Linear AT7120 Owner's Manual
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Linear AT7120 Owner's Manual

Linear AT7120 Owner's Manual

Advanced tv line 120w atsc uhf transmitter
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ADVANCED TV
LINE
Model AT7120
120W ATSC UHF Transmitter
OWNERS MANUAL
Linear Industries Incorporation
www.linear-tv.com
Made in USA

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Summary of Contents for Linear AT7120

  • Page 1 ADVANCED TV LINE Model AT7120 120W ATSC UHF Transmitter OWNERS MANUAL Linear Industries Incorporation www.linear-tv.com Made in USA...

  • Page 2: Table Of Contents

    Section 8 – DC/DC Converter ....................47 Section 9 – Memory Interface ....................48 Annex A – AT7120 Operational Software ................49 Annex B – Checking the RF Power LDMOS Transistors ............72 Annex C – Typical Final Test Reports Results ................ 73 Owner Manual Rev.

  • Page 3: User Notices And Warnings

    It is advisable that such personnel have familiarity with first-aid practices. Notice 5 To call our technical support center or for other customer service issues at Linear Inc, refer to the following number: 847 428-5793, or e-mail to broadcast@linear-tv.com...
  • Page 4 TYPES OF ELECTRONIC EQUIPMENT. THE INSTALLATION, OPERATION, AND MAINTENANCE OF THIS EQUIPMENT INVOLVE RISKS TO PERSONNEL AND ALSO TO THE EQUIPMENT. LINEAR, INC. SHALL NOT BE RESPONSIBLE FOR INJURY OR DAMAGE THAT IS THE RESULT OF IMPROPER PROCEDURES OR USE BY PERSONS IMPROPERLY TRAINED OR LACKING THE KNOWLEDGE TO PERFORM ASSOCIATED TASKS.
  • Page 5 When communicating with Linear please refer to your Order or Invoice Number. Unpacking Use care when unpacking the equipment. First perform a visual inspection of the item(s) to determine if any damage occurred during shipment. Be sure to retain all the shipping materials (crates and boxes or cartons) until such time that it has been determined that the received equipment arrived undamaged.

  • Page 6: Section 1 - At7120 General Description

    01 OCXO – Module 4292 When AT7120 is a TRANSMITTER that can be installed with or without a 6 pole elliptical filter on its RF output. In this application, the overall performance of the unit will meet or exceed the FCC requirements for out of channel spurious emission.
  • Page 7 AT7120 Block Diagram Owner Manual Rev. 1.1 – March 2009 AT7120 7/76...
  • Page 8 ATSC recommendation A/53 E. This module also performs the non-linear corrections that might be necessary to enhance the equipment efficiency to meet FCC spurious emissions requirements. In this case, an RF output filter is required.
  • Page 9 LCD screen in watts. Module 4442 AT7120 transmitter has two Modules 4442 connected in parallel, which work as digital TV end amplifiers in all UHF band. The amplifier is made of the following components:...

  • Page 10: Power Supply

    CIM3297 Control unit card The digital management of the DTV AT7120 transmitter is done by the control unit card, CIM3297. This control unit uses an A128 microcontroller programmed in assembler language. The unit process data regarding the following operational parameters: Warns of signal lock failure of the PLL in the up-converter.
  • Page 11 AT7120 External Interfaces Fig.1.2: AT7120 Front View Owner Manual Rev. 1.1 – March 2009 AT7120 11/76...
  • Page 12 External 10MHz Internal DB-9 (DB-9) RS232 Reference Input Not Used Hyper-terminal Interface ID Tag Power Switch Main Fuse Hot Air Outlets AC Power Cord RF Output Connector Fig.1.3: AT7120 Rear Panel View Owner Manual Rev. 1.1 – March 2009 AT7120 12/76...
  • Page 13 AT7120 - Modules and Parts Displacement RF Power Amplifier DC Fan Filter Module 4407 CIM6646 Memory Card & Interface CIP 8437 LCD Screen CIM3004 8VSB Modulator & DC/DC Master Clock Converter Module 4549 Module 4567 Up Converter Module 4492 Ref. 10MHz OCXO Module 4281 Fuse &...

  • Page 14: Specifications

    AT7120 - 120W ATSC UHF Transmitter - Technical Specifications Table XX: AT7120 Technical specifications Electrical Main 220 VAC, bi phase, 50-60 Hz. standard Consumption 400W @ 120W RMS/RF Power Factor Correction, FPC. Included Signal Input ATSC/MPEG2, compliant Transport Stream Input...

