Elettronika TXUD500 User Manual
ATSC TRANSMITTER
Digital TV
CODE APD043A
APD047A
APD045A
TITLE ATSC TRANSMITTER REV 0 DATE 20/02/08
ATSC Transmitter Family
CODE MODEL
AP D 043A ATSC UHF TRANSMITTER
AP D 047A ATSC VHF-III TRANSMITTER
APD045A ATSC VHF-I TRANSMITTER
Registration number: IT-17686
Registration number: IT-24436
SS 96 Km 113
70027 Palo del Colle (Ba) ITALY
Tel. +39 (0)80 626755
Fax +39 (0)80 629262
E-mail: elettronika@elettronika.it
Web site: http://www.elettronika.it
Summaries
ATSC Transmitter Family .................................................................................................. 2
Summaries ......................................................................................................................... 3
Warning .............................................................................................................................. 7
Warranty ............................................................................................................................. 8
Introduction ....................................................................................................................... 9
Content of the manual ...................................................................................................... 9
Treatment of electrical shock ......................................................................................... 11
First-aid ......................................................................................................................... 12
Treatment of electrical burns ......................................................................................... 12
Note ............................................................................................................................... 12
RoHS Normative .............................................................................................................. 13
ATSC TRANSMITTER ...................................................................................................... 15
Section 1 - Information ................................................................................................... 17
1.1 Description .............................................................................................................. 18
1.2 Main Features ......................................................................................................... 18
1.3 Technical Characteristics......................................................................................... 19
Front panel .................................................................................................................... 20
Rear panel ..................................................................................................................... 21
Block Diagram ...............................................................................................................22
1.4 Operational Details .................................................................................................. 23
1.4.1 TS Input Management ...................................................................................... 23
- Redundancy management .................................................................................. 23
- Reed Solomon FEC ............................................................................................ 24
- Bit rate adaptation ...............................................................................................24
- Squelch ............................................................................................................... 24
1.4.2 Synchronization and Clocks ............................................................................. 24
1.4.3 Output Signal ................................................................................................... 25
1.4.4 Non-Linear Precorrection ................................................................................. 25
1.4.5 Linear Precorrection ......................................................................................... 25
1.4.6 Control of the equipment .................................................................................. 26
1.4.7 Test Modes ....................................................................................................... 26
1.4.8 Power Handling ................................................................................................ 26
1.4.9 Alarms and Automation .................................................................................... 27
1.4.10 AGC: Implementation and Details .................................................................. 29
ATSC TRANSMITTER AGC Cable ............................................................................ 31
1.4.11 Log ................................................................................................................. 32
Section 2 - Installation .................................................................................................... 33
2.1 Operating Environment ........................................................................................... 34
2.2 First Installation ....................................................................................................... 34
2.3 ATSC TRANSMITTER with GPS Clock Source ...................................................... 35
2.4 ATSC TRANSMITTER remote control with Elettronika RCU ................................... 35
2.5 ATSC TRANSMITTER with PC ............................................................................... 36
Section 3 - Operation ...................................................................................................... 37
3.1 Local Control ...........................................................................................................38
3.2 LEDs ....................................................................................................................... 38
3.3 Menu Management ................................................................................................. 39
3.3.1 Title Bar ............................................................................................................ 39
3.3.2 Status Bar......................................................................................................... 39
3.3.3 Diagram Screen ............................................................................................... 40
3.3.4 Browsing the menus and parameters ............................................................... 41
3.3.5 Composition of a menu .................................................................................... 42
3.4 Parameters and menu description .......................................................................... 44
3.4.1 Input Menu ....................................................................................................... 44
- Configuration Submenu ...................................................................................... 44
- Stream1 Errors Submenu.................................................................................... 46
- Stream2 Errors Submenu.................................................................................... 46
3.4.2 Modulation Menu .............................................................................................. 47
3.4.3 RF Menu...........................................................................................................48
- Frequency Submenu ........................................................................................... 49
- Power Submenu.................................................................................................. 50
- Amplifier Submenu .............................................................................................. 52
- Output Submenu ................................................................................................. 53
- Precorrection Submenu ...................................................................................... 54
3.4.4 Setup Menu ...................................................................................................... 55
- Control Submenu ................................................................................................ 56
- Display Submenu ................................................................................................ 57
- Clock Submenu .................................................................................................. .57
- Power Supply Submenu...................................................................................... 58
- Versions Submenu .............................................................................................. 58
3.5 Log Screen ..............................................................................................................59
3.6 Alarm Screen ........................................................................................................... 59
3.7 Firmware Upgrade................................................................................................... 59
ATSC TRANSMITTER Menu Map ................................................................................. 61
Section 4 - Diagram ......................................................................................................... 63
- APD043A ATSC TRANSMITTER Cable Diagram ....................................................... 64
- APD047A ATSC TRANSMITTER Cable Diagram ....................................................... 65
- APD045A ATSC TRANSMITTER Cable Diagram ....................................................... 66
