1 Test Equipment, Service Aids, and Service Tools.......... 1-1
1.1 Test Equipment.............................................................................................................................. 1-1
1.2 Service Aids...................... ... ... ... .... ... ... .......................................... ... ............................................. 1-2
Chapter 2 DC Power Distribution........................................................ 2-1
2.1 DC Regulation and Distribution ..................................................................................................... 2-1
Chapter 3 Controller Theory of Operation.......................................... 3-1
3.1 Controller....................................................................................................................................... 3-1
3.1.1 Microprocessor Circuitry............................ .... ... ... .......................................... ... ... .... .........3-1
3.1.1.1 Memory Usage ........ ... ... .......................................... ... ... .... ... ................................... 3-2
3.1.1.2 Control and Indicator Interface ................................................................................ 3-2
3.1.1.3 Serial Bus Control of Circuit Blocks......................................................................... 3-2
3.1.1.4 Interface to RSS Programming................................................................................ 3-3
3.1.1.5 Storage of Customer-Specific Information............................................................... 3-3
3.1.1.6 Sensing of Externally-Connected Accessories........................................................3-3
3.1.1.7 Microprocessor Power-Up, Power-Down and Reset Routine.................................. 3-3
3.1.1.8 Boot Mode Control...................................................................................................3-4
3.1.1.9 Microprocessor 7.3975 MHz Clock..........................................................................3-4
3.1.1.10 Battery Gauge..........................................................................................................3-4
3.1.2 Audio Circuitry ..................................................................................................................3-4
3.1.2.1 Transmit and Receive Low-Level Audio Circuitry................. ... ... .... ... ...................... 3-4
3.1.2.2 Audio Power Amplifier .............................................................................................3-5
3.1.2.3 Internal Microphone Audio Voice Path .................................................................... 3-5
3.1.2.4 PTT Circuits.............................................................................................................3-5
3.1.2.5 VOX Operation ........................................................................................................ 3-6
3.1.2.6 Battery Charging Through Microphone Jack........................................................... 3-6
3.1.2.7 Programming and Flashing Through Microphone Jack........................................... 3-6
iv Table of Contents
June, 2005 6881096C25-B
Module 1: VHF 136-162, 146-174 MHz
Chapter 4 136-162 MHz VHF Theory Of Operation ............................ 4-1
4.1 Introduction....................................................................................................................................4-1
4.2 VHF Receiver........... ... ... ... .... ... ... ... .... .......................................... ... ...............................................4-1
4.2.1 Receiver Front-End..................... ... ... .... ... ... ... .... ... ... .......................................... ... ... .... .....4-1
4.2.2 Receiver Back-End ........................................ .... .......................................... ... ..................4-2
4.3 VHF Transmitter............. ... .......................................... .... ... ... ... ......................................................4-3
4.3.1 Transmit Power Amplifier..................................................................................................4-3
4.3.2 Antenna Switch.................................................................................................................4-3
4.3.3 Harmonic Filter..................................................................................................................4-3
4.3.4 Antenna Matching Network...............................................................................................4-4
4.3.5 P ower Control ....................... ... ... ... ... .... ... ... .......................................... ... .... ... ... ... ... .........4-4
4.4 VHF Frequency Generation Circuitry.............................................................................................4-4
4.4.1 F ract ional-N Synthesiz er................ ... .... ... ... ... .... ... ... ... .......................................... ... .... ... ..4-5
4.4.2 Voltage Controlled Oscillator (VCO) .................................................................................4-6
4.5 Keypad...........................................................................................................................................4-7
Chapter 5 146-174 MHz VHF Theory Of Operation ............................ 5-1
5.1 Introduction....................................................................................................................................5-1
5.2 VHF Receiver........... ... ... ... .... ... ... ... .... .......................................... ... ...............................................5-1
5.2.1 Receiver Front-End..................... ... ... .... ... ... ... .... ... ... .......................................... ... ... .... .....5-1
5.2.2 Receiver Back-End ........................................ .... .......................................... ... ..................5-2
5.3 VHF Transmitter............. ... .......................................... .... ... ... ... ......................................................5-3
5.3.1 Transmit Power Amplifier..................................................................................................5-3
5.3.2 Antenna Switch.................................................................................................................5-3
5.3.3 Harmonic Filter..................................................................................................................5-3
5.3.4 Antenna Matching Network...............................................................................................5-4
5.3.5 P ower Control ....................... ... ... ... ... .... ... ... .......................................... ... .... ... ... ... ... .........5-4
5.4 VHF Frequency Generation Circuitry.............................................................................................5-4
5.4.1 F ract ional-N Synthesiz er................ ... .... ... ... ... .... ... ... ... .......................................... ... .... ... ..5-5
5.4.2 Voltage Controlled Oscillator (VCO) .................................................................................5-6
5.5 Keypad...........................................................................................................................................5-7
Chapter 6 VHF Troubleshooting Tables............................................. 6-1
6.1 Troubleshooting Table for Receiver...............................................................................................6-1
6.2 Troubleshooting Table for Synthesizer..........................................................................................6-3
6.3 Troubleshooting Table for Transmitter...........................................................................................6-4
6.4 Troubleshooting Table for Board and IC Signals...........................................................................6-7
Chapter 7 VHF Schematic Diagrams, Overlays, and Parts Lists...... 7-1
7.1 Introduction....................................................................................................................................7-1
7.1.1 Notes For All Schematics and Circuit Boards...................................................................7-1
7.1.2 Six Layer Circuit Board .....................................................................................................7-3
7.2 Speaker and Microphone Schematic.............................................................................................7-3
7.2.1 Speaker and Microphone Parts List..................................................................................7-3
Table of Contents v
6881096C25-B June, 2005
Chapter 7 VHF 136-162 MHz (8486769Z02-A) Schematic Diagrams,
Overlays, and Parts Lists................................................... 7-5
Figure 7-3. VHF (136-162 MHz) Radio Circuit Block Interconnect Diagram (8486769Z02-A)........... 7-5
Figure 7-4. VHF (136-162 MHz) Receiver Front End Schematic Diagram (8486769Z02-A)..............7-6
Figure 7-5. VHF (136-162 MHz) Receiver Back End Schematic Diagram (8486769Z02-A).............. 7-7
Figure 7-6. VHF (136-162 MHz) Synthesizer Schematic Diagram (8486769Z02-A).......................... 7-8
Figure 7-7. VHF (136-162 MHz) Voltage Controlled Oscillator Schematic
Diagram (8486769Z02-A)................................................................................................. 7-9
Figure 7-8. VHF (136-162 MHz) Transmitter and Power Control Schematic
Diagram (8486769Z02-A)...............................................................................................7-10
Figure 7-9. VHF (136-162 MHz) Controller Interconnect Schematic Diagram (8486769Z02-A)...... 7-11
Figure 7-10. VHF (136-162 MHz) Microprocessor Circuitry Schematic Diagram (8486769Z02-A)...7-12
Figure 7-11. VHF (136-162 MHz) Audio Circuitry Schematic Diagram (8486769Z02-A) ................... 7-13
Figure 7-12. VHF (136-162 MHz) DC Regulation Schematic Diagram (8486769Z02-A) ...................7-14
Figure 7-13. VHF (136-162 MHz) Keypad Board Schematic Diagram (8466565A03-A).................... 7-15
Figure 7-14. VHF (136-162 MHz) Board Top Side View (8486769Z02-A) ......................................... 7-16
Figure 7-15. VHF (136-162 MHz) Board Bottom Side View (8486769Z02-A)....................................7-17
Figure 7-16. VHF (136-162 MHz) Keypad Board (8466565A03-B)............................................. ... ... . 7-18
VHF (136-162 MHz) Radio Parts List (8486769Z02-A)......................................................................... 7-19
