UBS Axcera LHV66ATD Users Manual

Instruction Manual

Innovator,

LX Series

Digital VHF

Transmitter

w/DM8

AXCERA, LLC

103 FREEDOM DRIVE, P.O. Box 525 LAWRENCE, PA 15055-0525 USA

[phone] • FAX [phone]

www.axcera.com • [e-mail]

Digital VHF Transmitter w/DM8 Table of Contents

TABLE OF CONTENTS

CHAPTER 1 INTRODUCTION
SECTION PAGE

1.1 Manual Overview...................................................................................1-1

1.2 Assembly Designation Numbers ..............................................................1-1

1.3 Safety..................................................................................................1-2

1.4 Contact Information ......................................................................... 1-2

1.5 Material Return Procedure......................................................................1-2

1.6 Limited One Year Warranty for Axcera Products........................................1-3

CHAPTER 2 SY ST E M DE SC RIPTION & RE MOT E CO NT RO L CO NNE CT I O N S

2.1 System Overview ..................................................................................2-1

2.2 Exciter Amplifier Chassis Assembly..........................................................2-1

2.2.1: DM8 Modulator Assembly.............................................................2-2

2.2.2: IF Processor Module ....................................................................2-2

2.2.3: VHF/UHF Upconverter Module ......................................................2-4

2.2.4: Control & Monitoring/Power Supply Module....................................2-5

2.2.5: Power Amplifier Module, VHF HB ..................................................2-6

2.2.6: Or Power Amplifier Module, VHF LB...............................................2-7

2.3: RF Output Assemblies...........................................................................2-9

2.4: Control and Status ...............................................................................2-9

2.4.1: Front Panel LCD Display Screen....................................................2-9

2.5: System Operation ................................................................................2-9

2.5.1: Principles of Operation.................................................................2-9

2.6: Maintenance...................................................................................... 2-11

2.7: Customer Remote Connections...................................................... 2-11

CHAPTER 3 : SITE CONSIDER A TI O N S , IN S T AL L ATI ON AND SETU P P ROCEDURES

3.1: Site Considerations ..............................................................................3-1

3.2: Unpacking the Chassis w/Modules..........................................................3-4

3.3: Installing the Chassis w/Modules ...........................................................3-5

3.4: AC Input .............................................................................................3-6

3.5: Setup and Operation ............................................................................3-6

3.5.1: Input Connections.......................................................................3-6

3.5.2: Initial Turn On ............................................................................3-8

3.5.2.1: DM8 Digital Modulator Module LEDs on Front Panel ...............3-8

3.5.2.2: IF Processor Module LEDs on Front Panel .............................3-8

3.5.2.3: VHF/UHF Upconverter Module LEDs on Front Panel................3-8

3.5.2.4: Controller Module LEDs on Front Panel.................................3-8

3.5.2.5: Power Amplifier Module LEDs on Front Panel.........................3-8

3.5.3: Front Panel Screens for the Exciter/Amplifier Chassis Assembly .......3-9

3.5.4: Operational Procedure ............................................................... 3-18

CHAPTER 4 : CI RC UI T DES C RI PT I O N S

4.1: DM8 Digital Modulator Module ...............................................................4-1

4.1.1: Digital Modulator Board ...............................................................4-1

4.1.1.1: SMPTE-310 Input...............................................................4-1

4.1.1.2: Channel Coder...................................................................4-1

LX Series, Digital, Rev. 4 January 14, 2009

i

Digital VHF Transmitter w/DM8 Table of Contents

TABLE OF CONTENTS - (Continued)

S ECTION PAGE

4.1.1.3: Analog Output Section........................................................4-1

4.1.1.4: Pilot Frequency Generation .................................................4-2

4.1.1.5: Voltage Requirements........................................................4-2

4.1.2: VSB Front Panel Board ................................................................4-2

4.2: IF Processor Module .............................................................................4-2

4.2.1: IF Processor Board......................................................................4-2

4.2.1.1: DM8 Modulator Selected.....................................................4-3

4.2.1.2: External Modulated IF Selected ...........................................4-3

4.2.1.3: Main IF Signal Path (Part 1 of 3)..........................................4-3

4.2.1.4: Input Level Detector Circuit ................................................4-3

4.2.1.5: Pin Diode Attenuator Circuit................................................4-4

4.2.1.6: Main IF Signal Path (Part 2 of 3)..........................................4-5

4.2.1.7: Amplitude and Phase Pre Correction Circuits.........................4-5

4.2.1.8: Main IF Signal Path (Part 3 of 3)..........................................4-6

4.2.1.9: ALC Circuit........................................................................4-7

4.2.1.10: Fault Command ...............................................................4-7

4.2.1.11: ±12 VDC Needed to Operate the Board..............................4-8

4.3: VHF/UHF Upconverter Module ...............................................................4-8

4.3.1: Downconverter Board..................................................................4-8

4.3.2: L-Band PLL Board .......................................................................4-8

4.3.3: First Conversion Board ................................................................4-9

4.3.4: Upconverter Control Board...........................................................4-9

4.4: Control Monitoring/Power Supply Module.............................................. 4-10

4.4.1: Power Protection Board ............................................................. 4-10

4.4.2: Control Board ...........................................................................4-11

4.4.2.1: Schematic Page 1............................................................ 4-11

4.4.2.2: Schematic Page 2............................................................ 4-12

4.4.2.3: Schematic Page 3............................................................ 4-12

4.4.2.4: Schematic Page 4............................................................ 4-13

4.4.2.5: Schematic Page 5............................................................ 4-13

4.4.3: Switch Board............................................................................ 4-13

4.4.4: Switching Power Supply Assembly ..............................................4-14

4.5: Power Amplifier Module Assembly, VHF High Band.................................4-14

4.5.1: 25 Watt VHF Driver Pallet .......................................................... 4-14

4.5.2: 200 Watt VHF Amplifier Assembly...............................................4-14

4.5.3: Coupler Board Assembly............................................................4-15

4.5.4: Amplifier Control Board .............................................................4-15

4.5.4.1: Schematic Page 1............................................................ 4-15

4.5.4.2: Schematic Page 2............................................................ 4-16

4.5.4.3: Schematic Page 2, Current Monitoring Circuits....................4-16

4.5.4.4: Schematic Page 3............................................................ 4-16

4.6: Or Power Amplifier Module Assembly, VHF Low Band............................. 4-17

4.6.1: 25 Watt VHF Driver Pallet .......................................................... 4-17

4.6.2: 200 Watt VHF Amplifier Assembly...............................................4-17

4.6.3: Coupler Board Assembly............................................................4-18

4.6.4: Amplifier Control Board .............................................................4-18

4.6.4.1: Schematic Page 1............................................................ 4-18

