5.3 Changing the Analog Translator Output Channel Procedure........................5-3
5.4 Adjusting Manual AGC, Auto AGC and AGC cutback in Analog Translator .....5-4
5.4.1 Setting the Manual AGC................................................................5-4
5.4.2 Setting the Auto AGC....................................................................5-4
5.4.3 Setting the AGC Cutback...............................................................5-4
5.5 Calibration of Forward & Reflected Power of Analog Translator ...................5-4
5.5.1 Calibration of the Translator Forward Output Power .........................5-5
5.5.2 Calibration of the Translator Reflected Power ..................................5-5
5.6 Linearity Correction Adjustment for the Analog Translator..........................5-6
5.7 Frequency Response Delay Equalization Adjustment for Analog Translator...5-6
APPENDICES
APPENDIX A SYSTEM AND EXCITER/AMPLIFIER DRAWINGS
LX Series, Rev. 0
vi
LX Series VHF Translator Chapter 1
Introduction
Chapter 1
Introduction
1.1 Manual Overview
This manual explains the installation,
setup, alignment, and maintenance
procedures for the Innovator LX Series
VHF translator. 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, System
Description, Maintenance & Remote
Control Connections, describes the
transmitter and includes discussions on
system control and status indicators,
maintenance, and remote control
connections. Chapter 3, Site
Considerations, Installation and Setup
Procedures, explains how to unpack,
install, setup, and operate the
transmitter. Chapter 4, Circuit
Descriptions, contains circuit level
descriptions for boards and board level
components in the transmitter.
Chapter 5, Detailed Alignment
Procedures, provides information on
adjusting the system assemblies for
optimal operation. Appendix A
contains the System, Remodulator &
Exciter/Amplifier drawings and parts
lists.
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.
LX Series, Rev. 0 1-1
Figure 1-1 Brady Marker Identification
Drawing
LX Series VHF Translator Chapter 1
Introduction
1.3 Safety
The VHF translator 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, Rev. 0 1-2
LX Series VHF Translator Chapter 1
Introduction
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 email 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 hoursof-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, Rev. 0 1-3
LX Series VHF Translator Chapter 1
Introduction
FWARNING!!!
×HIGH VOLTAGEØ
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, Rev. 0 1-4
LX Series VHF Translator Chapter 1
Introduction
EMERGENCY FIRST AID INSTRUCTIONS
Personnel engaged in the installation, operation, or maintenance of this equipment are urged to become
familiar with the 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.
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.
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
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.
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, Rev. 0 1-7
LX Series VHF Translator Chapter 1
0 -10 -20 -30 -40 -50 -60
-70
N
dB
Introduction
RETURN LOSS VS. VSWR
R
E
T
U
R
L
O
S
S
1.001 1.01 1.1 2.0
VSWR
LX Series, Rev. 0 1-8
LX Series VHF Translator Chapter 1
Introduction
ABBREVIATIONS/ACRONYMS
AC Alternating Current
AFC Automatic Frequency Control
ALC Automatic Level Control
AM Amplitude modulation
AGC Automatic Gain Control
ATSC Advanced Television Systems
Committee
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
VSBVestigial Side Band
LX Series, Rev. 0 1-9
LX Series VHF Translator Chapter 2, System Description,
A3
A5
A4
A6
A1 A2 A24
Maintenance & Remote Control Connections
Chapter 2
System Description, Maintenance & Remote Control Connections
2.0 System Overview
This analog translator is a complete VHF
internally diplexed modular television
translator. There are three systems, one
that operates at CH:6 at a nominal visual
output power of 20W or a DTV output of
10W, one that operates at CH:10 at a
nominal visual output power of 20W or a
DTV output of 10W, and one that
operates at CH:8 at a nominal visual
output power of 100W or a DTV output of
50W..
The Analog LX Series translator is made
up of the modules and assemblies as
listed in Table 2-1.
Figure 2-1:Exciter/Amplifier w/Remodulator Front View
This chassis assembly is factory set for
operation using 110 VAC. All of the
modules except the power amplifier
module and the power supply section of
the Control & Monitoring/Power Supply
Module, plug directly into a backplane
board. The backplane board provides
module to module interconnection as well
as interconnection to remote command
and control connectors.
2.2.1 (A1) Receiver Module
Assembly, VHF High Band
(1304001; Appendix A)
NOTE: The Receiver module is not used
in the digital system.
