UBS Axcera LU500ATD 500-Watt UHF Digital Transmitter User Manual Amplifier Operating Manual

UBS-Axcera 500-Watt UHF Digital Transmitter Amplifier Operating Manual

Contents

Amplifier Operating Manual

INSTRUCTION MANUAL
Innovator
LX Series
Digital Power Amplifier
Assembly
AXCERA, LLC
103 FREEDOM DRIVE P.O. BOX 525 LAWRENCE, PA 15055-0525 USA
(724) 873-8100 • FAX (724) 873-8105
www.axcera.com • info@axcera.com
LX Series Digital Table of Contents
Power Amplifier Assembly
Volume 2, Rev. 1 June 15, 2006
i
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 AMPLIFIER ASSEMBLY DESCRIPTION, MAINTENANCE
& REMOTE CONTROL CONNECTIONS
2.1 LX Series Power Amplifier Chassis Assembly Overview .............................2-1
2.1.1 Power Amplifier Chassis Configurations...........................................2-3
2.1.1.1 125 Watt Power Amplifier Chassis Configuration.....................2-3
2.1.1.2 250 Watt Power Amplifier Chassis Configuration.....................2-3
2.1.1.3 500W Power Amplifier Chassis Configuration..........................2-3
2.1.2 System Configurations..................................................................2-4
2.1.2.1 125W, 250W or 500W System Configurations ........................2-4
2.1.2.2 1 kW System Configuration..................................................2-4
2.1.2.3 1.5 kW System Configuration ...............................................2-4
2.1.2.4 2 kW System Configuration..................................................2-5
2.1.2.5 2.5 kW System Configuration ...............................................2-5
2.1.2.6 3 kW System Configuration..................................................2-6
2.1.3 Power Amplifier Module Assembly, 250W........................................2-8
2.1.4 Power Supply Module Assembly...................................................2-10
2.1.5 Front Panel LCD Display Screens..................................................2-10
2.2 External Assembly...............................................................................2-10
2.2.1 Visual/Aural Metering Board ........................................................2-10
2.3 System Operation................................................................................2-10
2.3.1 Principles of Operation................................................................2-11
2.4 Maintenance .......................................................................................2-12
2.5 Customer Remote Connections....................................................... 2-12
CHAPTER 3 SITE CONSIDERATIONS, INSTALLATION AND SETUP PROCEDURES
3.1 Site Considerations................................................................................3-1
3.2 Unpacking the Chassis w/Modules and bandpass filter...............................3-5
3.3 Installing the Chassis w/Modules and filters..............................................3-5
3.4 AC Input...............................................................................................3-6
3.5 Setup and Operation..............................................................................3-7
3.5.1 Input Connections........................................................................3-7
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 ..................................3-9
3.5.2.5 Power or Driver Amplifier Module LEDs on Front Panel ............3-9
3.5.3 Front Panel Screens for the Exciter/Amplifier Chassis Assembly.........3-9
3.5.4 Operation Procedure.....................................................................3-9
LX Series Digital Table of Contents
Power Amplifier Assembly
Volume 2, Rev. 1 June 15, 2006
ii
TABLE OF CONTENTS - (Continued)
SECTION PAGE
CHAPTER 4 CIRCUIT DESCRIPTIONS
Power Amplifier Chassis Assembly..........................................................4-1
4.1 Power Amplifier Module..........................................................................4-1
4.1.1 UHF Phase/Gain Board..................................................................4-1
4.1.2 150 Watt Driver Pallet Assembly....................................................4-2
4.1.3 150 Watt Driver, Dual Output Board...............................................4-2
4.1.4 UHF Module Assembly, RF Module Pallet, Philips ..............................4-2
4.1.5 2 Way UHF Combiner Assembly.....................................................4-3
4.1.6 Amplifier Control Board.................................................................4-3
4.2 Power Supply Assembly .........................................................................4-5
4.3 External Assembly.................................................................................4-5
4.3.1 Dual Peak Detector Board .............................................................4-5
APPENDICES
APPENDIX A INNOVATOR LX SERIES SPECIFICATIONS
APPENDIX B DRAWINGS AND PARTS LISTS
APPENDIX C TRANSMITTER LOG SHEET
LX Series Digital Table of Contents
Power Amplifier Assembly
Volume 2, Rev. 1
iii
LIST OF FIGURES
FIGURE PAGE
1-1 Brady Marker Identification Drawing.................................................1-1
2-1 500W Digital Power Amplifier Assembly Racking Plan.........................2-3
3-1 1 kW Minimum Ventilation Configuration...........................................3-4
3-2 Front and Rear View Exciter/Driver...................................................3-5
3-3 Front and Rear View 76” Cabinet Typical 2kW Configuration ...............3-6
3-4 AC Input Box Assembly...................................................................3-6
3-5 Rear View of LX Series Transmitter ..................................................3-7
4-1 125 Watt Digital UHF Amplifier Module .............................................4-2
LX Series Digital Table of Contents
Power Amplifier Assembly
Volume 2, Rev. 1
iv
LIST OF TABLES
TABLE PAGE
2-1 Typical LX Series Digital System Drawings and Parts Lists ..................2-4
2-2 LX Series Power Amplifier Chassis Assemblies ...................................2-8
2-3 Power Amplifier Status Indicators.....................................................2-9
2-4 Power Amplifier Control Adjustments................................................2-9
2-5 Power Amplifier Sample ..................................................................2-9
2-6 LX Series Customer Remote Connections.................................2-13
2-7 (Optional) Exciter Switcher Customer Remote Connections.... 2-15
3-1 LX Series Digital Transmitters AC Input and Current Requirements......3-1
3-2 Rear Chassis Connections for LX Series Transmitter...........................3-7
LX Series Digital Chapter 1, Introduction
Power Amplifier Assembly
Volume 2, Rev. 1 1-1
Chapter 1
Introduction
1.1 Manual Overview
This manual explains the installation,
setup, alignment, and maintenance
procedures for the Power Amplifier
Assembly for the Innovator LX Series
transmitter. Information and drawings
on the exciter/driver assembly are
contained in Volume 1. It is important
that you read all of the instructions,
especially the safety information in this
chapter, before you begin to install or
operate the unit.
This instruction manual is divided into five
chapters and supporting appendices.
Chapter 1, Introduction, contains
information on the assembly numbering
system used in the manual, safety,
maintenance, return procedures, and
warranties. Chapter 2, Amplifier
Assembly Description, Maintenance &
Remote Control Connections, describes
the amplifier assembly and includes
discussions on control and status
indicators and remote control connections.
Chapter 3, Site Considerations,
Installation and Setup Procedures,
explains how to unpack, install, setup, and
operate the power amplifier assembly.
Chapter 4, Circuit Descriptions, contains
circuit level descriptions for boards and
board level components in the power
amplifier. Appendix A contains system
specifications. Appendix B contains
drawings and parts lists. Appendix C
contains a transmitter log sheet.
1.2 Assembly Designators
Axcera has assigned assembly numbers,
Ax designations such as A1, where
x=1,2,3…etc, to all assemblies, modules,
and boards in the system. These
designations are referenced in the text of
this manual and shown on the block
diagrams and interconnect drawings
provided in the appendices. The Block
Diagrams, Interconnects, Schematics,
Assembly Drawings and Parts Lists are
arranged in increasing numerical order 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 Chapter 1, Introduction
Power Amplifier Assembly
Volume 2, Rev. 1 1-2
1.3 Safety
The UHF transmitter systems
manufactured by Axcera are designed to
be easy to use and repair while providing
protection from electrical and mechanical
hazards. Please review the following
warnings and familiarize yourself with the
operation and servicing procedures
before working on the transmitter
system.
Read All safety Instructions – All of
the safety instructions should be read
and understood before operating this
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 cautions listed in this safety section
and throughout the manual must be
followed.
Follow Operating Instructions – All of
the operating and use instructions for the
transmitter should be 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 the cabinet
and module front panels are provided for
ventilation. To ensure the reliable
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 servicing questions to qualified
Axcera service personnel.
Replacement Parts – 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 fire, electric shock, or other
hazards. Please contact the Axcera
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 at (724) 873-
8100 or by fax at (724) 873-8105.
Before calling Axcera, please be prepared
to supply the Axcera technician with
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 accompanied by a
Return Material Authorization Number
(RMA#).
LX Series Digital Chapter 1, Introduction
Power Amplifier Assembly
Volume 2, Rev. 1 1-3
The RMA# can be obtained from any
Axcera Field Service Engineer by
contacting the Axcera Field Service
Department at (724) 873-8100 or by fax
at (724) 873-8105. This procedure
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, an RMA# is included with the unit.
The RMA# is intended to be used when
the unit is returned to Axcera. In
addition, all shipping material should be
retained for the return of the unit to
Axcera.
Replacement assemblies are also sent
with an RMA# to allow for the proper
routing of the exchanged hardware.
Failure to close out this type of 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 include contact
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) 873-8100.
Axcera can also be contacted through e-
mail at info@axcera.com 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 limited 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 hours-
of-use or other warranties extended by
or enforceable against the manufacturer
at the time of delivery to the buyer.
NO WARRANTIES, WHETHER
STATUTORY, EXPRESSED, OR
IMPLIED, AND NO WARRANTIES OF
MERCHANTABILITY, FITNESS FOR
ANY PARTICULAR PURPOSE, OR
FREEDOM FROM INFRINGEMENT,
OR THE LIKE, OTHER THAN AS
SPECIFIED IN PATENT LIABILITY
ARTICLES, AND IN THIS ARTICLE,
SHALL APPLY TO THE EQUIPMENT
FURNISHED HEREUNDER.
LX Series Digital Chapter 1, Introduction
Power Amplifier Assembly
Volume 2, Rev. 1 1-4
!
!!
! 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.
$
$$
$ RADIO FREQUENCY RADIATION HAZARD $
$$
$
MICROWAVE, RF AMPLIFIERS AND TUBES GENERATE HAZARDOUS RF
RADIATION THAT CAN CAUSE SEVERE INJURY INCLUDING CATARACTS,
WHICH CAN RESULT IN BLINDNESS. SOME CARDIAC 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 INTERVALS.
LX Series Digital Chapter 1, Introduction
Power Amplifier Assembly
Volume 2, Rev. 1 1-5
EMERGENCY FIRST AID INSTRUCTIONS
Personnel engaged in the installation, operation, or maintenance of this equipment are urged to become
familiar with the following rules both in theory and practice. It is the duty of all operating 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 ear
close to his mouth and look at his
chest. If he is breathing you 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.
3. If he is still not breathing,
begin rescue breathing.
-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.
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 burned area to prevent burn from
going deeper into skin tissue.
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 Chapter 1, Introduction
Power Amplifier Assembly
Volume 2, Rev. 1 1-6
dBm, dBw, dBmV, dBµ
µµ
µV, & 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 MEGAWATTS +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 Chapter 1, Introduction
Power Amplifier Assembly
Volume 2, Rev. 1 1-7
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
3 to 30 kHz VLF - Very Low Frequency
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
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 Chapter 1, Introduction
Power Amplifier Assembly
Volume 2, Rev. 1 1-8
RETURN LOSS VS. VSWR
1.001 1.01 1.1 2.0
VSWR
0
-10
-20
-30
-40
-50
-60
-70
R
E
T
U
R
N
L
O
S
S
dB
LX Series Digital Chapter 1, Introduction
Power Amplifier Assembly
Volume 2, Rev. 1 1-9
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
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 Correction
FM Frequency modulation
Hz Hertz
ICPM Incidental Carrier Phase Modulation
I/P Input
IF Intermediate Frequency
LED Light emitting diode
LSB Lower Sideband
MPEG Motion Pictures Expert Group
O/P Output
PLL Phase Locked Loop
PCB Printed circuit board
QAM Quadrature Amplitude Modulation
SMPTE Society of Motion Picture and
Television Engineers
VSB Vestigial Side Band
LX Series Digital Chapter 2, Amplifier Assembly Description,
Power Amplifier Assembly Maintenance & Remote Control Connections
Volume 2, Rev. 1 2-1
Chapter 2
Amplifier Assembly Description, Maintenance
& Remote Control Connections
2.1 LX Series Power Amplifier Chassis
Assembly Overview
The power amplifier chassis assembly in
the LX Series contains modular television
amplifiers that slide into the assembly
each producing approximately 125 Watts
Digital output. There is also needed one
external Power Supply Module Assembly
for every two 125 Watt PA modules, which
also slide into the Power Amplifier Chassis
Assembly, under the PA Modules. One
On/Off circuit breaker, mounted on the
rear of the power amplifier assembly,
supplies AC to each power supply
assembly. Four PA modules and two
Power Supply modules are the maximum
number of modules in one Power Amplifier
Chassis Assembly producing 500W Digital
output power. Two Power Amplifier
Chassis Assemblies are required for 1 kW
digital output power, three Power
Amplifier Chassis Assemblies for 1.5 kW
digital, four Power Amplifier Chassis
Assemblies for 2 kW digital, five Power
Amplifier Chassis Assemblies for 2.5 kW
digital, and six Power Amplifier Chassis
Assemblies are required for 3 kW digital
output power.
In a 125W digital system the RF output of
the exciter/driver at the “N” connector J25
connects to the (A3) power amplifier
chassis assembly at the “N” connector
J201.
In a 250W or 500W digital system the RF
output of the exciter/driver at the “N”
connector J25 connects to the (A3) power
amplifier chassis assembly at the “N”
connector J200.
In a 1 kW digital system the RF output of
the exciter/driver connects to (A5) a 2
Way Splitter Assembly. The two outputs
of the splitter connect to the (A3) and
(A6) power amplifier chassis assemblies at
J200.
In a 1.5 kW digital system the RF output
of the exciter/driver connects to (A5) a 4
Way Splitter Assembly. Three outputs of
the splitter, the fourth at J5 is 5 Watt
terminated, connect to the (A3), (A6)
and (A13) power amplifier chassis
assemblies at J200.
