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AT7400

Owner Manual Rev. 2.0 – October 2006-10-23

1/1

ADVANCED TV

LINE

Model AT7400

400W ATSC UHF Transmitter

OWNERS MANUAL

Linear Industries Incorporation

www.linear-tv.com

Made in USA

Summary of Contents for AT7400

Page 1: ...AT7400 Owner Manual Rev 2 0 October 2006 10 23 1 1 1 ADVANCED TV LINE Model AT7400 400W ATSC UHF Transmitter OWNERS MANUAL Linear Industries Incorporation www linear tv com Made in USA...

Page 2: ...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 Amplif...

Page 3: ...in the installation operation or service of the equipment should seek proper medical attention It is advisable that such personnel have familiarity with first aid practices Notice 5 To call our techn...

Page 4: ...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 ALL LOCAL CODES FOR B...

Page 5: ...be charged All returns must be sent freight prepaid and properly insured by customer When communicating with Linear please refer to your Order or Invoice Number Unpacking Use care when unpacking the e...

Page 6: ...tion 1 1 7 1 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 Fi...

Page 7: ...Section 1 2 7 2 2 AT7400 RF line Up 3 AT7400 Cabinet Air Flux 0 25m3 sec 21ft3 sec Fig 1 4 Air flux path at AT4700 cabinet lateral view Darker area denotes the internal heat source or the RF drawers...

Page 8: ...Rate 10 76 MSymbol sec Digital Analog Converter 16 bit All Digital Linear Pre Correction Included Pilot frequency stability overall 0 3 ppm Peak to peak frequency response 0 15 dB Peak to peak group...

Page 9: ...Options Models A Mono phase 220Vac B 3 phase 220Vac 380Vac 3 wires C 3 phase 220Vac 380Vac 4 wires Options 01 Integrated GPS receiver 02 Adaptive digital pre correction 03 Dual Exciter 04 Analog Tran...

Page 10: ...AT7400 Owner Manual Rev 2 0 October 2006 10 23 Section 1 5 7 5 6 2 Frequency Response and Group Delay 6 3 Carrier Phase Noise...

Page 11: ...AT7400 Owner Manual Rev 2 0 October 2006 10 23 Section 1 6 7 6 6 4 Digital Modulation Error Rate...

Page 12: ...AT7400 Owner Manual Rev 2 0 October 2006 10 23 Section 1 7 7 7 6 5 Conducted Spurious Emissions...

Page 13: ...CU module 4459 2 Following the main functions of MCU 2 1 Monitor and display the alarm status on each of the transmitter units 2 2 Monitor the direct and reverse RF power out from the intermediate dir...

Page 14: ...AT7400 Owner Manual Rev 2 0 October 2006 10 23 Section 2 2 9 2 2 6 Module 4459 Block Diagram Fig 2 2 Module 4459 block diagram and PCBs displacement...

Page 15: ...IM3 45 3 SNMP I NTERFA CE RD RXD SNMP P I N 8 CON 1 CIM34 53 SNMP INTERFACE VL TX D S N MP P I N 9 CON 1 CIM345 3 SNMP I NTERFACE W H GND SNMP PIN 2 C ON 1 CI M3 453 SNMP INTERFACE YL BLACK LIGHT DISP...

Page 16: ...ntroller programmed on assembler language This integrated circuit controls this module 4459 and also the entire transmitter This IC carries a controlled software version and is programmed on factory o...

Page 17: ...on on analog format is available at the connectors P1 and P2 on the module 4459 s panel which are routed to CON 9 at the PCB CIM3297 On P1 P2 connectors are available the following analog reading from...

Page 18: ...djust on such way that the 4V is measured at pin 8 on the connector CON 9 located at PCB CIM3297 More details will be shown on specific sections of this manual 2 7 3 Alarm Detection The system alarms...

Page 19: ...CON 12 perform the RS485 communication link among the MCU the UHF exciter driver drawer and the UHF power amplifier drawers 2 7 5 Interface SNMP The interface SNMP is the PCB CIM3453 The connectors C...