NOTE: For analog translator operation
the Receiver IF output at A2-J13 is
connected to the Modulated IF input
Jack A2-J6 and the On Channel RF input
is connected to A2-J12.
Table 2-5: Receiver Front Panel Switch
SWITCH FUNCTION
When Manual ALC is selected, the level is set by the
Manual ALC Pot R57 located on the mixer/PLL board.
(NOTE: The pot is factory set and needs no adjustment
MAN/AUTO ALC
SW1
by the customer).
When Auto ALC is selected, the level control circuit will
automatically increase or decrease the ALC to maintain
the desired output level.
The VHF Receiver converts a low level
RF input signal (-65 to –15 dBm) to an
IF frequency of 44 MHz, filters off any
unwanted out of band energy, and
normalizes the level so that it can be
applied to the IF processor assembly.
The receiver consists of three boards,
the VHF High Band Preamplifier Board
(1306445), the Mixer/PLL Board
(1306472), and the IF ALC Board
(1304003). The RF input is applied first
to the VHF preamplifier board, which
filters off out of channel energy and
amplifies the input signal. The RF output
is connected to the Mixer/PLL board,
which converts the signal down to an IF
frequency of 44 MHz. The IF output is
cabled to the IF ALC board, which
amplifies the signal, filters off any
unwanted out of band energy and
controls its own IF gain to make sure
that the IF output level is constant.
There is also a provision to apply +12V
to the RF input center conductor to
power an external preamplifier.
CAUTION: Do not hook up the RF
input to any test equipment with the
DC bias applied. Always move the
jumper W1 on J2, on the UHF
Preamplifier Board, to the Bias off
position, between pins 2 & 3, to
prevent possible damage to the test
equipment.
LX Series, Rev. 0 2-2
LX Series VHF Translator Chapter 2, System Description,
Maintenance & Remote Control Connections
Table 2-6: Receiver Front Panel Status Indicators
LED FUNCTION
PLL1 Fault DS6 Displays the status of the Local oscillator PLL
PLL 2 Fault DS8 Displays status of optional input frequency correcting PLL
DC on center conductor DS4
Displays whether or not DC is applied to the RF input
center conductor
Man ALC Gain DS7 Displays when ALC is switched to Manual bypass
ALC Fault DS5 Displays ALC status
Table 2-7: Receiver Front Panel Control Adjustments
POTENTIOMETERS DESCRIPTION
Manual Gain R57 Adjusts the gain of the receiver when the ALC is bypassed.
A/V Ratio R50 Adjusts the ratio between the visual and aural carriers.
Table 2-8: Receiver Front Panel Samples
SMA CONNECTORS DESCRIPTION
Receiver IF J13 Sample of the IF output of the IF ALC Board.
Receiver LO J2 Sample of the LO generated on the UHF Mixer PLL Board.
2.2.2 (A3) IF Processor Module
Assembly (1301938; Appendix A)
The Control & Monitoring/Power Supply
module uses the IF Processor module for
System output power control. Through
the front panel display or a remote
interface, an operator can set the RF
output power level of the translator.
The range of RF power adjustment is
between 0% (full off) and 105% (full
The (A3) IF Processor Assembly contains
the IF Processor Board (1301977). The IF
Processor provides pre-correction to
ensure broadcast quality output signal.
The pre-correction consists of amplitude
linearity correction, Incidental Carrier
Phase Modulation (ICPM) correction and
frequency response correction.
The IF Processor module is configured
either for an analog or digital system.
Pin 13C of the IF Processor module is
grounded in analog systems and left not
connected in digital systems. An IF
Processor Interlock signal is used to
report the presence of the IF Processor
module to the Control Monitoring board.
If the IF Processor interlock signal is not
present, the LX Series translator RF
output is Muted (turned off). If an
analog IF Processor module is installed
and the Modulation Present signal is not
true, the LX Series Translator output is
Muted (turned off).
power plus). A front panel IF Processor
module potentiometer sets the upper
limit of RF power at 120%. The
system's Control Monitoring board
compares the RF Power Monitoring
module RF power level with the desired
level and uses the IF Power Control PWM
line to correct for errors.