- APD043A_APD047A_APD045A ATSC TRANSMITTER Component list.................... 67
- SCH0135A Control Board and Display ....................................................................... 69
- Description .............................................................................................................. 69
- Dip-switch............................................................................................................ 69
- Technical Characteristics ........................................................................................ 69
- SCH0135A Top layer Component layout..................................................................... 70
- SCH0135A Bottom layer Component layout ............................................................... 71
- SCH0135A Component list ......................................................................................... 72
- SCH0135A Electric Diagram ....................................................................................... 74
- A1592 ATSC UHF Modulator Module .......................................................................... 77
- Description .............................................................................................................. 77
- Main Features .........................................................................................................77
- Connectors .............................................................................................................. 77
- A1703 ATSC VHF-I/III Modulator Module.................................................................... 78
- Description .............................................................................................................. 78
- Main Features .........................................................................................................78
- Connectors .............................................................................................................. 78
- MTF0116A 5W UHF RMS Amplifier Module................................................................ 79
- Description .............................................................................................................. 79
- Technical Characteristics ........................................................................................ 79
- MTF0116A Component list ...................................................................................... 79
- MTF0116A Component layout................................................................................. 80
- SCH0417A Component layout ................................................................................ 81
- SCH0417A Component list ..................................................................................... 82
- SCH0417A Electric Diagram ................................................................................... 83
- MTF0118A 5W VHF-I/III RMS Amplifier Module.......................................................... 86
- Description .............................................................................................................. 86
- Technical Characteristics ........................................................................................ 86
- MTF0118A Component list ...................................................................................... 86
- MTF0118A Component layout................................................................................. 87
- SCH0436A Component layout ................................................................................ 88
- SCH0436A Component list ..................................................................................... 89
- SCH0436A Electric Diagram ................................................................................... 91
- MTF0125A 5W VHF-I RMS Amplifier Module ............................................................. 92
- Description .............................................................................................................. 92
- Technical Characteristics ........................................................................................ 92
- MTF0125A Component list...................................................................................... 92
- MTF0125A Component layout ................................................................................ 93
- SCH0320A Component layout ................................................................................ 94
- SCH0320A Component list ..................................................................................... 95
- SCH0320A Electric Diagram ................................................................................... 96
- SCH0388B Power Supply Interface Board ................................................................. 97
- SCH0388B Power Supply Interface Board Component layout ............................... 97
- SCH0388B Component list ..................................................................................... 98
- SCH0388B Electric Diagram ................................................................................... 99
- E0064 SP-320-27/48 Switching power supply .......................................................... 100
- Main Features ....................................................................................................... 100
- Mechanical Specifications ..................................................................................... 100
- Technical Characteristics ...................................................................................... 101
WARNING
The apparatus described in this manual has been designed and manufactured with devices to safeguard the users. In any case it is recommended that during any operation of installation, maintenance,
miscellaneous interventions and calibrations requiring the apparatus to be switched on,
THE USER TAKES ALL THE
PRECAUTIONS AGAINST INCIDENTS
It is required to use the proper clothes and protection gloves in order to prevent damages from incidental contacts with high-voltage parts.
The manufacturer declines every responsibility in case the recommendations above are not followed.
IMPORTANT
The component lists attached to the relevant electrical diagrams indicate for each item the reference,
the description and the type normally used.
The Elettronika S.r.l. though reserves the right to use or supply as spare parts components with
equivalent characteristics but of a different type, assuring anyway the optimal work of the apparatus
in accordance with the specifications.
The enclosed monographs are solely owned by Elettronika S.r.l.
The use of anything enclosed in this technical manual without explicit authorization given by Elettronika
S.r.l. will be prosecuted by the law.
The data and technical characteristics of the apparatus described in this manual are not compelling for
the manufacturer.
The Elettronika S.r.l. reserves the right to make, without previous notice, modifications or updates in
order to improve the quality of the product.
The general conditions of supply and sale are described in the contracts.
The delivery time are in accordance with the products and quantities ordered.
7
Warranty
Summary of warranty
We, ELETTRONIKA S.r.l., SS096 Km 113 Z.I. PALO DEL COLLE (BA) ITALY, warrant to the ORIGINAL PURCHASER of a NEW product, for a
period of one (1) year from the date of purchase by the original purchaser (the “warranty period”) that the new ELETTRONIKA product is free of defects
in materials and workmanship and will meet or exceed all advertised specifications for such a product. This warranty does not extend to any subsequent
purchaser or user, and automatically terminates upon sale or other disposition of our product.
Items excluded from this ELETTRONIKA warranty
We are not responsible for product failure caused by misuse, accident, or neglect. This warranty does not extend to any product on which the serial
number has been defaced, altered, or removed. It does not cover damage to loads or any other products or accessories resulting from ELETTRONIKA
product failure. It does not cover defects or damage caused by use of unauthorized modificstions, accessories, parts, or service.
What we will do
We will remedy any defect, in material or workmanship (except as excluded), in our sole discretion, by repair, replacement, or refund. If a refund is
elected, then you must make the defective or malfunctioning component available to us free and clear of all liens or other encumbrances. The refund will
be equal to the actual purchase price, not including interest, insurance, closing costs, and other finance charges less a reasonable depreciation on the
product from the date of original purchase. Warranty work can only be performed at our authorized service centers or at our factory. Expenses in
remedying the defect will be borne by ELETTRONIKA, including one-way surface freight shipping costs within the United States. (Purchaser must bear
the expense of shipping the product between any foreign country and the port of entry in the United States and all taxes, duties, and other custom’s fee(s)
for such foreign shipments).
How to obtain warranty service
You must notify us of your need for warranty service not later than ninety (90) days after the expiration of the warranty period. We will give you an
authorization to return the product for service. All components must be shipped in a factory pack or equivalent which, if needed, may
Desclaimer of consequential and incidental damages
You are not entitled to recover from us any consequential or incidental damages resulting from any defect in our product. This includes any damage
to another product or products resulting from such a defect.