4.6.4.2: Schematic Page 2............................................................ 4-18

4.6.4.3: Schematic Page 2, Current Monitoring Circuits....................4-19

4.6.4.4: Schematic Page 3............................................................ 4-19

LX Series, Digital, Rev. 4 January 14, 2009

ii

Digital VHF Transmitter w/DM8 Table of Contents

TABLE OF CONTENTS - (Continued)

CHAPTER 5: DETAILED ALIGNMENT PROCEDURES
S ECTION PAGE

5.1: System Preparation..............................................................................5-1

5.1.1: Module Replacement ...................................................................5-1

5.1.2: Initial Test Set Up.......................................................................5-1

5.2: LX Series Exciter/Amplifier Chassis Assembly..........................................5-1

5.2.1: IF Processor Module Assembly......................................................5-2

5.3: Setting up the drive level of the transmitter............................................5-2

5.3.1: Setting up the Manual AGC..........................................................5-2

5.3.2: Setting up the Auto AGC..............................................................5-2

5.4: Changing the transmitter channel procedure...........................................5-3

5.5: Calibration of Output & Reflected Power for transmitter............................5-4

5.5.1: Calibration of Output Power .........................................................5-4

5.5.2: Calibration of Reflected Power......................................................5-4

5.6: Setting ALC Gain, AGC1, AGC2 and AGC Cutback ....................................5-4

5.7: Linearity Correction Adjustment.............................................................5-5

5.8: Frequency Response Delay Equalization Adjustment................................5-7

APPENDIX

APPENDIX A DRAWINGS
APENNDIX B SPECIFICATIONS

LX Series, Digital, Rev. 4 January 14, 2009

iii

Digital VHF Transmitter w/DM8 Table of Contents

LIST OF FIGURES

FIGURE PAGE

1-1: Brady Marker Identification Drawing.................................................1-1

2-1: Digital LX Series Front View Trays and Assemblies.............................2-1

2-2: Rear View LX Series Exciter Chassis Assembly................................. 2-11

3-1: 1 kW Minimum Ventilation Configuration ..........................................3-4

3-2: Tray Slide Cabinet Mounting Diagram...............................................3-5

3-3: Front and Rear View Reconnection Drawing ......................................3-5

3-4: AC Input Box Assembly...................................................................3-6

3-5: Rear View of Exciter Driver..............................................................3-7

5-1: Typical 6 MHz Digital Spectrum........................................................5-6

LX Series, Digital, Rev. 4

iv

Digital VHF Transmitter w/DM8 Table of Contents

LIST OF TABLES

TABLE PAGE

2-1: Digital LX Series Modules and Assemblies .........................................2-1

2-2: DM-8 Status Indicators...................................................................2-2

2-3: DM-8 Sample.................................................................................2-2

2-4: DM-8 Alignment Port ......................................................................2-2

2-5: IF Processor Front Panel Switch .......................................................2-3

2-6: IF Processor Front Panel Status Indicators ........................................2-3

2-7: IF Processor Front Panel Control Adjustments ...................................2-4

2-8: IF Processor Front Panel Sample......................................................2-4

2-9: VHF/UHF Upconverter Front Panel Switch .........................................2-5

2-10: VHF/UHF Upconverter Front Panel Status Indicators...........................2-5

2-11: VHF/UHF Upconverter Front Panel Control Adjustments......................2-5

2-12: VHF/UHF Upconverter Front Panel Samples.......................................2-5

2-13: Controller/Power Supply Front Panel Display.....................................2-6

2-14: Controller/Power Supply Front Panel Status Indicators .......................2-6

2-15: Controller/Power Supply Front Panel Control Adjustments ..................2-6

2-16: HB Power Amplifier Front Panel Status Indicators ..............................2-7

2-17: HB Power Amplifier Front Panel Control Adjustments..........................2-7

2-18: HB Power Amplifier Front Panel Sample ............................................2-7

2-19: LB Power Amplifier Front Panel Status Indicators...............................2-8

2-20: LB Power Amplifier Front Panel Control Adjustments ..........................2-8

2-21: LB Power Amplifier Front Panel Sample.............................................2-8

2-22: LX Series Exciter Driver Customer Remote Connections.......... 2-12

3-1: Rear Chassis Connections for LX Series Digital Exciter/Driver..............3-7

Digital Exciter/Driver System Controller Screens

3-2: Menu 01 Splash Screen #1 .............................................................3-9

3-3: Menu 02 Splash Screen #2 .............................................................3-9

3-4: Menu 10 Main Screen ...................................................................3-10

3-5: Menu 11 Error List Access Screen .................................................. 3-10

3-6: Menu 12 Transmitter Device Data Access Screen.............................3-10

3-7: Menu 13 Transmitter Configuration Access Screen........................... 3-10

3-8: Menu 20 Error List Display Screen..................................................3-11

3-9: Menu 30 Transmitter Device Details Screen..................................3-11

3-10: Menu 30-1 System Details Screens..............................................3-11

3-11: Transmitter Device Parameters Detail Screens..............................3-11

3-12: Menu 40 Authorized Personnel Screen .........................................3-13

3-13: Menu 40-1 Transmitter Set Up: Power Control Screen ................... 3-13

3-14: Menu 40-2 Transmitter Set Up: Model Select Screen .....................3-14

3-15: Menu 40-3 Transmitter Set Up: Upconverter Channel Select Screen 3-14

3-16: Menu 40-4 Transmitter Set Up: Serial Address Screen ...................3-14

3-17: Menu 40-6 Transmitter Set Up: System Forward Power Cal. Screen.3-14
3-18: Menu 40-6 Transmitter Set Up: System Reflected Power Cal. Screen.3-14

3-19: Menu 40-7 Transmitter Set Up: Fwrd Pwr Fault Threshold Screen...... 3-15

3-20: Menu 40-8 Transmitter Set Up: Refl Power Fault Threshold Screen.... 3-15

3-21: Menu 40-10 Transmitter Set Up: Auto Standby Control Screen ......... 3-15

3-22: Menu 40-12 Transmitter Set Up: Inner Loop Gain Control Screen...... 3-15

3-23: Menu 40-13 Transmitter Set Up: Optional System Control Screen .....3-16

3-24: Menu 40-14 Transmitter Set Up: DM 8 Optional Mode Control...........3-16

3-25: Menu 40-15 Transmitter Set Up: DM 8 Source Select Control............3-16

3-26: Menu 40-16 Transmitter Set Up: DM 8 Nonlinear Correction Control..3-16
3-27: Menu 40-16 Transmitter Set Up: DM 8 Fixed Table Selection Control.3-16

LX Series, Digital, Rev. 4

v

Digital VHF Transmitter w/DM8 Chapter 1, Introduction

Chapter 1

Introduction

1.1: Manual Overview

This manual explains the installation,
setup, alignment, and maintenance
procedures for the LX Series modular
Digital VHF transmitter.

