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AT7120 Owner Manual Rev. 1.1

– March 2009 74/76

Frequency Response and Group Delay

Carrier Phase Noise

Содержание AT7120

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

Страница 2: ...tion 6 Section 2 Control Set 15 Section 3 8VSB Modulator and Master Clock 22 Section 4 IF UHF up converter 26 Section 5 UHF ATSC Exciter 31 Section 6 UHF ATSC Amplifier 35 Section 7 Power Supply 40 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 ...

Страница 3: ...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 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...

Страница 4: ...ARNING AT ALL TIMES DISCONNECT AC MAINS POWER BEFORE OPENING COVERS DOORS ENCLOSURES PANELS OR PROTECTIVE SHIELDS THAT EXPOSE LIVE CIRCUITS NEVER PERFORM MAINTENANCE MAKE ADJUSTMENTS OR SERVICE THE EQUIPMENT WHEN ALONE OR FATIGUED WARNING IF ELECTROLYTIC OR OIL FILLED CAPACITORS ARE UTILIZED IN THE EQUIPMENT AND THE COMPONENT APPEARS LEAKY OR IS BULGING OR IF THE CASE OR COVERING OF THE COMPONENT ...

Страница 5: ...ge 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 Find all PACKING LISTS and keep them to assist in locating and identifying any components or assemblies that may have been removed for safe Make sure that all shipping straps supports and packing materials are...

Страница 6: ...01 1Mbits memory card CIP8421 01 UHF ATSC Exciter Module 4407 01 up Digital Converter Module 4492 01 Power Supply Module 4401 versions M110 M220 B220 01 8VSB Modulator and Master Clock Generator Module 4549 01 DC DC Converter 2 5V and 5V Module 4567 02 UHF ATSC Amplifier Module 4442 01 OCXO Module 4292 When AT7120 is a TRANSMITTER that can be installed with or without a 6 pole elliptical filter on...

Страница 7: ...DULE 4281 RD ENA CLK DIN DO LD CONTROL UNIT 28V MODULE 4567 DC CONVERTER 5V 2 5V MEMORY MEMORY CARD CARD CIP8421 CIP8421 MEMORY INTERFACE MEMORY INTERFACE CIP8437 CIP8437 DCLK ASDI CS DATA FROM CONTROL UNIT 110 220V MONOPHASIC BIPHASIC ON OFF SWITCH 5A 220V 10A 110V FUSE FUSE 5A 220V 10A 110V 120W rms RF OUT RF PW REF PW 15V REFLT IN OUT MODULE 4166 FPB MODULE 4252 310M IN ASI IN EXT REF IN EXCITE...

Страница 8: ...dulator Module 4492 IF to UHF up Converter The IF carries the orthogonal I and Q signals generated in module 4549 8VSB Modulator which is then routed to the up converter module The output signal of this module is set on the FCC UHF operational 6MHz channel of the transmitter AT7120 Inside the converter the modulated IF band is mixed with the continuous wave local oscillator LO As a result of this ...

Страница 9: ... the input connector for the two amplification cells maintaining 50Ω impedance Cell A 35W Amplifier The amplification cell A is obtained by a Push Pull 35W amplifier class AB Transistor T1 is in this cell The polarization circuit of cell A is made of a VGS timer circuit with temperature compensation differential amplifier and gate impedance reducer Cell B 35W Amplifier Just as cell A cell B s ampl...

Страница 10: ...s Sets in the operational channel of the Up converter unit and transmits power levels via ALC Sets and monitors the operational channel frequency in the up converter unit as well as the transmit power levels which is controlled by the automatic level control circuits The control unit is directly connected to a keypad and LCD screen both located on the front panel of the transmitter AT7120 Numerous...

Страница 11: ...AT7120 Owner Manual Rev 1 1 March 2009 11 76 AT7120 External Interfaces Fig 1 2 AT7120 Front View ...

