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Linear AT7400 Owner's Manual

400w atsc uhf transmitter
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ADVANCED TV
LINE
Model AT7400
400W ATSC UHF Transmitter

OWNERS MANUAL

Linear Industries Incorporation
www.linear-tv.com
Made in USA
1
AT7400
Owner Manual Rev. 2.0 – October 2006-10-23
1/1

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  • Page 1: Owners Manual

    ADVANCED TV LINE Model AT7400 400W ATSC UHF Transmitter OWNERS MANUAL Linear Industries Incorporation www.linear-tv.com Made in USA AT7400 Owner Manual Rev. 2.0 – October 2006-10-23...
  • Page 2 AT7400 400W ATSC DTV TRANSMITTER ADVANCED TV LINE Owner Manual Table of Contents Section 1: Technical Specifications Typical Final Test Report Section 2: Master Control Unit Section 3: Exciter Drawer Section 4: Intermediate Directional Coupler Section 5: 220W UHF Power Amplifier...
  • Page 3 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: 630 346 6698. Notice 6 If you experience some specific difficulty and the technical information available in this manual is not enough to help you, do not hesitate to call LINEAR technical support center.
  • 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 Merchandise Return Authorization (MRA Number) is received from your Linear Sales representative or Linear Customer Service. Special shipping instruction will be provided which will assure proper handling. The circumstances and reasons for the return must be included in the request for return.
  • Page 6 Section 1 – AT7400 Technical Specifications 1. Introduction The AT7400 is a 400W UHF ATSC/8VSB transmitter assembled and tested in United States by LINEAR INDUSTRIES INC. (www.linear-tv.com). Fig1.1: AT7400 Front View, cabinet wheels are optional. AT7400 Owner Manual Rev. 2.0 – October 2006-10-23...

  • Page 7: Air Outlet

    2. AT7400 RF line Up 3. AT7400 Cabinet Air Flux: 0.25m /sec. - 21ft /sec. Air Outlet Cold Air Inlet Fig. 1.4: Air flux path at AT4700 cabinet, (lateral view). Darker area denotes the internal heat source, or the RF drawers, (1) Exciter and (2) PA’s.
  • Page 8 4. AT7400 – 400W UHF ATSC/8VSB Transmitter - Technical Specifications Electrical Main 220/240 VAC, bi phase, 50-60 Hz. 3w. Consumption 3200W. Included Signal Input Transport Stream Input ATSC/MPEG2, compliant to SMPTE310M Input Data Rate 19.39 Mbps External Reference Signal 10MHz. (0 to +10 dBm).
  • Page 9 3-phase; 220Vac – 380Vac; 4 wires. Options: Integrated GPS receiver Adaptive digital pre-correction Dual Exciter Analog Transmission Mode Cabinet 4 wheels 6. AT7400 Typical Test Report 6.1.Out of Channel Emissions AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 1 - 4/7...
  • Page 10 6.2.Frequency Response and Group Delay 6.3.Carrier Phase Noise AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 1 - 5/7...
  • Page 11 6.4.Digital Modulation Error Rate AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 1 - 6/7...

  • Page 12: Conducted Spurious Emissions

    6.5.Conducted Spurious Emissions AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 1 - 7/7...

  • Page 13: Section 2 - Master Control Unit

    2.5. MCU is composed by the following printed circuit boards: 2.5.1. 01 control unit; CIM3297. 2.5.2. 01 SNMP interface; CIM3453. 2.5.3. 01 Keyboard; CIM3112. 2.5.4. 01 LCD Display; CIM3108. AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 2 - 1/9...
  • Page 14 2.6.Module 4459 Block Diagram Fig.2.2: – Module 4459 block diagram and PCBs displacement. AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 2 - 2/9...
  • Page 15 BDM I N CON-5 CON-5 CON-6 CON-6 CON - 3 CON - 3 CON - 4 CON - 4 Fig. 2.3: - Module 4459 connection diagram for PCB CIM3297. AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 2 - 3/9...

  • Page 16: Digital Control

    In case of substitution of the CI-4 or even the entire PCB CIM3297, it is mandatory to inform the factory prior replacement, the programming identification number that is clearly indicated at the CI-4 body. AT7400 Owner Manual Rev. 2.0 – October 2006-10-23...