This inst ruction man ua l i s d iv id e d in to five
chapters and a supporting appendix.
Chapter 1, Introduction, contains
information on the assembly numbering
system used in the manual, safety,
maintenance, return procedures, and
warranties. Chapter 2, system
descrip t io n , m a in t e n a nc e a n d r em o te
control connections, descr ibes the
transmitter and includes discussions on
system control and status indicators,
maintenance and remote control
connections. Chapter 3, site
consideration s , installat i o n an d setup
procedures, explains how to unpack,
install, setup, and operate the transmitter.
Chapter 4, circuit descriptions, contains
circuit - le v el descrip t io n s fo r boards and
board-level compo ne nt s in t he
transmitter. Chapter 5, Detailed
Alignment Procedures, provides
inform a t io n on a d ju s t in g t h e s y s te m
assemblies for opt im a l o p eration.
Appendix A contains drawings and parts
lists.

1.2: Assembly Designators

Axcera has assigned assembly number s,
Ax designations such as A1, where
x=1,2,3…etc, to all assemb lie s, mo dule s,
and boards in the system. These
designations are referenced in the text of
this man ua l a n d shown on the b lo c k
diagrams and interconnect drawings

provided in the app e n d ices. The Blo ck
Diagrams, Interconnects, Schematics,
Assembly Drawings and Parts Lists are
arrange d in increasing nu m erical ord e r in
the appendices. Section titles in the text
for assembly or module descriptions or
alignment procedures contain the
associated part number(s) and the
relevant appendix that contains the
drawings for that item.

The cables that connect between the
boards within a tray or assembly and
that connect between the trays, racks
and cabinets are labeled using Brady
markers. Figure 1-1 is an example of a
Brady marked cable. There may be as
few as two or as many as four Markers
on any one cable. These Brady markers
are read starting furthest from the
connector. If there are four Brady
Markers, this marker is the transmitter
number such as transmitter 1 or
transmitter 2. The next or the furthest
Brady Marker is the rack or cabinet
number on an interconnect cable or the
board number within a tray. The next
number on an interconnect cable is the
Tray location or number. The Brady
marker closest to the connector is the
jack or connector number on an
interconnect cable or the jack or
connector number on the board within a
tray.

Figure 1-1: Brady Marker Identification
Drawing

LX Series, Digital, Rev. 4 1-1

Digital VHF Transmitter w/DM8 Chapter 1, Introduction

1.3: Safety

The VHF transmitter syste ms
manufactured by Axcera are designed to
be easy to use and rep a ir wh ile provid ing
protection from electrical and mechanical
hazards. Please review the following
warnings and fa mil ia r iz e yo u rself with the
operation and servicing procedures
before working on the transmitter
system.

Read All safet y Instructions – All o f
the safety instructions should be read
and unde rstood be fo r e ope r a t in g th is
equipment.

Retain Manuals – The manuals for the
transmitter should be retained at the
transmitter site for future reference.
Axcera provides two sets of manuals for
this purpose; one set can be left at the
office while one set can be kept at the
site.

Heed all Notes , Warnings, and
Cautions – All of the notes, warnings,

and caut ions liste d in t his safety se c t io n
and throughout the manual must be
followed.

Follow Operating In stru cti ons – A ll o f
the opera t ing a nd us e in s t r uc tions for the
transmit t e r s ho uld b e followed.

Cleaning – Unplug or otherwise
disconnect all power from the equipment
before cleaning. Do not use liquid or
aerosol cleaners. Use a damp cloth for
cleaning.

Ventilation – Openings in t he cabinet
and module front pa nels are prov id e d f or
ventilat io n . To e nsu r e th e re lia b le
operation of the driver/transmitter, and
to protect the unit from overheating,
these openings must not be blocked.

Servicing – Do not attempt to service
this product yourself until becoming
familiar with the equipment. If in doubt,
refer all s e r v icing quest io n s t o q u a lif ie d
Axcera service personnel.

Replacemen t Pa r ts – When
replacement parts are used, be sure that
the parts have the same functional and
performance characteristics as the
original part. Unauthorized substitutions
may result in fir e, electric shock, or other
hazards. Please contac t the Axce ra
Technical Service Department if you have
any questions regarding service or
replacement parts.

1.4: Contact Information

The Axcera Field Service Department can
be contacted by phone a t 1-724-873-
8100 or by fax at 1-724-873-8105.

Before calling Axcera, please be pre pared
to supply the Axcera te chn ician w it h
answers to the following questions. This
will save time and help ensure the most
direct resolution to the problem.

1. What are the Customers’ Name
and call letters?

2. What are the model number and
type of transmitter?

3. Is the transmitter digital or
analog?

4. How long has the transmitter
been on the air? (Approximately
when was the transmitter
installed.)

5. What are the symptoms being
exhibited by the transmitter?
Include the current control/power
supply LCD readings and the
status of LEDs on the front
panels of the modules. If
possible, include the
control/power supply LCD
readings before the problem
occurred.

1.5: Return Material Procedure

To insure the efficient handling of
equipment or components that have been
returned for repair, Axcera requests that
each returned item be a cc ompan ied by a
Return Material Authorization Number
(RMA#).

LX Series, Digital, Rev. 4 1-2

Digital VHF Transmitter w/DM8 Chapter 1, Introduction

The RMA# can be obtained from any
Axcera Field Service Engineer by
contacting the Axcera Field Service
Department at [phone] or by fax
at [phone]. Th is pr oc e dure
applies to all items sent to the Field
Service Department regardless of
whether the item was originally
manufactured by Axcera.

When equipment is sent to the field on
loan, the RMA# is included with the unit.
The RMA# is intended to be used when
the unit is returned to Axcera. In
addition, all shipping mater ial shou ld be
retained for the return of the unit to
Axcera.

Replacement assemblies are also sent
with the RMA# to allow for the proper
routing of the exchanged hardware.
Failure to close out this ty pe o f RMA# will
normally result in the customer being
invoiced for the value of the loaner item
or the exchanged assembly.

When shipping an item to Axcera, please
include the RMA# on the packing list and
on the shipping container. The packing
slip should also inc lude c ontac t
information and a brief description of why
the unit is being returned.

Please forward all RMA items to:

AXCERA, LLC
103 Freedom Drive
P.O. Box 525
Lawrence, PA 15055-0525 USA

For more information concerning this
procedure, call the Axcera Field Service
Department @ (724) 873-810 0.
Axcera can also be co ntac ted thr o ug h e­mail at [e-mail] and on the
Web at www.axcera.com.