Page 20: ...wed by the sign will cause a proportional RF power reduction implemented by the MCU logic control 2 7 7 Keyboard PCB CIM3112 This PCB holds the 8 key pads which externally allows local manual interfac...

Page 21: ...ber 2006 10 23 Section 2 9 9 9 2 7 9 Module 4459 Internal Wiring 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...

Page 22: ...GAV4452 rear view c Up convert the IF signal on UHF ATSC broadcast channel d The output RF power control e Generates the 172MHz Master Clock signal out from a 10MHz stable reference internally origin...

Page 23: ...nto the GAV4452 are x 01 Module 4454 8VSB Modulator and MASTER Clock Generator x 01 Module 4453 IF UHF Up Converter x 01 Module 4466 DDS x 01 Module 4464 20W UHF ATSC x 01 Module 4456 Power Supply x 0...

Page 24: ...3 V 5 V 3 2 V 1 5 V 5 V 1 5 V 3 3 V 1 2 V 1 5 V MO DULE 4470 VO LTAGE REGULATORS 5 V 2 5 V 1 2 V 3 3 V 8 V 1 2 V 3 2 V REST A RT ED RF OUT 30W UHF ATSC EXCITER MO DULE 4455 1 2 V 5 V SUBORDINATE CONT...

Page 25: ...ORS CON 10 CON 11 2 1 6 5 4 3 BK 15V CON 3 CIM3461 MOD 4456 POWER SUPPLY WH GROUND CON 5 CIM3458 MOD 4470 VOLTAGE REGULATORS BR 5V CON 2 CIM3459 MOD 4456 POWER SUPPLY BL 15V CON 2 CIM3461 MOD 4456 POW...

Page 26: ...IF UHF up conversion structure 3 1 1 Module 4454 PCB CIM3444 8VSB Modulator Pre Corrector The PCB CIM3444 is part of the Module 4454 It is the modulator that process the transport stream TS that carr...

Page 27: ...it identifies and removes the 47h byte 3 1 1 1 2 Randomizer This circuit equally spread the modulated signal energy over the channel band The final energy density is similar to a AWGN noise with this...

Page 28: ...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 The digital processing genera...

Page 29: ...a 10MHz generated by the DDS circuit out from the free running 172 16MHz oscillator The loop filter performs the integration of the phase comparator output generating the error signal that is feed ba...

Page 30: ...ON 5 CIM3297 SCU GR LOCK DETECTOR ALARM PIN 3 CON 6 CIM3297 SCU 50 BELDEN CABLE UHF ATSC CHANNEL TV CON 1 CIM3446 MOD 4455 30W UHF EXCITER CON 4 CON 5 LOCAL OSCILATOR CIM3443 MIXER CIM3442 BK NO IF AL...

Page 31: ...uency process The output local oscillator signal power is 5dBm 3 2 3 PCB CIM3443 Local Oscillator Block Diagram 3 3 PCB CIM3442 UHF Mixer The mixing operation translates the IF modulated signal freque...

Page 32: ...AT7400 Owner Manual Rev 2 0 October 2006 10 23 Section 3 11 39 3 3 1 PCB CIM3442 UHF Mixer Block Diagram...

Page 33: ...AT7400 Owner Manual Rev 2 0 October 2006 10 23 Section 3 12 39 3 3 2 PCB CIM3442 UHF Mixer Test Points Diagram...

Page 34: ...c UHF ATSC CHANNEL DTV BELOW MIXING LOCAL OSCILATOR SIGNAL UHF ATSC CHANNEL DTV ABOVE MIXING Fig 3 7 Level references for mixer ALC fine tuning The second adjust detects the protection signal at the c...

Page 35: ...AT7400 Owner Manual Rev 2 0 October 2006 10 23 Section 3 14 39 3 5 Module 4466 External Connections...

Page 36: ...istors are also used on this amplification stage Fig 3 2 illustrates the RF chain of the module 4464 RF UHF 2 3dBm Printed Circuit Board CIM 3446 SG9289 BLF1822 BLF1822 SG9289 G 16dB G 32dB Printed Ci...