Warranty alterations
No person has the authority to enlarge, or modify this warranty. The warranty is not extended by the lenght of time for which you are deprived of
the use of the product. Repairs and replacement parts are provided under the terms of this warranty shall carry only the unexpired portion of this
warranty.
Design changes
We reserve the right to change the design of any product from time to time without notice and with no obligation to make corresponding changes in
products previously manufactured.
Legal remedies of purchaser
There is no warranty which extends beyond the terms hereof. This written warranty is given in lieu of any oral or implied warranties not contained
herein. We disclaim all implied warranties, including without limitation any warranties of merchantability or fitness for a particular purpose. No action
to enforce this warranty shall be commenced later than ninety (90) days after expiration of the warranty period.
Warranty for electronic tubes
The warranty applied for electronic tubes is the one given by the manufacturer of the tube. In the event that the product shows anomalies within the
deadline of the validity of the warranty given by the manufacturer of the product itself, the buyer will have to return it to the seller with the needed
documents and the written description of the defect. The seller will ship the broken tube to the manufacturer in order to effect the necessary technical
tests to find out the cause of the anomaly. Meanwhile the buyer of the tube who needs to use, and as such to replace immediately the product, will have
to buy a new one and provide to the relevant payment, further to the issuing by the seller of a regular commercial invoice. After the adequate tests made
by the manufacturer, should the result be positive, that is confirm the defect in manufacturing, the seller will issue a regular credit note in the name of
the buyer and return the amount paid. Should the result be negative, that is detect a negligence in the installation or use by the buyer, he will have no
right against the seller.
8
INTRODUCTION
The apparatus described in this manual is the latest of this series, offering high performances, remarkable reliability and a wide range of characteristics, it all at a competitive cost.
Its is easy to install and use. It only takes to follow the installation procedure as shown in this manual:
after having removed all from the package, you only have to follow step by step the description in the
various sections.
Before starting to use the apparatus, remember to:
read carefully the general safety information contained in this section;
follow the instructions for the installation and set up of the apparatus;
read all the remaining sections of this manual in order to know well the apparatus and learn
how to obtain the best of its characteristics.
CONTENTS OF THE MANUAL
The chapter composing this manual contain all the information concerning the use of the apparatus.
For more information refer to ELETTRONIKA S.r.l.
This manual is made up of different chapters, each made up of various sections.
9
WARNING!
The currents and voltages in this equipment are dangerous!
Personnel must at all times observe safety regulation!
This manual is intended as a general guide for trained and qualified personnel who are aware of the
dangers inherent in handling potentially hazaedous electrical and electronic circuits.
It is not intended to contain a complete statement of all safety precautions which should be observed by
personnel in using this or other electronic equipment.
The installation, operation, maintenance and service of this equipment involves risks both to personnel
and equipment, and must be performed only by qualified personnel exercising due care.
Elettronika S.r.l. shall not be responsible for injury or damage resulting from improper procedures or
from the use of improperly trained or inexperienced personnel performing such tasks.
During installation and operation of this equipment, local building codes and fire protection standards
must be observed.
WARNING!
Always disconnect power before opening covers,
doors, enclosures, gates, panels or shields.
Always use grounding nsticks and short out high
voltage points before servicing. Never make
internal adjustments, perform maintenance or
service when alone or when fatigued.
Do not remove, short-circuit or tamper with interlock switches on access covers, doors, enclosures,
gates, panels or shields.
Keep away from live circuits, know your equipment and don’t take chances.
WARNING!
In case of emergency ensure that power has been disconnected.
10
Treatment of electrical shock
1) If victim is not responsive follow the A, B, C’s of basic life support.
PLACE VICTIM FLAT ON HIS BACK ON A HARD SURFACE
A - AIRWAY
If unconscious, open airway lift up neck, push
forehead back, clear out mouth if necessary,
observe for breathing.
B - BREATHING
If not breathing, begin artificial breathing. Tilt
head, pinch nostrils, make airttght seal, 4 quick
full breaths. Remember mouth to mouth resuscita-
tion must be commenced as soon as possible.
C - CIRCULATION
Check carotid pulse. If pulse
absent, begin artificial circulation.
Call for medical assistance as soon as possible.
Approx. 80sec.: 1 rescuer, 15 compressions, 2 quick breaths.
Approx. 60sec.: 2 rescuers, 5 compressions, 1 breath.
NOTE: DO NOT INTERRUPT RHYTHM
OF COMPRESSIONS WHEN SECOND PERSON
IS GIVING BREATH.
11
2) If victim is responsive:
- keep them warm;
- keep them as quiet as possible;
- loosen their clothing (a reclining position is recommended).
FIRST-AID
Personnel engaged in the installation, operation, maintenance or servicing of this equipment are urged
to become familiar with first-aid theory and practices. The following information is not intended to be
a complete first-aid procedure, it is brief and is only to be used as a reference. It is the duty of all
personnel using the equipment to be prepared to give adequate Emergency First Aid and thereby prevent avoidable loss of life.
TREATMENT OF ELECTRICAL BURNS
1) Extensive burned and broken skin.
- Cover area with clean sheet or cloth (cleansed available cloth article);
- do not break blisters, remove tissure, remove adhered particles of clothing, or apply any salve or
ointment;
- treat victim for shock as required;
- arrange transportation to a hospital as quickly as possible;
- if arms or legs are effected keep them elevated.