1.6: Limited One Year Warranty for
Axcera Products

Axcera warrants each new product that
it has manufactured and sold against

defects in material and workmanship
under normal use and service for a
period of one (1) year from the date of
shipment from Axcera's plant, when
operated in accordance with Axcera's
operating instructions. This warranty
shall not apply to tubes, fuses,
batteries, bulbs or LEDs.

Warranties are valid only when and if
(a) Axcera receives prompt written
notice of breach within the period of
warranty, (b) the defective product is
properly packed and returned by the
buyer (transportation and insurance
prepaid), and (c) Axcera determines, in
its sole judgment, that the product is
defective and not subject to any misuse,
neglect, improper installation,
negligence, accident, or (unless
authorized in writing by Axcera) repair
or alteration. Axcera's exclusive liability
for any personal and/or property
damage (including direct, consequential,
or incidental) caused by the breach of
any or all warranties, shall be limite d to
the following: (a) repairing or replacing
(in Axcera's sole discretion) any
defective parts free of charge (F.O.B.
Axcera’s plant) and/or (b) crediting (in
Axcera's sole discretion) all or a portion
of the purchase price to the buyer.

Equipment furnished by Axcera, but not
bearing its trade name, shall bear no
warranties other than the special hour s­of-use or other warranties extended by
or enforceable against the manufacturer
at the time of delivery to the buyer.

NO WAR R ANTIE S, WHETH ER
STATUTORY, EXPRESSED, OR
IMPLIED, AND NO WARRANTIES OF
MERCHANTABIL IT Y, FIT NE SS FOR
ANY PARTICULAR PURPOSE, OR
FREEDOM FROM INFRINGEMENT,
OR THE LIKE, OTHER THAN AS
SPECIFIED IN PATENT LIABILITY
ARTICLES, AND IN T H IS AR T ICLE,
SHALL APPLY TO THE EQUIPMENT
FURNISHED HEREUNDER.

LX Series, Digital, Rev. 4 1-3

Digital VHF Transmitter w/DM8 Chapter 1, Introduction

!

! WARNING!!!

!!

"""" HIGH VOLTAGE ####

DO NOT ATTEMPT TO REPAIR OR TROUBLESHOOT THIS EQUIPMENT UNLESS
YOU ARE FAMILIAR WITH ITS OPERATION AND EXPERIENCED IN
SERVICING HIGH VOLTAGE EQUIPMENT. LETHAL VOLTAGES ARE PRESENT
WHEN POWER IS APPLIED TO THIS SYSTEM. IF POSSIBLE, TURN OFF
POWER BEFORE MAKING ADJUSTMENTS TO THE SYSTEM.

$$$$ RADIO FREQUE NCY RAD IAT ION HAZ ARD $$$$

MICROWAVE, RF AMPLIFIERS AND TUBES GENERATE HAZARDOUS RF
RADIATION THAT CAN CAUSE SEVERE INJURY INCLUDING CATARACTS,
WHICH CAN RESULT IN BLINDNESS. SOME CARDIA C PACEMAKERS MAY BE
AFFECTED BY THE RF ENERGY EMITTED BY RF AND MICROWAVE
AMPLIFIERS. NEVER OPERATE THE TRANSMITTER SYSTEM WITHOUT A
PROPERLY MATCHED RF ENERGY ABSORBING LOAD ATTACHED. KEEP
PERSONNEL AWAY FROM OPEN WAVEGUIDES AND ANTENNAS. NEVER
LOOK INTO AN OPEN WAVEGUIDE OR ANTENNA. MONITOR ALL PARTS OF
THE RF SYSTEM FOR RADIATION LEAKAGE AT REGULAR INTERVA LS.

LX Series, Digital, Rev. 4 1-4

Digital VHF Transmitter w/DM8 Chapter 1, Introduction

EMERGENCY FIRST AID INSTRUCTIONS

Personnel engaged in the installation, operation, or maintenance of this equipment are urged to become
familiar with the follo wing rules both in theory and p ractice. It is the duty of all op erating personnel to be
prepared to give adequate Emergency First Aid and thereby prevent avoidable loss of life.

RESCUE BREATHING

1. Find out if the person is
breathing.

You must find out if the person
has stopped breathing. If you
think he is not breathing, place
him flat on his back. Put your e ar
close to his mouth and loo k at his
chest. If he is breathing y ou can
feel the air on your cheek. You
can see his chest move up and
down. If you do not feel the air
or see the chest move, he is not
breathing.

2. If he is not breathing, open
the airway by tilting his head
backwards.

Lift up his neck with one hand
and push down on his forehead
with the other. This opens the
airway. Sometimes doing this will
let the person breathe again by
himself.

BURNS

SKIN REDDENED: Apply ice cold water to burned

area to prevent burn from going deeper into skin
tissue. Cover area with a clean sheet or cloth to
keep away air. Consult a physician.

SKIN BLISTERED OR FLESH CHARRED: Apply
ice cold water to bur ned area to prevent burn fr om
going deeper into skin tissue .

3. If he is still not breathing,
begin rescue breath i n g.

-Keep his head tilted backward.
Pinch nose shut.

-Put your mouth tightly over his
mouth.

-Blow into his mouth once every
five seconds

-DO NOT STOP rescue breathing
until help arrives.

LOOSEN CLOTHING - KEEP
WARM

Do this when the victim is
breathing by himself or help is
available. Keep him as quiet as
possible and from becoming
chilled. Otherwise treat him for
shock.

Cover area with clean sheet or cloth to keep away
air. Treat victim for shock and take to hospital.

EXTENSIVE BURN - SKIN BROKEN: Cover area
with clean sheet or cloth to keep away air. Treat
victim for shock and take to hospital.