VHF (136-162 MHz) Keypad Board Parts List (8466565A03-B)..........................................................7-22
Chapter 7 VHF 136-162 MHz Schematic Diagrams, Overlays,
and Parts Lists (8486769Z04-C)....................................... 7-23
Figure 7-17. VHF (136-162 MHz) Radio Circuit Block Interconnect Diagram (8486769Z04-C).........7-23
Figure 7-18. VHF (136-162 MHz) Receiver Front End Schematic Diagram (8486769Z04-C) ...........7-24
Figure 7-19. VHF (136-162 MHz) Receiver Back End Schematic Diagram (8486769Z04-C)............7-25
Figure 7-20. VHF (136-162 MHz) Synthesizer Schematic Diagram (8486769Z04-C)........................ 7-26
Figure 7-21. VHF (136-162 MHz) Voltage Controlled Oscillator Schematic
Diagram (8486769Z04-C) .............................................................................................. 7-27
Figure 7-22. VHF (136-162 MHz) Transmitter and Power Control Schematic
Diagram (8486769Z04-C) .............................................................................................. 7-28
Figure 7-23. VHF (136-162 MHz) Controller Interconnect Schematic Diagram ( 8486769Z04-C)......7-29
Figure 7-24. VHF (136-162 MHz) Microprocessor Circuitry Schematic Diagram (8486769Z04-C)...7-30
Figure 7-25. VHF (136-162 MHz) Audio Circuitry Schematic Diagram (8486769Z04-C)................... 7-31
Figure 7-26. VHF (136-162 MHz) DC Regulation Schematic Diagram (8486769Z04-C)................... 7-32
Figure 7-27. VHF (136-162 MHz) Keypad Board Schematic Diagram (8466565A03-B).................... 7-33
Figure 7-28. VHF (136-162 MHz) Board Component Side View (8486769Z04-C)............................. 7-34
Figure 7-29. VHF (136-162 MHz) Board Solder Side View (8486769Z04-C)..................................... 7-35
Figure 7-30. VHF (136-162 MHz) Keypad Board (8466565A03-B)............................................. ... ... . 7-36
VHF (136-162 MHz) Radio Parts List (8486769Z04-C)........................... ..............................................7-37
VHF (136-162 MHz) Keypad Board Parts List (8466565A03-B)...........................................................7-40
Chapter 7 VHF 146-174 MHz (8486342Z13-C) Schematic Diagrams,
Overlays, and Parts Lists................................................. 7-41
Figure 7-31. VHF (146-174 MHz) Radio Circuit Block Interconnect Diagram (8486342Z13-C).........7-41
Figure 7-32. VHF (146-174 MHz) Receiver Front End Schematic Diagram (8486342Z13-C) ...........7-42
Figure 7-33. VHF (146-174 MHz) Receiver Back End Schematic Diagram (8486342Z13-C)............7-43
Figure 7-34. VHF (146-174 MHz) Synthesizer Schematic Diagram (8486342Z13-C)........................ 7-44
vi Table of Contents
June, 2005 6881096C25-B
Figure 7-35. VHF (146-174 MHz) Voltage Controlled Oscillator Schematic
Diagram (8486342Z13-C)...............................................................................................7-45
Figure 7-36. VHF (146-174 MHz) Transmitter and Power Control Schematic
Diagram (8486342Z13-C)........................... ............................................. .... ...................7-46
Figure 7-37. VHF (146-174 MHz) Controller Interconnect Schematic Diagram (8486342Z13-C)......7-47
Figure 7-38. VHF (146-174 MHz) Microprocessor Circuitry Schematic Diagram (8486342Z13-C)...7-48
Figure 7-39. VHF (146-174 MHz) Audio Circuitry Schematic Diagram (8486342Z13-C) ...................7-49
Figure 7-40. VHF (146-174 MHz) DC Regulation Schematic Diagram (8486342Z13-C) ...................7-50
Figure 7-41. VHF (146-174 MHz) Keypad Board Schematic Diagram (8466565A03-B)....................7-51
Figure 7-42. VHF (146-174 MHz) Board, Top Side (8486342Z13-C)....................................... ... .... ...7-52
Figure 7-43. VHF (146-174 MHz) Board, Bottom Side (8486342Z13-C)............................................7-53
Figure 7-44. VHF (146-174 MHz) Keypad Board (8466565A03-B) ....................................................7-54
VHF (146-174 MHz) Radio Parts List (8486342Z13-C) . ... ... .... ... ... ... .... ... ... ... ... .... ... ... ... .... ... ... .............7-55
VHF (146-174 MHz) Keypad Board Parts List (8466565A03-B) ........................................ ... ... ... ... .... ...7-58
Chapter 7 VHF 146-174 MHz Schematic Diagrams, Overlays,
and Parts Lists (8486769Z04-C)....................................... 7-59
Figure 7-45. VHF (146-174 MHz) Radio Circuit Block Interconnect Diagram (8486769Z04-C) .........7-59
Figure 7-46. VHF (146-174 MHz) Receiver Front End Schematic Diagram (8486769Z04-C)............7-60
Figure 7-47. VHF (146-174 MHz) Receiver Back End Schematic Diagram (8486769Z04-C)............7-61
Figure 7-48. VHF (146-174 MHz) Synthesizer Schematic Diagram (8486769Z04-C)........................7-62
Figure 7-49. VHF (146-174 MHz) Voltage Controlled Oscillator Schematic
Diagram 8486769Z04-C)................................................................................................7-63
Figure 7-50. VHF (146-174 MHz) Transmitter and Power Control Schematic
Diagram (8486769Z04-C)........................... ............................................. .... ...................7-64
Figure 7-51. VHF (146-174 MHz) Controller Interconnect Schematic Diagram (8486769Z04-C)......7-65
Figure 7-52. VHF (146-174 MHz) Microprocessor Circuitry Schematic Diagram (8486769Z04-C)...7-66
Figure 7-53. VHF (146-174 MHz) Audio Circuitry Schematic Diagram (8486769Z04-C) ...................7-67
Figure 7-54. VHF (146-174 MHz) DC Regulation Schematic Diagram (8486769Z04-C) ...................7-68
Figure 7-55. VHF (146-174 MHz) Keypad Board Schematic Diagram (8466565A03-B)....................7-69
Figure 7-56. VHF (146-174 MHz) Board Component Side View (8486769Z04-C).............................7-70
Figure 7-57. VHF (146-174 MHz) Board Solder Side View (8486769Z04-C)........................... ... .... ...7-71
Figure 7-58. VHF (146-174 MHz) Keypad Board (8466565A03-B) ....................................................7-72
VHF (146-174 MHz) Radio Parts List (8486769Z04-C)..................................... .... ... ... ... .... ... ... ... ... .... ...7-73
VHF (146-174 MHz) Keypad Board Parts List (8466565A03-B) ........................................ ... ... ... ... .... ...7-76
Module 2: UHF 403-440, 438-470, 465-495 MHz
Chapter 8 403-440 MHz UHF Theory Of Operation............................ 8-1
8.1 Introduction....................................................................................................................................8-1
8.2 UHF Receiver ................................................................................................................................8-1
8.2.1 Receiver Front End............................................ ... ... ... .... ... ... ... .........................................8-1
8.2.2 Receiver Back End ..................... ... ... .... ... ... ... .... ... ... ... .......................................... ... .... .....8-2
8.3 UHF Transmitter ............................................................................................................................8-3
8.3.1 T ransmitter Power Amplifier..............................................................................................8-3
8.3.2 Antenna Switch.................................................................................................................8-3
8.3.3 Harmonic Filter..................................................................................................................8-3
8.3.4 Antenna Matching Network...............................................................................................8-4
8.3.5 P ower Control ....................... ... ... ... ... .... ... ... .......................................... ... .... ... ... ... ... .........8-4
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6881096C25-B June, 2005
8.4 UHF Frequency Generation Circuitry ............................................................................................ 8-4
8.4.1 Fractional-N Synthesizer ..................................................................................................8-5
8.4.2 Voltage Controlled Oscillator (VCO)................................................................................. 8-6
8.5 Keypad........................................................................................................................................... 8-7
Chapter 9 438-470 MHz UHF Theory Of Operation............................ 9-1
9.1 Introduction.................................................................................................................................... 9-1
9.2 UHF Receiver ...... ... ... ... .... ... ... ... .... .......................................... ... ................................................... 9-1
9.2.1 Receiver Front End...........................................................................................................9-1
9.2.2 Receiver Back End ........................................................................................................... 9-2
9.3 UHF Transmitter........... .... ... ... .......................................... ... .... ... ...................................................9-3
9.3.1 Transmitter Power Amplifier ...... ... .... ... ... .......................................... ... .... ... ... ................... 9-3
9.3.2 Antenna Switch........................................................... ... ... ... ............................................. 9-3
9.3.3 Harmonic Filter .................................................................................................................9-3
9.3.4 Antenna Matching Network.................................................. ... .... ... ... ... .... ... ... ... ... .... ... ... ... 9-4
9.3.5 Power Control................................................................................................................... 9-4
9.4 UHF Frequency Generation Circuitry ............................................................................................ 9-4
9.4.1 Fractional-N Synthesizer ..................................................................................................9-5
9.4.2 Voltage Controlled Oscillator (VCO)................................................................................. 9-6
9.5 Keypad........................................................................................................................................... 9-7
Chapter 10 465-495 MHz UHF Theory Of Operation.......................... 10-1