  • Page 15: Section 2 - Control Set

    The control unit is directly connected to a keypad and LCD screen, both located on the front panel of the transmitter AT7120. Numerous parameters can be set via the keypad and monitored by the LCD screen. The same functions can be performed via RS232 HyperTerminal connection.
  • Page 16 The printed circuit board CIP8231 is referred to as the control unit, and provides the major functionality of the AT7120 digital control unit. For a better understanding of the functioning of this board please refer to Fig.2.1 “Control unity general block diagram”, above, which depicts the main components and connections.

  • Page 17: Fig.2.2: Cip8231- The Control Unit Board - Components And Connections

    The major components and functions of CIP8231 are described below: Integrated circuit CI-4 (A128) is a 16 bit microcontroller programmed in assembly that performs all system management functions. This component is programmed in the factory and includes a numeral Owner Manual Rev. 1.1 – March 2009 AT7120 17/76...
  • Page 18 Automatic Level Control (ALC) to zero volts (provided to the up-converter module 4492). For more details see the power control description on the next page. The following alarms reach the connectors CON-4, CON-5 and CON-6 at the CIP8231 board as digital information. Owner Manual Rev. 1.1 – March 2009 AT7120 18/76...
  • Page 19 (UHF) which is then sent over the SPI to the up-converter - Module 4492 - This stream of information is composed by data, clock and enabling code, and is presented on pins 1, 2 and 3 of connector CON-4 of the CIP8231 board. Owner Manual Rev. 1.1 – March 2009 AT7120 19/76...
  • Page 20 It is important to remember that the initial programming of the CIP8231 board for the transmitter AT7120 is made at the factory. These programming procedures are not accessible to the end user. In turn, Module 4492 sends the lock detected information to the CIP8231 board indicating that the PLL circuitry is in lock and ready for operation.
  • Page 21 The jumper J1, also located at CIP8231 board, can be set to the R61 position, if the LCD back light is desired to stay ON at all time. Owner Manual Rev. 1.1 – March 2009 AT7120 21/76...

  • Page 22: Section 3 - 8Vsb Modulator And Master Clock

    172MHz Master Clock Internal 10MHz TCXO ref. input 10MHz OCXO ref. output to Up Converter 10MHz External Reference Input Transport Stream Input Fig.3.1: Module 4549, (a) top view, (b) connectors, from rear panel Owner Manual Rev. 1.1 – March 2009 AT7120 22/76...
  • Page 23 MER, (Modulation Error Rate). The modulation process generates two identical but orthogonal signals, I and Q. The frequency of the IF carrier is 21.52MHz, and the center of the channel is 18.8MHz. Owner Manual Rev. 1.1 – March 2009 AT7120 23/76...
  • Page 24 The benefit of working with two orthogonal carriers is: the possibility to implement corrections on non- linear distortions, or simply implement digital pre-distortion. The digital pre-correction is possible using LUT (Look up Tables); refer to Section 9 for more details. This table synthesizes inverted responses regarding the RF power amplifier transfer function, reducing the IMD products.
  • Page 25 VCO. This way, the VCO is locked to the external reference signal. The oscillator signal is delivered via 3 connectors located on the CIP8358 board. Two of those signals are routed to the 8VSB Modulator - CIM3510 board. Owner Manual Rev. 1.1 – March 2009 AT7120 25/76...

  • Page 26: Section 4 - If/Uhf Up-Converter

    Simple conversion Orthogonal mixing, which performs the image and LO rejections Synthesized local oscillator via PLL, 22 bits serial fractional Allows channel offset programming @ 1Hz resolution when using external 10MHz? reference Owner Manual Rev. 1.1 – March 2009 AT7120 26/76...
  • Page 27 Stand-by for local oscillator, in case of a failure in the external reference signal Meets or exceeds the phase noise requirements for DTV transmission Module 4492 - General functional description - Refer to Fig.4.2. Fig.4.2: Module 4492 – block diagram Owner Manual Rev. 1.1 – March 2009 AT7120 27/76...
  • Page 28 DDS circuitry completes the up-conversion frequency process. The output local oscillator signal power is +5dBm. PCB CIM3443 – Local Oscillator – block diagram Fig.4.3: CIM3443 local oscillator – block diagram Owner Manual Rev. 1.1 – March 2009 AT7120 28/76...
  • Page 29 Each one of the DC levels must be adjusted to assure maximum rejection of the undesired vestigial side band, in conjunction with the LO rejection as well. The level Owner Manual Rev. 1.1 – March 2009 AT7120 29/76...
  • Page 30 RF output channel as required under mHz precision. A frequency error around 1Hz maximum is achieved as measured at the output of the UHF mixer circuit. Before the DDS signal leaves the module, it is amplified and filtered. Owner Manual Rev. 1.1 – March 2009 AT7120 30/76...