In a 2 kW digital system there are two
cabinet assemblies (A1 and A2). The
(A1) cabinet assembly contains the (A1-
A27) exciter/driver assembly and the
(A1-A6 and A1-A3) Power Amplifiers.
The (A2) cabinet assembly contains the
(A2-A6 and A2-A3) Power Amplifiers.
The RF output of the exciter/driver
connects to (A1-A5) a 4 Way Splitter
Assembly. Three outputs of the splitter
at J2, J4 and J5 connect to the (A1-A3),
(A2-A6) and (A2-A3) power amplifier
chassis assemblies at J200. The fourth
output of the splitter at J1 is connected
through A1-A5-A1, a phase matching
line, before it is connected to the input of
the (A1-A6) Power Amplifier.
In a 2.5 kW digital system there are two
cabinet assemblies (A1 and A2). The
(A1) cabinet assembly contains the (A1-
A27) exciter/driver assembly and the
(A1-A6 and A1-A3) Power Amplifiers.
The (A2) cabinet assembly contains the
(A2-A6, A2-A3 and A2-A13) Power
Amplifiers. The RF output of the
exciter/driver at J25 connects to (A1-A5-
A1) a 2 Way Splitter Assembly. One
output of the splitter connects to (A2-A5)
a 4 way splitter in the (A2) cabinet and
the other output connects to (A1-A5-A2)
a 4 way splitter in the (A1) cabinet. Two
of the outputs of the (A1-A5-A2) splitter
at J1, and J5 connect to the (A1-A3) and
(A1-A6) power amplifier chassis
assemblies at J200. The third and fourth
output of the (A1-A5-A2) splitter at J2
and J4 are terminated. The other output
of the (A1-A5-A1) 2 Way Splitter at J2
LX Series Digital Chapter 2, Amplifier Assembly Description,
Power Amplifier Assembly Maintenance & Remote Control Connections
Volume 2, Rev. 1 2-2
connects to the (A2) cabinet at J3 of (A2-
A5) a 4 way splitter. Three of the outputs
of the (A2-A5) splitter at J1, J2 and J4
connect to the (A1-A3), (A1-A6) and (A1-
A13) power amplifier chassis assemblies
at J200. The other output of the (A2-A5)
splitter at J4 is terminated.
In a 3 kW digital system there are two
cabinet assemblies (A1 and A2). The (A1)
cabinet assembly contains the (A1-A27)
exciter/driver assembly and the (A1-A6,
A1-A3, and A1-A13) Power Amplifiers.
The (A2) cabinet assembly contains the
(A2-A6, A2-A3, and A2-A13) Power
Amplifiers. The RF output of the
exciter/driver at J25 connects to (A1-A5-
A1) a 2 Way Splitter Assembly. One
output of the splitter connects to (A2-A5)
a 4 way splitter in the (A2) cabinet and
the other output connects to (A1-A5-A2) a
4 way splitter in the (A1) cabinet. Three
of the outputs of the (A1-A5-A2) splitter
at J1, J2 and J4 connect to the (A1-A3),
(A1-A6) and (A1-A13) power amplifier
chassis assemblies at J200. The fourth
output of the (A1-A5-A2) splitter at J5 is
terminated. The other output of the (A1-
A5-A1) splitter at J2 connects to the (A2)
cabinet at J3 of (A2-A5) a 4 way splitter.
Three of the outputs of the (A2-A5)
splitter at J1, J2, and J4 connect to the
(A2-A3), (A2-A6), and (A2-A13) power
amplifier chassis assemblies at J200. The
other output of the (A2-A5) splitter at J5
is terminated.
Data and control information for the
system is fed through the system serial
cable. In a 125W, 250W or 500W digital
system, the system serial cable connects
from J34 on the exciter/driver assembly to
J232 on the (A3) Power Amplifier
Assembly.
In a 1 kW digital system, the system
serial cable connects from J34 on the
exciter/driver assembly to J232 on the
(A3) Power Amplifier Assembly. The serial
cable then connects from J233 on the
(A3) power amplifier to J232 on the (A6)
power amplifier.
In a 1.5 kW digital system, the system
serial cable connects from J34 on the
exciter/driver assembly to J232 on the
(A3) Power Amplifier Assembly. The
serial cable then connects from J233 on
the (A3) power amplifier to J232 on the
(A6) power amplifier and from J233 on
the (A6) power amplifier to J232 on the
(A13) power amplifier.
In a 2 kW digital system, the system
serial cable connects from J34 on the
exciter/driver assembly to J232 on the
(A1-A3) Power Amplifier Assembly. The
serial cable then connects from J233 on
the (A1-A3) power amplifier to J232 on
the (A1-A6) power amplifier. The serial
cable next connects from J233 on (A1-
A6) to J233 on the (A2-A3) power
amplifier and then from J233 on the (A2-
A3) power amplifier to J232 on the (A2-
A6) power amplifier.
In a 2.5 kW digital system, the system
serial cable connects from J34 on the
exciter/driver assembly to J232 on the
(A1-A3) Power Amplifier Assembly. The
serial cable then connects from J233 on
the (A1-A3) power amplifier to J232 on
the (A1-A6) power amplifier. The serial
cable next connects from J233 on (A1-
A6) to J232 on the (A2-A3) power
amplifier. The serial cable next connects
from J233 on (A2-A3) to J232 on the
(A2-A6) power amplifier and then from
J233 on the (A2-A6) power amplifier to
J232 on the (A2-A13) power amplifier.
In a 3 kW digital system, the system
serial cable connects from J34 on the
exciter/driver assembly to J232 on the
(A1-A3) Power Amplifier Assembly. The
serial cable then connects from J233 on
the (A1-A3) power amplifier to J232 on
the (A1-A6) power amplifier. The serial
cable next connects from J233 on (A1-
A6) to J232 on the (A1-A13) power
amplifier. The serial cable next connects
from J233 on (A1-A13) to J232 on the
(A2-A3) power amplifier and then from
J233 on the (A2-A3) power amplifier to
J232 on the (A2-A6) power amplifier.
Finally the serial cable connects from
LX Series Digital Chapter 2, Amplifier Assembly Description,
Power Amplifier Assembly Maintenance & Remote Control Connections
Volume 2, Rev. 1 2-3
J233 on (A2-A6) to J232 on (A2-A13)
power amplifier.
2.1.1 Power Amplifier Chassis
Configurations
In the 125W digital power amplifier
chassis assembly the RF from J201
connects to the OSP Jack J111 in the
power amplifier assembly. In the power
amplifier chassis assemblies above 250W,
the RF from J200 connects to the SMA
Jack J100 on the 4 way splitter assembly.
The 4 outputs, in a 1 kW amplifier power
amplifier assembly, connect through the
output SMA jacks to OSP input jacks of
the four slide in power amplifier module
assemblies. J101 connects to jack J111
on power amplifier #1. J102 connects to
jack J121 on power amplifier #2. J103
connects to jack J131 on power amplifier
#3. J104 connects to jack J141 on power
amplifier #4.
2.1.1.1 125 Watt Digital Power Amplifier
Chassis Configuration
In a 125 Watt digital power amplifier
chassis assembly, the RF input at J201 is
connected to J111 on the power amplifier
module. The output of the power
amplifier at J112 connects to the RF
output jack J203 of the power amplifier
chassis assembly.
2.1.1.2 250 Watt Digital Power Amplifier
Chassis Configuration
In a 250 Watt digital power amplifier
chassis assembly, Jacks J103 and J104,
on the 4 way splitter assembly, are not
used and are terminated with 50Ω. Also,
the power amplifier modules #3 and #4
are not used. Finally a 2 way combiner is
used in place of the 4 way combiner.
2.1.1.3 500W Digital Power Amplifier
Chassis Configuration
In a 500W digital amplifier power
amplifier assembly, the output OSP jacks
connect to the OSP input jacks on the
four way combiner assembly. J112
connects to J151 on the 4 way combiner.
J122 connects to J152 on the 4 way
combiner power amplifier #2. J132
connects to J153 on the 4 way combiner.
J142 connects to J154 on the 4 way
combiner.
Figure 2-1. 500W Digital Power Amplifier
Assembly Racking Plan
In a 500W digital amplifier power
amplifier assembly, the (A5) power
supply #1 provides voltages to the (A1)
power amplifier #1 and the (A3) power
amplifier #3 assemblies and the (A6)
power supply #2 provides voltages to the
(A2) power amplifier #2 and the (A4)
power amplifier #4.
LX Series Digital Chapter 2, Amplifier Assembly Description,
Power Amplifier Assembly Maintenance & Remote Control Connections
Volume 2, Rev. 1 2-4
2.1.2 System Configurations
Table 2-1: Typical LX Series Digital System Configuration Drawings and Parts Lists
DIGITAL SYSTEM
CONFIGURATIONS INTERCONNECT RACKING PLAN PARTS LIST
125W 1303940 1303596 1303913
250W 1303940 1303596 1303893
500W 1303940 1303596 1303894
1 kW 1303941 1303596 1303895
NOTE: Refer to Table 2-1 for the
Interconnect, Racking Plan and Parts
List Numbers for your system. The
actual drawings and parts lists are
located in Appendix B of this manual.
A Drawing List of the order the
drawings appear in the Appendix is
found at the beginning of the section.
2.1.2.1 125 Watt, 250 Watt or 500W
Digital Output System Configurations
In a 125 Watt digital system, the output
of the (A3) power amplifier chassis
assembly at the 7/16” connector J203 is
cabled to (A9) the bandpass filter for the
system. In a 250 Watt or 500W digital
system, the output of the (A3) power
amplifier chassis assembly at the 7/16”
connector J205 is also cabled to the (A9)
bandpass filter. The filtered output
connects either directly to (A11) the
output coupler or first to the Optional 1
section or 2 section trap filter if more
filtering is needed and then to the output
coupler. The (A11) coupler assembly
supplies a forward and a reflected power
samples to the (A4) Dual Peak Detector
Board. The Dual Peak Detector Board
supplies reflected and forward output
power samples to the exciter/driver for
metering purposes. The reflected sample
connects to TB31-13 and the forward
sample at TB31-14. The RF output for the
transmitter is at J2 the 7/8” EIA connector
on the (A11) coupler assembly.
2.1.2.2 1 kW Digital Output System
Configuration
In a 1 kW digital system, the output of the
(A3) and the (A6) power amplifier chassis
assemblies, at the “7/16” connectors
J205, are cabled to (A7) the hybrid
combiner for the system, mounted to the
input of the bandpass filter. A 500 Watt
reject load (A9) connects to J4 on the
hybrid combiner to dissipate reject
power. A thermal switch (A9-A1) is
mounted to the reject load and supplies
an overtemperature fault, at 175º F., to
the driver assembly, at TB30-7 & TB30-
15, if a problem occurs in the output
lines. NOTE: If an overtemperature fault
occurs, it must be manually reset on the
system controller after repairs are made.
The combined output of the hybrid
combiner at the “7/8” Jack J3 is
connected to J1 on the digital bandpass
filter. The filtered output of the bandpass
filter is connected to (A14) the low pass
filter assembly. The output of the filter is
either cabled directly to the (A11) output
coupler or first to an optional 1 or 2
section trap filter and then to the output
coupler. The (A11) coupler assembly
supplies a forward and a reflected power
samples to the (A4) Dual Peak Detector
Board. The Dual Peak Detector Board
supplies reflected and forward output
power samples to the exciter/driver for
metering purposes. The reflected sample
connects to TB31-13 and the forward
sample at TB31-14. The RF output for
the transmitter is at J2 the 7/8” EIA
connector on the (A11) coupler
assembly.
2.1.2.3 1.5 kW Digital Output System
Configuration
In a 1.5 kW system, the outputs of A3,
A6 and A13 power amplifier chassis
assemblies, at the “N” connectors J205,
are cabled to (A7) the hybrid combiner
for the system mounting facing the rear
LX Series Digital Chapter 2, Amplifier Assembly Description,
Power Amplifier Assembly Maintenance & Remote Control Connections
Volume 2, Rev. 1 2-5
of the cabinet. A 500 Watt reject load
(A18), mounted on the roof of the
cabinet, connects to J4 on the hybrid
combiner to dissipate reject power.
Another 500 Watt reject load (A9), also
mounted on the roof, connects to J5 on
the hybrid combiner to dissipate reject
power. Thermal switches (A9-A1 & A18-
A1) are mounted to the reject loads and
supply overtemperature faults, at 175º F.,
to the driver assembly at TB30-7 & 15, if
a problem occurs in the output lines.
NOTE: If an overtemperature fault occurs,
it must be manually reset on the system
controller after repairs are made. The
combined output of the hybrid combiner is
cabled to the externally mounted
assemblies, which consist of (A15) the
digital bandpass filter, (A14) the low pass
filter, (A10) the optional output trap filter
and (A11) the output coupler. The output
coupler assembly supplies a forward and a
reflected sample to the (A44) Dual Peak
Detector Board. The Dual Peak Detector
Board supplies samples to the
exciter/driver for metering purposes. The
reflected sample connects to TB31-13 and
the forward sample to TB31-14. The RF
output for the transmitter is at J2 the 3-
1/8” EIA connector on the (A11) output
coupler assembly.
2.1.2.4 2kW Digital Output System
Configuration
In a 2 kW digital system, the outputs of
the four power amplifier chassis
assemblies must be combined. This is
accomplished by combining two power
amplifier chassis assemblies, creating two
outputs then combing these into one
output. In the (A1) cabinet assembly, the
outputs of the (A1-A3 and A1-A6) power
amplifiers at the “7/16” connectors J205,
are cabled to the (A1-A7) hybrid
combiner, mounted to the input jack of
the (A1-A8) bandpass filter. A 1 kW
reject load (A1-A9), that dissipates reject
power, is mounted on a shelf inside the
(A1) cabinet and is connected to (J4) on
the hybrid combiner. A thermal switch
(A1-A9-A1) is mounted to the reject load
and supplies an overtemperature fault, at
175º F., to the driver assembly at TB30-7
& 15, if a problem occurs in the output
lines for the (A1) amplifier cabinet. The
combined output at (A1-A7-J3) of the
hybrid combiner connects to the (A1-A8)
bandpass filter for filtering before it is
connected either directly to the “7/8”
Jack J1 on (A3) the 2 way combiner
assembly mounted on the roof of the
cabinets, or through the optional (A1-
A12) trap filter and then to the 2 way
combiner.