10.1 Introduction.................................................................................................................................. 10-1
10.2 UHF Receiver ................................ ... .......................................... ... .............................................. 10-1
10.2.1 Receiver Front End.........................................................................................................10-1
10.2.2 Receiver Back End .........................................................................................................10-2
10.3 UHF Transmitter .................................. ... ... .... ... ... ... .... .......................................... ... ... .................10-3
10.3.1 Transmitter Power Amplifier ......... .... ... ... ... .......................................... .... ... ... ... ... .... ... ....10-3
10.3.2 Antenna Switch.................... ... ... ... .... ... ... ........................................................................ 10-3
10.3.3 Harmonic Filter ...............................................................................................................10-3
10.3.4 Antenna Matching Network.............................................................................................10-4
10.3.5 Power Control................................................................................................................. 10-4
10.4 UHF Frequency Generation Circuitry ..........................................................................................10-4
10.4.1 Fractional-N Synthesizer ................................................................................................10-5
10.4.2 Voltage Controlled Oscillator (VCO)...............................................................................10-6
10.5 Keypad.........................................................................................................................................10-7
Chapter 11 UHF Troubleshooting Tables........................................... 11-1
11.1 Troubleshooting Table for Receiver .. ... ... ... .... ... ... ... .... ... ... ............................................. ... ...........11-1
11.2 Troubleshooting Table for Synthesizer....................... ... ... ... .... ... ... ... ... .... ... ... ... .... ... ... ... ..............11-3
11.3 Troubleshooting Table for Transmitter. ...... ..................................................................................11-4
11.4 Troubleshooting Table for Board and IC Signals......................................................................... 11-6
Chapter 12 UHF Schematic Diagrams, Overlays, and Parts Lists ... 12-1
12.1 Introduction.................................................................................................................................. 12-1
12.1.1 Notes For All Schematics and Circuit Boards................................................................. 12-1
12.1.2 Six Layer Circuit Board...................................................................................................12-3
12.2 Speaker and Microphone Schematic...... ... .... ..............................................................................12-3
12.2.1 Speaker and Microphone Parts List................................................................................ 12-3
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June, 2005 6881096C25-B
Chapter 12 UHF 403-440 MHz (8486635Z03-O) Schematic Diagrams,
Overlays, and Parts Lists................................................. 12-5
Figure 12-3. UHF (403-440 MHz) Radio Circuit Block Diagram (8486635Z03-O)..............................12-5
Figure 12-4. UHF (403-440 MHz) Receiver Front End Schematic Diagram (8486635Z03-O) ...........12-6
Figure 12-5. UHF (403-440 MHz) Receiver Back End Schematic Diagram (8486635Z03-O)............12-7
Figure 12-6. UHF (403-440 MHz) Synthesizer Schematic Diagram (8486635Z03-O) .......................12-8
Figure 12-7. UHF (403-440 MHz) Voltage Controlled Oscillator Schematic
Diagram (8486635Z03-O) ..............................................................................................12-9
Figure 12-8. UHF (403-44 0 MH z) Trans mit te r an d Pow er Cont ro l Sche m atic
Diagram (8486635Z03-O) .................................... ... ............................................. ... .....12-10
Figure 12-9. UHF (403-440 MHz) Controller Interconnect Schematic Diagram (8486635Z03-O)....12-11
Figure 12-10. UHF (403-440 MHz) Microprocessor Circuitry Schematic Diagram (8486635Z03-O) 12-12
Figure 12-11. UHF (403-440MHz) Audio Circuitry Schematic Diagram (8486635Z03-O)..................12-13
Figure 12-12. UHF (403-440 MHz) DC Regulation Schematic Diagram (8486635Z03-O).................12-14
Figure 12-13. UHF (403-440 MHz) Keypad Board Schematic Diagram (8466565A03-B)..................12-15
Figure 12-14. UHF (403-440 MHz) Board Top Side View (8486635Z03-O).................. .... ... ... ... ....... .12-16
Figure 12-15. UHF (403-440 MHz) Board Bottom Side View (8486635Z03-O)..................................12-17
Figure 12-16. UHF (403-440 MHz) Keypad Board (8466565A03-B)..................................................12-18
UHF (403-440 MHz) Radio Parts List (8486635Z03-O) ......................................................................12-19
UHF (403-440 MHz) Keypad Board Parts List (8466565A03-B) ........................................................12-22
Chapter 12 UHF 438-470 MHz (8486348Z13-C) Schematic Diagrams,
Overlays, and Parts Lists............................................... 12-23
Figure 12-17. UHF (438-470 MHz) Radio Circuit Block Diagram (8486348Z13-C)............................12-23
Figure 12-18. UHF (438-470 MHz) Receiver Front End Schematic Diagram (8486348Z13-C) .... .... .12-24
Figure 12-19. UHF (438-470 MHz) Receiver Back End Schematic Diagram (8486348Z13-C)..........12-25
Figure 12-20. UHF (438-470 MHz) Synthesizer Schematic Diagram (8486348Z13-C)......................12-26
Figure 12-21. UHF (438-470 MHz) Voltage Controlled Oscillator Schematic
Diagram (8486348Z13-C).............................................................................................12-27
Figure 12-22. UHF (438-470 MHz) Transmitter and Power Control Schematic
Diagram (8486348Z13-C)........................... ............................................. .... .................12-28
Figure 12-23. UHF (438-470 MHz) Controller Interconnect Schematic Diagram (8486348Z13-C)....12-29
Figure 12-24. UHF (438-470 MHz) Microprocessor Circuitry Schematic Diagram (8486348Z13-C).12-30
Figure 12-25. UHF (438-470 MHz) Audio Circuitry Schematic Diagram (8486348Z13-C).................12-31
Figure 12-26. UHF (438-470 MHz) DC Regulation Schematic Diagram (8486348Z13-C).................12-32
Figure 12-27. UHF (438-470 MHz) Keypad Option Schematic Diagram (8466565A03-B).................12-33
Figure 12-28. UHF (438-470 MHz) Board Top Side View (8486348Z13-C).......................................12-34
Figure 12-29. UHF (438-470 MHz) Board Bottom Side View (8486348Z13-C)..................................12-35
Figure 12-30. UHF (438-470 MHz) Keypad Board (8466565A03-B)..................................................12-36
UHF (438-470 MHz) Radio Parts List (8486348Z13-C).......................................................................12-37
UHF (438-470 MHz) Keypad Board Parts List (8466565A03-B) ........................................................12-40
Chapter 12 UHF 465-495 MHz (8486634Z02-O) Schematic Diagrams,
Overlays, and Parts Lists............................................... 12-41
Figure 12-31. UHF (465-495 MHz) Radio Circuit Block Diagram (8486634Z02-O)............................12-41
Figure 12-32. UHF (465-495 MHz) Receiver Front End Schematic Diagram (8486634Z02-O) .........12-42
Figure 12-33. UHF (465-495 MHz) Receiver Back End Schematic Diagram (8486634Z02-O)..........12-43
Figure 12-34. UHF (465-495 MHz) Synthesizer Schematic Diagram (8486634Z02-O) .....................12-44
Table of Contents ix
6881096C25-B June, 2005
Figure 12-35. UHF (465-495 MHz) Voltage Controlled Oscillator Schematic
Diagram (8486634Z02-O)............................................................................................ 12-45
Figure 12-36. UHF (465-495 MHz) Transmitter and Power Control Schematic
Diagram (8486634Z02-O)............................................................................................ 12-46
Figure 12-37. UHF (465-495 MHz) Controller Interconnect Schematic Diagram (8486634Z02-O)....12-47
Figure 12-38. UHF (465-495 MHz) Microprocessor Circuitry Schematic Diagr am (8486634Z02-O) 12-48
Figure 12-39. UHF (465-495 MHz) Audio Circuitry Schematic Diagram (8486634Z02-O)................. 12-49
Figure 12-40. UHF (465-495 MHz) DC Regulation Schematic Diagram (8486634Z02-O)................. 12-50
Figure 12-41. UHF (465-495 MHz) Keypad Board Schematic Diagram (8466565A03-B) .................12-51
Figure 12-42. UHF (465-495 MHz) Board Top Side View (8486634Z02-O).......................................12-52
Figure 12-43. UHF (465-495 MHz) Board Bottom Side View (8486634Z02-O) ................................. 12-53
Figure 12-44. UHF (465-495 MHz) Keypad Board (8466565A03-B)......... ... .... ... ... ... .... ... ... ...... .... ... .. 12-54
UHF (465-495 MHz) Radio Parts List (8486634Z02-O)....................... ... ... ... .... ... ... ... .... ... ... ... ... .... ... .. 12-55
UHF (465-495 MHz) Keypad Board Parts List (8466565A03-B)........................................................12-58
INDEX................................................................................... 1-1
x Table of Contents
June, 2005 6881096C25-B
List of Figures
Figure 1-1. Programming/Test Cable............ ... ... .... ... ... ... .... ... ... ... .... ... .......................................... .....1-4
Figure 1-2. Wiring of the Connectors..................................................................................................1-4
Figure 2-1. DC Power Distribution Block Diagram..............................................................................2-1
Figure 4-1. VHF Receiver Block Diagram...........................................................................................4-1
Figure 4-2. VHF Transmitter Block Diagram.......................................................................................4-3
Figure 4-3. VHF Frequency Generation Unit Block Diagram..............................................................4-5
Figure 4-4. VHF Synthesizer Block Diagram ......................................................................................4-6