NOTE
If medical help will not be available within an hour and the victim is conscious and not vomiting, give
him a weak solution of salt and soda: 1 level teaspoonful of salt and 1/2 level teaspoonful of baking
soda to each quart of water (neither hot or cold).
Allow victim to sip slowly about 4 ounces (half a glass) over a period of 15 minutes.
Discontinue fluid if vomiting occurs (do not give alcohol).
2) Less severe burns - (1st & 2nd degree).
- Apply cool (not ice cold) compresses using the cleansed available cloth article;
- do not break blisters, remove tissue, remove adhered particles of clothing, or apply salve or ointment;
- apply clean dry dressing if necessary;
- treat victim for shock as required;
- arrange transportation to a hospital as qickly as possible;
- if arms or legs are affected keep them elevated.
12
Communication N°1 -2002/95/CE - RoHS Directive
Further to the directives issued by the European Community, 2002/95/CE, 2002/95/CE and 2003/108/
CE, and to the Italian Decree of Law n° 151 dated 25 July 2005, this is to inform the customers of Elettronika
S.r.l. living within the boundaries of the European Community about the following obligations:
1) It is forbidden to trash RAEE products (which includes all broadcasting products which are not expressly
labelled as lead-free) along with normal wastes;
2) Such devices must be brought to proper centres able to perform the adequate processing in order to
recycle their parts where possible and dispose of the raw materials contained therein;
3) For equipment purchased from Elettronika after the 13th of August 2005, the gathering, transport, processing,
recycle and disposal operations are responsibility of Elettronika who will bear all related expenses;
4) For equipment purchased from Elettronika before the 13th of August 2005 , the gathering, transport,
processing, recycle and disposal operations are responsibility of Elettronika, who will bear all related expenses,
only if you are purchasing from us new equipment in substitution of the disposed one;
5) Electric and electronic devices contains lead in soldering, cables, etc. This substance pollutes the environment
and may be accumulated in the organism of plants and mammals. It is dangerous for humans because it may
affect blood, bone marrow, peripheral and central nervous system and kidneys, causing anaemia,
encephalopathies (e.g., convulsions), peripheral neuropathies, cramps of the abdomen and kidney damages.
Besides it affects human reproduction and growth.
These devices also contain mercury. From the environmental point of view, this substance is highly toxic for
aquatic life, and can be accumulated in the organism of fish.
Long-term damages to humans can affect the central nervous system and the kidneys, producing irritability,
emotional instability, tremors, damages to the mind and the memory, language disorders. It may also irritate
and whiten the gums, and its effects may be cumulative. Based on tests on animals, it may affect the human
reproduction or growth.
There is also chrome, which may result in irritation of the eyes and respiration system.
Cadmium is also present. In humans it may damage lungs, due to repeated or prolonged contact with its dust,
and kidneys. It may cause cancer.
6) The symbol below marks the devices which cannot be disposed of along with normal wastes, as stated in
1) and 2) above.
7) The payment of fees is foreseen for the non-allowed disposal of such devices.
13
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14
DIGITAL TV
ATSC TRANSMITTER
User’s manual
15
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16
Section 1 - Information
Contents:
1.1 Description
1.2 Main features
1.3 Technical characteristics
Front Panel
Rear Panel
Block Diagram
1.4 Operational details
17
ATSC TRANSMITTER
1.1 DESCRIPTION
The ATSC TRANSMITTER is an 8-VSB ATSC professional exciter, designed for the most demanding
digital TV broadcasting applications. It integrates a modulator module with up-to-date FPGA technology and
advanced digital signal processing algorithms in order to generate an absolutely accurate output 8-VSB signal,
with exceptionally optimized modulation and the output filtering techniques.
Very high linearity performances are possible thanks to very careful RF design over the entire VHF and UHF
bands and with an optimal digital precorrection engine working simultaneously in the time and frequency
domains. A high degree of reliability is guaranteed, moreover, by the use of oversized cooling devices and by
control circuits operated by modern microprocessor technologies.
The ATSC TRANSMITTER can be used as a stand-alone 5W RMS transmitter or as a driver stage for
amplifiers of greater power. The excellent spectral purity of the conversion oscillator lets the ATSC
TRANSMITTER radiate an 8-VSB signal with an excellent MER value.
The ATSC TRANSMITTER is equipped with a powerful ASI/SMPTE inputs management block which
allows to manage the Transport Stream (TS) inputs in a fully redundant configuration, thus significantly improving
the reliability of the whole broadcasting system in every operating condition.
The ATSC TRANSMITTER is totally compliant to the A53, A/54 and A/64 ATSC recommendations with
6MHz output channel bandwidth, in VHF and UHF bands.
1.2 MAIN FEATURES
- Compact and cost competitive;
- Top-quality air cooling system;
- Agile output frequency step 1Hz over VHF and UHF bands;
- Complies and exceeds the ATSC recommendations;
- Multi-platform remote control;
- User-friendly Graphical User Interface;
- Very high power efficiency thanks to accurate digital precorrection;
- Easy frequency synchronization.