In the (A2) cabinet, the outputs of the
(A2-A3 and A2-A6) power amplifiers at
the “7/16” connectors J205, are cabled to
(A2-A7) hybrid combiner. A 1 kW reject
load (A2-A9) connects to (J4) on the
hybrid combiner to dissipate reject
power. A thermal switch (A2-A9-A1) is
mounted to the reject load and supplies
an overtemperature fault, at 175º F., to
the driver assembly at TB30-7 & 15, if a
problem occurs in the output lines for the
(A2) amplifier cabinet. The combined
output at (A2-A7-J3) of the hybrid
combiner connects to the (A2-A8)
bandpass filter for filtering before it is
connected either directly to the “7/8”
Jack J2 on (A3) the 2 way combiner
assembly mounted on the roof of the
cabinets, or through the optional (A2-
A12) trap filter and then to the 2 way
combiner. The combined output of the
(A3) 2 way combiner at the 1-5/8”
connector (A3-J3) is connected to the
input of the (A4) output coupler. The
output coupler assembly supplies a
forward power sample at (A4-J3) and a
reflected sample at (A4-J6) to the (A44)
Dual Peak Detector Board. The Dual
Peak Detector Board supplies a reflected
power sample to TB31-13 and a forward
power sample to TB31-14 on the
exciter/driver for metering purposes.
The RF output for the transmitter is at J2
the 1-5/8” connector on the (A4) output
coupler assembly.
2.1.2.5 2.5kW Digital Output System
Configuration
In a 2.5 kW digital system, the outputs of
the five power amplifier chassis
assemblies must be combined. This is
LX Series Digital Chapter 2, Amplifier Assembly Description,
Power Amplifier Assembly Maintenance & Remote Control Connections
Volume 2, Rev. 1 2-6
accomplished by combining three power
amplifier chassis assemblies, creating one
combined output, and combining the
other two power amplifier chassis
assemblies, creating another combined
output. The two combined outputs are
then combined into one output. In the
(A2) cabinet assembly, the outputs of the
(A2-A3, A2-A6, and A2-A13) power
amplifiers at the “7/16” connectors J205,
are cabled to the J1, J2 & J3 input jacks of
(A2-A7) a 3 way hybrid combiner. A 500
Watt reject load (A2-A5), that dissipates
reject power, is mounted near the top of
the (A2) cabinet facing the rear and is
connected to (J5) on the hybrid combiner.
A thermal switch (A2-A5-A1) is mounted
to the reject load and supplies an
overtemperature fault, at 175º F., to the
driver assembly at TB30-7 & 15, if a
problem occurs in the combining process
for the (A2) amplifier cabinet. Another
500 Watt reject load (A2-A8), that
dissipates reject power, is mounted next
to the other load also facing the rear of
the (A2) cabinet and is connected to (J4)
on the hybrid combiner. A thermal switch
(A2-A9-A1) is mounted to the reject load
and supplies an overtemperature fault, at
175º F., to the driver assembly at TB30-7
& 15, if a problem occurs in the combining
process in the (A2) amplifier cabinet. This
fault is in parallel with the other fault line.
The combined output of the A2 cabinet at
(A2-A7-J6) of the hybrid combiner
connects to one of the input jacks (J1) on
(A3) the 2 way combiner mounted on the
roof of the cabinets.
In the (A1) cabinet, the outputs of the
(A1-A3 and A1-A6) power amplifiers at
the “7/16” connectors J205, are cabled to
(A1-A7) hybrid combiner. A 500 Watt
reject load (A1-A18) connects to (J4) on
the hybrid combiner to dissipate reject
power. A thermal switch (A1-A18-A1) is
mounted to the reject load and supplies
an overtemperature fault, at 175º F., to
the driver assembly at TB30-7 & 15, if a
problem occurs during the combining in
the (A1) amplifier cabinet. The combined
output of the A1 cabinet at (A1-A7-J3) of
the hybrid combiner connects to the other
input jack (J2) on (A3) the 2 way
combiner mounted on the roof of the
cabinets. J4 on the combiner connects to
a 1.5 kW reject load (A1-A9), which
dissipates reject power, which is
mounted inside the cabinet facing the
rear of the (A1) cabinet. A thermal
switch (A1-A9-A1) is mounted to the
reject load and supplies an
overtemperature fault, at 175º F., to the
driver assembly at TB30-7 & 15, if a
problem occurs in the combing of the
(A1) and the (A2) amplifier cabinets.
This fault is in parallel with the other
overtemperature fault lines.
The combined output of the (A3)
combiner connects to the (A8) digital
bandpass filter for filtering before it is
connected through the (A12) low pass
trap filter, for additional filtering, to the
input of the (A11) output coupler. The
output coupler assembly supplies a
forward power sample at (A1-A44-J1)
and a reflected sample at (A1-A44-J2) to
the (A44) Dual Peak Detector Board. The
Dual Peak Detector Board supplies a
reflected power sample to TB31-13 and a
forward power sample to TB31-14 on the
exciter/driver for metering purposes.
The RF output for the transmitter is at J2
the 3-1/8” connector on the A11 output
coupler assembly.
2.1.2.6 3kW Digital Output System
Configuration
In a 3 kW system, the outputs of the six
power amplifier chassis assemblies must
be combined. This is accomplished by
combining three power amplifier chassis
assemblies, creating one combined
output, and combining the other three
power amplifier chassis assemblies,
creating another combined output. The
two combined outputs are then combined
into one output. In the (A1) cabinet
assembly, the outputs of the (A1-A3, A1-
A6, and A1-A13) power amplifiers at the
“7/16” connectors J205, are cabled to the
J1, J2 & J3 input jacks of (A1-A7) a 3
way hybrid combiner. A 500 Watt reject
load (A1-A9), that dissipates reject
power, is mounted on the roof of the
(A1) cabinet and is connected to (J5) on
LX Series Digital Chapter 2, Amplifier Assembly Description,
Power Amplifier Assembly Maintenance & Remote Control Connections
Volume 2, Rev. 1 2-7
the hybrid combiner. A thermal switch
(A1-A9-A1) is mounted to the reject load
and supplies an overtemperature fault, at
175º F., to the driver assembly at TB30-7
& 15, if a problem occurs in the output
lines for the (A1) amplifier cabinet.
Another 500 Watt reject load (A1-A18),
that dissipates reject power, is mounted
on the roof of the (A1) cabinet and is
connected to (J4) on the hybrid combiner.
A thermal switch (A1-A18-A1) is mounted
to the reject load and supplies an
overtemperature fault, at 175º F., to the
driver assembly at TB30-7 & 15, if a
problem occurs in the output lines for the
(A1) amplifier cabinet. This fault is in
parallel with the other fault line. The
combined output of the A1 cabinet at (A1-
A7-J6) of the hybrid combiner connects to
one of the input jacks (J1) on (A3) the 2
way combiner mounted on the roof of the
cabinets.
In the (A2) cabinet, the outputs of the
(A2-A3, A2-A6, and A3-A13) power
amplifiers at the “7/16” connectors J205,
are cabled to (A2-A7) hybrid combiner. A
500 Watt reject load (A2-A9) connects to
(J4) on the hybrid combiner to dissipate
reject power. A thermal switch (A2-A9-
A1) is mounted to the reject load and
supplies an overtemperature fault, at
175º F., to the driver assembly at TB30-7
& 15, if a problem occurs in the output
lines for the (A2) amplifier cabinet.
Another 500 Watt reject load (A2-A18),
that dissipates reject power, is mounted
on the roof of the (A2) cabinet and is
connected to (J4) on the hybrid combiner.
A thermal switch (A2-A18-A1) is mounted
to the reject load and supplies an
overtemperature fault, at 175º F., to the
driver assembly at TB30-7 & 15, if a
problem occurs in the output lines for the
(A2) amplifier cabinet.
The combined output of the A2 cabinet at
(A2-A7-J6) of the hybrid combiner
connects to the other input jack (J2) on
(A3) the 2 way combiner mounted on the
roof of the cabinets. J4 on the combiner
connects to a 1.5 kW reject load (A5),
that dissipates reject power, which is
mounted inside the cabinet facing the
rear of the (A2) cabinet. A thermal
switch (A5-A1) is mounted to the reject
load and supplies an overtemperature
fault, at 175º F., to the driver assembly
at TB30-7 & 15, if a problem occurs in
the output lines for the (A2) amplifier
cabinet. This fault is in parallel with the
other overtemperature fault lines. The
combined output of the (A3) combiner
connects to the (A8) bandpass filter for
filtering before it is connected through
the (A12) trap filter, for additional
filtering, to the input of the (A11) output
coupler. The output coupler assembly
supplies a forward power sample at (A1-
A44-J1) and a reflected sample at (A1-
A44-J2) to the (A44) Dual Peak Detector
Board. The Dual Peak Detector Board
supplies a reflected power sample to
TB31-13 and a forward power sample to
TB31-14 on the exciter/driver for
metering purposes. The RF output for
the transmitter is at J2 the 3-1/8”
connector on the A11 output coupler
assembly.
NOTE: If an overtemperature fault
occurs in any system configuration, it
must be manually reset on the system
controller after repairs are made.
The LX Series power amplifier assembly
is made up of the modules and
assemblies listed in Table 2-2.
LX Series Digital Chapter 2, Amplifier Assembly Description,
Power Amplifier Assembly Maintenance & Remote Control Connections
Volume 2, Rev. 1 2-8
Table 2-2: Typical LX Series Power Amplifier Chassis Assemblies
ASSEMBLY
DESIGNATOR ASSEMBLY NAME PART NUMBER
500W/1 kW (250W/500W Digital) Chassis
Assembly 1303953
A3 & (Opt A6 & A13) Power Amplifier Assembly, 250W (125W
Digital) 1302868
Power Supply Assembly 1302863(2kW)
1306971(1kW)
Opt A5 2 or 4 Way Splitter Assembly 1303567 (2 Way)
1303347 (4 Way)
A11 Coupler Assembly 450029
A4 or A44 Dual Peak Detector Board 11159965
2.1.3 Power Amplifier Module
Assembly, 250 Watt, 125W Digital
(1302868; Appendix B)
The 125 Watt Power Amplifier Module
Assembly is made up of (A6) an Amplifier
Control Board (1303682, 1301962 or
1303702), (A1) a UHF Phase/Gain Board
(1303213), (A2) a 150 Watt Driver Pallet
Assembly (1303293), (A3 & A4) two RF
Module Pallets, Philips (1300116), and
(A5) a 2-Way Combiner Board
(1303208).
The Power Amplifier Module contains
Broadband LDMOS amplifiers that cover
the entire UHF band with no tuning
required. Each module amplifies the RF
to a nominal 300W output power. The
Power Amplifier assembly is used to
amplify the RF output of the
Transmitter/Exciter Driver. A cable,
located on the rear chassis, connects the
RF output from the Exciter/Driver at J25
to J200 the RF input to the PA Assembly.
This module contains RF monitoring
circuitry for both an analog and a digital
system. 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 Transmitter/Exciter Driver Power
Amplifier module and any External
Power Amplifier modules contain the
same control and monitoring board.
This board monitors RF output power,
RF reflected power, the current draw of
amplifier sections, the supply voltage,
and the temperature of the PA heat sink.
The RF power detector circuit outputs
vary with operating frequency. These
circuits must be calibrated at their
intended operating frequency. The
following front panel potentiometers are
used to set the Power Amplifier
Calibrations.
R201 Reflected Power Cal
R202 Forward Power Cal
R204 Meter Offset Zero
In digital systems, the Forward power of
an Exciter Driver Power Amplifier and
the Forward power of any external
amplifier, is reported by the system
Control Monitoring module.
If the Control Monitoring module is
monitoring a 5-50 Watt Digital system,
power is measured in the Power
Amplifier module. The wired
connections are transferred through the
power supply connector to the
backplane board on a five position
header. All four positions of control
board switch SW1 must be set on to
LX Series Digital Chapter 2, Amplifier Assembly Description,
Power Amplifier Assembly Maintenance & Remote Control Connections
Volume 2, Rev. 1 2-9
route these lines as the system's RF
power signals. In systems of output
power greater than 50 Watts digital,
system power is monitored by an
external module that is connected to
TB31 and control board SW1 switches
must be set off.
The Forward Power of the
Transmitter/Exciter Driver 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 2-3. Power Amplifier Status Indicator
LED FUNCTION
ENABLED
(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.
DC OK
(Green)
When lit Green, it indicates that the fuse protected DC inputs to the PA
module are OK.
TEMP
(Green)
When lit Green, it indicates that the temperature of the heatsink
assembly in the module is below 78ûC.
MOD OK
(Green)
When lit Green, it indicates that the PA Module is operating and has no
faults.
MOD OK
(Red)
If the Module OK LED is Red and blinking a fault is present.
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.
Table 2-4. Power Amplifier Control Adjustments
POTENTIOMETERS DESCRIPTION
RFL CAL Adjusts the gain of the Reflected Power monitoring circuit
FORWARD CAL Adjusts the gain of the Dual Peak Detector Board. Forward Power
monitoring circuit
METER ZERO Adjusts the offset of the Forward Power monitoring circuit
Table 2-5. Power Amplifier Sample
DISPLAY FUNCTION
FWD SAMPLE RF sample of the amplified signal being sent out the module on J25.
LX Series Digital Chapter 2, Amplifier Assembly Description,
Power Amplifier Assembly Maintenance & Remote Control Connections
Volume 2, Rev. 1 2-10
2.1.4 Power Supply Module
Assembly, LX Series (1302863(2kW)
or 1306971(1kW); Appendix B)
The Power Supply Module Assembly
1302863 is made up of (A1) a
+32V/2000W Switching Power Supply
and (A2) a ±12V/40W Switching Power
Supply. The Power Supply Module
Assembly 1306971 is made up of (A1) a
+32V/1000W Switching Power Supply
and (A2) a ±12V/40W Switching Power
Supply.