Figure 4-5. VHF VCO Block Diagram........... ... ... .... ... ... ... .... ... ... ... .... ... ... ... ... ......................................4-7
Figure 4-6. Keypad Block Diagram.....................................................................................................4-7
Figure 5-1. VHF Receiver Block Diagram...........................................................................................5-1
Figure 5-2. VHF Transmitter Block Diagram.......................................................................................5-3
Figure 5-3. VHF Frequency Generation Unit Block Diagram..............................................................5-5
Figure 5-4. VHF Synthesizer Block Diagram ......................................................................................5-6
Figure 5-5. VHF VCO Block Diagram........... ... ... .... ... ... ... .... ... ... ... .... ... ... ... ... ......................................5-7
Figure 5-6. Keypad Block Diagram.....................................................................................................5-7
Figure 7-1. Six-Layer Circuit Board: Copper Steps in Layer Sequence..............................................7-3
Figure 7-2. Speaker and Microphone Schematic................................................................................7-3
Figure 7-3. VHF (136-162 MHz) Radio Circuit Block Interconnect Diagram (8486769Z02-A) ...........7-5
Figure 7-4. VHF (136-162 MHz) Receiver Front End Schematic Diagram (8486769Z02-A)..............7-6
Figure 7-5. VHF (136-162 MHz) Receiver Back End Schematic Diagram (8486769Z02-A) ..............7-7
Figure 7-6. VHF (136-162 MHz) Synthesizer Schematic Diagram (8486769Z02-A)..........................7-8
Figure 7-7. VHF (136-162 MHz) Voltage Controlled Oscillator Schematic
Diagram (8486769Z02-A).................................................................................................7-9
Figure 7-8. VHF (136-162 MHz) Transmitter and Power Control Schematic
Diagram (8486769Z02-A)..................................... ... ... .... ... ... ... .......................................7-10
Figure 7-9. VHF (136-162 MHz) Controller Interconnect Schematic Diagram (8486769Z02-A) ......7-11
Figure 7-10. VHF (136-162 MHz) Microprocessor Circuitry Schematic Diagram (8486769Z02-A)...7-12
Figure 7-11. VHF (136-162 MHz) Audio Circuitry Schematic Diagram (8486769Z02-A) ... ... ... ....... ...7-13
Figure 7-12. VHF (136-162 MHz) DC Regulation Schematic Diagram (8486769Z02-A) ...................7-14
Figure 7-13. VHF (136-162 MHz) Keypad Board Schematic Diagram (8466565A03-A)....................7-15
Figure 7-14. VHF (136-162 MHz) Board Top Side View (8486769Z02-A) .........................................7-16
Figure 7-15. VHF (136-162 MHz) Board Bottom Side View (8486769Z02-A) ....................................7-17
Figure 7-16. VHF (136-162 MHz) Keypad Board (8466565A03-B) ....................................................7-18
Figure 7-17. VHF (136-162 MHz) Radio Circuit Block Interconnect Diagram (8486769Z04-C) .........7-23
Figure 7-18. VHF (136-162 MHz) Receiver Front End Schematic Diagram (8486769Z04-C)............7-24
Figure 7-19. VHF (136-162 MHz) Receiver Back End Schematic Diagram (8486769Z04-C)............7-25
Figure 7-20. VHF (136-162 MHz) Synthesizer Schematic Diagram (8486769Z04-C)........................7-26
Figure 7-21. VHF (136-162 MHz) Voltage Controlled Oscillator Schematic
Diagram (8486769Z04-C)...............................................................................................7-27
Figure 7-22. VHF (136-162 MHz) Transmitter and Power Control Schematic
Diagram (8486769Z04-C)........................... ............................................. .... ...................7-28
Figure 7-23. VHF (136-162 MHz) Controller Interconnect Schematic Diagram (8486769Z04-C)......7-29
Figure 7-24. VHF (136-162 MHz) Microprocessor Circuitry Schematic Diagram (8486769Z04-C)...7-30
Figure 7-25. VHF (136-162 MHz) Audio Circuitry Schematic Diagram (8486769Z04-C) ...................7-31
Figure 7-26. VHF (136-162 MHz) DC Regulation Schematic Diagram (8486769Z04-C) ...................7-32
Figure 7-27. VHF (136-162 MHz) Keypad Board Schematic Diagram (8466565A03-B)....................7-33
Figure 7-28. VHF (136-162 MHz) Board Component Side View (8486769Z04-C).............................7-34
Figure 7-29. VHF (136-162 MHz) Board Solder Side View (8486769Z04-C)........................... ... .... ...7-35
Figure 7-30. VHF (136-162 MHz) Keypad Board (8466565A03-B) ....................................................7-36
Figure 7-31. VHF (146-174 MHz) Radio Circuit Block Interconnect Diagram (8486342Z13-C) .........7-41
Table of Contents xi
6881096C25-B June, 2005
Figure 7-32. VHF (146-174 MHz) Receiver Front End Schematic Diagram (8486342Z13-C) ...........7-42
Figure 7-33. VHF (146-174 MHz) Receiver Back End Schematic Diagram (8486342Z13-C)............7-43
Figure 7-34. VHF (146-174 MHz) Synthesizer Schematic Diagram (8486342Z13-C)........................ 7-44
Figure 7-35. VHF (146-174 MHz) Voltage Controlled Oscillator Schematic
Diagram (8486342Z13-C) .............................................................................................. 7-45
Figure 7-36. VHF (146-174 MHz) Transmitter and Power Control Schematic
Diagram (8486342Z13-C) .............................................................................................. 7-46
Figure 7-37. VHF (146-174 MHz) Controller Interconnect Schematic Diagram ( 8486342Z13-C)......7-47
Figure 7-38. VHF (146-174 MHz) Microprocessor Circuitry Schematic Diagram (8486342Z13-C)...7-48
Figure 7-39. VHF (146-174 MHz) Audio Circuitry Schematic Diagram (8486342Z13-C)................... 7-49
Figure 7-40. VHF (146-174 MHz) DC Regulation Schematic Diagram (8486342Z13-C)................... 7-50
Figure 7-41. VHF (146-174 MHz) Keypad Board Schematic Diagram (8466565A03-B).................... 7-51
Figure 7-42. VHF (146-174 MHz) Board, Top Side (8486342Z13-C)................................................. 7-52
Figure 7-43. VHF (146-174 MHz) Board, Bottom Side (8486342Z13-C)............................................ 7-53
Figure 7-44. VHF (146-174 MHz) Keypad Board (8466565A03-B)............................................. ... ... . 7-54
Figure 7-45. VHF (146-174 MHz) Radio Circuit Block Interconnect Diagram (8486769Z04-C).........7-59
Figure 7-46. VHF (146-174 MHz) Receiver Front End Schematic Diagram (8486769Z04-C) ...........7-60
Figure 7-47. VHF (146-174 MHz) Receiver Back End Schematic Diagram (8486769Z04-C)............7-61
Figure 7-48. VHF (146-174 MHz) Synthesizer Schematic Diagram (8486769Z04-C)........................ 7-62
Figure 7-49. VHF (146-174 MHz) Voltage Controlled Oscillator Schematic
Diagram (8486769Z04-C) .............................................................................................. 7-63
Figure 7-50. VHF (146-174 MHz) Transmitter and Power Control Schematic
Diagram (8486769Z04-C) .............................................................................................. 7-64
Figure 7-51. VHF (146-174 MHz) Controller Interconnect Schematic Diagram ( 8486769Z04-C)......7-65
Figure 7-52. VHF (146-174 MHz) Microprocessor Circuitry Schematic Diagram (8486769Z04-C)...7-66
Figure 7-53. VHF (146-174 MHz) Audio Circuitry Schematic Diagram (8486769Z04-C)................... 7-67
Figure 7-54. VHF (146-174 MHz) DC Regulation Schematic Diagram (8486769Z04-C)................... 7-68
Figure 7-55. VHF (146-174 MHz) Keypad Board Schematic Diagram (8466565A03-B).................... 7-69
Figure 7-56. VHF (146-174 MHz) Board Component Side View (8486769Z04-C)............................. 7-70
Figure 7-57. VHF (146-174 MHz) Board Solder Side View (8486769Z04-C)..................................... 7-71
Figure 7-58. VHF (146-174 MHz) Keypad Board (8466565A03-B)............................................. ... ... . 7-72
Figure 8-1. UHF Receiver Block Diagram ..........................................................................................8-1
Figure 8-2. UHF Transmitter Block Diagram ...................................................................................... 8-3
Figure 8-3. UHF Frequency Generation Unit Block Diagram .............................................................8-5
Figure 8-4. UHF Synthesizer Block Diagram......................................................................................8-6
Figure 8-5. UHF VCO Block Diagram.................................................................................................8-7
Figure 8-6. Keypad Block Diagram.....................................................................................................8-7
Figure 9-1. UHF Receiver Block Diagram ..........................................................................................9-1
Figure 9-2. UHF Transmitter Block Diagram ...................................................................................... 9-3
Figure 9-3. UHF Frequency Generation Unit Block Diagram .............................................................9-5
Figure 9-4. UHF Synthesizer Block Diagram......................................................................................9-6
Figure 9-5. UHF VCO Block Diagram.................................................................................................9-7
Figure 9-6. Keypad Block Diagram.....................................................................................................9-7
Figure 10-1. UHF Receiver Block Diagram ........................................................................................10-1
Figure 10-2. UHF Transmitter Block Diagram .................................................................................... 10-3
Figure 10-3. UHF Frequency Generation Unit Block Diagram ...........................................................10-5
Figure 10-4. UHF Synthesizer Block Diagram.................................................................................... 10-6
Figure 10-5. UHF VCO Block Diagram...............................................................................................10-7
Figure 10-6. Keypad Block Diagram...................................................................................................10-7
Figure 12-1. Six-Layer Circuit Board: Copper Steps in Layer Sequence ........................................... 12-3
Figure 12-2. Speaker and Microphone Schematic .............................................................................12-3
Figure 12-3. UHF (403-440 MHz) Radio Circuit Block Diagram (8486635Z03-O) ...... ... ... ... ... .... ... ... . 12-5
Figure 12-4. UHF (403-440 MHz) Receiver Front End Schematic Diagram (8486635Z03-O)........... 12-6