Page 37: ...lifier due optimization reasons the amplifier is built in 4 frequency operational bands as follows x channel 14 to 25 B1 channel 26 to 38 B2 channel 39 to 53 B3 channel 54 to 69 B4 Despite the differe...

Page 38: ...CTERISTIC SPECIFICATION SMPTE310M INPUT FREQUENCY 470 862MHz IMPEDANCE 75 Ohms CONNECTOR BNC FEMALE RETURN LOSS 22dB RF OUTPUT GAIN FROM 45 TO 48dB ATSC AVERAGE POWER UNTIL 20W HARMONICS 60dB SPURIOUS...

Page 39: ...pe class A polarization 90 degree out of phase able to delivery up to 1W of power usable for DTV ATSC standard over the 470MHz 806MHz UHF band Fig 3 9 Module 4464 CIM3446 block diagram Each amplificat...

Page 40: ...AT7400 Owner Manual Rev 2 0 October 2006 10 23 Section 3 19 39 3 9 3 Module 4464 CIM 3446 Technical Specifications...

Page 41: ...TPO 2 VGS T4 HI 2 HI 1 CON 1 T3 T1 C41 C4 TPO 1 VGS T2 C13 12V 5V R7 R23 R14 R15 BLF1822 BLF1 822 GY BR RD RD 8359 LINEAR MODULE 4464 30dB 50W ATTENUATO R 6 5 C5 C9 C 1 3 T1 C35 C39 T2 CI 4 CI 2 TPO...

Page 42: ...b clock wise up to the point that T4 starts to conduct meaning few mili volts will be read at the multi meter Continue it up to a 3Vdc reading be shown over R28 IMPORTANT The amplifiers at CIM3446 are...

Page 43: ...s 1 2V 1 2V HC 1 BA LUN DC BL OCKE R C31 B ALU N DC BLOCKE R C26 BALUN DC BLOCKE R C56 AMP LIFIER A1 OU TPUT T1 AMPLIFIER A2 OUTPUT T1 T1 GATE BIAS TP O 1 FILTER L 5 C27 C22 C2 5 FILTER L 5 C27 C22 C2...

Page 44: ...esistive termination On the ends of the second transmission line the coupled RF signal feeds the 2 amplification cells Fig 3 10 ID current adjust trim pots location on PCB CIM 3440 3 9 5 2 UHF 12 5W D...

Page 45: ...ned The combination circuit is completed with the absorber load R11 50 60W R11 dissipates the extra power in case of failure of one cell not disturbing the output impedance on the cell that did not fa...

Page 46: ...PUT GAIN 13 TO 16dB RF POWER UNTIL 20WRMS HARMONICS 60dB SPURIOUS EMISSION 54dB INTERMODULATION 46dB IMPEDANCE 50 Ohms GENERAL VOLTAGE SUPPLY 32V CONSUMPTION 12A AB CLASS 3 9 7 Module 4464 PCB CIM3440...

Page 47: ...he transistor 2 Measure the voltage drop over R10 Set the multi meter for 100mVdc full scale 3 Slowly start to turn the TPO 1 trim pot clockwise up to the point one read 60mVdc over R10 IMPORTANT The...

Page 48: ...F IN RF OUT NETWORK ANALYZER 30dB 50W ATTENUATOR 32V 2A 32V 2A MODULE 4464 Fig 3 12 Suggested gain and curve response evaluation for PCB CIM3440 The network analyzer level should be set upfront for 20...

Page 49: ...erates the following voltage values for this drawer internal use only Voltage Current 32V Fixed 2A 32V ON OFF according to command 15A 15V Direct 1A 15V 2A 15V 200 mA 5V 5 A 2 5V 5 A Table 2 Module 44...

Page 50: ...AT7400 Owner Manual Rev 2 0 October 2006 10 23 Section 3 29 39 Fig 3 13 Module 4456 Circuit functions electrical schematic diagram CIM and printed circuit board CIP...

Page 51: ...AT7400 Owner Manual Rev 2 0 October 2006 10 23 Section 3 30 39 3 10 1 Module 4456 Block Diagram...

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