The power supply module provides the
+32 VDC and the +12 VDC and –12 VDC
to the power amplifier module assembly.
There is one On/Off Circuit Breaker,
which is mounted on the rear of the
power amplifier chassis assembly, which
supplies AC to each power supply module
assembly.
2.1.5 Front Panel Display Screens
A 4 x 20 display located on the front of
the Control & Monitoring/Power Supply
Module is used in the LX Series
transmitter for control of the operation
and display of the operating parameters
of the entire transmitter.
2.2 External Assembly
2.2.1 (A4, A13, A44 or A45) Dual
Peak Detector Board (1159965;
Appendix B)
The Dual Peak Detector Board provides
detected outputs of the Forward at J3-4
that connects to TB31-14 on the
Driver/Amplifier Assembly and Reflected
at J3-9 that connects to TB31-13 on the
Driver/Amplifier Assembly, which are
used for monitoring on the controller
display. The board also provides
adjustments for the calibration of the
readings on the meter. These readings
are attained from the samples of the
Forward Power that connects to J1 and
Reflected Power that connects to J3 of
the system from the output coupler
assembly.
2.3 System Operation
When the transmitter is in operate, as set
by the menu screen located on the
Control & Monitoring Module in the
exciter/driver assembly. The IF
Processor will be enabled, the mute
indicator on the front panel will be
extinguished. The +32 VDC stage of the
Power Supply in the Control & Monitoring
Module is enabled, the operate indicator
on the front panel is lit and the DC OK on
the front panel should also be green.
The enable and DC OK indicators on the
PA Module will also be green.
When the transmitter is in standby. The
IF Processor will be disabled, the mute
indicator on the front panel will be red.
The +32 VDC stage of the Power Supply
in the Control & Monitoring Module is
disabled, the operate indicator on the
front panel will be extinguished and the
DC OK on the front panel should remain
green. The enable indicator on the PA
Module is also extinguished.
If the transmitter does not switch to
Operate when the operate menu is
switched to Operate, check that all faults
are cleared and that the remote control
terminal block stand-by signal is not
active.
The transmitter can be controlled by the
presence of a modulated input signal. If
the input signal to the transmitter is lost,
the transmitter will automatically cutback
and the input fault indicator on the IF
Processor module will light. When the
video input signal returns, the
transmitter will automatically return to
full power and the input fault indicator
will be extinguished.
If alignment or calibration is required to
the transmitter, refer to Volume 1,
Chapter 5 of the instruction manual.
LX Series Digital Chapter 2, Amplifier Assembly Description,
Power Amplifier Assembly Maintenance & Remote Control Connections
Volume 2, Rev. 1 2-11
2.3.1 Principles of Operation
Operating Modes
This transmitter is either operating or in
standby mode. The sections below
discuss the characteristics of each of
these modes.
Operate Mode
Operate mode is the normal mode for
the transmitter when it is providing RF
power output. To provide RF power to
the output, the transmitter will not be in
mute. Mute is a special case of the
operate mode where the +32 VDC
section of the power supply is enabled
but there is no RF output power from
the transmitter. This condition is the
result of a fault condition that causes
the firmware to hold the IF Processor
module in a mute state.
Operate Mode with Mute Condition
The transmitter will remain in the
operate mode but will be placed in mute
when the following fault conditions
exists in the transmitter.
• Upconverter is unlocked
• Upconverter module is not present
• IF Processor module is not present
Entering Operate Mode
Entering the operate mode can be
initiated a few different ways by the
transmitter control board. A list of the
actions that cause the operate mode to
be entered is given below:
• A low on the Remote Transmitter
Operate line.
• User selects "OPR" using switches
and menus of the front panel.
• Receipt of an “Operate CMD” over
the serial interface.
There are several fault or interlock
conditions that may exist in the
transmitter that will prevent the
transmitter from entering the operate
mode. These conditions are:
• Power Amplifier heat sink
temperature greater than 78ûC.
• Transmitter is Muted due to
conditions listed above.
• Power Amplifier Interlock is high
indicating that the amplifier is not
installed.
Standby Mode
The standby mode in the transmitter
indicates that the output amplifier of the
transmitter is disabled.
Entering Standby Mode
Similar to the operate mode, the
standby mode is entered using various
means. These are:
• A low on the Remote Transmitter
Stand-By line.
• Depressing the “STB” key on
selected front panel menus.
• Receipt of a “Standby CMD” over the
serial interface.
Auto Standby Mode
The FCC requires that certain
transmitters automatically switch to
standby operation on loss of video input.
The LX Series transmitter incorporates
this feature as a user configurable
setting. When Auto Standby on
modulation loss is selected in the set-up
menus, the transmitter temporarily
switches to standby after ten seconds of
modulation loss. When the modulated
signal as reported by the IF Processor
module is again present, the transmitter
automatically returns to Operate mode.
This feature is implemented in
LX Series Digital Chapter 2, Amplifier Assembly Description,
Power Amplifier Assembly Maintenance & Remote Control Connections
Volume 2, Rev. 1 2-12
transmitter software version 1.4 and
above.
RF System Interlock
A RF System Interlock signal is provided
through TB30-5. When this interlock
circuit is completed to ground such as
through a jumper between TB30-5 and
TB30-15, the transmitter is allowed to
operate. If this circuit is opened, the
transmitter switches to a Mute condition.
The interlock must be in place for the
system to operate. This interlock circuit
may be completed through coax relay
contacts and/or reject load contact
closures to assure the RF output system
is available to receive the transmitter's
output RF signal before the transmitter
is allowed to operate. This feature is
implemented in transmitter software
version 1.4 and above.
Operating Frequency
NOTE: The exact output frequency of
the transmitter was set at the factory
and needs no customer adjustment.
If change of frequency is required, refer
to Volume 1 Chapter 5 of the Instruction
Manual for more information and to the
Axcera field support department at 724-
873-8100.
2.4 Maintenance
The LX Series Transmitter is designed
with components that require little or no
periodic maintenance except for the
routine cleaning of the fans and the front
panels of the modules.
The amount of time between cleanings
depends on the conditions within the
transmitter room. While the electronics
have been designed to function even if
covered with dust, a heavy buildup of
dust, dirt, or insects will affect the
cooling of the components. This could
lead to a thermal shutdown or the
premature failure of the affected
modules.
When the front panels of the modules
become dust covered, the top covers
should be taken off and any accumulated
foreign material should be removed. A
vacuum cleaner, utilizing a small, wand-
type attachment, is an excellent way to
suction out the dirt. Alcohol and other
cleaning agents should not be used
unless you are certain that the solvents
will not damage components or the silk-
screened markings on the modules and
boards. Water-based cleaners can be
used, but do not saturate the
components. The fans and heatsinks
should be cleaned of all dust or dirt to
permit the free flow of air for cooling
purposes.
It is recommended that the operating
parameters of the amplifier assembly and
transmitter be recorded from the LEDs on
the modules and the LCD system
metering on the control/monitoring
module at least once a month. It is
suggested that this data be retained in a
rugged folder or envelope.
2.5 Customer Remote Connections
The remote monitoring and operation of
the transmitter is provided through
terminal blocks TB30 and TB31 located
on the rear of the chassis assembly. If
remote connections are made to the
transmitter, they must be made through
terminal blocks TB30 and TB31 at the
positions noted on the transmitter
interconnect drawing and Table 2-6.
LX Series Digital Chapter 2, Amplifier Assembly Description,
Power Amplifier Assembly Maintenance & Remote Control Connections
Volume 2, Rev. 1 2-13
Table 2-6: LX Series Chassis Assembly Hard Wired Remote Interface Connections to
TB30 or TB31, which are 18 position Terminal Blocks located on the rear
of the Assembly
Signal Name Pin
Designations Signal Type/Description
RMT Transmitter
State TB30-1 Discrete Open Collector Output - A low indicates that the
transmitter is in the operate mode.
RMT Transmitter
Interlock TB30-2
Discrete Open Collector Output - A low indicated the
transmitter is OK or completes an interlock daisy chain.
When the transmitter is not faulted, the interlock circuit is
completed.
RMT Transmitter
Interlock
Isolated Return
TB30-3
Ground - Configurable ground return which can be either
jumpered directly to ground or it can be the “source” pin of
an FET so that the transmitter interlock can be daisy
chained with other transmitters. This signal does not
directly interface to the microcontroller.
RMT AUX IO 1 TB30-4
Discrete Open Collector Inputs, Discrete Open Drain
Outputs, or 0 - 5 VDC Analog Input - When used as an
output, this line is pulled to +5 VDC with a 1.0 kΩ resistor
for logic high and pulled to ground for a low. A diode allows
this line to be pulled up to 12 VDC. When used as a digital
input, this line considers all values over 2 Volts as high and
those under 1 volt as low. As an analog input, this line is
protected by a 5.1 Zener diode.
*RF System
Interlock TB30-5
When this signal's circuit is completed to ground such as
through a jumper between TB30-5 and TB30-15, the
transmitter is allowed to operate. If this circuit is opened,
the transmitter switches to a Mute condition. May be used
as an external interlock with TB30-15.
RMT
Transmitter
Operate
TB30-6
Discrete Open Collector Input - A pull down to ground on
this line indicates that the transmitter is to be placed into
the operate mode.
RMT
Transmitter
Stand-By
TB30-7
Discrete Open Collector Input - A pull down to ground on
this line indicates that the transmitter is to be placed into
the standby mode.
RMT Power
Raise TB30-8
Discrete Open Collector Input - A pull down to ground on
this line indicates that the transmitter power is to be raised.
TB30
TB31
LX Series Digital Chapter 2, Amplifier Assembly Description,
Power Amplifier Assembly Maintenance & Remote Control Connections
Volume 2, Rev. 1 2-14
Signal Name Pin
Designations Signal Type/Description
RMT Power
Lower TB30-9
Discrete Open Collector Input - A pull down to ground on
this line indicates that the transmitter power is to be
lowered.
RMT
System Reflect
Power
TB30-10
Analog Output - 0 to 4.0 V- This is a buffered loop through
of the calibrated “System Reflected Power ” and indicates
the transmitter's reflected output power. The scale factor is
25%/3.2V.
RMT System
Forward Power TB30-11
Analog Output - 0 to 4.0 V- This is a buffered loop through
of the calibrated “System Avg. Power ”. Indicates the
transmitter's Average power. Scale factor is 100%/3.2V.
RMT
System Aural
Power
TB30-12
(NOT USED) Analog Output - 0 to 4.0 V- This is a buffered
loop through of the calibrated “System Aural Power ”.
Indicates the transmitter's forward Aural output power. The
scale factor is 100%/3.2V.
RMT Spare 1 TB30-13 Remote connection to spare module - Use is TBD.
RMT Spare 2 TB30-14 Remote connection to spare module - Use is TBD.
*System Reflect
Power TB31-13
Analog Input - 0 to 1.00 V- This is the input of the “System
Reflected Power ” indicating the transmitter's reflected
output power. The scale factor is 25%/0.80V.
*System
Forward Power TB31-14
Analog Input - 0 to 1.00 V- This is the input of the “System
Forward Power ” indicating the transmitter's Forward output
power. The scale factor is 100%/0.80V.
System Aural
Power TB31-15
(NOT USED) Analog Input - 0 to 1.00 V- This is the input of
the “System Aural Power ” indicating the transmitter's
forward Aural output power. The scale factor is
100%/0.80V.
*RMT Ground TB30-15
Ground pins available through Remote for interlock.
Typically connected to TB30-5. May be used as an external
interlock with TB30-5.
RMT Ground
TB30-17,
TB31-1, 2, 6
to 12, and 17
Ground pins available through Remote
*+12 VDC TB30-16 +12 VDC to Dual Peak Detector Board through 2 Amp re-
settable fuse
RMT +12 VDC TB31-16 +12 VDC available through Remote w/ 2 Amp re-settable
fuse
*-12 VDC TB30-18 -12 VDC to Dual Peak Detector Board through 2 Amp re-
settable fuse
RMT -12 VDC TB31-18 -12 VDC available through Remote w/ 2 Amp re-settable
fuse
* Indicates that this function is used by the system and not for remote use.
LX Series Digital Chapter 2, Amplifier Assembly Description,
Power Amplifier Assembly Maintenance & Remote Control Connections
Volume 2, Rev. 1 2-15
Table 2-7: (Optional) Exciter Switcher Hard Wired Remote Interface Connections to TB1,
18 pos. Terminal Block are located on the Rear of the Exciter Switcher Tray Assembly.
Signal Name Pin
Designations Signal Type/Description
Select Automatic
Operation TB1-1 0 = SET, NC = No Change
Select Manual Operation TB1-2 0 = SET, NC = No Change
Select Exciter A (1) TB1-3 0 = SET, NC = No Change
Select Exciter B (2) TB1-4 0 = SET, NC = No Change
Selected Exciter to
Operate TB1-5 0 = SET, NC = No Change
Selected Exciter to
Standby TB1-6 0 = SET, NC = No Change
Selected Exciter Power
Raise TB1-7 0 = SET, NC = No Change
Selected Exciter Power
Lower TB1-8 0 = SET, NC = No Change
TB1-9 NOT USED IN THIS CONFIGURATION
TB1-10 NOT USED IN THIS CONFIGURATION
TB1-11 NOT USED IN THIS CONFIGURATION
Selected Operation TB1-12 0 = Auto, Open = Manual
Selected Exciter TB1-13 0 = A, Open = B
Selected Exciter Logged
Faults TB1-14 0 = None, 1 = 1 or More
Selected Exciter Current
Errors TB1-15 0 = None, 1 = 1 or More
Alternate Exciter Logged
Faults TB1-16 0 = None, 1 = 1 or More
Alternate Exciter
Current Errors TB1-17 0 = None, 1 = 1 or More
Ground TB1-18 Ground
NOTE: In versions previous to 2.0, for the automatic switching to the back up exciter,
the Error, Fault, Log in the back up exciter must be cleared of all Previous Faults..