18
1.3 TECHNICAL CHARACTERISTICS
SIGNAL PROCESSING SECTION
Reference Standard ATSC A/53, A/54, A/64
ATSC Mode 8-VSB 2/3 Trellis Code
Constellation 8-VSB
Code Rate 2/3
Network Support MFN
Bandwidth 6MHz
Digital Pre-Correction Linear and Non-Linear
Automatic PCR Restamping User enabled with Bitrate adaptation
Test Modes 23-bit PRBS Generator, Single-tone output
INPUT SECTION
TS Input 2 DVB-ASI + 2 SMPTE-310M inputs fully redundant
Input TS Format SPTS/MPTS, Burst Mode - Continuous Mode (ASI inputs)
MPEG-2 Packet Length 188/204 bytes (ASI), 188 bytes (SMPTE)
Input Data Rate 19.392658Mbit/s (SMPTE), up to 60Mbit/s (ASI)
Internal VCTCXO 10MHz reference
- Stability (full temperature range) < 1ppm (0-50°C)
- Aging < ±1ppm/year
- Tuning ±5ppm
10MHz output 0dBm ±3dB
External Frequency Reference 10MHz ±5ppm
Frequency Reference Interface BNC, 50Ω, -15dBm to +15dBm
OUTPUT SECTION
RF Output Frequency VHF band (57-240MHz) step 1Hz
Output Level 5W RMS
Output Interface N type connector, 50Ω
Spectrum Polarity Non-inverted and Inverted
Harmonics and Spurious < -50dBc
Pilot Carrier phase noise < -106dBc/Hz @20kHz
EVM < 2.5% without equalizer
Inband SNR > 32dB without equalizer
Shoulders > 50dB
Inband ripple < ±5dB
GENERAL
Physical Case 19”-2U, 420mm deep, 12kg
Remote Control Port RS232/RS485
Remote Control Options PSTN, GSM, Ethernet, SNMP (with external unit)
Front Panel User Interface LCD Display + Rotating knob + 3 LEDs
Power Supply Voltage 90 - 240VAC 50/60Hz
Power Consumption 150VA max
Operating Temperature 0 - 50°C
Specifications and characteristics are subject to change without notice
UHF band (470-860MHz) step 1Hz
19
Front panel
5
3
4
1 Graphical LCD
2 Rotating Knob
3 Status LEDs
4 RS232 Socket
5 RF Monitor Connector
DESCRIPTION
2
RS232 for Serial pin-to-pin connection
to PC with ERCos software
and for firmware upgrade
1
Pin 2: TX
Pin 3: RX
Pin 5: GND
20
Rear panel
2
DESCRIPTION
1 Main Switch
LINE SOCKET
2 AC Socket with Fuse-Holder (2A)
1
3 RS485 Socket
3
RS485
TELEMEASURES
4
ASI2
ASI1
5
SMPTE1
SMPTE2
4 Telemeasures Connector
TS Input Connectors
- ASI1 Input
5
- ASI2 Input
- SMPTE1 Input
- SMPTE2 Input
6 10MHz OUT Connector
7 10MHz IN Connector
8 RF Output Connector
IN
OUT
10MHz
10MHz
6
7
for Serial pin-to-pin connection
to RCU for remote control
Pin 2: RXPin 3: RX+
8
RF OUT
Pin 4: +5V
Pin 5: GND
Pin 6: +5V
Pin 7: TXPin 8: TX+
RS485
Pin 1: FWD power (Analog out)
Pin 2: REF power (Analog out)
Pin 3: Temperature (Analog out)
Pin 4: FWD power (Analog in)
Pin 5: GND
Pin 6-7:Alarm or Squelch (user selectable)
Pin 8: External AGC Alarm (Digital in)
Pin 9: Remote ON/OFF (Digital in)
Wired Telemeasures connector
Alarm: Open=Normal / Closed=Alarm
Squelch: Open=No Squelch / Closed=Squelch
(Digital out, Free contact relay)
Open=Normal / GND=Alarm
Open=ON / GND=OFF
21
Block diagram
RF OUTPUT
OUTPUT
AMPLIFIER
DIGITAL-TO-ANALOG BANDPASS
8-VSB
FILTER
MODULATOR CONVERTER
DUAL-STAGE
FREQUENCY CONVERTER
SYNTHESIZER
AGILE LOW-NOISE
POWER SUPPLY SYNCHRONIZATION CONTROL & MONITORING MONITORING OUTPUT
CONTROL
REDUNDANCY
90-250Vac 10MHz IN 1 0MHz OUT RS232 TELEMEASURESRS485
22
ASI1 INPUT
ASI2 INPUT
SMPTE1 INPUT
SMPTE2 INPUT
1.4 OPERATIONAL DETAILS
All the sections of the ATSC TRANSMITTER, as showed in the block diagram above, are described in this
section in order to give the user a general understanding of the operations of the equipment.
1.4.1 TS INPUT MANAGEMENT
The ATSC TRANSMITTER is equipped with 2 ASI inputs and 2 SMPTE-310M inputs. Each input standard
is available with two inputs in order to enable redundant operation for the transport stream input. You can
decide to operate with SMPTE input or with ASI input depending on your network interfacing needs. In
either case a complete redundancy is guaranteed thanks to a duplicated input.
The ATSC transmission scheme is built over a very stable and accurate data stream clock. The SMPTE310M data clock shall have the exact standardized clock frequency. The modulator module takes its
synchronization from this input data stream to be able to recover the same clock frequency. If an external
clock reference is used (10 MHz), the global clock synchronization might be plesiochronous (i.e. not perfect
synchronization between the multiplexer clock and the modulator reference clock). In that case, it is
recommended to enable the "bit rate adaptation" on the ATSC TRANSMITTER.
When this mode of operation is enabled, the input processing module discards or inserts Null Packets in order
to adapt the MPEG-TS input bit rate to the precise bit rate defined by the ATSC recommendation. PCR restamping is then executed accordingly.