LX Series, Digital, Rev. 4 1-5

Digital VHF Transmitter w/DM8 Chapter 1, Introduction

dBm, dBw, dBmV, dBµµµµV, & VOLTAGE

EXPRESSED IN WATTS

50 Ohm System

WATTS PREFIX dBm dBw dBmV dBµV VOLTAGE
1,000,000,000,000 1 TERAWATT +150 +120
100,000,000,000 100 GIGAWATTS +140 +110
10,000,000,000 10 GIGAWATTS +130 +100
1,000,000,000 1 GIGAWATT +120 + 99
100,000,000 100 MEGAWATTS +110 + 80
10,000,000 10 MEG AWATTS +100 + 70
1,000,000 1 MEGAWATT + 90 + 60
100,000 100 KILOWATTS + 80 + 50
10,000 10 KILOWATTS + 70 + 40
1,000 1 KILOWATT + 60 + 30
100 1 HECTROWATT + 50 + 20
50 + 47 + 17
20 + 43 + 13
10 1 DECAWATT + 40 + 10
1 1 WATT + 30 0 + 77 +137 7.07V

0.1 1 DECIWATT + 20 - 10 + 67 +127 2.24V

0.01 1 CENTIWATT + 10 - 20 + 57 +117 0.707V

0.001 1 MILLIWATT 0 - 30 + 47 +107 224mV

0.0001 100 MICROWATTS - 10 - 40

0.00001 10 MICROWATTS - 20 - 50

0.000001 1 MICROWATT - 30 - 60

0.0000001 100 NANOWATTS - 40 - 70

0.00000001 10 NANOWATTS - 50 - 80

0.000000001 1 NANOWATT - 60 - 90

0.0000000001 100 PICOWATTS - 70 -100

0.00000000001 10 PICOWATTS - 80 -110

0.000000000001 1 PICOWATT - 90 -120

TEMPERATURE CONVERSION

°°°°F = 32 + [(9/5) °°°°C]

°°°°C = [(5/9) (°°°°F - 32)]

LX Series, Digital, Rev. 4 1-6

Digital VHF Transmitter w/DM8 Chapter 1, Introduction

USEFUL CONVERSION FACTORS

TO CONVERT FROM TO MULTIPLY BY

mile (US statute) kilometer (km) 1.609347
inch (in) millimeter (mm) 25.4
inch (in) centimeter (cm) 2.54
inch (in) meter (m) 0.0254
foot (ft) meter (m) 0.3048
yard (yd) meter (m) 0.9144
mile per hour (mph) kilometer per hour(km/hr) 1.60934
mile per hour (mph) meter per second (m/s) 0.44704
pound (lb) kilogram (kg) 0.4535924
gallon (gal) liter 3.7854118
U.S. liquid
(One U.S. gallon equals 0.8327 Canadian gallon)
fluid ounce (fl oz) milliliters (ml) 29.57353
British Thermal Unit watt (W) 0.2930711
per hour (Btu/hr)
horsepower (hp) watt (W) 746

NOMENCLATURE OF FREQUENCY BANDS

FREQUENCY RANGE DESIGNATION

30 to 300 kHz LF - Low Frequency
300 to 3000 kHz MF - Medium Frequency
3 to 30 MHz HF - High Frequency
30 to 300 MHz VHF - Very High Frequency
300 to 3000 MHz UHF - Ultrahigh Frequency
3 to 30 GHz SHF - Superhigh Frequency
30 to 300 GHz EHF - Extremely High Frequency

3 to 30 kHz VLF - Very Low Frequency

LETTER DESIGNATIONS FOR UPPER FREQUENCY

BANDS

LETTER FREQ. BAND

L 1000 - 2000 MHz
S 2000 - 4000 MHz
C 4000 - 8000 MHz
X 8000 - 12000 MHz
Ku 12 - 18 GHz
K 18 - 27 GHz
Ka 27 - 40 GHz
V 40 - 75 GHz
W 75 - 110 GHz

LX Series, Digital, Rev. 4 1-7

Digital VHF Transmitter w/DM8 Chapter 1, Introduction

RETURN LOSS VS. VSWR

0

-10

-20

R
E
T
U
R
N

L
O
S
S

-30

dB

-40

-50

-60

-70

1.001 1.01 1.1 2.0

VSWR

LX Series, Digital, Rev. 4 1-8

Digital VHF Transmitter w/DM8 Chapter 1, Introduction

ABBREVIATIONS/ACRONYMS

AC Alternating Current
AFC Automatic Frequency Control
ALC Automatic Level Control
AM Amplitude modulation
AGC Automatic Gain Control
AWG American wire gauge
BER Bit Error Rate
BW Bandwidth
DC Direct Current
D/A Digital to analog
DSP Digital Signal Processing
DTV Digital Television
dB Decibel
dBm Decibel referenced to 1 milliwatt
dBmV Decibel referenced to 1 millivolt
dBw Decibel referenced to 1 watt

FEC Forward Error Co rr ect ion
FM Frequency modulation
FPGA Field Programmable Gate Array
Hz Hertz
ICPM Incidental Carrier Phase Modulation
I/P Input
IF Intermediate Frequency
LED Light emitting diode
LSB Lower Sideband
MPEG Motion Pictures Exp ert Gr ou p
O/P Output
PLL Phase Lock ed Lo op
PCB Printed circuit board
QAM Quadrat ure Amplitude Modulation
SMPTE Society of Motion Picture and

Television Engineers
VSB Vest igial Side Band

LX Series, Digital, Rev. 4 1-9

Digital VHF Transmitter w/DM8 Table of Contents

LIST OF TABLES – (continued)

TABLE ................................................................................................PAGE

3-28: Menu 40-16 Transmitter Set Up: DM 8 Fixed Phase Selection Control 3-16
3-29: Menu 40-16 Transmitter Set Up: DM 8 Find Table Selection Control ..3-17

3-30: Menu 40-17 Transmitter Set Up: DM 8 Linear Correction Control.......3-17

3-31: Menu 40-18 Transmitter Set Up: AGC Mode Control.........................3-17

3-32: Menu 40-19 Transmitter Set Up: Amplifier Output Power Warning.....3-17

3-33: Menu 40-19 Transmitter Set Up: Remote Commands Control ...........3-18

4-1: Firmware Configuration Switch SW2 Operating Positions ..................4-12

LX Series, Digital, Rev. 4

vi

Digital VHF Transmitter w/DM8 Chapter 2, System Description &
Remote Control Connections

Chapter 2

System Description & Remote Control Connections

2.1 System Overview

The LX Series are complete Digital VHF
modular television transmitters that
operate at an average output power of 5
Watts to 50 Watts.

The model number scheme for a
Innovator LX Series transmitter is as
follows (where #### = power in
watts):

LHV####ATD - LX Series VHF High Band
Digital Transmitter
(Example):
LHV50ATD is a 50 Watt Digital VHF High
Band Transmitter.

The LX Series digital transmitter is made
up of the modules and assemblies as listed
in Table 2-1 and shown in Figure 2-1.