LX Series Digital Chapter 3, Site Considerations,
Power Amplifier Assembly Installation and Setup Procedures
Volume 2, Rev. 1 3-1
Chapter 3
Site Considerations, Installation and Setup Procedures
Table 3-1: LX Series Digital Transmitters AC Input and Current Requirements.
Transmitter Voltage Current
125 Watt 220 VAC 10 Amps to the Exciter/Amplifier Cabinet
250 Watt 220 VAC 15 Amps to the Exciter/Amplifier Cabinet
500 Watt 220 VAC 25 Amps to the Exciter/Amplifier Cabinet
1000 Watt 220 VAC 45 Amps to the Exciter/Amplifier Cabinet
1500 Watt 220 VAC 65 Amps to the Exciter/Amplifier Cabinet
220 VAC 45 Amps to the Exciter/Amplifier Cabinet
2000 Watt 220 VAC 40 Amps to the Amplifier Cabinet
220 VAC 45 Amps to the Exciter/Amplifier Cabinet
2500 Watt 220 VAC 60 Amps to the Amplifier Cabinet
220 VAC 65 Amp to the Exciter/Amplifier Cabinet
3000 Watt 220 VAC 60 Amps to the Amplifier Cabinet
3.1 Site Considerations
There are special considerations that
need to be taken into account before the
LX Series digital driver/transmitter can
be installed. For example, if the
installation is completed during cool
weather, a heat-related problem may not
surface for many months, suddenly
appearing during the heat of summer.
This section provides planning
information for the installation and set up
of the transmitter.
The AC input and current requirements
for LX Series digital transmitter/drivers
are shown in Table 3-1.
NOTES: The transmitter is factory set
for either 110 VAC or 220 VAC
operation as directed by customer.
Transmitters above 125 Watts use
220 VAC Input only.
Transmitters 2000 Watts and above
require two 220 VAC Inputs, one to
each cabinet.
The LX Series Digital Transmitters are
designed and built to provide long life
with a minimum of maintenance. The
environment in which they are placed is
important and certain precautions must
be taken. The three greatest dangers to
the transmitter are heat, dirt, and
moisture. Heat is usually the greatest
problem, followed by dirt, and then
moisture. Over-temperature can cause
heat-related problems such as thermal
runaway and component failure. Each
amplifier module in the transmitter
contains a thermal interlock protection
circuit that will shut down that module
until the temperature drops to an
acceptable level.
A suitable environment for the
transmitter can enhance the overall
performance and reliability of the
transmitter and maximize revenues by
minimizing downtime. A properly
designed facility will have an adequate
supply of cool, clean air, free of airborne
particulates of any kind, and no
excessive humidity. An ideal environment
will require temperature in the range of
40° F to 70° F throughout the year,
reasonably low humidity, and a dust-free
room. It should be noted that this is
rarely if ever attainable in the real world.
However, the closer the environment is
to this design, the greater the operating
capacity of the transmitter.
The fans are designed and built into the
transmitter will remove the heat from
within the modules, but additional means
are required for removing this heat from
the building. To achieve this, a few issues
need to be resolved. The first step is to
LX Series Digital Chapter 3, Site Considerations,
Power Amplifier Assembly Installation and Setup Procedures
Volume 2, Rev. 1 3-2
determine the amount of heat to be
removed from the transmitter room.
There are generally three sources of heat
that must be considered. The first and
most obvious is the heat from the
transmitter itself. This amount can be
determined for a 1000W digital
transmitter by subtracting the average
power to the antenna (1000 watts) from
the AC input power (6700 watts) and
taking this number in watts (5700) and
then multiplying it by 3.41. This gives a
result of 19,437, the BTUs to be removed
every hour. 12,000 BTUs per hour equals
one ton. Therefore, a 1-3/4-ton air
conditioner will cool a 1000W digital
transmitter.
The second source of heat is other
equipment in the same room. This
number is calculated in the same way as
the equation for BTUs. The third source
of heat is equally obvious but not as
simple to calculate. This is the heat
coming through the walls, roof, and
windows on a hot summer day. Unless
the underside is exposed, the floor is
usually not a problem. Determining this
number is usually best left up to a
qualified HVAC technician. There are far
too many variables to even estimate this
number without reviewing the detailed
drawings of the site that show all of the
construction details. The sum of these
three sources is the bulk of the heat that
must be removed. There may be other
sources of heat, such as personnel, and
all should be taken into account.
Now that the amount of heat that must
be removed is known, the next step is to
determine how to accomplish this. The
options are air conditioning, ventilation,
or a combination of the two. Air
conditioning is always the preferred
method and is the only way to create
anything close to an ideal environment.
Ventilation will work quite well if the
ambient air temperature is below 100° F,
or about 38° C, and the humidity is kept
at a reasonable level. In addition, the air
stream must be adequately filtered to
ensure that no airborne particulates of
any kind will be carried into the
transmitter. The combination of air
conditioning for summer and ventilation
during the cooler months is acceptable
when the proper cooling cannot be
obtained through the use of ventilation
alone and using air conditioning
throughout the year is not feasible.
Caution: The use of air conditioning
and ventilation simultaneously is not
recommended. This can cause
condensation in the transmitters.
The following precautions should be
observed regarding air conditioning
systems:
1. Air conditioners have an ARI
nominal cooling capacity rating. In
selecting an air conditioner, do not
assume that this number can be
equated to the requirements of
the site. Make certain that the
contractor uses the actual
conditions that are to be
maintained at the site in
determining the size of the air
conditioning unit. With the desired
conditioned room temperature
under 80° F, the unit must be
derated, possibly by a substantial
amount.
2. Do not have the air conditioner
blowing directly onto the
transmitter. Under certain
conditions, condensation may
occur on, or worse in, the
transmitter.
3. Do not separate the front of the
transmitter from the back with the
thought of air conditioning only
the front of the unit. Cooling air is
drawn in at the front of all
transmitters and in the front and
back of others. Any attempt to
separate the front of the
transmitter from the rear of the
unit will adversely affect the flow
of cooling air.
LX Series Digital Chapter 3, Site Considerations,
Power Amplifier Assembly Installation and Setup Procedures
Volume 2, Rev. 1 3-3
4. Interlocking the transmitter with
the air conditioner is
recommended to keep the
transmitter from operating without
the necessary cooling.
5. The periodic cleaning of all filters
is a must.
When using ventilation alone, the
following general statements apply:
1. The blower, with attendant filters,
should be on the inlet, thereby
pressurizing the room and
preventing dirt from entering the
transmitter.
2. The inlet and outlet vents should
be on the same side of the
building, preferably the leeward
side. As a result, the pressure
differential created by wind will be
minimized. Only the outlet vent
may be released through the roof.
3. The inlet and outlet vents should
be screened with 1/8-inch
hardware cloth (preferred) or
galvanized hardware cloth
(acceptable).
4. Cooling air should enter the room
as low as practical but in no case
higher than four feet above the
floor. The inlet must be located
where dirt, leaves, snow, etc., will
not be carried in with the cooling
air.
5. The exhaust should be located as
high as possible. Some ducting is
usually required to insure the
complete flushing of heated air
with no stagnant areas.
6. The filter area must be large
enough to insure a maximum air
velocity of 300 feet per minute
through the filter. This is not a
conservative number but a never-
exceed number. In a dusty or
remote location, this number
should be reduced to 150 CFM.
7. The inlet and outlet(s) must have
automatic dampers that close any
time the ventilation blower is off.
8. In those cases in which
transmitters are regularly off for a
portion of each day, a
temperature-differential sensor
that controls a small heater must
be installed. This sensor will
monitor inside and outside
temperatures simultaneously. If
the inside temperature falls to
within 5° F of the outside
temperature, the heater will come
on. This will prevent condensation
when the ventilation blower comes
on and should be used even in the
summer.
9. A controlled-air bypass system
must be installed to prevent the
temperature in the room from
falling below 40° F during
transmitter operation.
10. The blower should have two
speeds, which are thermostatically
controlled, and be interlocked with
the transmitter.
11. The blower on high speed must be
capable of moving the required
volume of air into a half inch of
water pressure at the required
elevation. The free air delivery
method must not be used.
12. Regular maintenance of the filters,
if used, can not be
overemphasized.
13. Above 4000 feet, for external
venting, the air vent on the
cabinet top must be increased to
an 8-inch diameter for a 1-kW
transmitter and to a 10-inch
diameter for 5-kW and 6-kW
transmitters. An equivalent
rectangular duct may be used but,
LX Series Digital Chapter 3, Site Considerations,
Power Amplifier Assembly Installation and Setup Procedures
Volume 2, Rev. 1 3-4
in all cases, the outlet must be
increased by 50% through the
outlet screen.
14. It is recommended that a site plan
be submitted to Axcera for
comments before installation
begins.
In calculating the blower requirements,
filter size, and exhaust size, if the total
load is known in watts, 2000 CFM into ½
inch of water will be required for each
5000 watts. If the load is known in BTUs,
2000 CFM into ½ inch of water will be
required for each 17,000 BTUs. The inlet
filter must be a minimum of seven
square feet, larger for dusty and remote
locations, for each 5000 watts or 17,000
BTUs. The exhaust must be at least four
square feet at the exhaust screen for
each 5000 watts or 17,000 BTUs.
The information presented in this section
is intended to serve only as a general
guide and may need to be modified for
unusually severe conditions. A
combination of air conditioning and
ventilation should not be difficult to
design (see Figure 3-1).
System interlocking and thermostat
settings should be reviewed with Axcera.
As with any equipment installation, it is
always good practice to consult the
manufacturer when questions arise.
Axcera can be contacted at (724) 873-
8100.
Figure 3-1. 500 Watt Minimum Ventilation Configuration
LX Series Digital Chapter 3, Site Considerations,
Power Amplifier Assembly Installation and Setup Procedures
Volume 2, Rev. 1 3-5
3.2 Unpacking the Chassis
w/modules and bandpass filter
Thoroughly inspect the chassis with
modules and all other materials upon
their arrival. Axcera certifies that upon
leaving our facility the equipment was
undamaged and in proper working order.
The shipping containers should be
inspected for obvious damage that
indicates rough handling.
Remove the chassis and modules, along
with bandpass filter and optional trap
Filter, from the crates and boxes. Check
for dents and scratches or broken
connectors, switches, display, or
connectors. Any claims against in-transit
damage should be directed to the carrier.
Inform Axcera as to the extent of any
damage as soon as possible.
The modules are mounted to the chassis
assembly with slides that are on the top
and the bottom of the modules. There
are two thumb screws on the front panel
that hold each of the modules in place.
3.3 Installing the Chassis w/modules
and filters
The exciter/driver and power amplifier
chassis assemblies are made to mount in
a standard 19” rack. The chassis
assemblies mount using the four #10
clearance mounting holes on the ends.
The chassis should be positioned; to
provide adequate air intake into the front
and the air exhaust of the fan in the rear;
the ability to slide the modules out for
replacement purposes; the installation of
the bandpass filter; optional trap filter;
the coupler assembly; and output
transmission line. The chassis or cabinet
in which it is mounted should be
grounded using copper strapping
material.
NOTE: To remove the driver/power
amplifier module, mounted in the
exciter/driver assembly, the input and
output cables must be removed from the
rear of the module and also a 6/32” x ½”
Philips screw, mounted between the two
connectors, needs to be removed before
the module will pull out. After removal of
the screw, which is used to hold the
module in place during shipping, it does
not need to be replaced. (See Figure 3-2)
NOTE: To remove the Combiner Module,
found in the power amplifier assembly in
high power transmitters, the output cable
must be removed from the rear of the
module and also two 8/32” x ½” Philips
screws, mounted above the connector,
need to be removed before the module
will pull out. After removal of the screws,
which are used to hold the module in
place during shipping, they do not need
to be replaced.
Figure 3-2. Front and Rear View Exciter/Driver
Shipping Screw
LX Series Digital Chapter 3, Site Considerations,
Power Amplifier Assembly Installation and Setup Procedures
Volume 2, Rev. 1 3-6
3Kw
2Kw
Figure 3-3. Front and Rear View 76” Cabinet Typical 2kW Digital Configuration
Connect the transmission line for the
antenna system to the output of the
coupler assembly or the Bandpass Filter.
If the optional trap filter is present in
your system, a BNC sample jack is
located on the trap filter and can be used
for test purpose.
3.4 AC Input
Once the chassis and output connections
are in place, the AC can be connected to
the transmitter. The AC Input to the
high power transmitter connects to the
terminal block mounted in the AC input
box located toward the rear, right side
near the top of the cabinet. Connect the
AC Input Line 1 to Line 1 on the terminal
block, the AC Input Line 2 to Line 2 on
the terminal block and the AC Input
Ground to Ground on the terminal block.
Refer to Table 3-1 at the beginning of
this chapter for typical AC Input and
Current requirements for Digital
Transmitters.
Figure 3-4. AC Input Box Assembly.
NOTES: Transmitters 2000 Watts and
above require two 220 VAC Inputs,
one to each cabinet.
An On/Off circuit breaker is located
on the rear of the exciter/driver
assembly near the AC input jack.
One On/Off circuit breaker is located
on the rear of the Power Amplifier
Chassis Assembly for each Power
Supply Assembly.
This completes the unpacking and
installation of the LX Series UHF
television transmitter. Refer to the setup
ON/OFF
CIRCUIT BREAKERS
ON/OFF
CIRCUIT BREAKER
LX Series Digital Chapter 3, Site Considerations,
Power Amplifier Assembly Installation and Setup Procedures
Volume 2, Rev. 1 3-7
and operation procedures that follow
before applying power to the transmitter.
3.5 Setup and Operation
Initially, the transmitter should be turned
on with the RF output at the directional
coupler terminated into a dummy load of
at least the rated power of the
transmitter. If a load is not available,
check that the output of the directional
coupler is connected to the antenna for
your system.