Страница 12: ...76 Fig 1 3 AT7120 Rear Panel View Power Switch ID Tag External 10MHz Reference Input Main Fuse ASI SMPTE310M Transport Stream Input AC Power Cord DB 9 RS232 Hyper terminal Interface Hot Air Outlets GND RF Output Connector Internal DB 9 Not Used ...

Страница 13: ...t Key Pad CIM3003 RF Power Amplifier Module 4407 LCD Screen CIM3004 Memory Card Interface CIP 8437 DC DC Converter Module 4567 DC Fan Filter CIM6646 Digital Control Card CIM3297 CIP8231A 32V Power Supply Module 4401 Ref 10MHz OCXO Module 4281 Power Switch Fuse GND Up Converter Module 4492 8VSB Modulator Master Clock Module 4549 ...

Страница 14: ...Rate 10 76 MSymbol sec Digital Analog Converter 16 bit Linearization Pre Correction Included Pilot frequency stability overall 4 6 ppm Initial tolerance 1 0 ppm Vs temperature in operating temperature range steady state 10 ppb Holdover 24 hours full temp range 12 ppb 24 hours drift after 30 days 1 0 ppb Long term stability over 15 years 3 5 ppm Peak to peak frequency response 0 15 dB Peak to peak ...

Страница 15: ...s and displays power supply voltage s Sets in the operational channel of the Up converter unit and transmits power levels via ALC Sets and monitors the operational channel frequency in the up converter unit as well as the transmit power levels which is controlled by the automatic level control circuits The control unit is directly connected to a keypad and LCD screen both located on the front pane...

Страница 16: ...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 Figure 2 2 below shows a detailed schematic of CIP8231 including connector pin layout 01 control unit board CIP8231 CIM3297 01 keypad board CIP8002 CIM3003 ...

Страница 17: ...8388 MOD 4492 UHF UPCONVERTER OR DATA IN PIN 2 CON 2 CIP8357 MOD 4549 8VSB MODULATOR RD MODULATOR CLOCK PIN 4 CON 2 CIP8357 MOD 4549 8VSB MODULATOR GR MODULATOR ENABLE PIN 5 CON 2 CIP8357 MOD 4549 8VSB MODULATOR VL MODULATOR READ PIN 6 CON 2 CIP8357 MOD 4549 8VSB MODULATOR VL DATA DAC PIN 6 CON 6 CIP8388 MOD 4492 UHF UPCONVERTER YL TX ON PIN 3 CON DB9 REAR PANEL RD ENABLE IDAC PIN 9 CON 6 CIP8388 ...

Страница 18: ... Con 9 can be adjusted during setup or maintenance when external equipment is used to assure proper calibration reading Each module that generates analog control monitoring information has an associated test point on the unit If during the calibration process external measurements indicate the correct nominal value for that function a trimpot is adjusted to set the voltage on the test point to 4Vo...

Страница 19: ...arm state that has been resolved or that has ended PAST The occurrence of an alarm will automatically end the transmission When the reason for this alarm is resolved a symbol will appear and the transmission will be restored automatically To erase old alarms just press the CLR ALL key on the front panel of the equipment or when using a hyper terminal press 1 on the keyboard Communication with 8VSB...

Страница 20: ...ical value of trellis voltage at normal rated power output is between 3V and 4V In case of failures or malfunctions the power control is responsible for acting immediately to set the RF power level to zero thus correspondingly the trellis voltage is set to zero This may occur in during any alarm state where transmission must be terminated to protect equipment or to maintain regulatory compliance A...

Страница 21: ...CIP8002 board The CIP8002 board contains five key buttons SW1 to SW5 located on the front panel of the transmitter This board is a matrix of electrical ON OFF contacts The responses are made available at the connector CON 3 LCD CIM3004 board CIM3004 board is a LCD Liquid Crystal Display of 20 columns by 2 lines The back light of this display is controlled by the CIP8231 board which sends 5V betwee...

Страница 22: ... these printed circuit boards are located below one of the two lateral covers of module 4549 as it shows the drawing of external connections of this module a b Fig 3 1 Module 4549 a top view b connectors from rear panel Internal 10MHz TCXO ref input 10MHz OCXO ref output to Up Converter 172MHz Master Clock 8VSB IF Modulated 18 8339 MHz IF I carrier IF Q carrier 8VSB Modulator Section Master Clock ...