Figure 12-5. UHF (403-440 MHz) Receiver Back End Schematic Diagram (8486635Z03-O) ...........12-7
xii Table of Contents
June, 2005 6881096C25-B
Figure 12-6. UHF (403-440 MHz) Synthesizer Schematic Diagram (8486635Z03-O) .......................12-8
Figure 12-7. UHF (403-440 MHz) Voltage Controlled Oscillator Schematic
Diagram (8486635Z03-O) ..............................................................................................12-9
Figure 12-8. UHF (403-44 0 MH z) Trans mit te r an d Pow er Cont ro l Sche m atic
Diagram (8486635Z03-O) .................................... ... ............................................. ... .....12-10
Figure 12-9. UHF (403-440 MHz) Controller Interconnect Schematic Diagram (8486635Z03-O)....12-11
Figure 12-10. UHF (403-440 MHz) Microprocessor Circuitry Schematic Diagram (8486635Z03-O) 12-12
Figure 12-11. UHF (403-440MHz) Audio Circuitry Schematic Diagram (8486635Z03-O)..................12-13
Figure 12-12. UHF (403-440 MHz) DC Regulation Schematic Diagram (8486635Z03-O).................12-14
Figure 12-13. UHF (403-440 MHz) Keypad Board Schematic Diagram (8466565A03-B)..................12-15
Figure 12-14. UHF (403-440 MHz) Board Top Side View (8486635Z03-O).................. .... ... ... ... ....... .12-16
Figure 12-15. UHF (403-440 MHz) Board Bottom Side View (8486635Z03-O)..................................12-17
Figure 12-16. UHF (403-440 MHz) Keypad Board (8466565A03-B)..................................................12-18
Figure 12-17. UHF (438-470 MHz) Radio Circuit Block Diagram (8486348Z13-C)............................12-23
Figure 12-18. UHF (438-470 MHz) Receiver Front End Schematic Diagram (8486348Z13-C) .... .... .12-24
Figure 12-19. UHF (438-470 MHz) Receiver Back End Schematic Diagram (8486348Z13-C)..........12-25
Figure 12-20. UHF (438-470 MHz) Synthesizer Schematic Diagram (8486348Z13-C)......................12-26
Figure 12-21. UHF (438-470 MHz) Voltage Controlled Oscillator Schematic
Diagram (8486348Z13-C).............................................................................................12-27
Figure 12-22. UHF (438-470 MHz) Transmitter and Power Control Schematic
Diagram (8486348Z13-C)........................... ............................................. .... .................12-28
Figure 12-23. UHF (438-470 MHz) Controller Interconnect Schematic Diagram (8486348Z13-C)....12-29
Figure 12-24. UHF (438-470 MHz) Microprocessor Circuitry Schematic Diagram (8486348Z13-C).12-30
Figure 12-25. UHF (438-470 MHz) Audio Circuitry Schematic Diagram (8486348Z13-C).................12-31
Figure 12-26. UHF (438-470 MHz) DC Regulation Schematic Diagram (8486348Z13-C).................12-32
Figure 12-27. UHF (438-470 MHz) Keypad Option Schematic Diagram (8466565A03-B).................12-33
Figure 12-28. UHF (438-470 MHz) Board Top Side View (8486348Z13-C).......................................12-34
Figure 12-29. UHF (438-470 MHz) Board Bottom Side View (8486348Z13-C)..................................12-35
Figure 12-30. UHF (438-470 MHz) Keypad Board (8466565A03-B)..................................................12-36
Figure 12-31. UHF (465-495 MHz) Radio Circuit Block Diagram (8486634Z02-O)............................12-41
Figure 12-32. UHF (465-495 MHz) Receiver Front End Schematic Diagram (8486634Z02-O) .........12-42
Figure 12-33. UHF (465-495 MHz) Receiver Back End Schematic Diagram (8486634Z02-O)..........12-43
Figure 12-34. UHF (465-495 MHz) Synthesizer Schematic Diagram (8486634Z02-O) .....................12-44
Figure 12-35. UHF (465-495 MHz) Voltage Controlled Oscillator Schematic
Diagram (8486634Z02-O) ............................................................................................12-45
Figure 12-36. UHF (465-495 MHz) Transmitter and Power Control Schematic
Diagram (8486634Z02-O) .................................... ... ............................................. ... .....12-46
Figure 12-37. UHF (465-495 MHz) Controller Interconnect Schematic Diagram (8486634Z02-O)....12-47
Figure 12-38. UHF (465-495 MHz) Microprocessor Circuitry Schematic Diagram (8486634Z02-O) 12-48
Figure 12-39. UHF (465-495 MHz) Audio Circuitry Schematic Diagram (8486634Z02-O).................12-49
Figure 12-40. UHF (465-495 MHz) DC Regulation Schematic Diagram (8486634Z02-O).................12-50
Figure 12-41. UHF (465-495 MHz) Keypad Board Schematic Diagram (8466565A03-B)..................12-51
Figure 12-42. UHF (465-495 MHz) Board Top Side View (8486634Z02-O).................. .... ... ... ... ....... .12-52
Figure 12-43. UHF (465-495 MHz) Board Bottom Side View (8486634Z02-O)..................................12-53
Figure 12-44. UHF (465-495 MHz) Keypad Board (8466565A03-B)..................................................12-54
Table of Contents xiii
6881096C25-B June 6, 2005
List of Tables
Table 1-1. Recommended Test Equipment.......................................................................................1-1
Table 1-2. Service Aids ..................................................................................................................... 1-2
Table 1-3. Recommended Service Tools.......................................................................................... 1-2
Table 2-1. Voltage Regulators........................................................................................................... 2-2
Table 3-1. Radio Memory Requirements........................................................................................... 3-1
Table 3-2. SPI Bus Signal Definitions................................................................................................ 3-2
Table 6-1. Troubleshooting Table for Receiver................................................................................. 6-1
Table 6-2. Troubleshooting Table for Synthesizer............................................................................. 6-3
Table 6-3. Troubleshooting Table for Transmitter............................................................................. 6-4
Table 6-4. Troubleshooting Table for Board and IC Signals ............................................................. 6-7
Table 11-1. Troubleshooting Table for Receiver...............................................................................11-1
Table 11-2. Troubleshooting Table for Synthesizer...........................................................................11-3
Table 11-3. Troubleshooting Table for Transmitter........................................................................... 11-4
Table 11-4. Troubleshooting Table for Board and IC Signals ........................................................... 11-6
Related Publications
PR400 Basic Service Manual .........................................................................................................6881096C24
PR400 Non-Display User Guide.......... ... ... .... ... ... ... ... .... ... ... ... .......................................... .... ... ... ....6881096C27
PR400 Half-Keypad User Guide.....................................................................................................6881096C26
PR400 Full-Keypad User Guide......................................................................................................6881096C23
Product Safety and RF Exposure Compliance ...............................................................................6881095C98
PR400 User Guide CDROM ..............................................................................................................HKLN4219
xiv Table of Contents
June, 2005 6881096C25-B
Chapter 1 Test Equipment, Service Aids, and
Service Tools
1.1 Test Equipment
Table 1-1 lists test equipment required to service the PR400 Radios.
Table 1-1. Recommended Test Equipment
Motorola Part No. Description Characteristics Application
R2600 series System analyzer This item will substitute for
items with an asterisk (*)
Frequency/deviation meter and
signal generator for wide-range
troubleshooting and alignment
*R1074A Fluke 87 digital multi-
meter
True RMS metering,
200 kHz frequency
counter, 32-segment bar
graph with backlit display
Digital voltmeter is recommended for AC/DC voltage and
current measurements
Fluke 85 RF probe 500 MHz, 30 VAC max Use with Fluke 87 digital multi-
meter for RF voltage measurements.
*R1377A AC voltmeter 1 mV to 300 mV, 10 mega-
ohm input impedance
Audio voltage measurements
R1611A Dual channel
100 MHz oscilloscope (Agillent)
Two-channel, 100 MHz
bandwidth, 200 M sample
rate/sec, 2 MB memory/
channel
Waveform measurements
S1339A RF millivolt meter 100 µV to 3V RF, 10 kHz to
1 GHz frequency range
RF level measurements
*R1013B or
*R1370A
SINAD meter or
SINAD meter with
RMS
Without RMS audio voltmeter or
With RMS audio voltmeter
Receiver sensitivity measurements
June, 2005 6881096C24-B
1-2 Test Equipment, Service Aids, and Service Tools: Service Aids
1.2 Service Aids
Ta b le 1- 2 lists service aids recommended for working on the PR400 Radios. While all of these items
are available from Motorola, most are standard shop equipment items, and any equivalent item
capable of the same performance may be substituted for the item listed.
Table 1-2. Service Aids
Motorola Part
No.
Description Application
RLN4460 Por table Test Set Enables connection to the audio/accessory jack.
Allows switching for radio testing.
RLN4510 Battery Interface Regulates DC current and voltage between radio and
power supply.
RVN4191 Customer Programming Soft-
ware and Global Tuner Software
on CD Rom
Program customer option and channel data.
AAPMKN4004 Programming Test Cable Connects radio to RIB (PLN4008).
AAPMKN4003 Radio-to-Radio Cloning Cable
Allows a radio to be duplicated from a master radio by
transferring programmed data from the master radio to
the other.
RLN4008 Radio Interface Box Enables communications between the radio and the
computer’s serial communications adapter.
5886564Z01 RF Adaptor Adapts radio’s antenna port to BNC cabling of test
equipment.
0180305K08 Shop Battery Eliminator Interconnects radio to power supply.
HSN9412 Wall-Mounted Power Supply Used to supply power to the RIB (120 VAC).
3080369B71 or
3080369B72
Computer Interface Cable Use B72 for the IBM PC AT or newer (9-pin serial
port). Use B71 for older models (25-pin serial port).
Connects the computer’s serial communications
adapter to the RIB (PLN4008).
6686533Z01 Knob Remover/Chassis Opener Used to remove the front cover assembly.
HKN9216 IBM Computer Interface Cable Connection from computer to RIB.
8180384N65 Housing Eliminator Allows testing of the radio outside of the housing.
Table 1-3. Recommended Service Tools
Motorola Part
No.