3.5.1 Input Connections
The input connections to the transmitter
are to the rear of the Exciter/Driver
Chassis Assembly for the transmitter.
Refer to the tables and description that
follows for detailed information.
Figure 3-5: Rear View of LX Series Transmitter/Translator
Table 3-2: Rear Chassis Connections for the LX Series Transmitter.
Port Type Function Impedance
J1 IEC AC Input N/A
TB02 Term (Not Used) Base Band Audio Input 600Ω
J3 BNC (Not Used) Composite Audio Input 75Ω
J4 BNC (Not Used) SAP / PRO Audio Input 50Ω
J5 BNC (Not Used) CW IF Input 50Ω
J6 BNC Modulated IF Input (Jumper from J13) 50Ω
J7 BNC (Not Used) Video Input (Isolated) 75Ω
J8 BNC (Not Used) Visual IF Loop-Thru Output 50Ω
J9 BNC (Not Used) Aural IF Loop-Thru Output 50Ω
J10 BNC External 10 MHz Reference Input 50Ω
J11 BNC System 10 MHz Reference Output 50Ω
J12 BNC MPEG Input 50Ω
J1
J24
J25
J21 TB30
TB31
J32 J34
J33
J11
J10
J23
J6
J5
J19
J18 TB02
J3
J4
J7
J17
J8
J9
J12
J13
J14
SPARE
J15
SPARE
LX Series Digital Chapter 3, Site Considerations,
Power Amplifier Assembly Installation and Setup Procedures
Volume 2, Rev. 1 3-8
Port Type Function Impedance
J13 BNC 8 VSB IF Output (Jumper to J6) 50Ω
J14 BNC RF Spare 2 50Ω
J15 BNC RF Spare 1 50Ω
J17 BNC (Not Used) Video Loop-Thru (Isolated) 75Ω
J18 BNC (Not Used) Visual IF Loop-Thru Input 50Ω
J19 BNC (Not Used) Aural IF Loop-Thru Input 50Ω
J23 BNC Upconverter RF Output 50Ω
J24 BNC Power Amplifier RF Input 50Ω
J25 N Power Amplifier RF Output 50Ω
TB30 Term Remote Control & Monitoring N/A
TB31 Term Remote Control & Monitoring N/A
J32 RJ-45 SCADA (Input / Loop-Thru) CAT5
J33 RJ-45 SCADA (Input / Loop-Thru) CAT5
J34 RJ-45 System RS-485 Serial CAT5
3.5.2 Initial Turn On
Once the unit has been installed and all
connections have been made, the
process of turning on the equipment can
begin. First verify that AC power is
present and connected to the AC Input
Box of the transmitter. Verify all cables
are properly connected and are the
correct type. Once all of these things are
completed, the unit is ready to be turned
on following the procedures below.
Turn on the main AC power source that
supplies the AC to the transmitter. Check
that the AC power plug is connected to
J1 on the rear of the chassis assembly.
Check that the On/Off circuit breakers
located on the rear of the exciter/driver
and Power Amplifier Chassis Assemblies
are switched On. On the Power Amplifier
Chassis Assemblies, there is one circuit
breaker per Power Supply Assembly.
Monitor the LCD display located on the
front of the control/monitoring module
as you proceed through this section.
When the transmitter is in the operate
mode, the STB menu appears. When in
the standby mode, the OPR menu
appears. Press the NXT key after each
menu to continue through to the next
sequence.
3.5.2.1 DM8 Digital Modulator
Module LEDs on Front Panel
Status Indicators:
MPEG: This illuminates Green if the
MPEG stream at the J1-2B input jack is
valid.
PLL A: This illuminates Green if the
DM8 symbol clock is locked to the
frequency of the 10 MHz reference.
PLL B: This illuminates Green if the
pilot frequency is locked to the 10 MHz
reference.
3.5.2.2 IF Processor Module LEDs on
Front Panel
Fault Indicators:
INPUT FAULT: This illuminates Red if
the input to the module is missing or
low.
ALC FAULT: This illuminates RED when
the needed ALC value to maintain the
output level is beyond the range of the
circuitry.
MUTE: This indicator will illuminate Red
when the transmitter is muted.
LX Series Digital Chapter 3, Site Considerations,
Power Amplifier Assembly Installation and Setup Procedures
Volume 2, Rev. 1 3-9
3.5.2.3 VHF/UHF Upconverter Module
LEDs on Front Panel
Fault Indicators:
AGC FAULT: This illuminates Red if the
required gain to produce the desired
output level is beyond the value set by
the AGC circuit. AGC out of range.
AGC OVERRIDE: This illuminates Red if
the drive to the driver module is too
high.
MAN GAIN: This illuminates Red if the
AGC is bypassed in Manual.
PLL 1: This illuminates Red if the 1 GHz
PLL is unlocked.
PLL 2: This illuminates Red if the 1.1-
1.9 GHz PLL is unlocked.
3.5.2.4 Controller Module LEDs on
Front Panel
Status Indicators:
OPERATE: This illuminates Green when
transmitter is in operate.
FAULT: This illuminates Red when a
fault has occurred in the transmitter.
DC OK: This illuminates Green when the
DC outputs that connect to the modules
in the transmitter are present.
3.5.2.5 Power Amplifier or Driver
Module LEDs on Front Panel
NOTE: Both the PA Module and
Driver Module have the same front
panel LEDs.
Status Indicators:
ENABLED: This illuminates Green when
the PA is in operate.
DC OK: This illuminates Green when the
DC inputs to the PA module are present.
TEMP: This illuminates Green when the
temperature of the heatsink in the PA is
below 78°C.
MOD OK: This illuminates Green when
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
3.5.3 Front Panel Screens for the
Exciter/Amplifier Chassis Assembly
A 4 x 20 display located on the front of
the Control & Monitoring/Power Supply
Module is used in the LX Series
transmitter for control of the operation
and display of the operating parameters
of the transmitter. The ↑ and ↓
characters are special characters used
to navigate up or down through the
menu screens. Display text flashes on
discrete fault conditions for all screens
that display a fault condition. When the
transmitter is in operate mode, the STB
menu appears. When the transmitter is
in standby mode, the OPR menu
appears.
NOTE: A detailed description of the
front panel screens is given in Volume 1
Chapter 3.
3.5.4 Operation Procedure
If necessary, connect the transmitter to
the antenna. Check that the output is
100% and if needed, adjust the ALC
Gain adjust pot on the front panel of the
IF Processor to attain 100%. The power
raise / lower settings, in the menus, are
LX Series Digital Chapter 3, Site Considerations,
Power Amplifier Assembly Installation and Setup Procedures
Volume 2, Rev. 1 3-10
only to be used for temporary reductions
in power. The power set-back values do
not directly correspond to the power of
the transmitter. Setting for 50% output
sets a linear circuit voltage that is
controlling a non-linear power circuit.
This completes the Installation, Set Up
and Turn On of the Transmitter.
If a problem occurred during the setup
and operation procedures, refer to
Volume 1 Chapter 5, Detailed Alignment
Procedures, of this manual for more
information.
LX Series Digital Chapter 4, Circuit Descriptions
Power Amplifier Assembly
Volume 2, Rev. 1 4-1
Chapter 4
Circuit Descriptions
Power Amplifier Chassis Assembly
The RF from the exciter/driver assembly
connects from the RF Output “N” Jack J25,
through a RG-55 cable, to the PA RF Input
“N” Jack J200 or J201, located on the rear
of the PA chassis assembly. In systems
with multiple Power Amplifier Assemblies,
the RF output from the exciter/driver is
split and then fed to each of the PA RF
Input Jacks. The RF Input is wired
through UT-141 cable to the OSP port
J111, J121, J131 or J141 on the PA
chassis assembly, one for each 250W PA
module slide in assembly. Jack J1 on the
250W PA module assembly connects to
the OSP port when the module assembly
is slid into the PA slot. In the 250W PA
module, the RF is amplified and connected
to the PA RF Output Jack or J2, located on
the rear of the PA Module assembly. Jack
J2 on the PA module connects to the J112,
J122, J132 or J142 port, on the main
chassis assembly, when the module
assembly is slid into place. In a 125W
Digital system the output at J12 connects
directly to J203 the 7/16” Jack that is
located on the rear of the PA chassis
assembly.
The RF outputs of the PA module
assemblies are combined in a 2 way
combiner in a 250 Watt system or in a 4
way combiner in a 500W system. The RF
output jack of the PA chassis assembly is
the output of the combiner at the 7/16”
Jack J205 that is located on the rear of
the PA chassis assembly.
There is one On/Off Circuit Breaker, two
maximum, which is mounted on the rear
of the power amplifier chassis assembly.
The breaker supplies AC to each power
supply assembly. Each Power Supply
Assembly supplies voltages to two power
amplifier assemblies.
4.1 (A4) Power Amplifier Module
Assembly
The Power Amplifier Module Assembly
contains (A1) a UHF Phase/Gain Board
(1303213), (A2) a 150W Driver Pallet,
Dual Output (1303293), (A3 & A4) UHF RF
Module Pallet Assemblies (1300116), (A5)
a 2 Way UHF Combiner Assembly
(1303208), (A6) an Amplifier Control
Board (1303682) and (A7) a Temperature
Sensor IC.
4.1.1 (A1) UHF Phase/Gain Board
(1303213; Appendix B)
The RF input from J1 on the PA assembly
connects to J1 on the Phase/Gain Board.
The UHF phase/gain board provides the
circuits that adjust the gain and the phase
of the RF signal for the PA amplifier
assembly in which it is mounted. The input
signal connects to the gain circuit through
the capacitor C13. The gain circuit consists
of U1, R16, CR4, R22, R17, CR5, R23, R27
and the gain pot, R25. U1 is a 90°, 2-way
splitter. The signal at pin 1 of U1 is split
and applied to pins 3 and 4. The signal
reflects off CR4 and CR5 and is passed to
pin 2. The gain between pins 1 and 2
changes with the voltage applied across
CR4 and CR5. This voltage is controlled by
the gain-adjust pot R25. The more
positive the voltage, the more the diodes
CR4 and CR5 conduct therefore the less
gain through the circuit. The gain
controlled output is coupled through C14
and the pi-type divider circuit consisting of
R8, R5 and R9 that drops the level before it
applied to the phase-shifter circuit.
The level controlled signal connects to the
phase-shifter circuit that consists of U2,
C20, C21, CR2, and CR3. U2 is a 90°, 2-
way splitter. The signal at pin 1 of U2 is
split and applied to pins 3 and 4. The signal
reflects off CR2 and CR3 and is passed to
pin 2. The phase shift between pins 1 and
2 changes with the voltage applied across
LX Series Digital Chapter 4, Circuit Descriptions
Power Amplifier Assembly
Volume 2, Rev. 1 4-2
CR2 and CR3. This voltage is controlled
by the phase-adjust pot R24 through
R26, R18 and R19. +12 VDC from an
external switching power supply is
applied to J3 on the board and is used as
the reference that is applied to the
phase-control pot. The gain and phase
controlled output connects to J2 on the
board.
4.1.2 (A2) 150 Watt Driver Pallet
Assembly, Dual Output (1303293;
Appendix B)
The output of the Phase/Gain Board is
connected to the input J1 of (A2) the 150
Watt UHF amplifier assembly. The
assembly contains a 150 Watt CW UHF
Driver Board, Dual Output (1303169).
4.1.3 150 Watt Driver, Dual Output
(1303169; Appendix B)
The board operates class AB and is a
highly linear broadband amplifier for the
frequency range of 470 to 860 MHz. It
can deliver an output power of 150
watts (CW) with approximately 14 dB of
gain.
The amplification circuit consists of
LDMOS transistors Q1 and Q2 connected
in parallel and operating class AB. The
paralleling network is achieved with the
aid of 3 dB couplers U3 and U4. The
quiescent current settings are achieved
by means of potentiometers R6 and
R10. C39 and C38 are adjusted for best
response. The settings are factory
implemented and should not be altered.
PIN diode VR1 is a variable-damping
circuit that is used to adjust the
amplification of the module. The
adjustment is performed with the Gain
potentiometers R10 and R6. A
readjustment of the amplification may be
required, after repair work, to ensure that
the PAs in multiple PA transmitters deliver
the same output power.
4.1.4 (A3 & A4) UHF Module
Assembly, RF Module Pallet, Philips
(1300116;Appendix B)
The UHF Module Assembly module (Figure
4-1) is a broadband amplifier for the
frequency range 470 to 860 MHz. The
amplifier is capable of delivering an output
power of 70 W
rms
. The amplification is
approximately 13 dB.
The amplification circuit consists of the
parallel connected push-pull amplifier
blocks V1 and V2 operating in class AB. In
order to match the transistor impedance
to the characteristic impedance of the
input and output sides, matching networks
are placed ahead and behind the amplifier
blocks. Transformers Z3 to Z6 serve to
balance the input and output signals. The
paralleling circuit is achieved with the aid
of 3-dB couplers Z1 and Z2.
The working point setting is factory
implemented by means of potentiometers
R9, R11, and R12 and should not be
altered.
V 1
3 dB Coupler
Z 2
RF
Output
RF
Input 3 dB Coupler
Z 1
R 2
R 1
Matching
Network
Matching
Network
V 2
Matching
Network
Matching
Network
Z 3 Z 5
Z 4 Z 6
+Uop
N 1
R 11 R 12
R 9
R 10 Dynamic
Figure 4-1. UHF Amplifier Module, 125 Watts Digital
LX Series Digital Chapter 4, Circuit Descriptions
Power Amplifier Assembly
Volume 2, Rev. 1 4-3
4.1.5 (A5) 2 Way UHF Combiner
Assembly (1303208; Appendix B)
The 2 Way UHF combiner board assembly
combines the two outputs of the UHF
Module Assemblies and also provides
forward and reflected power samples of
the output to (A6) the amplifier control
board where it connects to the input of
the overdrive-protection circuit.