A1 A3 A5 A4 A6

Figure 2-1: Driver/Amplifier Chassis Exciter w/DM8 Front View Modules

Table 2-1: Digital LX Series Modules and Assemblies w/DM8

ASSEMBLY DESIGNATOR MODULE/ASSEMBLY NAME PART NUMBER

Chassis Assembly 1304052 (110 VAC)

A11 Backplane Board, LX Series 1304047

A1 DM8 Digital Modulator Module 1306342
A3 IF Processor Module 1301938
A5 VHF/UHF Upconverter Module 1303829

A4

A6

Control & Monitoring/Power
Supply Module
VHF HB DTV Power Amplifier
Module, 50 Watt

1301936 (110 VAC)

1309218 or

VHF LB Power Amplifier Module 1312015

2.2 Exciter Amplifier Chassi s
Assembly, V2, 110 VAC
(1304052; Appendix A)

The chassis assembly is factory set for
operation using 110 VAC. All of the
modules, except the power amplifier

the Control & Monitoring/Power Supply
Module, plug directly into a backplane
board. The backplane board provides
module to module interconnection as well
as interconnection to remote command
and control connectors.

module and the power supply section of

LX Series, Digital, Rev. 4 2-1

Digital VHF Transmitter w/DM8 Chapter 2, System Description &
Remote Control Connections

2.2.1 DM-8 Modulator Assembly
(1306342; Appendix A)

The DM8 modulator is an ATSC
compliant 8 VSB modulator that slides
into the left most slot in the Innovator

Table 2-2: DM-8 Digital Modulator Status Indicators

LED FUNCTION

MPEG (Green)

PLL A (Green)

PLL B (Green)

Table 2-3: DM-8 Digital Modulator Sample

SAMPLE DESCRIPTION

IF Sample

Table 2-4: .DM-8 Digital Modulator Alignment Port

PORT DESCRIPTION

RS-232 Serial port used for the initial DM8 modulator alignment.

2.2.2 (A3) IF Processor Module
Assembly (1301938; Appendix A)

The (A3) IF Processor Assembly contains
the IF Processor Board (1301977). The IF
Processor provides pre-correction to
ensure broadcast quality output signal.
The pre-correction consists of amplitude
linearity correction, Incidental Carrier

Indicates the presence of a valid MPEG stream at the J1-2B
input jack.
Indicates that the DM8 symbol clock is locked to the
frequency of the 10 MHz reference.
Indicates that the pilot frequency is locked to the incoming
10 MHz reference.

Provides a sample of the IF output from the modulator at
approximately a –20 dBm level.

LX Driver chassis assembly. The DM8
modulator accepts a SMPTE-310 MPEG
data stream input and outputs a 6 MHz
wide IF output centered at 44 MHz with
a pilot carrier at 46.69 MHz. The DM8
modulator provides linear and nonlinear
correction capability for the transmission
path as well as internal test sources that
are used during initial transmitter
installation. All of the functions of the
DM8 modulator are controlled from the
LX Controller LCD display and
pushbuttons.

Phase Modulation (ICPM) correction and
frequency response correction.

The IF Processor module is configured
either for an analog or digital system.
Pin 13C of the IF Processor module is
grounded in analog systems and left not
connected in digital systems. An IF
Processor Interlock signal is used to
report the presence of the IF Processor
module to the Control Monitoring board.
If the IF Processor interlock signal is not
present, the LX Series Transmitter
Exciter Driver RF output is Muted
(turned off).

The Control & Monitoring/Power Supply
module uses the IF Processor module for
System output power control. Through
the front panel display or a remote

LX Series, Digital, Rev. 4 2-2

Digital VHF Transmitter w/DM8 Chapter 2, System Description &
Remote Control Connections

interface, an operator can set the
transmitter's RF output power. The
range of RF power adjustment is
between 0% (full off) and 105% (full
power plus). A front panel IF Processor
module potentiometer sets the upper
limit of RF power at 120%. The
system's Control Monitoring board
compares the RF Power Monitoring
module RF power level with the desired
level and uses the IF Power Control PWM
line to correct for errors.

In digital systems, a digital level control
(DLC) voltage is generated on the IF
Processor module and sent to the digital
modulator. RF power control is
implemented by changing the DLC
voltage provided to the digital
modulator. The 'RF High' potentiometer
sets the upper adjusted range of RF
control circuit output to 120%.

The IF Processor module provides a
reference ALC voltage to the system's
Upconverter. When the ALC voltage
decreases, the Upconverter
automatically lowers the system output
power through the AGC circuits.

The IF Processor module has a front
panel switch to select Auto or Manual

Table 2-5: IF Processor Front Panel Switch

SWITCH FUNCTION

When Manual ALC is selected, the reference ALC voltage is set
by the ALC Gain front panel potentiometer.

MAN/AUTO ALC

Table 2-6: IF Processor Front Panel Status Indicators

LED FUNCTION

INPUT FAULT (Red)

ALC Fault (Red)

MUTE (Red)

When Auto ALC is selected, the IF level control circuit will
automatically increase the IF output until the desired output
power is attained.

When lit it indicates that there is a loss of the IF Input signal to the
IF Processor. Transmitter can be set to Mute on an IF Input Fault.
When lit it indicates that the required gain to produce the desired
output power level has exceeded the operational range of the ALC
circuit. The LED will also be lit when ALC is in Manual.
When lit it indicates that the IF input signal is cut back but the
enable to the Power Supply is present and the +32 VDC remains on.

ALC. When Manual ALC is selected, the
reference ALC voltage is set by a front
panel potentiometer. In this condition,
the RF power level control circuit is
removed from use. When the ALC select
switch is changed to Auto, the RF power
level control circuit will start at low
power and increase the RF output until
the desired output power is attained.

The IF Processor module Modulation
Present signal is monitored. If the
modulation level is too low or non­existent, a Modulation Present fault is
reported to the Control Monitoring
board. When the controller detects this
fault, it can be set to Automatically Mute
the transmitter or in Manual mode the
transmitter will continue to operate at
25% output.

The IF Processor module Input Signal
level is monitored. If the signal level is
too low or non-existent, an Input fault is
reported on the Control Monitoring
board. When the IF Processor board
detects an Input Signal fault it
automatically Mutes the transmitter.
The system controller does not Mute on
an IF Processor Input fault.

LX Series, Digital, Rev. 4 2-3

Digital VHF Transmitter w/DM8 Chapter 2, System Description &

j

Remote Control Connections
Table 2-7: IF Processor Front Panel Control Adjustments

POTENTIOMETERS DESCRIPTION

FREQUENCY

RESPONSE

EQUALIZER

ALC GAIN

MAN GAIN

These three variable resistors, R103, R106 & R274, adjust the
depth of gain for the three stages of frequency response correction.

Adjusts the gain of the transmitter when the transmitter is in the
Auto ALC position.
Adjusts the gain of the transmitter when the transmitter is in the
Manual ALC position.
These three variable resistors adjust the threshold cut in for the

LINEARITY

CORRECTION

three stages of linearity pre-correction. R211 and R216, the top
two pots, are ad

usted to correct for in phase amplitude distortions.
R 231, the bottom pot, is adjusted to correct for quadrature phase
distortions.