  • Page 31: Section 5 - Uhf Atsc Exciter

    First Stage - Class A This section uses the bipolar transistor T1 (SGA 9289). This transistor’s polarization is class A, which insures highly linear amplification. The transistor T1 is connected to the +18V main power supply, Module 4401. This voltage is available at the pin-1 of connector CON-2 –...
  • Page 32 This final amplifier device is the LDMOS transistor T3 (MRF373). This amplifier stage is configured as a Class AB to assure superior efficiency without sacrificing linear performance. The drain voltage in transistor T3 is obtained from the +28V main power supply – Module 4401. This voltage is available at the pins 1, 2, 3, 4, 5 and 6 out of the CON-3 connector found in Module 4407.
  • Page 33 The reverse RF power reading is performed by diode D2A, the operational CI-4A and for trimpot TPO- 5, which adjusts the level of reading measured at pin 2 of connector CON-5. Even though the reverse RF power reading is present at CIP8208, this reading is not planned for the AT7120 transmitter. Technical specifications PARAMETERS...

  • Page 34: Block Diagram

    Block Diagram Owner Manual Rev. 1.1 – March 2009 AT7120 34/76...

  • Page 35: Section 6 - Uhf Atsc Amplifier

    Module 4442 General Functional Description AT7120 transmitter has two Modules 4442 connected in parallel, which work as digital TV end amplifiers in all UHF band. Module 4442 offers high linear precision that works satisfactorily with digital TV signals. However, to...
  • Page 36 This voltage is sent to pin 2 of connector CON-7 in the subordinate feeding power supply corresponding to the amplification module. In this Owner Manual Rev. 1.1 – March 2009 AT7120 36/76...
  • Page 37 Channels 14 to 25 = 15dB GAIN Channels 26 to 69 = 14dB ATSC AVERAGE POWER 70Wrms HARMONICS 2 <-25dBc SPURIUS EMISSION <-40dBc SHOULDER 36dB IMPEDANCE 50 Ohms CONNECTOR N FEMALE GENERAL VOLTAGE SUPPLY +32V CONSUMPTION Owner Manual Rev. 1.1 – March 2009 AT7120 37/76...
  • Page 38 4. Slowly adjust trimpot TPO-1 clock wise until T1 is set; then some loss in voltage (few mV) will be observed. Continue adjusting TPO-1 until its voltage measures 60mVdc, what translates to a drain current of 900mA for the BLF861A transistor. Owner Manual Rev. 1.1 – March 2009 AT7120 38/76...
  • Page 39 2 of the thermal sensor, and it relates to the temperature value in Module 4442 (i.e.: for a temperature of 50˚C, it should measure 5V). Owner Manual Rev. 1.1 – March 2009 AT7120 39/76...

  • Page 40: Section 7 - Power Supply

    The group of diodes D1/D4 rectifies the AC voltage from the AC network and delivers this rectified voltage to the capacitors C9 and C10 for filtering. These capacitors could be connected in parallel or in series, according with the set of the jumps for 120/240Vac. Owner Manual Rev. 1.1 – March 2009 AT7120 40/76...
  • Page 41 In the event of over-current, in any one of the outputs, the voltage in the inverting input of comparators CI-3 and CI-4, transferred by the electrical current readings, will be greater that the voltage of reference in the non inverting entrance. Owner Manual Rev. 1.1 – March 2009 AT7120 41/76...
  • Page 42 +5V to pin 6 of connector CON-8 of CIM3388 (CIP8111) card in Module 4401. Having this voltage, the switch transistor will be saturated and, consequently, the output voltage of +32V RECONNECTED will be enabled. Owner Manual Rev. 1.1 – March 2009 AT7120 42/76...
  • Page 43 Fig.6.1: Module 4401 Block Diagram Owner Manual Rev. 1.1 – March 2009 AT7120 43/76...
  • Page 44 Switching Pulse (RD) +12V FAN CI-1 pin 14 – OUTPUT +32V WITHOUT LOAD CI-1 pin 14 – OUTPUT +32V WITH LOAD 220V 110V Fig.6.2: Module 4401 – Main components board displacement Owner Manual Rev. 1.1 – March 2009 AT7120 44/76...
  • Page 45 The module 4401, on its rear side, is built in such way that it is possible to access the 110/220Vac switching voltage jump. The pictures below illustrate the jump position for each desired operational voltage. This is the only required maneuver to change the voltage operation on the AT7120 unit. Owner Manual Rev. 1.1 – March 2009...
  • Page 46 Fig.6.3: Jump connection for 110Vac operation, (CON5-CON4) Fig.6.4: Jump connection for 110Vac operation, (CON4-CON3) Fig.6.5: Module 4401 - +32V Switching Power Supply Owner Manual Rev. 1.1 – March 2009 AT7120 46/76...