Страница 23: ...nal to be modulated must be in either ASI or SMPTE310M format 19 39Mbps bit rate and 800mVpp 75 ohms The ASI SMPTE 310M input is located on the rear panel by a BNC connector First the circuit responsible for the clock rate is used to perform the protocol interface After that there is a rate equalization of the TS performed by the insertion or removal of null packets At the end the symbol rate is r...

Страница 24: ... bytes on each 187 bytes of the MPEG2 package With this method it is possible to detect and correct data errors that occur during the transmission process Interleaving Data stream interleaving is utilized to lower the transmissions susceptibility to interference that causes burst data errors Trellis Code Trellis code is closely related to the channel modulation It is a convolution coder utilizing ...

Страница 25: ...ircuit There are two possible 10MHz signals but the external reference takes priority over the internal The first signal comes to CIP8358 via a SMB connector CON 1 The second signal is also 10MHz generated by the DDS Direct Digital Synthesizer circuit out of the free running 172 16MHz oscillator The loop filter performs the integration of the phase comparator output generating the error signal tha...

Страница 26: ...iter The desired channel is entered via the keypad and the LCD display in the factory Channel changes are not allowed by the end user Fig 4 1 Module 4492 RF connections The main features associated with this module are 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 r...

Страница 27: ...high linearity Overdrive protection circuit maintains the RF output power at acceptable levels Automatically reduces the exciter RF output power in absence of IF signal either Q or I carriers 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...

Страница 28: ...face composed by 3 high speed transfer lines of 20MHz The microcontrollers inside the up converter perform the following functions needs clarification PCB CIM3443 Local Oscillator The local oscillator is designed based on a PLL circuit This oscillator is able to synthesize frequencies within the band from 450MHz up to 900MHz To guarantee a high quality local oscillator signal 4 VCO s voltage contr...

Страница 29: ...range variable attenuator The control of this attenuator is related with the DC level generated by the ALC Automatic Level Control In case of absence of an IF signal a valid IF signal locked via PLL or any of the 4 possible IF signals the attenuator assumes its highest level of attenuation and shuts down the RF amplification chain PCB CIM3442 UHF Mixer block diagram Fig 4 4 CIM3442 UHF mixer block...

Страница 30: ...l at the center of the band If 1 out of 4 controls signals are absent the DC monitoring voltage level exceeds the min threshold and shuts down the RF output signal The DC threshold adjust is performed by TPO 5 and should be set for 2 5V Module 4466 Direct Digital Synthesizer DDS Module 4466 is a signal reference generator based on a DDS circuit This module is able to synthesize frequencies up to 5...

Страница 31: ... T1 is connected to the 18V main power supply Module 4401 This voltage is available at the pin 1 of connector CON 2 Module 4407 where voltage regulator CI 1 reduce voltage to 5V this is the input voltage on T1 The trimpot TPO 1 adjusts the collector current IC of T1 This adjust is made by measuring the loss of voltage in resistor R8 1Ω 1W as the voltage is adjusted to 300mV which corresponds to 30...

Страница 32: ...6mA in the ID in standby Note Because this is Class AB stage the measurement of T3 s drain current increases as the input RF level increases in the module The correct measurements are obtained when the module is in standby in other words there is no input RF signal in the module VGS Polarization Circuit for T2 and T3 Integrated circuit CI 5 is responsible for providing VGS to transistors T2 and T3...

Страница 33: ...ing 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 SPECS INPUT FREQUENCY 470 to 860MHz MAXIMUM LEVEL 0dBm IMPEDANCE 50Ω CONNECTOR SMB MALE RETURN LOSS ...