The switching is not expected to be seamless. However, in case of feeding the exact data stream on both
inputs (Primary & Secondary), then the ATSC TRANSMITTER performs a seamless switching from one to
the other input. Switching is always performed on a packet basis.
The user may enable or disable the automatic mute when an error on the SMPTE-310M or on the ASI input
is detected. The delay for the detection of the lost of SMPTE-310M is 1 second from its occurrence. In case
the user disables the automatic mute, null packets are inserted in order to feed the modulator section with the
exact ATSC bit rate.
Two test modes are available for testing and alignment procedures. The 23-bit PRBS test mode generates a
pseudo-random data sequence in order to produce a correct output spectrum even in absence of a valid TS
input. The single-tone test mode produces a sinusoidal output useful for frequency converters alignment. The
test modes are useful only for testing purposes and shall not be used for real broadcasting operation.
- Redundancy management
When set in Automatic Switching mode (default), the input management unit automatically detects the presence
of a valid MPEG Transport Stream (MPEG-TS) on the main or auxiliary inputs. If no valid MPEG-TS flow
23
is detected, the unit switches automatically to the other input. The periodic occurrence of the Sync byte in the
MPEG-TS packets is used to decide if a MPEG-TS flow is valid or not. If the user chooses to operate in
Manual switching mode then he has to force which input is active.
- Reed Solomon FEC
If the ASI incoming inputs (note: only for ASI input mode) include the Reed Solomon codes (204 bytes
packets), the module performs the error correction thanks to the 16 RS bytes.
- Bit rate adaptation
When operating in ASI input mode, the input management unit can perform an automatic bit-rate adaptation,
if required. When this mode of operation is activated, the unit automatically removes and/or inserts null packets
in order to adapt the incoming ASI bit-rate to the exact bit-rate defined by the ATSC recommendation. PCR
restamping is then executed in real time.
- Squelch
The RF output signal can be muted if one of the following conditions occurs:
- a hardware problem is present (for example, the amplifier temperature is too high, the modulator does not communicate
with the controller and so on);
- an error in the input signals is present (input TS missing and Mute on input error feature enabled).
In the first condition, the output is muted to protect valuable internal parts of the equipment and/or save power. In the
second condition, the output is muted because the signal is most probably unusable by receivers. This muting action
is known as Squelch.
In a dual drive or 1+1 transmitter, the changeover control unit should discriminate if the output power reduction is
caused by a hardware problem (the changeover takes place) or by an input signal problem (the changeover is not
performed). The user can change the meaning of the digital output in the TLM port choosing "Alarm" (useful to
interface a custom remote control system) or "Squelch" (useful to interface a changeover control unit).
1.4.2 SYNCHRONIZATION AND CLOCKS
The ATSC TRANSMITTER includes its own clock and synchronization generator. A high stability 10MHz
VCTCXO provides the internal clock reference to the clock system of the digital processing section of the
equipment. An external 10MHz reference may be used if a higher stability is needed, or if there is a need to
lock the modulator processing clock or the output carrier frequency to an external reference (i.e. operation in
frequency offset mode).
In special cases, the 10MHz internal clock may be locked to the system clock embedded into the ASI/
SMPTE input signal. In this case, you can not enable the Bit-Rate Adaptation function and the input bit rate
has to be the exact ATSC bit-rate (19.392658Mbit/s). If the ATSC TRANSMITTER is set up to operate
with either of the two external references (from ASI/SMPTE input or from the external 10MHz reference), it
will automatically switch to the internal reference if the external reference is missing. The switching from the
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external 10MHz reference to the 10MHz internal clock is totally seamless. The processing clock of the numerical
section of the ATSC TRANSMITTER is always locked to the internal or to the external 10MHz reference.
1.4.3 OUTPUT SIGNAL
The ATSC TRANSMITTER output signal is available at the output labelled RF OUT on a 50Ω N-type
female connector. The frequency of the output signal can be set in the VHF and UHF bands, depending on the
model type. The frequency can be set by choosing the standard/channel/offset combination (for example,
UHF standard, channel 45 and offset 0Hz) or by choosing directly the center frequency of the output signal.
An attenuated version of the output signal is available at the RF Monitor terminal located on the front panel of
the equipment. The maximum nominal output level is 5W RMS, the output power level can be controlled in
AGC (Automatic Gain Control) mode or in manual mode and can be adjusted by the rotating knob located
on the front panel. The output signal may be muted either manually by the user or automatically depending on
some given conditions. The mute can be direct (abrupt muting) or progressive (linearly decreasing function).
1.4.4 NON-LINEAR PRECORRECTION
Any solid-state or tube power amplifier will produce intermodulation distortion when fed by the ATSC 8VSB signal. Non-linear precorrection is used to compensate the effects of these distortions in order to radiate
a signal with the maximum possible MER value.
The ATSC TRANSMITTER is able to perform non-linear precorrection over a 20MHz bandwidth. For this
purpose, two tables (AM-AM and AM-PM) of maximum 16 taps are used by the modulator.
The AM-AM precorrection table defines the AM-AM curve that will be applied to the output spectrum. For
each tap, the abscissa can be defined from -12dB to +12dB by 0.05dB step and the ordinate can be defined
from -6dB to +6dB by 0.05dB step.
The AM-PM precorrection table defines the AM-PM curve that will be applied to the output spectrum. For
each tap, the abscissa can be defined from -12dB to +12dB by 0.05 step and the ordinate can be defined
from -25 degrees to +25 degrees by 0.2 degrees step.