  • Page 47: Section 8 - Dc/Dc Converter

    4567 generates +2.5V and +5V, via standard IC regulators, see below: GND wire +18V Input +5V Output Yellow wire +2.5V Output Brown wire Fuse Fig.7.1: DC/DC Converter Board CIM3490 (CIP8390) INPUT OUTPUT +2.5V (CON-2/2) +18V +5.0V (CON-2/3) Owner Manual Rev. 1.1 – March 2009 AT7120 47/76...

  • Page 48: Section 9 - Memory Interface

    Module CIM3516 – General Functional Description The 1Mbit LUT memory card – Module CIM3516 - is connected to the memory interface - Module 3535. This module holds all the non-volatile data parameters related with the digital linear and non- linear pre-correction.

  • Page 49: Annex A - At7120 Operational Software

    AT1012_ASM version 1.2 1 Introduction The LINEAR family of ADVANCED TV transmitter equipment possesses a system for measurement (measures), configuration (SETUP) and alarms (alarms) controlled by microprocessor system. This document will demonstrate the navigation, operation and configuration of these functions.
  • Page 50 LINEAR LINEAR INDUSTRIES INDUSTRIES INDUSTRIES Main screens INC. INC. INC. [ Any Key ] [ Any Key ] AT720P AT7120 [ Esc ] [ Esc ] [ Esc ] [ Esc ] MEASURES MEASURES MEASURES MEASURES SETUP SETUP SETUP SETUP...
  • Page 51 + 9V: + ALC STATUS: ALC STATUS: ALC STATUS: -18V: - -18V: - -18V: - ALC R.V: ALC R.V: ALC R.V: P.A. TEMPERATURE: P.A. TEMPERATURE: P.A. TEMPERATURE: [Enter Key ] [Enter Key ] Owner Manual Rev. 1.1 – March 2009 AT7120 51/76...
  • Page 52 VERSION: PHASE PHASE PHASE PHASE [Software ] [Software ] [Software ] DPD SCALE : DPD SCALE : DPD SCALE : DPD SCALE : DPD ACTIVE: DPD ACTIVE: DPD ACTIVE: DPD ACTIVE: Owner Manual Rev. 1.1 – March 2009 AT7120 52/76...
  • Page 53 TYPE DPD SCALE: DPD ACTIVE: DPD ACTIVE: DPD ACTIVE: DPD ACTIVE: ALC. R.V.: ALC. R.V.: ALC. R.V.: POWER POWER POWER TYPE CONFIG.: TYPE CONFIG.: TYPE CONFIG.: [Enter Key ] [Enter Key ] Owner Manual Rev. 1.1 – March 2009 AT7120 53/76...
  • Page 54 Please report this status to Linear Industries Inc to get the necessary steps of action. Following the LOADING message, the name of the manufacturer, the type number of the equipment, normal rated RMS power and the operating channel are displayed.
  • Page 55 NOTE: The screens above are a rolling type, allowing access to all of the voltage measurements by using the UP and DOWN keys. 4.1.2 POWER SUPPLY MENU This screen displays the voltages and currents of the main equipment power supplies. Owner Manual Rev. 1.1 – March 2009 AT7120 55/76...
  • Page 56 Selecting the “NXT” option provides access to more options of measurement. The sequence for access of these measurements is shown below: 4.1.5 MENU TR.STR. TR STR shows information about the input digital signal. Owner Manual Rev. 1.1 – March 2009 AT7120 56/76...
  • Page 57 PASSWORD ON: NO - indicates that the requirement of a password is not necessary to enter into the SETUP MENU and open access is available. Owner Manual Rev. 1.1 – March 2009 AT7120 57/76...
  • Page 58 To have access to this menu, navigate via the STATUS option and then select PILOT LEVEL, press the UP and DOWN key and then the factory programmed channel can be viewed. PILOT LEVEL: PILOT LEVEL: PILOT LEVEL: CHANNEL: CHANNEL: CHANNEL: Owner Manual Rev. 1.1 – March 2009 AT7120 58/76...
  • Page 59 This is a scale (or intensity) of the pre-distortion level applied to the transmission signal. TX.BAL.Q: TX.BAL.Q: TX.BAL.Q: DPD SCALE: < 0000 to 4095> PHASE PHASE PHASE DPD SCALE : DPD SCALE : DPD SCALE : DPD ACTIVE: DPD ACTIVE: DPD ACTIVE: Owner Manual Rev. 1.1 – March 2009 AT7120 59/76...