In digital systems, a digital level control
(DLC) voltage is generated on the IF
Processor module and sent to an
external digital modulator (DT1B/C). RF
power control is implemented by
changing the DLC voltage provided to
the external digital modulator. The 'RF
High' potentiometer sets the upper
adjusted range of RF control circuit
output to 120%.
The IF Processor module provides a
reference ALC voltage to the system's
Upconverter. When the ALC voltage
decreases, the Upconverter
automatically lowers the system output
power through the AGC circuits.
LX Series, Rev. 0 2-3
LX Series VHF Translator Chapter 2, System Description,
Maintenance & Remote Control Connections
The IF Processor module has a front
panel switch to select Auto or Manual
ALC. When Manual ALC is selected, the
reference ALC voltage is set by a front
panel potentiometer. In this condition,
the RF power level control circuit is
removed from use. When the ALC select
switch is changed to Auto, the RF power
level control circuit will start at low
power and increase the RF output until
the desired output power is attained.
The IF Processor module Modulation
Present signal is monitored. If the
modulation level is too low or nonexistent, a Modulation Present Fault is
reported to the Control Monitoring
board. When the controller detects this
fault, it can be set to Automatically Mute
the translator or in Manual mode the
translator will continue to operate at
25% output.
The IF Processor module Input Signal
level is monitored. If the signal level is
too low or non-existent, an Input Fault
is reported on the Control Monitoring
board. When the IF Processor board
detects an Input Signal Fault it
automatically Mutes the translator. The
system controller does not Mute on an
IF Processor Input Fault.
Table 2-9: IF Processor Front Panel Switch
SWITCH FUNCTION
When Manual ALC is selected, the reference ALC voltage is set
by the ALC Gain front panel potentiometer.
MAN/AUTO ALC
When Auto ALC is selected, the IF level control circuit will
automatically increase the IF output until the desired output
power is attained.
Table 2-10: IF Processor Front Panel Status Indicators
LED FUNCTION
INPUT FAULT (Red)
When lit it indicates that there is a loss of the IF Input signal to the
IF Processor. Translator can be set to Mute on an IF Input Fault.
When lit it indicates that the required gain to produce the desired
ALC Fault (Red)
output power level has exceeded the operational range of the ALC
circuit. The LED will also be lit when ALC is in Manual.
MUTE (Red)
When lit it indicates that the IF input signal is cut back but the
enable to the Power Supply is present and the +32 VDC remains on.
Table 2-11: IF Processor Front Panel Control Adjustments
POTENTIOMETERS
FREQUENCY
RESPONSE
EQUALIZER
ALC GAIN
MAN GAIN
These three variable resistors, R103, R106 & R274, adjust the
depth of gain for the three stages of frequency response correction.
Adjusts the gain of the translator when the translator is in the Auto
ALC position.
Adjusts the gain of the translator when the translator is in the
Manual ALC position.
DESCRIPTION
These three variable resistors adjust the threshold cut in for the
LINEARITY
CORRECTION
three stages of linearity pre-correction. R211 and R216, the top
two pots, are adjusted to correct for in phase amplitude distortions.
R 231, the bottom pot, is adjusted to correct for quadrature phase
distortions.
Table 2-12: IF Processor Front Panel Sample
SMA CONNECTOR DESCRIPTION
IF SAMPLE Sample of the pre-corrected IF output of the IF Processor
LX Series, Rev. 0 2-4
LX Series VHF Translator Chapter 2, System Description,
Maintenance & Remote Control Connections
2.2.3 (A5) VHF/UHF Upconverter
Module Assembly (1303829;
Appendix A)
The VHF/UHF Upconverter Module
Assembly contains (A1) a Downconverter
Board Assembly (1303834), (A3) a First
Conversion Board, LX Series (1303838),
(A2) a L-Band PLL Board, LX Series
(1303846) and (A4) an Upconverter
Control Board (1304760).
A 0 dBm 44 MHz IF input to the
upconverter through the backplane
board is applied to a mixer mounted on
the first conversion board. Also applied
to the mixer is a nominal 1 GHz LO1.
The mixer converts it to a nominal
frequency centered at 1044 MHz. A
filter selects the appropriate conversion
product, which is then amplified to a
level of approximately –4 dBm. The
frequency of the first conversion LO1
can be shifted by ± 10 kHz to generate
channel offsets of 10kHz. For +offsets
Table 2-13: VHF/UHF Upconverter Front Panel Switch
SWITCH FUNCTION
When Manual AGC is selected, the reference AGC voltage is
set by the AGC Manual Gain front panel potentiometer.