Up to 10 non-linear precorrection curves (10 AM-AM and 10 AM-PM tables) can be downloaded and
saved into the equipment memory. For each curve a 10-characters name is associated. By using the local or
remote control it is possible to disable the non-linear precorrection at all or activate one of the saved curves.
Besides the 10 customizable curves, a non-customizable "Null" curve is always available: the AM-AM and
AM-PM tables of this curve are filled by zeros.
1.4.5 LINEAR PRE-CORRECTION
Any output cavity filter will produce amplitude and group delay distortion over the ATSC 8-VSB signal
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generated by the transmitter. Linear precorrection is used to exactly compensate these distortions in order to
generate a signal which is maximally flat both in amplitude and group delay. The ATSC TRANSMITTER is
able to perform amplitude and group delay correction over the full spectrum of the output signal.
The linear precorrection is a factory procedure, so the equipment is delivered with the optimal linear precorrection
curve already operating.
By operating on the front panel user interface, the user may decide to switch off or switch on the linear
precorrection curve stored by the Elettronika production department.
1.4.6 CONTROL OF THE EQUIPMENT
The ATSC TRANSMITTER can be controlled by means of a user-friendly LCD graphical interface with a
single rotating knob for the menu navigation and for the selections or remotely through a RS232, RS485 or
TELEMEASURES port. The functions of the local and remote control are:
- Setting the operating mode of the ATSC TRANSMITTER and the associated parameters. All these parameters
are stored in a local memory, so the previous operating mode is automatically restored each time after a power cycle.
- Monitoring the status of the equipment.
- Recording events and alarms.
- Firmware upgrades.
- Digital Precorrection through RS232 port and dedicated PC software interface.
1.4.7 TEST MODES
Two test modes are available, to be used only for laboratory or field test. The test modes are directly accessible
from the user menus and are:
1) PRBS Sequence: the ASI/SMPTE input signals are ignored and a 23-bit PRBS sequence replaces the in-
put payload of the MPEG-TS packets. This test allows measurements on the modulated signal without the
need of a valid ASI/SMPTE input signal.
2) Single Tone: the normal 8-VSB output spectrum is switched off and replaced by a sinusoidal output useful
for frequency converters alignment.
Note: If test mode 2) is active, the ATSC TRANSMITTER does not generate a valid ATSC 8-VSB signal.
1.4.8 POWER HANDLING
After the ATSC TRANSMITTER is powered on, it starts radiating a valid ATSC 8-VSB signal within a short
time. The maximum initial power-on delay is about 20s as factory default value. Any modification of this initial
power-on delay is to be done with the support of the Elettronika Customer Service.
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If a valid MPEG-TS signal is received over one of the ASI/SMPTE inputs, then the equipment will immediately
generate the signal on the RF output. In absence of a valid MPEG-TS signal the equipment can be set to be
muted or not.
Enabling the muting function is possible by the user menus, as explained in the Menu Management section of
the present manual.
All the working parameters of the ATSC TRANSMITTER are stored into a non-volatile memory in the
modulator section, so that there is no need to restore the parameters after a power off/on cycle.
The power handling is characterized by 3 states: MUTE, POWER UP and POWER ON.
z MUTE (POWER LED off, fan off): the internal amplifier is switched off by inhibiting the RF transistors gate.
z POWER UP (POWER LED blinking, fan on): the internal amplifier is switched on and the output power,
starting from -3dB to the final level, is slowly increased following a linear ramp law.
z POWER ON (POWER LED on, fan on): the internal amplifier is switched on (normal working operation).
Moving from MUTE to POWER ON state (for example, after switching on or when an active alarm disappears)
is performed by moving through a temporary POWER UP state. Instead, moving from POWER ON to
MUTE state (for example, when a serious alarm occurs or the ASI/SMPTE inputs are corrupted or absent)
is immediate.
1.4.9 ALARMS AND AUTOMATION
The ATSC TRANSMITTER is fully protected against any malfunctioning event that could damage the expensive
internal components. The user should clearly understand what happens in presence of alarms and warnings,
in order to face these situations properly and reduce the inactivity time.
In case of any alarm condition, the ALARM LED on the front panel lights up and a bell icon appears in the
status bar of the display. When the alarm condition ceases, the ALARM LED is turned off and the bell icon
starts blinking, in order to show that an anomaly occurred since the last visit to the log. To know the details
about the alarm event (for example the time and date of its occurrence), the log menu can be used. Once the
user enters the log screen, the bell icon disappears. When you note an active alarm (the bell icon is shown and
not blinking and the ALARM LED
is on), go to the ALARM screen to see which alarms are present. For certain dangerous situations, the ATSC
TRANSMITTER immediately switches off the output power, by acting on the RF power transistors gate, in
order to save the internal parts from an unrecoverable damage. When the alarm disappears, the power is
automatically switched on again. Once the output power has been inhibited for 5 times, the ATSC
TRANSMITTER goes into "Lockout" state: the power remains off until the user resets the Lockout condition,
or switches the equipment off for repair. After one hour from the last alarm and without the Lockout condition,
the Lockout counter is automatically cleared. The list of the automatic interventions in case of anomalies can
be found below.