Description Application
RSX4043A TORX screwdriver Tighten and remove chassis screws
6680387A70 T6 TORX bit Removable TORX screwdriver bit
R1453A Digital readout solder station Digitally controlled soldering iron
RLN4062A Hot air workstation, 120 V Tool for hot air soldering/desoldering of surface
mounted integrated circuits
6881096C24-B June 6, 2005
Test Equipment, Service Aids, and Service Tools: Service Aids 1-3
0180386A78 Illuminated magnifying glass with
lens attachment
Illumination and magnification of components
0180302E51 Master lens system
0180386A82 Anti-static grounding kit Used during all radio assembly and disassembly pro-
cedures
6684253C72 Straight prober
6680384A98 Brush
1010041A86 Solder (RMA type), 63/67,
0.5mm diameter, 1 lb. spool
0180303E45 SMD tool kit (included with
R1319A)
R1319A ChipMaster (110 V) Surface mount removal and assembly of surface
mounted integrated circuits and/or rework station
shields. Includes 5 nozzles.
R1321A ChipMaster (220 V)
ChipMaster Nozzles:
6680332E83 PLCC-28* nozzle
Soldering and Un-soldering IC’s
6680332E82 PLCC-44* nozzle
6680332E94 PLCC-52 nozzle
6680332E96 PLCC-84 nozzle
6680334E67 QFP-160 nozzle
6680333E46 SOL-18 nozzle
6680332E84 SOIC-20 nozzle
6680332E87 SOL-20J nozzle
6680333E45 SOL-24 nozzle
6680333E55 TSOP-64 nozzle
* Included with ChipMaster packages
Table 1-3. Recommended Service Tools (Continued)
Motorola Part
No.
Description Application
June, 2005 6881096C24-B
1-4 Test Equipment, Service Aids, and Service Tools: Service Aids
Programming/Test Cable
Figure 1-1. Programming/Test Cable
Figure 1-2. Wiring of the Connectors
25 POSITION
FEMALE CONNECTOR
25 POSITION
MALE CONNECTOR
36.0”
CABLE
36.0”
CABLE
P1
P2 P3
P2
25 pin Male D Connector
Components molded inside
1
5
24
7
20
8
15
16
9
47
ohm
33K
+
1UF,16V 5%
Orange
Blue
White
Spiral
Yellow
P1
2.5mm stereo and
3.5mm
1
2
5
3
4
3.5mm Tip
(Speaker +)
3.5mm
Sleeve
2.5mm Tip
(Microphone)
2.5mm
2.5mm
Center
P3
25 pin Female
D Connector
1
15
4
11
1
2
3
4
5
3.5mm mono
2.5mm stereo
To Test Box
To Test Box
Chapter 2 DC Power Distribution
2.1 DC Regulation and Distribution
A block diagram of the DC power distribution throughout the radio is shown in Figure 2-1.
Figure 2-1. DC Power Distribution Block Diagram
Battery voltage enters at connector J301 and is routed through fuse F301 to become USWB+.
VR301 protects against ESD, and D301 provides reverse polarity protection. This voltage is routed
to:
• FET switch Q170 in the TX power control circuit (turned on during transmit)
• TX power amplifier module U110 (via R150)
• input pins of regulators U310, U320 and U330
• FET switch Q493 (turned on whenever the radio is on)
• on-off switch S444 (part of on-off-volume control) to become SWB+
SWB+
Fuse
Low Battery
Detect
Antenna
Switch
PA, Driver
PCIC(ALC)
LI Ion
3.3V
Reg.
Audio
Power
Amplifier
ASFIC_CMP
VCOBIC
FRACTN
LCD
Driver
5V
MECH.
SWB+
UNSWB+
Vdda
Accessories
20 pin Connector
Keypad/Option Board
Vddd
MCU, ROM
and EEPROM
Tx
Led
Control
7.5V
Battery
Vddd
Regulator
Vdda
Regulator
5V
Regulator
On/Off
Switch
RF AMP, IF AMP,
RX/TX Buffers
IFIC
June, 2005 6881096C25-B
2-2 DC Power Distribution: DC Regulation and Distribution
When the radio is turned on, SWB+ is present and is applied to:
• transistor switch Q494 (pins 1 and 6) which turns on Q4 93
• RX audio power amplifier U490
• voltage divider R420/R421 and port PE0, a microprocessor A/D input which measures battery
voltage and radio on/off status
The output of FET switch Q493 is applied to the control pins of regulators U310, U320 and U330,
turning them on. The following regulators are used:
The 5 V source is applied to:
• RX back end circuitry
• synthesizer super filter input and charge pump supply
• RED/GRN LEDs
• RX audio buffer U510
• portions of ASFIC U451
The 5 V source is also applied to FET switches Q311 and Q312. Q311 is turned on by Q313 when
RX_ENA (from U401 pin 49) is high, and supplies the "5R" source to the RF front end stages Q21Q22, and the VCO RX injection buffer Q280. Q312 is turned on by Q313 when TX_ENA (from U40 1
pin 50) is high, and supplies the "5T" source to the first transmitter stage Q100.
The digital 3.3 volt source from U320 (D_3.3 V) is applied to:
• microprocessor U401
• EEPROM U402
•S-RAM U403
• flash ROM U404
The 3 V regulated source from U330 is applied to:
• synthesizer IC U201
• VCO/buffer IC U251
• portions of ASFIC U451
• microphone bias circuitry
While the radio is turned on, port PH3 (U401 pin 44) is he ld high. When the radio is turn ed off, SWB+
is removed and port PE0 (U401 pin 67) goes low, initiating a power-down routine. Port PH3 (pin 44)
remains high, keeping the voltage regulators on via Q493 and Q494, until the operating state of the
radio has been stored in EEPROM and other turn-off data functions have been completed. PH3 then
goes low, turning off Q494 and Q493, and all regulated voltages are removed.
Table 2-1. Voltage Regulators
Reference No. Description Type
U310 5 V Regulator TK71750S
U320 Digital 3.3 V Regulator LP2986
U330 3 V Regulator TK71730S
Chapter 3 Controller Theory of Operation
3.1 Controller
The controller provides the following functions:
• interface with controls and indicators
• serial bus control of major radio circuit blocks
• encoding and/or decoding of selective signaling formats such as PL, DPL , MDC1200 a nd QuikCall II
• interface to CPS programming via the microphone connector
• storage of customer-specific information such as channel frequencies, scan lists, and signaling
codes
• storage of factory tuning parame ters such as tra nsmitter powe r and de viation, r eceiver squelch
sensitivity, and audio level adjustments
• power-up, power-down and reset routines
Figure 7-31 (VHF) shows the interconnection between the controller and the various other radio
blocks. Figure 7-37 show the connections between the following circuit areas which comprise the
controller block:
• microprocessor circuitry
• audio circuitry
• DC regulation circuitry (refer to Chapter 2, DC Regulations and Distribution.)
• rotary and pushbutton controls and switches
• option board interface
The majority of the circuitry described below is contained in the (VHF) Mi croprocessor Circuitry
schematic diagrams (Figure 7-38). Portions are also found in the Audio and DC Regulation
schematics (Figures 7-39 and 7-40).
3.1.1 Microprocessor Circuitry
The microprocessor circuitry includes microprocessor (U401) and associated EEPROM, S-RAM (not
used in PR400 models), and Flash ROM memories. The following memory IC's are used:
Table 3-1. Radio Memory Requirements
Reference No. Description Type Size
U402 Serial EEPROM AT25128 16K x 8
U403 Static RAM (not used)
U404 Flash ROM AT49LV001N_70 V 128K x 8
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3-2 Controller Theory of Operation: Controller
3.1.1.1 Memory Usage
Radio operation is controlled by software that is stored in external Flash ROM memory (U404).
Radio parameters and customer specific information is stored in external EEPROM (U402). The
operating status of the radio is maintained in RAM located within th e microprocessor . When the radio
is turned off, the operating status of the radio is written to EEPROM before operating voltage is
removed from the micropro cessor. See secti on “3.1.1.7 Microprocessor Power-Up, Power-Down and
Reset Routine” on page 3-3 for a discussion of the power-down routine.
Parallel communication with U403 and U404 is via:
• address lines A(0)-A(16), from U401 port F ADDR0-ADDR13 and port G XA14-XA16
• data lines D(0)-D(7), from U401 port C DATA0-DATA7
• chip-select for U403, from PH6 (U401 pin 41)
• chip-enable for U404, from PH7 (U401 pin 38)
• output enable for U404, from PA7 (U401 pin 86)
• write-enable for both U403 and U404, from PG7_R/W (U401 pin 4)
Serial communication with U402 is via:
• the SPI bus (see section “3.1.1.3 Serial Bus Control of Circuit Blocks” on page 3-2)
• chip-select for U402, from PD6 (U401 pin 3)
3.1.1.2 Control and Indicator Interface
Ports PI3 and PI4 are outputs which control the top-mounted LED indicator. When PI3 is high, the
indicator is red. When PI4 is high, the indicator is green. When both are high, the indicator is amber.
When both are low, the indicator is off.
Pressing the side-mounted PTT button (S441) provides a lo w to port PJ0 (U401 pin 71), which
indicates PTT is asserted. Side-mounted option buttons 1 and 2 (S442 and S443) are connected to
Ports PJ6 (pin 77) and PJ7 (pin 78), respectively.
3.1.1.3 Serial Bus Control of Circuit Blocks
The microprocessor communicates with other circuit blocks via a SPI (serial peripheral interface) bus
using ports PD2 (data into uP), PD3 (data out of uP) and PD4 (clock). The signal names and
microprocessor ports are defined in Table 3-2.