  • Page 60: Menu Setup

    YES in the ENABLE PASSWORD menu is indicated. The RIGTH ARROW and LEFT ARROW keys position the cursor in each one of the four possible digits and the ENTER and Owner Manual Rev. 1.1 – March 2009 AT7120 60/76...
  • Page 61 RIGTH ARROW and LEFT ARROW keys locate the cursor on one of the four digits to be changed and the ENTER and UP and DOWN keys change the digits. Pressing “ENTER” key then informs the new password to the control system and returns to the main options menu. Owner Manual Rev. 1.1 – March 2009 AT7120 61/76...
  • Page 62 SETUP SETUP 4.2.2.5 < SET LO NULL I? > This menu allows the DC voltage adjustment for “nulling” the “I” signal from the local oscillator inter- modulation in the Up -Converter. Owner Manual Rev. 1.1 – March 2009 AT7120 62/76...
  • Page 63 This menu allows the adjustment of the “I” phase of the image rejection signal in the 8VSB modulator. range of values: < 00000 to 32767 >. TYPE PHASE I: TYPE PHASE I: Owner Manual Rev. 1.1 – March 2009 AT7120 63/76...
  • Page 64 DOWN keys increase and decrease the power level. The RIGTH ARROW and LEFT ARROW keys do not possess any function in this screen. The “ENTER” key saves the desired value. ALC. R.V.: ALC. R.V.: POWER POWER Owner Manual Rev. 1.1 – March 2009 AT7120 64/76...
  • Page 65 Up Converter or final RF amplifier. This type of occurrence should be reported to the Linear Industries Inc. In this screen, the ALC is disabled for precision adjustments of the power level and to have full manual control of power, use the ENTER and UP and DOWN keys.
  • Page 66 PAST PAST Select CURRENT and press ENTER 4.3.2 PAST MENU This menu displays the past or old alarm messages, i.e. alarms that indicate some equipment alarm occurrence that has been cleared. Owner Manual Rev. 1.1 – March 2009 AT7120 66/76...
  • Page 67 SETUP SETUP Select NXT and press ENTER ALARMS ALARMS ALARMS REMOTE REMOTE REMOTE Select ALARMS and press ENTER CURRENT CURRENT PAST PAST Select PAST and press ENTER CLR. ALL CLR. ALL Owner Manual Rev. 1.1 – March 2009 AT7120 67/76...
  • Page 68 5. Operation of the Hyper-terminal The AT7120 transmitter system parameters can be monitored and configured using the Windows® Hyper-terminal. The range of values is the same as described previously in the equipment front panel operation (LCD display and keys). It is possible to adjust the transmitter power with the Hyper-terminal interface, however, the ALC system must be first disconnected using the equipment front panel and only within the limits set from the front panel configuration.
  • Page 69 “WRONG PASSWORD" will be shown. When the password is correct a warning question is asked. Reply YES (y), which then allows access to the SETUP environment. A NO (n) reply will return to the menu to the previous screen 1. Owner Manual Rev. 1.1 – March 2009 AT7120 69/76...
  • Page 70 (down) or Y (Yes) or N (No) to display the values of the configuration. For safety reasons, the values entered are only confirmed when exiting from the screen. Exit from the screen by using the ESC key. The W key will refresh the screen. Owner Manual Rev. 1.1 – March 2009 AT7120 70/76...
  • Page 71 (Typical example of screen shot) Owner Manual Rev. 1.1 – March 2009 AT7120 71/76...

  • Page 72: Annex B - Checking The Rf Power Ldmos Transistors

    580Ω DRAIN SOURCE ∞ SOURCE DRAIN In case these 2 measurements cannot be verified, the transistor must be substituted. Owner Manual Rev. 1.1 – March 2009 AT7120 72/76...

  • Page 73: Annex C - Typical Final Test Reports Results

    Annex C – Typical Final Test Reports Results Out of Channel Emissions Owner Manual Rev. 1.1 – March 2009 AT7120 73/76...
  • Page 74 Frequency Response and Group Delay Carrier Phase Noise Owner Manual Rev. 1.1 – March 2009 AT7120 74/76...
  • Page 75 Digital Modulation Error Rate Owner Manual Rev. 1.1 – March 2009 AT7120 75/76...
  • Page 76 Conducted Spurious Emissions Owner Manual Rev. 1.1 – March 2009 AT7120 76/76...

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