MAN/AUTO AGC
(Left Manual, Right AGC)
When Auto AGC is selected, the RF power level control circuit
will automatically increase the RF output until the desired
output power is attained.
the frequency is 999.99 MHz and for –
offsets the frequency is 1000.01 MHz.
This signal is applied to a second mixer
mounted on the downconverter board
that converts it back to a broadcast
channel (2-69) by an LO2 that operates
in 100kHz steps between 1.1-1.9 GHz
depending on the channel selected. The
LO2 frequency equals the Channel
center frequency plus the LO1 frequency
plus 44 MHz. (As an example CH14+:
Center Frequency is 473.01 MHz and
LO1 is 999.99 MHz therefore LO2 is
473.01 + 999.99 + 44, which equals
1517.00 MHz.)
The output of the mixer is applied to a
900 MHz Low pass filter to remove
unwanted conversion products. The
resulting signal is amplified and applied
to a Pin diode attenuator before it is
connected to the output of the
upconverter. This pin diode attenuator
adjusts the gain of the module and is
controlled by an Automatic Gain Control
circuit, which maintains a constant
power out of the upconverter, and also
the translator, that connects to the
power amplifier module.
LX Series, Rev. 0 2-5
LX Series VHF Translator Chapter 2, System Description,
Maintenance & Remote Control Connections
Table 2-14: VHF/UHF Upconverter Front Panel Status Indicators
LED FUNCTION
PLL 1 Fault
(Red)
PLL 2 Fault
(Red)
AGC Fault
(Red)
AGC Override
(Red)
Man Gain
(Amber)
Table 2-15: VHF/UHF Upconverter Front Panel Control Adjustments
POTENTIOMETERS
MAN GAIN ADJ
AGC ADJ
AGC CUTBACK ADJ
(AGC OVERRIDE)
Table 2-16: VHF/UHF Upconverter Front Panel Samples
SMA CONNECTOR DESCRIPTION
LO1 SAMPLE
LO2 SAMPLE
RF SAMPLE Sample of the On Channel RF Output of the Upconverter
2.2.4 (A4) Control/Power Supply
Module Assembly, 110VAC
(1301936; Appendix A)
This (A4) Control & Monitoring/Power
Supply Assembly was configured at the
factory for operation at 110 VAC. The
assembly is made up of a Control Board
(1302021), a Power Protection Board
(1302837) and a Switch Board (1527-
1406).
When lit it indicates that the 1 GHz PLL is unlocked
When lit it indicates that the 1.1 –1.9 GHz PLL is unlocked
When lit it indicates that the AGC is out of range.
When lit it indicates that the AGC is cutting back due to too much
drive to the driver module.
When lit it indicates that the AGC is bypassed in Manual.
DESCRIPTION
Adjusts the gain of the upconverter and translator when in the
Manual AGC position.
Adjusts the gain of the upconverter and translator when in the Auto
AGC position.
Adjusts the point at which the translator will cut back in power, due
to too much drive, when the Translator is in Auto AGC.
Sample of the 1 GHz nominal LO1 signal in the Upconverter as
generated on the L-Band PLL Board.
Sample of the 1.1-1.9 GHz LO2 signal in the Upconverter as
generated on the First Conversion Board.
The Assembly also contains a switching
power supply that provides ±12 VDC to
the rest of the modules in the chassis
and +32 VDC to the Power Amplifier
module.
The Assembly provides all translator
control and monitoring functions. The
Front panel LCD allows monitoring of
system parameters, including forward
and reflected power, transistor currents,
module temperatures and power supply
voltages. The LCD screens are detailed
in Chapter 3.
LX Series, Rev. 0 2-6
LX Series VHF Translator Chapter 2, System Description,
Maintenance & Remote Control Connections
Table 2-17: Controller/Power Supply Display
DISPLAY FUNCTION
A 4 x 20 display providing a four-line readout of the internal
LCD
Table 2-18: Controller/Power Supply Status Indicator
LED FUNCTION
OPERATE
(green)
FAULT
(red or green)
DC OK
( red or green )
Table 2-19: Controller/Power Supply Control Adjustments
POTENTIOMETERS
DISPLAY CONTRAST Adjusts the contrast of the display for desired viewing of screen.
functions, external inputs, and status. See Chapter 3,
Controller/Power Supply Display Screens, for a listing of displays.