Страница 34: ...MAL SENSOR S1 12V SGA9289 MRF9030 MRF373 5V REGULATOR CI 1 5V REGULATOR CI 1 12V REGULATOR CI 3 12V REGULATOR CI 3 VGS REGULATOR BIAS T2 AND T3 CI 5 VGS REGULATOR BIAS T2 AND T3 CI 5 TPO 3 VGS Adjust of T3 TPO 3 VGS Adjust of T2 TPO 1 VGS Adjust of T1 T1 T2 T3 RF DETECTOR D2 RF DETECTOR D2 DC AMPLIFIER CI 4B DC AMPLIFIER CI 4B DC AMPLIFIER CI 4A DC AMPLIFIER CI 4A TPO 4 Reading Adjus t of Direct P...

Страница 35: ...h cell has a double Push Pull transistor with LDMOS technology This module can offer up to 70W To better understand how the amplifier works refer to the block diagram in the upcoming pages The amplifier is made of the following components Input Coupler The input RF coupler equally divides the UHF signal present in the input connector for the two amplification cells maintaining 50Ω impedance The 3d...

Страница 36: ...ed between resistors R36 and R37 that are in parallel and its resulting ohm value that is 0 06Ω Trimmers C23 C26 and C29 adjust input paring up and this cell s gain The circuit RL made of resistors R30 and inductor L6 plus resistor R31 and inductor L5 avoid transistor T2 s auto oscillation in frequencies below 200 MHz for which it is not pared up Resistors R29 and R32 together with transistor T4 r...

Страница 37: ...trol unit will order the subordinate power supply to send 28V to the correspondent Module 4442 Technical Specifications CHARACTERISTIC SPECIFICATION INPUT FREQUENCY 470 806MHz LEVEL 36 to 34dBm IMPEDANCE 50 Ohms CONNECTOR N FEMALE RETURN LOSS 25dB OUTPUT GAIN Channels 14 to 25 15dB Channels 26 to 69 14dB ATSC AVERAGE POWER 70Wrms HARMONICS 2 RD 25dBc SPURIUS EMISSION 40dBc SHOULDER 36dB IMPEDANCE ...

Страница 38: ...nts To adjust ID drain currents of both transistors T1 and T2 Module 4442 must be idle Never adjust ID drain currents of Module 4442 LDMOS transistors while there is an input signal in the module To adjust currents make sure Module 4442 input signal is in standby otherwise the transistor might be damaged To perform a more accurate adjustment it is best to wait at least 5 minutes after module has b...

Страница 39: ... are obtained with the module in standby in other words without input RF signal In the case that these adjustments are not possible measure the gate resistance with a multimeter this resistance got to be at least 330 ohms If the gate resistance is close to 0 ohm it is possible that the transistor is broken Check for temperature alarm Module 4442 has a thermal sensor S1 that when connected to opera...

Страница 40: ...sible for feeding the 60W amplifier Module 4407 The consumption in Amps from the 32V RE CONNECTABLE power supply is basically the consumption associated with the drain electrical current of the LDMOS transistors of the amplifier Because of this configuration the LDMOS currents are measured at the power supply Module 4401 These current measurements are routed to the control unit In case of extreme ...

Страница 41: ...on and Filtering The pulses delivered by switching power devices are rectified by D8 to D14 and filtered by C32 the C47 The inductor L2 has multiple sections and stores the transferred energy helping to filter the voltage provided The resistors at the output act as bleeders avoiding undesirable transients and oscillations Pulse Width Modulation This block is composed basically by the integrated ci...

Страница 42: ...with a TPO for full scale adjustment 4V proportional to the nominal output voltage TPO 5 32V TPO 6 32V RECONNECTED TPO 7 18V TPO 8 18V TPO 9 9V Notes 1 The current reading is only for the output voltage of 32V 2 It does not have reading for the voltage of 32V RECONNECTED Reconnection Process The output of 32V RECONNECTED power supply Module 4401 is used to exclusively feed the UHF amplifier Module...