The RF inputs to the 2 way UHF combiner
assembly, from the UHF amplifier
modules, are soldered to the external
connection points J3 and J4. The RF is
combined by the stripline tracks and R5 a
100Ω matching resistor across the two
inputs, to the RF Output solder
connection point at J5. A hybrid-coupler
circuit picks off a power sample that is
connected to SMA type connector jack J1
as the forward power sample. Another
power sample is taken from the coupler
circuit that is connected to SMA type
connector jack J2 as the reflected power
sample. Two 50Ω terminations, created
from two 100Ω resistors in parallel, used
as dissipation loads, connect from the
forward and reflected ports to ground.
4.1.6 (A5) Amplifier Control Board
1303682; Appendix B)
The amplifier control board provides LED
fault and enable indications on the front
panel of the module and also performs
the following functions: overdrive
cutback, when the drive level reaches the
amount needed to attain 110% output
power; and overtemperature, VSWR, and
overdrive faults. The board also provides
connections to the LCD Display for
monitoring the % Reflected Power, %
Output Power, and the power supply
voltage
If the Module OK LED on the front panel
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
Page 1
U4, located upper center of page, is an in
circuit microcontroller. The controller is
operated at the frequency of 3.6864 MHz
using crystal Y1. Programming of this
device is performed through the serial
programming port J2. U4 selects the
desired analog channel of U1 through the
settings of PA0-PA3. The outputs of Port A
must be set and not changed during an
analog input read of channels PA5-PA7.
PA4 of U4 is a processor operating LED
that monitors the +/-12 VDC. PA5 is used
to monitor the +12VDC supply to the
board. PA6 is the selected channel of
analog switch U1. PA7 is connected to a
via, V10, for future access.
U6 is a serial to RS-485 driver IC. U7 is a
watchdog IC used to hold the
microprocessor in reset, if the supply
voltage is less than 4.21 VDC. U7
momentarily resets the microcontroller if
Pin 6 (!ST) is not clocked every second. A
manual reset switch is provided but should
not be needed. Located in the Upper left
corner, U3 is used to determine where the
amplifier control board is located. The
eight inputs come from the main amp
connector and are used to set the SCADA
address of the controller. Pull-up resistors
set a default condition of logic high.
U5 below U3 is used for getting digital
input information of the board. Page two
has several monitoring circuits that provide
information on the amplifier’s status. Many
of these circuits automatically shut down
the amplifier if a specific fault occurs.
U8 below U5 is used to control four board
mounted status LEDs. A FET is turned On
LX Series Digital Chapter 4, Circuit Descriptions
Power Amplifier Assembly
Volume 2, Rev. 1 4-4
to shunt current away from the LED to
turn it Off. U9 below U8 is used to
enable different features within the
software. Actual use is to be determined.
Page 2
In the lower right corner are voltage
regulator circuits. U22 should allow for
0.14 amps of power using its 92 C/W
rating if Ta = 60°C max and Tj = 125°C
max 0.26 amps can be obtained from
U22 if the mounting pad is 0.5 square
inches. The controller will not need this
much current.
U23 and U24 are low drop out +5 VDC,
voltage regulators with a tolerance
greater than or equal to 1%. 100mA of
current is available from each device but
again the controller will not need this
much current.
In the upper left section are circuits with
U12 and U13. U12 is used to generate a
regulated voltage that is about 5 volts
less than the +32 VDC supply,
approximately +26.25 VDC. When the
+32 VDC supply is enabled, the circuitry
around U13B is used to provide gate
voltage to Q10 that is 5 volts greater
than the source pin of this FET. The gate
of Q10 can be turned Off by any one of a
few different circuits.
U10A is used to turn Off the gate of Q10
in the event of high current in amplifier
#1. At 0.886 VDC the current to
amplifier #1 should be greater than 5
Amps. U11B is used to turn off the Q10
FET, if high current is detected in
amplifier #2. U11A is used to turn off
the Q10 FET, if high current is detected
in amplifier #3. With 2.257 VDC at Pin 5
of U11B or Pin 3 of U11A, the voltage
output of current sense amplifier U17 or
U18 at high current shut down should be
greater than 15 Amps.
U14B is used to turn Off the gate of Q10
in the event of high power supply
voltage, approximately +35.4 VDC.
U14A is used to keep the FET disabled in
the event of low power supply voltage,
approximately +25.4 VDC.
Current monitoring sections of the board.
The ICs U16, U17 and U18 along with
associated components set up the current
monitoring sections of the board. R67,
R68 and R69 are 0.01Ω/5W 1% through
hole resistor is used for monitoring the
current through several sections of the
amplifier. The voltage developed across
these resistors are amplified for current
monitoring by U16, U17 or U18. The
LT1787HVCS8 precision high side current
sense IC amplifier accepts a maximum
voltage of 60 VDC. The 43.2 kΩ resistor
from pin 5 to ground sets the gain of the
amplifier to about 17.28. This value is not
set with much accuracy since the
manufacturer internally matches the
resistors of this part but their actual
resistance value is not closely defined. A
trimming resistor is suggested to give a
temperature stability of –200 ppm/C, but
instead the microcontroller will determine
the exact gain of the circuit and use a
correction factor for measurements.
Circuit loading components are located in
the lower portion of each current
monitoring circuit. These components
allow for short duration high current
loading of the supply. By measuring the
current through the sense resistor with and
without the additional four 30.1 Ω 1%
resistors. For very short duration pulses, a
1206 resistor can handle up to 60 watts.
The processor requires 226 uSec per
conversion. A supply voltage of +32 VDC
will pass 1.06 amps + 1% through the load
resistors.
A6 is a temperature sensor thermistor
that is used to monitor the temperature of
the module's heat sink. It connects to J6
pins 1 & 2 on the board and is wired to
the comparator IC U10B. If the
temperature increases above 75°C the
output will go Low that is used as a
temperature fault output, which generates
a Fault alert at U15A and disables
Amplifier #1.
LX Series Digital Chapter 4, Circuit Descriptions
Power Amplifier Assembly
Volume 2, Rev. 1 4-5
Forward and Reflected power detector
sections of the board.
Page 3
A Forward Power Sample enters the
board at SMA Jack J3 and is split. One
part connects to J4 on the board that is
cabled to J1, the SMA Forward Power
Sample Jack, located on the front panel
of the assembly. The other part of the
split forward power sample is detected by
CR17 and the DC level amplified by
U25A. The output of U25A at pin 1 is
split with one part connected to the Aural
Power sample, which is not used in this
digital transmitter. The other split output
connects to U265A that is part of the
Forward Average Power circuit. The
detected level is connected to L4 that is
part of an intercarrier notch filter circuit
that is tuned to eliminate the 4.5 MHz
aural intercarrier, if present. The
Average power sample is amplified by
U26D and connected through the
average calibration pot R166 to U26C.
The output of U26C is connected to the
comparator IC U26B that has Aural Null
and Offset Null, if present in the system,
connected to the other input. The output
Average Forward power level connects to
J9 pin 2 of the board.
A Reflected Power Sample enters the
board at SMA Jack J5 and is detected by
CR20 and the DC level amplified by
U28B. The output of U28B at pin 7 is
connected through the reflected
calibration pot R163 to U28C. The
output is split with one part connected to
J9 pin 5, the Reflected Power Output
level of the board. The other part of the
split from U28C connects to the
comparator IC U28D that has a reference
level connected to the other input. If the
reflected level increases above the
reference level a low output is produced
and connected to the Reflected Power
Shutdown circuit at CR28. The low shuts
off Q14 causing pin 3 to go high that is
connected to the inverter U15C. The
output of U15C goes low producing a
Reflected Power Fault that is connected
to an output of the board, the Fault Alert
circuit and also shuts down Amplifier #1.
Gain of the power measurements is
completed through software. Only the
Aural Null and Offset Null need to be done
through front panel pots.
4.2 Power Supply Assembly
(1302863(2kW) or 1306971(1kW);
Appendix B)
The 1302863 Power Supply Assembly
contains (A1) a +32V/2000W switching
power supply (1301504) and (A2) a
±12V/40W switching power supply
(1303242). The 1306971 Power Supply
Assembly contains (A1) a +32V/1000W
switching power supply (1305168) and
(A2) a ±12V/40W switching power supply
(1303242).
The +32VDC connects through J1
(+32VDC) and J2 (RTN) to the rest of the
amplifier assembly. The +/-12VDC
outputs, the +32VDC control lines and the
220VAC connect to the assembly through
Jack J3.
An On/Off Circuit Breaker, that is mounted
on the rear of the power amplifier chassis
assembly, supplies AC to the power supply
assembly. Each Power Supply Assembly
supplies voltages to two power amplifier
assemblies.
This completes the description of the Power
Amplifier Chassis Assembly, the Power
Amplifier Module Assembly and the Power
Supply Assembly.
4.3 External Assembly
4.3.1 (A4, A13, A44 or A45) Dual Peak
Detector Board (1159965; Appendix
B)
The function of the dual peak detector
board is to detect forward and reflected
output power samples and generate output
voltages that are proportional to the power
levels of the sampled signals for use by the
control monitoring assembly in the exciter.
LX Series Digital Chapter 4, Circuit Descriptions
Power Amplifier Assembly
Volume 2, Rev. 1 4-6
There are two identical signal paths on
the board: one for forward power and
one for reflected power. A sample of
forward output power, from the external
DTV mask filter, enters the board at the
SMA jack J1. Resistors R1 and R2 form
an input impedance-matching network of
50Ω. The forward power signal is
detected by CR1, R7, R25, C1, and C7.
For digital operation the jumpers, W1 on
J6 and W3 on J8, are both between pins
1 & 2. The detected output is buffered
by the operational amplifier U1C before it
is split. One part is connected to the
forward uncalibrated power output jack
J4. The other split output is connected to
forward power adjust pot R9, which
adjusts the gain of U1D. The output of
U1D is split with one part connected to
J3-4 Forward Power Metering Output #1.
The other output of U1D is connected to
J3-6 Forward Power Metering Output #2.
A sample of reflected output power, from
the external DTV mask filter, enters the
board at the SMA jack J2. Resistors R3
and R4 form an input impedance-
matching network of 50Ω. The reflected
power signal is detected by CR2, R26,
R8, C3, and C8. For digital operation the
jumper W2 on J7 is between pins 1 & 2.
The detected output is buffered by the
operational amplifier U1B before it is split.
One part is connected to the reflected
uncalibrated power output jack J5. The
other split output is connected to reflected
power adjust pot R10, which adjusts the
gain of U1A. The output of U1A is split
with one part connected to J3-9 Reflected
Power Metering Output #3. The other
output of U1A is connected to J3-11
Reflected Power Metering Output #4.
The +12 VDC needed for the operation of
U1 on the board enters the board at J3-2
and is connected through a filter and
isolation circuit consisting of C5, C9 and L3
before it is connected to U1. The -12 VDC
needed for the operation of U1 on the
board enters the board at J3-8 and is
connected through a filter and isolation
circuit consisting of C6, C12 and L6 before
it is connected to U1.
This completes the circuit description of the
external power amplifier assembly and
external assemblies.
APPENDIX A
LX SERIES
SYSTEM SPECIFICATIONS
Innovator LX
Low Power DTV Transmitter 5W - 3kW
Designed to provide broadcasters with a product that will meet their needs like
no other solution on the market, this new low to medium power transmitter
line uses the latest LDMOS devices for broadband operation across the entire
UHF band. This allows users to minimize spare parts stock, which is especially
important to group owners and networks, and also enables simple and
inexpensive channel changes.
The very compact and completely modular design uses a chassis/backplane
configuration with parallel amplifier and power supply modules which can be
removed and replaced while the transmitter is on the air.
Configurations are available in power levels from 10 watts to 6 kilowatts
analog and up to 3 kilowatts DTV, and all are manufactured in the USA by
Axcera - The RF Experts.
LU1000AT Shown
Specifications published here are current as of the date of publication of this document. Because we are continuously improving our products, Axcera reserves the right to change specifications without prior notice. At any time, you may verify
product specifications by contacting our office. Axcera views it’s patent portfolio as an important corporate asset and vigorously enforces its patents. Products or features contained herein may be covered by one or more U.S. or foreign patents.
0311R4 © 2004 AXCERA All Rights Reserved An Equal Opportunity Employer
103 Freedom Drive, PO Box 525, Lawrence, PA 15055 t: 724-873-8100 f: 724-873-8105
General
Model Number LU5ATD LU50ATD LU125ATD LU250ATD LU500ATD LU1000ATD LU1500ATD LU2000ATD LU2500ATD LU3000ATD
Power Output (Average) 5 W 50 W 125 W 250 W 500 W 1000 W 1500 W 2000 W 2500 W 3000 W
Output Connector 7/8” EIA 31/8” EIA
Power Consumption (Watts) 250 W 650 W 1000 W 1700 W 3400 W 6700 W 10,500 W 13,500 W 17,000 W 20,500 W
Input Power
Line Voltage (Volts) 117/230 ±10% 230 ± 10%
Power Requirements Single Phase, 50 or 60 Hz
Size (H x W x D) 55”x22”x34” 76”x22”x34” 76”x44”x34”
Weight (lbs.) 300 300 340 360 400 550 700 1030 1180 1330
Operational Temperature Range 0 to +50°, derate 2°C/1000 ft.