These signals are routed to:
• the audio filter IC (U451) to control internal functions such as gain change betwee n 25 kHz and
12.5 kHz channels, transmit or receive mode, volume adjustment, etc.
• the synthesizer IC U201 to load receive and transmit channel frequencies
• option board connector J460-1 for internal option configuration and control
• serial EEPROM U402 (both SPI_DATA_IN and SPI_DATA_OUT are used).
Table 3-2. SPI Bus Signal Definitions
Signal Name Microprocessor Port Microprocessor Pin
SPI-DATA_IN PD2-MISO U401 Pin 99
SPI_DATA_OUT PD3-MOSI U401 pin 100
SPI_CLK PD4-SCK U401 pin 1
6881096C25-B June, 2005
Controller Theory of Operation: Controller 3-3
In order for each circuit block to respond only to the data intended for it, each peripheral has its own
chip select (or chip enable) line. The device will only respond to data when its enable line is pulled
low by one of the microprocessor ports, as follows:
• port PD5 (U401 pin 2) for the audio filter IC
• port PH0 (U401 pin 47) for the synthesizer IC
• port PH4 (U401 pin 43) for the option board/display enable
• port PD6 (U401 pin 3) for the serial EEPROM.
3.1.1.4 Interface to RSS Programming
The radio can be programmed, or the programmed information can be read, using a computer with
CPS (Customer Programming Software) connected to the radio via a RIB (radio interface box) or
with the RIB-less cable. Connection to the radio is made via the microphone connector (part of
accessory connector J471). The SCI line connects the programming contact (J471 pin 6) to ports
PD0_RXD (data into uP, pin 97) and PD1_TXD (data out of uP, pin 98). Transistor Q410 isolates the
input and output functions by allowing PD1 to pull the line low , but does not af fect incoming data from
being read by port PD0. This isolation allows high-speed 2-wire pr ogramm ing via TP401 and TP402
for factory programming and tuning.
3.1.1.5 Storage of Customer-Specific Information
Information that has been programmed using CPS, such as channel frequencies or selective
signaling codes, are stored in the external EEPROM, where it is retained permanently (unless
reprogrammed) without needing DC power applied to the microprocessor.
3.1.1.6 Sensing of Externally-Connected Accessories
Port PJ1 is used to detect the presence of externally connecte d accessor ies. Port PJ1 (U401 pin 72)
is normally low, unless accessories (lapel speaker microphone, lightweight headset, etc.) are used
with the radio. This port is used to detect an accessory PTT or auto sensing of a VOX accessory.
If VOX is programmed into the radio channe l codeplug information, and PJ1 is high during power-u p,
the radio will activate VOX operation. If a low is present at port PJ1 during power-up, the radio will
use this port as an external PTT indicator.
3.1.1.7 Microprocessor Power-Up, Power-Down and Reset Routine
On power-up, the microprocessor is held in reset until the digital 3.3 V regulator (U320 pin 5)
provides a stable supply voltage. Once the dig ital supply reaches steady st ate and releases the re set
line (U320 pin 7), the microprocessor begins to start up. The ASFIC_CMP (U451) has already
started running and is providing the startup clock to the microprocessor. After reset release by all
circuits, the software within the microprocessor begins executing port assignments, RAM checking,
and initialization. A fixed delay of 100 ms is added to allow the audio circuitry to settle. Next, an alert
beep is generated and the steady state software begins to execute (buttons are read, radio circuits
are controlled).
When the radio is turned off, SWB+ is removed and port PE0 (U401 pin 67) goes low, initiating a
power-down routine. Port PH3 (pin 44) remains high, keeping the voltage regulators on via Q493
and Q494, until the operating state of the radio has been stored in EEPROM. PH3 then goes low,
and all regulated voltages are removed.
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3-4 Controller Theory of Operation: Controller
The microprocessor reset line (pin 94) can be controlled directly by the digital 3.3 V regulator (U320
pin 7), the microphone jack (part of accessory connector J471) via Q472 and Q471, and the
microprocessor itself. U320 pulls the reset line low if the digital 3.3 V source loses regulation. This
prevents possible MOS latch-up or overwriting of registers in the microprocessor because the reset
line is higher in voltage than the microprocessor VDD ports (U401 pins 12, 39, 59, 88). The
microprocessor can drive the reset line low if it detects a fault condition such as an expired watchdog
timer, software attempting to execute an infinite loop, unplanned hardware inputs, static discharge,
etc. Finally, the Q471 can pull the reset line low during use of the programming cable and CPS by
the application of a sufficiently negative voltage to the microphone connector tip contact (J471 pin 4),
however this reset method is not utilized.
3.1.1.8 Boot Mode Control
When power-up reset occurs, the microprocessor will boot into either normal or flash mode
depending on the logic level of ports MODA (U401 pin 58) a nd MODB (pin 57). T he Flash Adapter is
a programming accessory which provides negative 9 volts dc via a 1K resistor to microphone
connector J471 pin 4. This turns on Q471 and Q472 via D471 and VR472, pulling MODA and MODB
low and allowing booting in the flash mode by cycling power to reset the radio. Software upgrades
can then performed by loading the new software code into Flash ROM U404.
3.1.1.9 Microprocessor 7.3975 MHz Clock
The 7.3975 MHz clock signal (uP_CLK) is provided from the ASFIC_CMP (U451 pin 28). Upon
startup the 16.8MHz crystal provides the signal to the ASFIC_CMP, which sends out the uP_CLK at
3.8MHz until a steady-state condition is reached and the clock is increased to 7.3975MHz for the
microprocessor.
3.1.1.10 Battery Gauge
Various battery types are available having different capacities. The different battery types contain
internal resistors connected from the BATT_CHARGE contact to ground (which is routed to the
microprocessor as BATT_DETECT). A voltage divider is formed with R255 producin g a different DC
voltage for each battery type, which is read by microprocessor port PE2 (pin 65). This allows the
software to recognize the battery chemistry being used and adjust the battery gauge fo r best
accuracy.
3.1.2 Audio Circuitry
3.1.2.1 Transmit and Receive Low-Level Audio Circuitry
The majority of RX and TX audio processing is performed by U451, the Audio Filter IC
(ASFIC_CMP), which provides the following functions:
• Tone PL/Digital PL encode and decode filtering
• Tone PL/Digital PL rejection filter in RX audio path
• TX pre-emphasis amplifier
• TX audio modulation limiter
• Post-limiter (splatter) filter
• TX deviation adjust (digitally-controlled attenuators)
• Programmable microphone gain attenuator
• RX audio volume control (digitally controlled attenuator)
• Carrier squelch adjustment (digitally controlled attenuator)
• Microprocessor output port expansion
6881096C25-B June, 2005
Controller Theory of Operation: Controller 3-5
• 2.5 volt dc reference source
• Microprocessor clock generation (from the 16.8 MHz reference oscillator input)
The parameters of U451 that are programmable are selected by the microprocessor via the CLOCK
(U451 pin 21), DATA (U451 pin 22) and chip enable (U451 pin 20) lines.
RX audio buffer U510 amplifies the audio level from the DEMOD output of the IFIC before being
applied to the audio filter IC input (DISC, U451 p in 2). The buffer is DC coupled to avoid corruption of
low-frequency data waveforms such as DPL. Because such waveforms are polarity sensitive, this
buffer is configured as a single-stage inverting amplifier (U510-1 only) for VHF models where highside first injection is used, or is configured as a two-stage non-inver ting amplifie r (U510-1 and -2 ) for
UHF models using low-side first injection. The gain of the buffer is 1.5 times or 3.5 dB.
Volume adjustment is performed by a digital attenuator within U451. The volume control (10KO, part
of S444) is connected to D_3.3 V and ground via R506 and R507. When the volume control is
rotated, it varies the dc volt age applie d to micr oprocessor A/D input por t PE1 (U4 01 pin 66) between
approximately 0 volts dc at minimum volume to 3.3 volts dc at maximum volume. Depending on this
voltage, the appropriate setting of the digital volume attenuator is selected. This technique is less
susceptible to noise than a conventional analog volume control.
3.1.2.2 Audio Power Amplifier
The audio power amplifier IC U490 amplifies receiver audio from U451 pin 41 to a level sufficient to
drive a loudspeaker. U490 is a bridge amplifier delivering 3.46 volts rms between pins 5 and 8
without distortion, which is sufficient to develop 500 milliwatts of audio power into the internal 24 ohm
speaker or an external 24 ohm load. The audio power amplifier is muted whenever speaker audio is
not required to reduce current drain. The audio amp is muted when U451 pin 14 is low. When U451
pin 14 is high, U490 pin 1 is pulled low by Q490, enabling the audio amplifier.
Because the power amplifier is a bridge-type, neither speaker terminal is gro unded. Care should be
taken that any test equipment used to measure the speaker audio voltage does not ground either
speaker output terminal, otherwise damage to the audio power amplifier IC may result. When a 24ohm load resistor is used it should be connected between the tip and the sleeve of accessory jack
J471 (3.5mm port), never to ground. External SPKR plug insertion mechanically disconnects the
internal speaker. Voltage measurements using test equipment that is not isolated from ground may
be made from one side of the speaker or load r esistor (either the tip or the sle eve of J471) to chassis
ground, in which case the voltage indicated will be one half of the voltage applied to the speaker or
load resistor . The Motorola RLN44 60 Port able Test Set and AAPMKN4004 Programming Test Cable
provide the proper interface between the radio's ungrounded audio output and ground-referenced
test equipment.