Страница 43: ...2 D L2 F C47 CI 1 TF 4 TF 3 D5 D7 T3 CI 2 CI 3 CI 4 CURRENT DETECTION 32V RESTARTED 32V CON 6 1 2 GND TPO 1 ADJUSTMENT 32V R35 R36 R44 R38 CON 4 110V CON 5 CON 3 220V 110 220VAC CON 1 CON 2 GND 32V 18V 9V CURRENT READING CI 5 CI 7 CON 7 1 2 3 TPO 3 TPO 4 TPO 9 ADJUSTMENT READING 9V TPO 8 ADJUSTMENT READING 18V TPO 7 ADJUSTMENT READING 18V TPO 5 ADJUSTMENT READING 32V 9V 18V 18V 32V FILTER VOLTAGE ...

Страница 44: ...h T1 and T2 soldiers in the board Tip in S and tip in D 500 Tip in S and tip in D infinite resistance CI 1 SG3525 Switching Pulse 11 14 Shut Down 10 Oscillator 5 4 5V soft start 8 Ground GND 12 15V supply 13 15 5V 2 PINS 16 5V reference voltage CI 1 pin 14 OUTPUT 32V WITH LOAD CI 1 pin 14 OUTPUT 32V WITHOUT LOAD TPO 1 Adjustment output voltage 32V TPO 2 Adjustment reading output current 32V TPO 3 ...

Страница 45: ...V 18V 9V EFFICIENCY BETTER THAN 80 OUTPUT OVER CURRENT LIMIT 30 UPPER NOMINAL VALUE RESTART VOLTAGE HIGH LEVEL 3 5 TO 5Vdc LOW LEVEL 3 3Vdc SHUTDOWN VOLTAGE HIGH LEVEL 0 7 TO 5Vdc LOW LEVEL 0 7Vdc POWER SUPPLY CIRCUIT CIM CIP POWER 3388A 8111A MODULE 4401 Changing the Mains Voltage Operation The module 4401 on its rear side is built in such way that it is possible to access the 110 220Vac switchin...

Страница 46: ...AT7120 Owner Manual Rev 1 1 March 2009 46 76 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 ...

Страница 47: ...s module generates specific voltages not present at the main power supply module 4401 The module 4567 generates 2 5V and 5V via standard IC regulators see below Fig 7 1 DC DC Converter Board CIM3490 CIP8390 INPUT OUTPUT 18V 2 5V CON 2 2 5 0V CON 2 3 Fuse 2 5V Output Brown wire 5V Output Yellow wire 18V Input GND wire ...

Страница 48: ... are communication connectors with the memory interface CIP8421 mother board 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 Fig 8 1 LUT Memory card module 3535 ...

Страница 49: ...sesses 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 2 Navigation and Signals 2 1 Keypad and Display 2 1 1 Keypad Moves the cursor up Moves the cursor right Moves the cursor left Moves the cursor down Yellow Key Center ENTER ...

Страница 50: ... the presence of an old alarm LOCK Indicates that the equipment is configured with password and to access that part of the menu the password must be entered The UP and DOWN arrows assist in the navigation between screens When they appear the UP or DOWN key must be used to move between screens If in a measurement screen to return to the previous menu any key can be pressed 3 Screen Flow Charts 3 1 ...

Страница 51: ... Measures Esc Power P Supply Up and Down Keys Enter Key MEASURES SETUP NXT ESC MEASURES SETUP NXT ESC MEASURES SETUP NXT ESC POWER P SUPPLY NXT ESC POWER P SUPPLY NXT ESC FWD PWR W RFL PWR W FWD PWR W RFL PWR W ALC STATUS ALC R V V ALC STATUS ALC R V V P A TEMPERATURE P A TEMPERATURE 32V V 18V V 32V V 18V V 18V V 9V V 18V V 9V V 18V V I1 A I1 A Measures Esc Power P Supply Up and Down Keys Enter Ke...

Страница 52: ...ON PASSWORD ON PILOT LEVEL CHANNEL LO N I mV LO N Q mV TX BAL I PHASE I TX BAL Q PHASE Q DPD SCALE DPD ACTIVE Status Tr Stream Up and Down keys Enter Key Software TR STR STATUS NXT SOFTWARE ESC TR STR STATUS NXT SOFTWARE ESC DATA PACKETS RATE Mbps DATA PACKETS RATE Mbps NULL PACKETS RATE Mbps NULL PACKETS RATE Mbps FIFO OCCUPATION FIFO OCCUPATION TRANSPORT STREAM TRANSPORT STREAM SOFTWARE VERSION ...