  • Page 17: Analog Readings

    CON-9 at the PCB CIM3297. On P1-P2 connectors are available the following analog reading from external measurements: Fig. 2.5: - Module 4459 external connections and internal connections view. AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 2 - 5/9...

  • Page 18: Alarm Detection

    At the time when an alarm source cease, the transmission is reestablished, and the “!” sign is switched to a “#” sign, and registered. Old records can be manually erased by pressing the key “CLEAR” on the MCU front panel keyboard. AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 2 - 6/9...

  • Page 19: Rs485 Communication Bus

    The interface SNMP is the PCB CIM3453. The connectors CON-4 and CON-10 located at the PCB CIM 3297 links the 2 PCBs. Fig. 2.6: - Module 4459 SNPM interface, PCB CIM3453, internal and external view. AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 2 - 7/9...
  • Page 20 CON-2 at PCB CIM 3297, exception for the pin 13 and pin 14 that have each other exchanged its positions by the flat cable. Fig. 2.8: - Module 4459 local command keyboard and LCD panel external view. AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 2 - 8/9...
  • Page 21 Fig. 29: - Module 4459 wiring diagram. 2.7.10. Module 4459 Schematic Diagrams: SEE ANNEX A 2.7.10.1 - PCB CIM3297 2.7.10.2 - PCB CIM3112 2.7.10.3 - PCB CIM3108 2.7.10.4 - PCB CIM3453 AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 2 - 9/9...
  • Page 22 Via a DDS circuitry, generates 1Hz steps over the UHF channel frequency. Generates DC voltages for all internal modules, and the +32V externally to the DC/DC converter, module 4147. The 30W/47dB gain UHF/ATSC power amplifier. AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 3 - 1/39...
  • Page 23 01 Module 4466 - DDS 01 Module 4464 - 20W UHF / ATSC 01 Module 4456 - Power Supply 01 Subordinate Control Unit (SCU) – CIM3297 Fig.3.2: GAV4452 modules displacement, top view. AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 3 - 2/39...
  • Page 24 2.GAV4452 – 30W UHF/ATSC Exciter – Block Diagram AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 3 - 3/39...
  • Page 25 (WH) GROUND ? CON-5 – CIM3458 – MOD.4470 – VOLTAGE REGULATORS MASTER CLOCK 8VSB MODULATOR CIM3445 CIM3444 MASTER CLOCK 8VSB MODULATOR CIM3445 CIM3444 Fig.3.3: Module 4454 – Left: Front View, Right: Top View. AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 3 - 4/39...
  • Page 26 Fig.3.5: CIM3444 – Block Diagram The 8VSB channel modulator inserts the forward error correction, (FEC), into the transport stream MPEG2. The modulator follows the ATSC standard A/53 annex D. AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 3 - 5/39...
  • Page 27 (-7, -5, -3, -1, +1, +3, +5, +7), having as ultimate goal improve the threshold on the signal-to-noise ratio of the system. 3.1.1.1.6. Synchronism Insertion The synchronism insertion built the symbol overall structure, creating the fields and frames as specified on the A/53E standard. AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 3 - 6/39...
  • Page 28 The value for the system when working with 2 orthogonal carriers is because it is possible to implement corrections on non-linear distortions, or simply implement digital pre-distortion. The digital pre-correction is possible using LUT, (Look up Tables). This table synthesizes inverted responses regarding the RF power amplifier transfer function, reducing the IMD products.
  • Page 29 DDS circuit, module 4456. 3.2. Module 4453 - UHF ATSC Up-Converter The Up-Converter module is composed by the mixer circuitry, PCB CIM3442, and a local oscillator, PCB CIM3443. AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 3 - 8/39...
  • Page 30 (5 0 BELDEN CABLE ) UHF / ATSC CHANNEL TV ? CON -1 – CIM3446 – MOD.4455 – 30W UHF EXCITER MIXER MIXER LOCAL OSCILAT OR LOCAL OSCILAT OR CIM3443 CIM3443 CIM 3442 CIM 3442 AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 3 - 9/39...
  • Page 31 IF signal or valid IF signal (locked via PLL) of any of the 4 possible IF signals, the attenuator assumes it higher level of attenuation, and shutting down the RF chain of amplification. AT7400 Owner Manual Rev. 2.0 – October 2006-10-23...
  • Page 32 3.3.1. PCB CIM3442 – UHF Mixer – Block Diagram AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 3 - 11/39...
  • Page 33 3.3.2. PCB CIM3442 – UHF Mixer – Test Points Diagram AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 3 - 12/39...
  • Page 34 RF output channel as required under mHertz precision. At the end, is expected a frequency error around 1Hz max., when measured at the output of the UHF mixer circuit. Before leaves the module, the DDS signal is amplified and filtered. AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 3 - 13/39...
  • Page 35 3.5. Module 4466 – External Connections AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 3 - 14/39...
  • Page 36 BLF861A G = 32dB BLF861A G = 16dB Fig.3.8: UHF 48dB gain RF amplification chain, simplified block diagram Fig.3.9: Module 20W UHF ATSC power amplifier – module 4464 AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 3 - 15/39...