Table 2-8: IF Processor Front Panel Sample

SMA CONNECTOR DESCRIPTION

IF SAMPLE Sample of the pre-corrected IF output of the IF Processor

2.2.3 (A5) VHF/UHF Upconverter
Module Assembly
(1303829; Appendix A)

channel offsets of 10kHz. For +offsets
the frequency is 999.99 MHz and for –
offsets the frequency is 1000.01 MHz.

This signal is applied to a second mixer
mounted on the downconverter board
that converts it back to a broadcast
channel (2-69) by an LO2 that operates
in 100kHz steps between 1.1-1.9 GHz
depending on the channel selected. The
LO2 frequency equals the Channel
center frequency plus the LO1 frequency

The VHF/UHF Upconverter Module
Assembly contains (A1) a Downconverter
Board Assembly (1303834), (A3) a First
Conversion Board, LX Series (1303838),
(A2) a L-Band PLL Board, LX Series
(1303846) and (A4) an Upconverter
Control Board (1304760).

A 0 dBm 44 MHz IF input to the
upconverter through the backplane
board is applied to a mixer mounted on
the first conversion board. Also applied
to the mixer is a nominal 1 GHz LO1.
The mixer converts it to a nominal
frequency centered at 1044 MHz. A
filter selects the appropriate conversion
product, which is then amplified to a
level of approximately –4 dBm. The

plus 44 MHz. (As an example CH14+:
Center Frequency is 473.01 MHz and
LO1 is 999.99 MHz therefore, LO2 is

473.01 + 999.99 + 44, which equals

1517.00 MHz.)

The output of the mixer is applied to a
900 MHz Low pass filter to remove
unwanted conversion products. The
resulting signal is amplified and applied
to a Pin diode attenuator before it is
connected to the output of the
upconverter. This pin diode attenuator
adjusts the gain of the module and is
controlled by an Automatic Gain Control
circuit, which maintains a constant
power out of the upconverter, and also
the transmitter, that connects to the
power amplifier module.

frequency of the first conversion LO1
can be shifted by ± 10 kHz to generate

LX Series, Digital, Rev. 4 2-4

Digital VHF Transmitter w/DM8 Chapter 2, System Description &
Remote Control Connections

Table 2-9: VHF/UHF Upconverter Front Panel Switch

SWITCH FUNCTION

When Manual AGC is selected, the reference AGC voltage is
set by the AGC Manual Gain front panel potentiometer.

MAN/AUTO AGC

(Left Manual, Right AGC)

When Auto AGC is selected, the RF power level control circuit
will automatically increase the RF output until the desired
output power is attained.

Table 2-10: VHF/UHF Upconverter Front Panel Status Indicators

LED FUNCTION

PLL 1 Fault

(Red)

PLL 2 Fault

(Red)

AGC Fault

(Red)

AGC Override

(Red)

Man Gain

(Amber)

When lit it indicates that the 1 GHz PLL is unlocked

When lit it indicates that the 1.1 –1.9 GHz PLL is unlocked

When lit it indicates that the AGC is out of range.

When lit it indicates that the AGC is cutting back due to too much
drive to the driver module.

When lit it indicates that the AGC is bypassed in Manual.

Table 2-11: VHF/UHF Upconverter Front Panel Control Adjustments

POTENTIOMETERS DESCRIPTION

MAN GAIN ADJ

AGC ADJ

AGC CUTBACK ADJ

(AGC OVERRIDE)

Adjusts the gain of the upconverter and transmitter when in the
Manual AGC position.
Adjusts the gain of the upconverter and transmitter when in the
Auto AGC position.
Adjusts the point at which the transmitter will cut back in power,
due to too much drive, when the Transmitter is in Auto AGC.

Table 2-12: VHF/UHF Upconverter Front Panel Samples

SMA CONNECTOR DESCRIPTION

LO1 SAMPLE

LO2 SAMPLE

Sample of the 1 GHz nominal LO1 signal in the Upconverter as
generated on the L-Band PLL Board.
Sample of the 1.1-1.9 GHz LO2 signal in the Upconverter as
generated on the First Conversion Board.

RF SAMPLE Sample of the On Channel RF Output of the Upconverter

2.2.4 (A4) Control & Monitoring/
Power Supply Mo dul e Asse mbl y,
110 VAC (1301936; Appendix A)

(1527-1406). The Assembly also
contains a switching power supply that
provides ±12 VDC to the rest of the
modules in the chassis and +32 VDC to
the Power Amplifier module.

The Assembly provides all transmitter
control and monitoring functions. The

The (A4) Control & Monitoring/Power
Supply Assembly is made up of a Control
Board (1302021), a Power Protection
Board (1302837) and a Switch Board

Front panel LCD allows monitoring of
system parameters, including forward
and reflected power, transistor currents,
module temperatures and power supply
voltages.

LX Series, Digital, Rev. 4 2-5

Digital VHF Transmitter w/DM8 Chapter 2, System Description &
Remote Control Connections

Table 2-13: Controller/Power Supply Display

DISPLAY FUNCTION

A 4 x 20 display providing a four-line readout of the internal

LCD

Table 2-14: Controller/Power Supply Status Indicator

LED FUNCTION

OPERATE

( green )

FAULT

( red or green )

DC OK

( red or green )

Table 2-15: Controller/Power Supply Control Adjustments

POTENTIOMETERS DESCRIPTION

DISPLAY CONTRAST Adjusts the contrast of the display for desired viewing of screen.

functions, external inputs, and status. See Chapter 3,

Controller/Power Supply Display Screens, for a listing of displays.

When lit it indicates that the transmitter is in the Operate Mode. If
transmitter is Muted the Operate LED will stay lit, the transmitter
will remain in Operate, until the input signal is returned.
Red indicates that a problem has occurred in the transmitter. The
transmitter will be Muted or placed in Standby until the problem is
corrected.
Green indicates that the switchable fuse protected DC outputs that
connect to the modules in the transmitter are OK.

2.2.5 (A6) Power Amplifier Module
Assembly, VHF HB, 75W DTV
(1312589; Appendix A)

NOTE: The 1312589 PA Assembly is
used in LHV66ATD Transmitters.
Refer to the 13 120 15 PA As s embl y ,
that is described in the next section,
for the PA used in LLV5 0A TD
transmitters.

The (1312538) Power Amplifier Module
Assembly is made up of a VHF HB
Coupler Board Assembly (1141-1002), an
Amplifier Control Board (1308260), a
Delta RF 25 Watt VHF Driver Assembly
(1305820) and a Delta RF 400 Watt VHF
Amplifier Assembly (1301322).

The Power Amplifier Module contains
Broadband LDMOS amplifiers that cover
the VHF High Band with no tuning
required. They amplify the RF to the
output power of the transmitter.