Страница 53: ... MEASURES SETUP NXT ESC MEASURES SETUP NXT ESC TYPE PASSWORD TYPE PASSWORD NXT YES PREV ESC NXT YES PREV ESC WRONG PASSWORD WRONG PASSWORD TYPE PASSWORD TYPE PASSWORD ENABLE PASSWORD YES NO ENABLE PASSWORD YES NO TYPE PILOT LEVEL TYPE PILOT LEVEL TYPE CHANNEL FACTORY SETUP TYPE CHANNEL FACTORY SETUP TYPE LO NULL I TYPE LO NULL I TYPE LO NULL Q TYPE LO NULL Q TYPE AMPLITUDE I TYPE AMPLITUDE I TYPE ...

Страница 54: ...ately every 2 seconds The backlight switches off after approximately 20 seconds After the initialization of the equipment this first information will remain indefinitely until another key is pressed When pressing another key the backlight will light again Depending on the type of screen the cursor will automatically locate itself in one of the options To execute some of these options after the bac...

Страница 55: ...at the output of the equipment measured at the output power reflectometer Also displayed are the ALC reference voltage and the temperature of the final RF output amplifier To have access to the POWER screen the following sequence of screens is necessary Access MEASURES Access POWER Use the key DOWN to see the next set of screens To return to the previous screen press the UP key To return to the PO...

Страница 56: ...e 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 M E A S U R E S S E T U P N X T E S C M E A S U R E S S E T U P N X T E S C M E A S U R E S S E T U P N X T E S C P O W E R P S U P P L Y N X T E S C P O W E R P S U P P L Y N X T E S C M E A S U R E S S E...

Страница 57: ...d to enter into the SETUP MENU and the user will be asked for it each time this menu is accessed PASSWORD ON NO indicates that the requirement of a password is not necessary to enter into the SETUP MENU and open access is available T R S T R S T A T U S N X T S O F T W A R E E S C T R S T R S T A T U S N X T S O F T W A R E E S C DATA PACKETS RATE Mbps NULL PACKETS RATE Mbps FIFO OCCUPATION TRANSP...

Страница 58: ...s the UP and DOWN keys to navigate to other STATUS screens 4 1 6 3 Transmission channel This screen displays the factory programmed transmission channel CHANNEL 2 to 53 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 T R S T R S T A T U S N X T S O F T W A R E E S C T R S T R S T ...

Страница 59: ...nd phase signal for rejection of the image frequency TX BAL Q 00000 to 32767 PHASE Q 32767 to 32767 TX BAL I 00000 to 32767 PHASE I 32767 to 32767 4 1 6 6 Pre distortion scale level This is a scale or intensity of the pre distortion level applied to the transmission signal DPD SCALE 0000 to 4095 TX BAL Q PHASE Q DPD SCALE DPD ACTIVE TX BAL Q PHASE Q TX BAL Q PHASE Q DPD SCALE DPD ACTIVE DPD SCALE ...

Страница 60: ...le digits The and keys the ENTER and UP and DOWN keys change the digits The ENTER key finalizes the numerical value to the control system Without pressing the ENTER key the value is not saved Before the ENTER key is pressed the parameter is only adjusted in real time for review of the measured results If the equipment is switched off during a parameter configuration before pressing the ENTER key t...

Страница 61: ... OPTIONS The following allows navigation in the equipment configuration options NXT executes the navigation option PREV returns to the previous menu YES indicates access to that particular option ESC returns to the main options menu To see the options select NXT and press ENTER When the required option is shown locate the cursor on the YES and press ENTER 4 2 2 1 SET NEW PASSWORD This menu allows ...