  • Page 37: General Functional Description

    8359 FINAL STAGE 3440 8352 Table 3.1: Module- 4464 PCB assembles references. NOTE: CIM stands for the PCB version, and CIP stands for the bill of material version. AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 3 - 16/39...

  • Page 38: Specification

    UNTIL 20W AVERAGE POWER £ -60dB HARMONICS SPURIOUS < -54dB EMISSION INTERMODULATION < -52dB CONECTOR N FEMALE GENERAL POWER SUPPLY +32V / +12V / +5V CONSUMPTION 14A (AB CLASS) AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 3 - 17/39...
  • Page 39 Each amplification cell is composed first by a BJT transistor followed by a LDMOS transistor. The serial connection of these 2 devices delivery 500mW.The parallel combination of these 2 cells via H-2 hybrid, is able than to delivery 1W of RF power. AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 3 - 18/39...
  • Page 40 3.9.3. Module 4464 – CIM 3446 – Technical Specifications AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 3 - 19/39...
  • Page 41 No RF signal should be present at the RF input of the module 4464. Turn the module ON and wait for 3 minutes for thermal stabilization of the circuit. Use a good quality multi-meter able to read mVdc, avoid to used auto-range multi-meters. AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 3 - 20/39...
  • Page 42 The same PCB hardware is used for all 4 bands, the CIP8053. The nominal RF output power of each cell is 12.5W, totaling 20W following the output combiner. The overall gain of this stage is between 13dB and 16dB depending on the assigned channel 6MHz UHF band. AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 3 - 21/39...
  • Page 43 According with the Fig. 3.2: block diagram: AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 3 - 22/39...
  • Page 44 Trimmers C5, C9 and C13, tunes and adjusts the input impedance. A combination among the trimmers’ physical position and transmission lines’ length determines the bandwidth behavior. At the input, the capacitor C1 is a input DC de-coupling, and at the output C26 as well. AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 3 - 23/39...

  • Page 45: Temperature Alarm

    #7 at the CON-6 at SCU (PCB CIM3297). If the module temperature exceeds the limits on the module 4464, as consequence, the SCU will send a command to the sub-module 4456 that disrupts the +32V to the module 4464. AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 3 - 24/39...
  • Page 46 Always proceed to adjustment with the CIM3440 terminated by a 50 RF load, and make sure that there is no RF signal present at the input of the module during the ID current adjustments. AT7400 Owner Manual Rev. 2.0 – October 2006-10-23...
  • Page 47 LDMOS transistor replacement. The cap trimmers are tuning point for the PCB, they should be tune seeking for best curve/gain response. Fig.3.11: Cap trimmers location on PCB CIM 3440 AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 3 - 26/39...
  • Page 48 PFC, circuit. Besides correct the power factor to close to 1, this circuit also contributes to reduce the harmonic content returning from the unit into the AC mains. AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 3 - 27/39...
  • Page 49 200 mA +2.5V Table 2 - Module 4456: Listing of Voltage and current, per each power supply. The multiple power supply module 4456 is composed by the following PCB’s: AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 3 - 28/39...
  • Page 50 Fig. 3.13: Module 4456 - Circuit functions: electrical schematic diagram, (CIM), and printed circuit board, (CIP). AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 3 - 29/39...
  • Page 51 Module 4456 – Block Diagram 3.10.1. AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 3 - 30/39...

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