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...
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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...
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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.
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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.
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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.
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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...
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.
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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).
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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...
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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...
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...
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...
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...
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...
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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...
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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...
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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...
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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...
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(-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...
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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.
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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...
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(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...
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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...
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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...
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...
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...
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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...
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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...
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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...
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According with the Fig. 3.2: block diagram: AT7400 Owner Manual Rev. 2.0 – October 2006-10-23 Section 3 - 22/39...
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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...
#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...
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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...
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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...
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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...
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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...