The Power Amplifier is used to amplify
the RF output of the Upconverter
module. A jumper cable, located on the
rear chassis, connects the RF output from
the LO/Upconverter at J23 to J24 the RF
input to the PA Assembly.

The Power Amplifier module contains an
amplifier control and monitoring board.
This board monitors the RF output
power, RF reflected power, the current
draw of amplifier sections, the supply
voltage, and the temperature of the PA
heat sink. The Control and monitoring
lines to the Power Amplifier module are
routed through the floating blind-mate
connector of the Control &
Monitoring/Power Supply module.

The RF power detector circuit outputs
vary with operating frequency. These
circuits must be calibrated at their
intended operating frequency. Front
panel adjustment potentiometers, R201
for Reflected Power and R202 for
Forward Power, are used for calibration.

The Forward Power of the Power
Amplifier module is routed to the
Upconverter module as AGC #1. A
system over-drive condition is detected

LX Series, Digital, Rev. 4 2-6

Digital VHF Transmitter w/DM8 Chapter 2, System Description &
Remote Control Connections

when this value rises above 1.6 VDC on
the Upconverter Screen. When an over­drive condition is detected, the
Upconverter module reduces its RF

Table 2-16: Power Amplifier Status Indicator

LED FUNCTION

ENABLED

(Green)

DC OK

(Green)

TEMP

(GREEN)

MOD OK

(Green)

MOD OK

(RED)

MOD OK
(Amber)

Table 2-17: Power Amplifier Control Adjustments

POTENTIOMETERS DESCRIPTION

RFL CAL Adjusts the gain of the Reflected Power monitoring circuit

FORWARD CAL Adjusts the gain of the Forward Power monitoring circuit

Table 2-18: Power Amplifier Sample

DISPLAY FUNCTION

FWD SAMPLE RF sample of the amplified signal being sent out the module on J25.

2.2.6 (A6) VHF LB Power Amplifier
Module (1312015; Appendix A)

NOTE: The 1312015 PA Assembly is
used in LLV50ATD transmitters.
Refer to the 13 092 18 PA As s embl y ,
that is described in the previous
section, for the PA used in
LHV50ATD transmitters.

When lit Green, it indicates that the PA is in the Operate Mode. If a Mute
occurs, the PA will remain Enabled, until the input signal is returned.
When lit Green, it indicates that the fuse protected DC inputs to the PA
module are OK.
When lit Green, it indicates that the temperature of the heatsink
assembly in the module is below 78ûC.
When lit Green, it indicates that the PA Module is operating and has no
faults.
If the Module OK LED is Red and blinking a fault is present. The
meaning of the blinking LED is as follows.

1 Blink indicates Amplifier Current Fault.
2 Blinks indicate Temperature Fault.
3 Blinks indicate +32V Power Supply Over Voltage Fault.
4 Blinks indicate +32V Power Supply Under Voltage Fault.
5 Blinks indicate Reflected Power Fault.
6 Blinks indicate +12V or –12V Power Supply Fault

A blinking Amber Mod OK LED indicates the power output of the amplifier

module is below 65%. (NOTE: Only in Amplifier Code Versions 3.7A or

later & System Controller Code Versions 3.9C or later.)

output level. For values less than 1.6
VDC, the Upconverter uses this voltage
for automatic gain.

The (1312015) Power Amplifier Module
Assembly is made up of a Coupler Board
Assembly (1153-1104), an Amplifier
Control Board (1308260), a Delta RF 25
Watt VHF LB Driver Assembly (1308372)
and a Delta RF 400 Watt VHF LB
Amplifier Assembly (1304348).

The Power Amplifier Module contains
Broadband LDMOS amplifiers that cover
the VHF Low Band with no tuning
required. They amplify the RF to the
output power of the transmitter.

The Power Amplifier is used to amplify
the RF output of the Upconverter

LX Series, Digital, Rev. 4 2-7

Digital VHF Transmitter w/DM8 Chapter 2, System Description &
Remote Control Connections

module. A jumper cable, located on the
rear chassis, connects the RF output from
the Upconverter at J23 to J24 the RF
input to the PA Assembly.

The Power Amplifier module contains an
amplifier control and monitoring board.
This board monitors the RF output
power, RF reflected power, the current
draw of amplifier sections, the supply
voltage, and the temperature of the PA
heat sink. The Control and monitoring
lines to the Power Amplifier module are
routed through the floating blind-mate
connector of the Control &
Monitoring/Power Supply module.

The RF power detector circuit outputs
vary with operating frequency. These

circuits must be calibrated at their
intended operating frequency. Front
panel adjustment potentiometers, R201
for Reflected Power and R202 for
Forward Power, are used for calibration.

NOTE: The Aural Cal and Aural Null pots

are not used in this digital transmitter.

The Forward Power of the Power
Amplifier module is routed to the
Upconverter module as AGC #1. A
system over-drive condition is detected
when this value rises above 0.9 VDC.
When an over-drive condition is
detected, the Upconverter module
reduces its RF output level. For values
less than 0.9 VDC, the Upconverter uses
this voltage for automatic gain.

Table 2-19. Power Amplifier Status Indicator

LED FUNCTION

ENABLED

(Green)

DC OK

(Green)

TEMP

(Green)

MOD OK

(Green)

When lit Green, it indicates that the PA is in the Operate Mode. If a
Mute occurs, the PA will remain Enabled, until the input signal is
returned.
When lit Green, it indicates that the fuse protected DC inputs to the
PA module are OK.
When lit Green, it indicates that the temperature of the heatsink
assembly in the module is below 78ûC.
When lit Green, it indicates that the PA Module is operating and has
no faults.
If the Module OK LED is Red and blinking a fault is present.
1 Blink indicates Amplifier Current Fault.

MOD OK

(Red)

2 Blinks indicate Temperature Fault.
3 Blinks indicate +32V Power Supply Over Voltage Fault.
4 Blinks indicate +32V Power Supply Under Voltage Fault.
5 Blinks indicate Reflected Power Fault.
6 Blinks indicate +12V or –12V Power Supply Fault.

Table 2-20. Power Amplifier Control Adjustments

POTENTIOMETERS DESCRIPTION

RFL CAL Adjusts the gain of the Reflected Power monitoring circuit

VIS/FWD CAL Adjusts the gain of the Forward Power monitoring circuit

AURAL CAL (NOT USED) Adjusts the gain of the Aural Power monitoring circuit

AURAL NULL

(NOT USED) Adjusts the offset of the Forward Power monitoring

circuit based on the Aural signal level.

Table 2-21. Power Amplifier Sample

DISPLAY FUNCTION

FORWARD SAMPLE RF sample of the amplified signal being sent out the module on J25.

LX Series, Digital, Rev. 4 2-8