Страница 62: ...sired level of the ATSC signal pilot carrier with the following range of values 511 TO 2048 4 2 2 4 SET CHANNEL For equipment safety reasons changing channel is not allowed in the on site configuration This procedure can only be done in the factory Changing the channel without the permission of a factory trained engineer can potentially void any warranty on the product 4 2 2 5 SET LO NULL I This m...

Страница 63: ... has the following potential values 0 00 to 49 75 mV 4 2 2 7 SET TX BAL AMP I This menu allows the adjustment of the I amplitude of the image rejection signal in the 8VSB modulator range of values 00000 to 32767 4 2 2 8 SET PHASE I 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 LO NULL I TYPE LO NULL I TYPE LO ...

Страница 64: ...nal range of values 0000 to 4095 4 2 2 12 SET DPD ACTIVE This menu allows the activation or not of the digital pre distortion tables YES activates the use of the digital pre distortion look up tables LUT s NO deactivates the use of the digital pre distortion look up tables LUT s 4 2 2 13 SET POWER This allows the configuration of normal rated power at the output of the equipment The ENTER and UP a...

Страница 65: ...G It is important not to set the programmed values of the ALC and consequently the final RF power level above the nominal value of the equipment This may cause damage to the internal modules and may void the warranty on the unit 4 3 ALARMS MENU This transmission equipment has a system of alarms These are illustrated by symbols at the right side of the display screen and The signal represents the o...

Страница 66: ...T alarms menu Select NXT and press ENTER Select ALARMS and press ENTER 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 MEASURES SETUP NXT ESC MEASURES SETUP NXT ESC MEASURES SETUP NXT ESC ALARMS REMOTE NXT ESC ALARMS REMOTE NXT ESC ALARMS REMOTE NXT ESC CURRENT PAST ESC C...

Страница 67: ...es are also erased when the equipment is turned off Option ESC returns to the previous screen The follow are messages that can appear in the past alarms list ALARMS LIST START OVER FIFO MPEG LOSS DWR NOT PROGRAMMED TEMPERATURE LOCK CLOCK LOCK LO OUTPUT POWER ZERO REFLECTED POWER ALARMS LIST END Below are the screens necessary to display the PAST alarms menu Select NXT and press ENTER Select ALARMS...

Страница 68: ...nel configuration The password can be accepted or not and when accepted it allows access to the SETUP environment In the SETUP environment it is possible to enable or to disable the password and also to choose a new password The insertion of new password occurs with the cursor automatically moving to the next digit when the highest value has been reached After reaching the desired number the curso...

Страница 69: ...tes of the alarms and offers options for access to other functions of the equipment Typical example of screen shot When the password of the equipment is qualified screen 2 will be displayed A password of 4 digits must be entered to access the SETUP environment In the case where the typed password is incorrect the message WRONG PASSWORD will be shown When the password is correct a warning question ...

Страница 70: ...the parentheses should be selected by using standard keyboard keys Select the option desired and then use the keyboard characters U up and D 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 ...

Страница 71: ...AT7120 Owner Manual Rev 1 1 March 2009 71 76 Typical example of screen shot ...

Страница 72: ... of its value counterclockwise the reading at the multimeter should be close of 370Ω Adjusting TPO 1 for the maximum of its value the reading at the multimeter should be close of 720Ω T3 Adjust TPO 3 for the minimum of its value counterclockwise the reading at the multimeter should be close of 550Ω Adjusting TPO 1 for the maximum of its value the reading at the multimeter should be close of 705Ω T...

Страница 73: ...AT7120 Owner Manual Rev 1 1 March 2009 73 76 Annex C Typical Final Test Reports Results Out of Channel Emissions ...

Страница 74: ...AT7120 Owner Manual Rev 1 1 March 2009 74 76 Frequency Response and Group Delay Carrier Phase Noise ...

Страница 75: ...AT7120 Owner Manual Rev 1 1 March 2009 75 76 Digital Modulation Error Rate ...

Страница 76: ...AT7120 Owner Manual Rev 1 1 March 2009 76 76 Conducted Spurious Emissions ...

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