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z Amplifier Voltage
An amplifier power supply voltage alarm occurs when the monitored voltage is outside the nominal level
±10% range. The nominal voltage level is a factory setting (usually, 28V). This alarm does not trigger a
powering off of the output signal. If the monitored voltage is near 0V, most probably the fuse located near the
power amplifier stage is burned.
z Amplifier Current
An amplifier power supply current alarm occurs when the monitored current drained by the amplifier is 20%
above the nominal level. The nominal current level is a factory setting. This alarm does not trigger a powering
off of the output signal.
z Amplifier Temperature
The temperature is monitored on the hottest point, located near the power amplifier stage on the cooling heat sink.
If the fans work well, and the ambient temperature is inside the working conditions limits, all of the internal parts
should reach safe temperature levels. In some circumstances (for example, when a fan is blocked or damaged), the
temperature may increase too much, and some internal components may break. In order to avoid this unpleasant
situation, a temperature alarm occurs when the temperature is over a maximum threshold (75°C). This alarm
triggers an immediate powering off of the output signal and an increase of the lockout counter.
The power will be switched on again only when the temperature goes below a second threshold, lower than the first
(70°C).
z Forward and Reflected Powers
A forward or reflected power alarm occurs when the relevant monitored power level is over a threshold
(factory setting). Both alarms trigger an immediate powering off of the output signal and an increase of the
lockout counter.
You can see the levels of the power thresholds in the Amplifier menu (see the Menu Management paragraph).
z Power supply voltages (+5V, +12V, -12V)
Besides the amplifier power supply voltage (+28V), the ATSC TRANSMITTER uses three additional main
voltages: +5V, +12V, -12V. These voltages are continuously monitored by the control system and any variation
above 10% of the nominal value generates an alarm condition. This alarm does not trigger a powering off of
the output signal.
z No communication with the modulator
The 8-VSB Modulator module continuously communicates with the control system. If this communication
fails, the control board triggers a "No communication" alarm.
This is a serious malfunction that must be solved as soon as possible.
In presence of a no communication alarm, the control system is not able to know the working condition of the
modulator (for example, the modulated output signal level), so it inhibits the power amplifier stage and the
output power is brought to zero level.
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z External reference alarm
When external or ASI/SMPTE reference is set, the modulator continuously monitors the presence of such
reference. If it is not able to find a correct signal, it automatically switches to the internal reference. In this
situation, an external reference alarm is triggered. This alarm does not trigger a powering off event. See the
Synchronization and Clocks paragraph for more information.
z ASI/SMPTE inputs alarm
There are several conditions related to input streams that could trigger an alarm, depending on the working
conditions. They are:
- MPEG-TS synchronization missing;
- uncorrected input packet (only in 204 RS coded mode with ASI input mode);
- bit rate underflow/overflow (only if bit rate adaptation is performed).
The above conditions trigger an alarm only for the input which is currently used by the ATSC TRANSMITTER.
1.4.10 AGC: IMPLEMENTATION AND DETAILS
The use of external AGC helps the ATSC TRANSMITTER to maintain stable the output power of a highpower transmitter. With a menu setting (see the Menu Management paragraph) you can choose among
stabilizing the output power of the exciter (external AGC disabled) or stabilizing the output power of a highpower transmitter (external AGC enabled). In this case a proper cabling between the ATSC TRANSMITTER
and the high-power amplifier stage is necessary. The cable (AGC cable) shall be connected to the TLM port
of the ATSC TRANSMITTER on one side. In the following table the three signals and pins used in the TLM
port are listed. The pinout connection of the cable depends on the specific amplifier used. Refer to your
amplifier user's manual to find the port and pins of the corresponding signal.
PIN I/O DESCRIPTION
4 I Forward Power (0-5V)
5-GND
8 I Alarm (GND=Alarm / Open=Normal)
The AGC goal is to maintain the output power stable. Output power in fact can change due to the increase of
the amplifier temperature. Note that when you change the operating frequency the output power changes due
to the different gain at different frequency, but this change is not stabilized by the AGC algorithm. The transmitter
power to be stabilized is read from TLM port.
To keep the power stable, the AGC changes the power gain of the ATSC TRANSMITTER.
The AGC algorithm is based on the acquisition of the optimal output power level, stored when you confirm the
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output power level in the Power menu (see the Menu management paragraph) and the use of 4 thresholds
as below:
____action threshold
________goal threshold
___________optimal power value
________goal threshold
____action threshold
The distance of the thresholds from the optimal value is of ±20mV and ±30mV measured as monitor voltage.
The AGC changes the output power to bring the power from the amplifier inside the goal thresholds range.
When this goal is achieved, the AGC stops until the power goes outside the action thresholds range.
The AGC is stopped immediately (output power remains blocked to the value reached at the moment in
which the AGC stops) when one of the following conditions occurs:
z RF output is muted for an alarm condition or user setting;
z the AGC is chosen as external but the amplifier stage triggers an alarm;
z the ATSC TRANSMITTER output power is too low;
z the AGC has corrected the output power too much.
In order to simplify the understanding of the AGC behaviour, the status of the external AGC is written in the
Power menu (Ext AGC Status parameter). The possible statuses of the AGC are listed below.
z Disabled: external AGC is disabled.
z Idle: external AGC is stopped (for example, during the slow increase of the power immediately after swit-
ching on the equipment).
z Low Set: external AGC is stopped because external power reading was too low when the nominal output
power has been chosen.
z Alarm: external AGC is stopped because an alarm signal from the power amplifier stage is active.
z Locked: the transmitter output power has reached the desired level.
z Max/Min: external AGC is stopped because the power correction is too high.
z Pull Up/Down: external AGC is moving the power level up or down.
Warning! When changing from AUTO to MANUAL power control mode, the external AGC will be disabled.
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