Maximum Altitude3 8500 feet (2600m) AMSL
Operational Humidity Range 0% to 95% non-condensing
RF Load Impedance 50 Ω
Performance
Frequency Range1 470 to 860 MHz
Output Impedance 50 Ω
Frequency Stability ±1kHz (max 30 day variation)
w/Precise Frequency Option ±2Hz
Regulation of RF Output Power 3%
Out of Band -Compliant with FCC Mask2
Channel Edge ±500kHz -47 dB or better
6MHz from Channel Edge -110 dB or better
Signal to Noise (SNR) 27 dB or better
Data Interface
Input Rate 19.39 Mbps, 6 MHz Channel
Input Interface SMPTE 310M, Serial Differential
ECL & TTL
Test Signals Internal PRBS 23 MPEG Stream
Options
Dual Exciter with Automatic Switcher
AC Surge Protector
Precise Frequency Kit
Spare Parts Kit
1 Other Frequencies - Consult Factory
2 Measured in 30 KHz RBW, relative to total average power
3 Above 8,500 feet - Consult Factory
Innovator LX
Low Power DTV Transmitter 5W - 3kW
APPENDIX B
DRAWING LISTS
LX Series Digital Appendix B, Drawings and Parts Lists
Power Amplifier Assembly
Volume 2, Rev. 1 B-1
LX Series Digital High Power System
LX Series Transmitter Block Diagrams......................(50W-1 kW Digital) 1302633,
LX Series Digital Transmitter Interconnects......... (125W, 250W & 500W) 1303940,
LX Series 50-1000 Watt Digital Transmitter Typical Racking Plan ............. 1303596
Chassis Assembly, Power Amplifier, LX Series
Power Amplifier Chassis Assembly Block Diagram................................... 1303962
500W or 1 kW LX Series Power Amplifier Chassis Assembly Interconnect ..1303807
500 Watt LX Series DC Harness Chassis/Airbox Interconnect ...................1303964
500 Watt LX Series AC Harness Chassis/Airbox Interconnect.................... 1303965
500 Watt LX Series Coax Assembly Chassis/Airbox Interconnect ..............1303963
500W/1 kW LX Series AC Harness Chassis/Airbox I/C ............................. 1303960
500W/1 kW LX Series DC Harness Chassis/Airbox I/C ............................. 1303961
500W/1 kW LX Series Coax Assembly Chassis/Airbox Interconnect........... 1303480
2 Way Splitter/Phase Shifter Assembly (Used with multiple Power Amplifier Assemblies)
2 Way Splitter/Phase Shifter Schematic.................................................1303569
4 Way Splitter Module Assembly (Used with multiple Power Amplifier Assemblies)
Contains a 4 Way Splitter Board (1303234).
4 Way Splitter Board
Schematic.......................................................................................... 1303237
2 Way Combiner Module Assembly (Used with two Power Amplifier Assemblies)
2 Way Combiner Board Schematic ........................................................ 1303580
4 Way Combiner Module Assembly (Used with four Power Amplifier Assemblies)
4 Way Combiner Board Schematic ........................................................ 1303655
External Amplifier Signal Board, LX Series
Schematic.......................................................................................... 1303346
Dual Peak Detector Board
Schematic.......................................................................................... 1159976
Power Amplifier Assembly, 250 Watt, LX Series
(Each Amplifier Assembly supplies 250 Watts)
Block Diagram.................................................................................... 1303585
Interconnect....................................................................................... 1303510
RF Module Pallet w/o Transistors
Made into a RF Module Pallet, w/ Philips Transistors (1300116).
Schematic........................................................................51-5379-309-00 WSP
RF Module Pallet, Philips
Made from a RF Module Pallet w/o Transistors (1152336).
Amplifier Control Board
Schematic.......................................................................................... 1303683
LX Series Digital Appendix B, Drawings and Parts Lists
Power Amplifier Assembly
Volume 2, Rev. 1 B-2
150 Watt UHF Driver Pallet Assembly
Schematic.......................................................................................... 1303171
2-Way Combiner Board Assembly
Schematic.......................................................................................... 1303211
UHF Phase/Gain Board
Schematic.......................................................................................... 1303216
Power Supply Assembly, 2 kW, LX Series
(One Power Supply Assembly Supplies Power to Two Amplifier Assemblies)
Block Diagram.................................................................................... 1303886
Interconnect....................................................................................... 1303479
Power Supply Assembly, 1 kW, LX Series
(One Power Supply Assembly Supplies Power to Two Amplifier Assemblies)
Block Diagram.................................................................................... 1305175
Interconnect....................................................................................... 1305176
APPENDIX C
TRANSMITTER LOG SHEET
UHF LX Series Digital Transmitter Appendix C, Log Sheet
- Page 1 of 1 -
DESCRIPTION OF
PARAMETER TRANSMITTER READING FROM LCD DISPLAY
DATE READINGS TAKEN
Model Number
Code Version
Firmware Number
OUTPUT MEASUREMENTS
% FORWARD POWER
% REFLECTED POWER
DM8 DIGITAL MODULATOR
DETAILS
MODE
SOURCE
LINEAR EQ
NON-LINEAR EQ
(Settings Customized per
System)
EQL PEAK LEVEL
PSF PEAK LEVEL
AGC MODE
AGC LEVEL
D/A PEAK DETECT
TAP ENERGY
CLIP DETECTOR STATUS
AGG
ISL
D/A
HBF
IFC
COR
ODC
CODE VERSION
IF PROCESSOR DETAILS
INPUT SIGNAL STATE
MODULATION
INPUT IF
DLC CONTROL LOCK
ALC LEVEL
ALC MODE
UPCONVERTER DETAILS
AFC 1 LEVEL
AFC 2 LEVEL
PLL 1 CIRCUIT
PLL 2 CIRCUIT
AGC 1 LEVEL
AGC 2 LEVEL
UHF LX Series Digital Transmitter Appendix C, Log Sheet
- Page 2 of 2 -
DESCRIPTION OF
PARAMETER TRANSMITTER READING FROM LCD DISPLAY
INT. 10 MHz
IF INPUT LEVEL
SYSTEM CONTROL DETAILS
Power Supply Enable For
DRIVER AND PA DETAILS
POWER SUPPLY STATE, 32V
FORWARD POWER
REFLECTED POWER
AMP 1 CURRENT
AMP 2 CURRENT
TEMPERATURE
CODE VERSION
EXT. PA AMPLIFIER MODULES ONLY IN HIGH POWER SYSTEMS
AMP SET 1 MODULE 1 Will indicate Amp Set and Module within the
Set. Will step through each Set and Module.
POWER SUPPLY VOLTAGE, 32V
32V SUPPLY
FORWARD POWER
REFLECTED POWER
AMP CURRENT 1
AMP CURRENT 2
AMP CURRENT 3
AMP TEMPERATURE
CODE VERSION
AMP SET 1 MODULE 2
POWER SUPPLY VOLTAGE, 32V
32V SUPPLY
FORWARD POWER
REFLECTED POWER
AMP CURRENT 1
AMP CURRENT 2
AMP CURRENT 3
AMP TEMPERATURE
CODE VERSION
AMP SET 1 MODULE 3
POWER SUPPLY VOLTAGE, 32V
32V SUPPLY
FORWARD POWER
REFLECTED POWER
AMP CURRENT 1
AMP CURRENT 2
AMP CURRENT 3
AMP TEMPERATURE
CODE VERSION
UHF LX Series Digital Transmitter Appendix C, Log Sheet
- Page 3 of 3 -
DESCRIPTION OF
PARAMETER TRANSMITTER READING FROM LCD DISPLAY
AMP SET 1 MODULE 4
POWER SUPPLY VOLTAGE, 32V
32V SUPPLY
FORWARD POWER
REFLECTED POWER
AMP CURRENT 1
AMP CURRENT 2
AMP CURRENT 3
AMP TEMPERATURE
CODE VERSION
AMP SET 2 MODULE 1
POWER SUPPLY VOLTAGE, 32V
32V SUPPLY
FORWARD POWER
REFLECTED POWER
AMP CURRENT 1
AMP CURRENT 2
AMP CURRENT 3
AMP TEMPERATURE
CODE VERSION
AMP SET 2 MODULE 2
POWER SUPPLY VOLTAGE, 32V
32V SUPPLY
FORWARD POWER
REFLECTED POWER
AMP CURRENT 1
AMP CURRENT 2
AMP CURRENT 3
AMP TEMPERATURE
CODE VERSION
AMP SET 2 MODULE 3
POWER SUPPLY VOLTAGE, 32V
32V SUPPLY
FORWARD POWER
REFLECTED POWER
AMP CURRENT 1
AMP CURRENT 2
AMP CURRENT 3
AMP TEMPERATURE
CODE VERSION
UHF LX Series Digital Transmitter Appendix C, Log Sheet
- Page 4 of 4 -
DESCRIPTION OF
PARAMETER TRANSMITTER READING FROM LCD DISPLAY
AMP SET 2 MODULE 4
POWER SUPPLY VOLTAGE, 32V
32V SUPPLY
FORWARD POWER
REFLECTED POWER
AMP CURRENT 1
AMP CURRENT 2
AMP CURRENT 3
AMP TEMPERATURE
CODE VERSION
AMP SET 3 MODULE 1
POWER SUPPLY VOLTAGE, 32V
32V SUPPLY
FORWARD POWER
REFLECTED POWER
AMP CURRENT 1
AMP CURRENT 2
AMP CURRENT 3
AMP TEMPERATURE
CODE VERSION
AMP SET 3 MODULE 2
POWER SUPPLY VOLTAGE, 32V
32V SUPPLY
FORWARD POWER
REFLECTED POWER
AMP CURRENT 1
AMP CURRENT 2
AMP CURRENT 3
AMP TEMPERATURE
CODE VERSION
AMP SET 3 MODULE 3
POWER SUPPLY VOLTAGE, 32V
32V SUPPLY
FORWARD POWER
REFLECTED POWER
AMP CURRENT 1
AMP CURRENT 2
AMP CURRENT 3
AMP TEMPERATURE
CODE VERSION
UHF LX Series Digital Transmitter Appendix C, Log Sheet
- Page 5 of 5 -
DESCRIPTION OF
PARAMETER TRANSMITTER READING FROM LCD DISPLAY
AMP SET 3 MODULE 4
POWER SUPPLY VOLTAGE, 32V
32V SUPPLY
FORWARD POWER
REFLECTED POWER
AMP CURRENT 1
AMP CURRENT 2
AMP CURRENT 3
AMP TEMPERATURE
CODE VERSION
AMP SET 4 MODULE 1
POWER SUPPLY VOLTAGE, 32V
32V SUPPLY
FORWARD POWER
REFLECTED POWER
AMP CURRENT 1
AMP CURRENT 2
AMP CURRENT 3
AMP TEMPERATURE
CODE VERSION
AMP SET 4 MODULE 2
POWER SUPPLY VOLTAGE, 32V
32V SUPPLY
FORWARD POWER
REFLECTED POWER
AMP CURRENT 1
AMP CURRENT 2
AMP CURRENT 3
AMP TEMPERATURE
CODE VERSION
AMP SET 4 MODULE 3
POWER SUPPLY VOLTAGE, 32V
32V SUPPLY
FORWARD POWER
REFLECTED POWER
AMP CURRENT 1
AMP CURRENT 2
AMP CURRENT 3
AMP TEMPERATURE
CODE VERSION
UHF LX Series Digital Transmitter Appendix C, Log Sheet
- Page 6 of 6 -
DESCRIPTION OF
PARAMETER TRANSMITTER READING FROM LCD DISPLAY
AMP SET 4 MODULE 4
POWER SUPPLY VOLTAGE, 32V
32V SUPPLY
FORWARD POWER
REFLECTED POWER
AMP CURRENT 1
AMP CURRENT 2
AMP CURRENT 3
AMP TEMPERATURE
CODE VERSION
AMP SET 5 MODULE 1
POWER SUPPLY VOLTAGE, 32V
32V SUPPLY
FORWARD POWER
REFLECTED POWER
AMP CURRENT 1
AMP CURRENT 2
AMP CURRENT 3
AMP TEMPERATURE
CODE VERSION
AMP SET 5 MODULE 2
POWER SUPPLY VOLTAGE, 32V
32V SUPPLY
FORWARD POWER
REFLECTED POWER
AMP CURRENT 1
AMP CURRENT 2
AMP CURRENT 3
AMP TEMPERATURE
CODE VERSION
AMP SET 5 MODULE 3
POWER SUPPLY VOLTAGE, 32V
32V SUPPLY
FORWARD POWER
REFLECTED POWER
AMP CURRENT 1
AMP CURRENT 2
AMP CURRENT 3
AMP TEMPERATURE
CODE VERSION
UHF LX Series Digital Transmitter Appendix C, Log Sheet
- Page 7 of 7 -
DESCRIPTION OF
PARAMETER TRANSMITTER READING FROM LCD DISPLAY
AMP SET 5 MODULE 4
POWER SUPPLY VOLTAGE, 32V
32V SUPPLY
FORWARD POWER
REFLECTED POWER
AMP CURRENT 1
AMP CURRENT 2
AMP CURRENT 3
AMP TEMPERATURE
CODE VERSION
AMP SET 6 MODULE 1
POWER SUPPLY VOLTAGE, 32V
32V SUPPLY
FORWARD POWER
REFLECTED POWER
AMP CURRENT 1
AMP CURRENT 2
AMP CURRENT 3
AMP TEMPERATURE
CODE VERSION
AMP SET 6 MODULE 2
POWER SUPPLY VOLTAGE, 32V
32V SUPPLY
FORWARD POWER
REFLECTED POWER
AMP CURRENT 1
AMP CURRENT 2
AMP CURRENT 3
AMP TEMPERATURE
CODE VERSION
AMP SET 6 MODULE 3
POWER SUPPLY VOLTAGE, 32V
32V SUPPLY
FORWARD POWER
REFLECTED POWER
AMP CURRENT 1
AMP CURRENT 2
AMP CURRENT 3
AMP TEMPERATURE
CODE VERSION
UHF LX Series Digital Transmitter Appendix C, Log Sheet
- Page 8 of 8 -
DESCRIPTION OF
PARAMETER TRANSMITTER READING FROM LCD DISPLAY
AMP SET 6 MODULE 4
POWER SUPPLY VOLTAGE, 32V
32V SUPPLY
FORWARD POWER
REFLECTED POWER
AMP CURRENT 1
AMP CURRENT 2
AMP CURRENT 3
AMP TEMPERATURE
CODE VERSION
NOTE: The previous Log Sheet readings can be taken from the System Details
Screen, Menu 30-1, on the 4 x 20 Display located on the front of the Control &
Monitoring/Power Supply Module.

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