3.1.2.3 Internal Microphone Audio Voice Path
Microphone audio from internal microphone is routed from J470-1 via C475, L471, and C470 to the
ASFIC_CMP mic audio input (MICINT, U451 pin 46). During transmit, Q470 is turned on by a low at
U451 pin 35, providing dc bias for the internal MIC via R478. External MIC plug insertion
mechanically disconnects the internal microphone. External MIC audio is coupled through L4 71 and
C470 to the mic audio input. An input level of 10 mV at J471 pin 4 produces 200 mV at the output of
U451 pin 40, which corresponds to 60% deviation.
3.1.2.4 PTT Circuits
The internal side-mounted PTT switch (S441) is sensed directly by microprocessor port PJ0 (U401
pin 71). External mic PTT is sensed by measuring the current drawn through the accessory
connector (J471-4) by the mic cartridge (which is in series with the accessory PTT switch). This
current is drawn through the base (pin 5) and emitter (pin 4) of a transistor in Q470, causing its
collector (pin 3) to supply a logic-high to microprocessor port PJ1 (pin 72).
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3-6 Controller Theory of Operation: Controller
3.1.2.5 VOX Operation
VOX audio accessories do not have a PTT switch. Instead, the mic cartridge is wired directly from
J471-4 to ground. If the radio has been programmed for VOX operation an d the VOX accessory is
plugged in prior to turning the radio on, the current drawn by the cartridge will turn on Q470 (pins 34-5) and a logic high will be seen at port PJ1 at turn-on. The microprocessor then assumes VOX
operation, with PTT controlled by the presence of audio at the mic cartridge. A dc voltage
proportional to the audio level at the input of the ASFIC_CMP (U451 pin 46) is fed to a n A/D in put of
microprocessor U401 (pin 62). During VOX operation, PT T is activate d whe n the dc leve l exceeds a
preset threshold.
3.1.2.6 Battery Charging Through Microphone Jack
A wall-type charging power supply may be connected to the 2.5 mm microphone jack (p art of
accessory connector J451). The voltage present at the tip contact (pin 4) is app lied to the center
charging contact of the battery via diode D470. Another diode, internal to the battery, applies this
voltage to the (+) battery terminal. Only the recommended charger and battery type should be
charged in this manner.
Different battery types contain internal resistors connected from the BATT_CHARGE contact to
ground, which is routed to the microprocessor as BATT_DETECT. A voltage divider is formed with
R255 producing a DC voltage which is read by microprocessor port PE2 (pin 65). This allows the
software to recognize the battery chemistry being used and adjust the battery gauge fo r best
accuracy. The value of R255 is chosen so that the voltage at the BATT_CHARGE node (cathode of
D470) is never low enough to turn on the EXT_MIC_PTT sense transistor (part of Q470).
3.1.2.7 Programming and Flashing Through Microphone Jack
The ring contact on the 2.5 mm microphone jack is used for reading, pr ogramming or re-flashing the
radio using CPS. This contact (J471 pin 6) is routed to port s PD0_RXD (data into uP, pin 97) and
PD1_TXD (data out of uP, pin 98). Transistor Q410 isolates the input and output functions by
allowing PD1 to pull the line low, but does not affect incoming data from being read by port PD0.
To re-flash the radio (overwrite the software in the Flash ROM with new software), the radio must
power up in the boot mode. This is accomplished by using a flash adapter acce ssory, which provides
SCI communication with the programming ring contact (J471 pin 6) and also allows a negative
voltage (negative 9 volts dc via a 1K resistor) to be applied to the tip contact (J471 pin 4). This
voltage is sufficient to turn on the base-emitter junction (pins 1 and 2) of Q472 via L471, D471,
VR472 and R471. Pin 6 of Q472 goes high, turning on Q471 (pins 3 and 4) and pulling the
BOOT_ENA line (ports MODA and MODB of the microprocessor) low. Cycling power generates a
reset which causes the radio to boot in the flash mode.
Chapter 4 136-162 MHz VHF Theory Of Operation
4.1 Introduction
This chapter provides a detailed theory of operation for the radio components. Schematic diagrams
for the circuits described in the following paragraphs are located in Chapter 7 of this manual.
4.2 VHF Receiver
The VHF receiver covers the range of 136-162 MHz and provides switchable IF bandwidth for use
with 12.5 kHz or 20/25 kHz channel spacing systems. The receiver is divided into two major blocks as
shown in Figure 4-1.
•Front End
• Back End
Figure 4-1. VHF Receiver Block Diagram
4.2.1 Receiver Front-End
Incoming RF signals from the antenna are first routed throug h the harmonic filter and ante nna switch,
part of the transmitter circuitry, before being applied to the receiver front end. The receiver front end
consists of a preselector filter, RF amplifier, an interstage filter, and a double-balanced first mixer.
The preselector filter is a fixed-tuned 4-pole design using discrete elements (L1-L4 and C1-C9) in a
series/shunt resonator configuration. It has a 3 dB bandwidth of 43 MHz, an in sertion loss of 2 dB and
image attenuation of 37 dB at 226 MHz, with increasing attenuation at higher frequencies. Diode CR1
protects the RF amplifier by limiting excessive RF levels.
The output of the filter is matched to the base of RF amplifier Q21, which provides 18 dB of gain and
a noise figure of 2 dB. Operating voltage is obtained from the 5R source, which is turned off during
transmit to reduce dissipation in Q21. Current mirror Q22 maintains the operating current of Q21
Demodulator
Crystal
Filter
1st Mixer
RF
Amp
IF
Amp
Preselector
Filter
Interstage
Filter
Recovered Audio
RSSI
RX from
Antenna Switch
Inj Filter
First LO
from Synthesizer
Ceramic
Resonator
Cer Fltr
Switching
4E
6E
6G
BW_SEL
June, 2005 6881096C25-B
4-2 136-162 MHz VHF Theory Of Operation: VHF Receiver
constant at 6.2 mA regardless of device and temperature variations, for optimum dynamic range and
noise figure.
The output of the RF amplifier is applied to the interstage filter, a fixed-tuned 3-pole series-coupled
resonator design having a 3 dB bandwidth of 54 MHz and insertion loss of 1.8 dB. This filter has an
image rejection of 40 dB at 226 MHz, with increasing attenuation at higher frequencies.
The output of the interstage filter is connected to the passive double-balanced mixer consisting of
components T41, T42, and CR41. This mixer has a conversion loss of 7 dB. High-side injection from
the frequency synthesizer is filtered by L40-L41 and C40-C44 to remove second harmonic energy
that may degrade half-IF spurious rejection performance. The injection filter has a 3 dB bandwidth of
52 MHz and an insertion loss of 1.5 dB. The filtered injection signal is applied to T42 at a level of +6
dBm.
The mixer output is applied to a diplexer network (L51-L52, C51, R51) which ma tches the 44 .85 MHz
IF signal to crystal filter FL51, and terminates the mixer into 50Ω at all other frequencies
4.2.2 Receiver Back-End
The receiver back end is a dual conversion design. High IF selectivity is provided by FL51, a 4-pole
fundamental mode 44.85 MHz crystal filter with a minimum 3 dB bandwidth of + 6.7 kHz, a maximum
20 dB bandwidth of ±12.5 kHz, and a maximum insertion loss of 3.5 dB. The output is matched to IF
amplifier stage Q51 by L53 and C93. Q5 1 provides 16 dB of gain and a noise figure of 1.8 dB. The dc
operating current is 1 mA. The output of Q51 is applied to the input of the receiver IFIC U51. Diode
CR51 limits the maximum RF level applied to the IFIC.
The IFIC is a low-voltage monolithic FM IF system incorporating a mixer/oscillator, two limiting IF
amplifiers, quadrature detector, logarithmic received signal strength indicator (RSSI), voltage
regulator and audio and RSSI op amps. The second LO frequency, 44.395 MHz, is determined by
Y51. The second mixer converts the 44.85 MHz high IF frequency to 455 kHz.
Additional IF selectivity is provided by two ceramic filters, FL52 (between the second mixer and IF
amp) and FL53 or FL54 (between the IF amp and the limiter input). The wider filter FL53 is used for
20/25 kHz channel spacing, and the narrower filter FL54 is used for 12.5 kHz channels. When the
BW_SEL line is high, the two upper diodes in packages D51 and D52 are forward biased, selecting
FL53 for 20/25 kHz channels. When the BW_SEL line is low, the two lower diodes in packages D51
and D52 are forward biased, selecting FL54 for 12.5 kHz channels.
Ceramic resonator Y70 provides phase vs. frequency characteristic required by the quadrature
detector, with 90 degree phase shift occurring at 455 kHz. Buffer Q70 pr ovides a lower driving
impedance from the limiter to the resonator, improving the IF waveform and lowering the distortion of
the recovered audio signal. The recovered audio level at the DEMOD output is 120 mV rms (25 kHz
channel, 3 kHz deviation) or 60 mV rms (12.5 kHz chan n el, 1. 5 kHz devia tio n) . An ad dit ion a l RSSI
output provides a DC voltage level that is proportio nal to RF signal level. This volt age is measured by
an A/D converter contained in the microprocessor (PE4_AN4, U401 pin 63).
FL52 FL53 FL54
Number of Elements: 4 6 6
Insertion Loss: 4 dB 4 dB 4 dB
6 dB Bandwidth: 15 kHz 15 kHz 9 kHz
50 dB Bandwidth: 30 kHz 30 kHz 22 kHz
Stopband Rejection: 27 dB 47 dB 47 dB
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