When lit it indicates that the translator is in the Operate Mode. If
translator is Muted the Operate LED will stay lit, the translator will
remain in Operate, until the input signal is returned.
Red indicates that a problem has occurred in the translator. The
translator will be Muted or placed in Standby until the problem is
corrected.
Green indicates that the switchable fuse protected DC outputs that
connect to the modules in the translator are OK.
DESCRIPTION
LX Series, Rev. 0 2-7
LX Series VHF Translator Chapter 2, System Description,
Maintenance & Remote Control Connections
2.2.6 (A6) Power Amplifier Module
Assembly, VHF High Band,
(1305833; Appendix A)
NOTE: This 20W Analog power amplifier
module is used in the VHF High Band
Translator.
The (A6) Power Amplifier Module
Assembly is made up of a VHF High Band
Coupler Board (1211-1004), a VHF
Amplifier Control Board (1308260), and a
High Band VHF Amplifier Pallet Assembly
(1305820).
The Power Amplifier Module contains
Broadband LDMOS amplifiers that cover
the VHF High Band with no tuning
required. The module amplifies the RF
output of the Upconverter to
approximately 22 watts Peak of Sync
Visual. A cable, located on the rear
chassis, connects the RF output from the
Upconverter at J23 to J24 the RF input to
the PA Assembly. The High Band VHF
Amplifier Pallet Assembly (1305820) is
made from a Delta RF Technology pallet
PA25-VHF-HB.
The PA 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
Driver Power Amplifier module contains
a 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. Front
panel adjustment potentiometers are
used to calibrate the following:
Power Amplifier Calibration Adjustments
in Analog Systems
R201 Reflected Power Cal
R202 Visual/Forward Power Cal
R203 Aural Power Cal
R204 Visual Offset Zero
R205 Aural Null
In analog systems, the Aural power of
an Exciter Driver Power Amplifier and
the Aural power of any external PA
amplifiers will not be reported by the
system Control Monitoring module.
Additionally the Visual power of these
amplifiers is reported as Forward Power
just like in digital systems. In analog
systems, aural and visual power will only
be reported for the final system RF
output.
In this translator, 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 route these lines as the system's
RF power signals.
The Forward Power of the 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.
LX Series, Rev. 0 2-8
LX Series VHF Translator Chapter 2, System Description,
Maintenance & Remote Control Connections
Table 2-23: Power Amplifier Status Indicator
LED FUNCTION
ENABLED
(Green)
DC OK
(Green)
TEMP
(Green)
MOD OK
(Green)
When lit Green, it indicates that the PA is in the Operate Mode. If a Mute
occurs, the PA will remain Enabled, until the input signal is returned.
When lit Green, it indicates that the fuse protected DC inputs to the PA
module are OK.
When lit Green, it indicates that the temperature of the heatsink assembly in
the module is below 78°C.
When lit Green, it indicates that the PA Module is operating and has no faults.
If the Module OK LED is Red and blinking a fault is present.
1 Blink indicates Amplifier Current Fault. If the Module OK LED is Red and
blinking a fault is present, as indicated below by the number of blinks and a
MOD OK
(Red)
pause then a repeat of the number of blinks and a pause.
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.
MOD OK
(Amber)
A blinking Amber Mod OK LED indicates the power output of the amplifier
module is below 65%. (NOTE: Only in Amplifier Code Versions 3.7A or later &
System Controller Code Versions 3.9C or later.)
Table 2-24: Power Amplifier Control Adjustments
POTENTIOMETERS
DESCRIPTION
RFL CAL Adjusts the gain of the Reflected Power monitoring circuit
VISUAL CAL Adjusts the gain of the Visual / Forward Power monitoring circuit
AURAL CAL Adjusts the gain of the Aural Power monitoring circuit
VISUAL ZERO Adjusts the offset of the Forward Power monitoring circuit
AURAL NULL
Adjusts the offset of the Forward Power monitoring circuit based on
the Aural signal level.
Table 2-25: Power Amplifier Sample
DISPLAY FUNCTION
FWD SAMPLE RF sample of the amplified signal being sent out the module on J25.
LX Series, Rev. 0 2-9
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