ADVANCED TV LINE Model AT7120 120W ATSC UHF Transmitter OWNERS MANUAL Linear Industries Incorporation www.linear-tv.
AT7120 120W UHF 8VSB-ATSC TRANSMITTER ADVANCED TV LINE Owner Manual Table of Contents User Notices and WARNINGS .................................................................................................. 3 Section 1 – AT7120 General Description................................................................................... 6 Section 2 – Control Set ............................................................................................................
User Notices and WARNINGS USER NOTICES IT IS VERY IMPORTANT TO READ THE FOLLOWING MANUAL SECTIONS PRIOR TO OPERATION OF THIS TRANSMITTER! Notice 1 The transmitter main operating voltage setting is marked on the rear of the chassis. Notice 2 The transmitter operating frequency is set from the factory. Notice 3 For adjusting the RF output power setting a qualified technician should always employ the use of an RF Wattmeter and a calibrated dummy load.
THIS OWNER’S MANUAL IS INTENDED AS A GENERAL GUIDE FOR TRAINED AND QUALIFIED PERSONNEL WHO ARE AWARE OF THE DANGERS THAT ARE INHERENT IN THE HANDLING AND OPERATION OF POTENTIALLY HAZARDOUS ELECTRICAL AND ELECTRONIC CIRCUITS. IT IS NOT THE INTENT OF THIS MANUAL TO PROVIDE A COMPLETE SET OF SAFETY INSTRUCTIONS OR PRECAUTIONS THAT SHOULD ALREADY BE UNDERSTOOD BY TRAINED OR EXPERIENCED PERSONNEL IN USING THIS OR OTHER TYPES OF ELECTRONIC EQUIPMENT.
properly insured by customer. 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.
Section 1 – AT7120 General Description The ATSC DTV transmitter model AT7120 is part of the ADVANCED TV line, having modular construction meeting EIA 19”rack standards, and is composed for the following modules: 01 Main Control unit - CIM3297 01 Keypad - CIM3003 01 Display LCD 20 columns x 02 lines - CIM3004 01 Memory interface - CIP8421 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 Modu
MODULE 4281 10MHz MODULE 4549 LD CONTROL UNIT RD ENA 8VSB MODULATOR AND MASTER CLOCK DO OCXO RD ENA CLOCK DIN DO LD EXCITER FORWARD POWER FORWARD POWER REFLECTED POWER I1 MAIN POWER SUPPLY PA1 CURRENT ID1 PA1 CURRENT ID2 PA2 CURRENT ID3 PA2 CURRENT ID4 +28V MAIN POWER SUPPLY +18V MAIN POWER SUPPLY -18V MAIN POWER SUPPLY +9V MAIN POWER SUPPLY +32V 1 SUBORDINATE POWER SUPPLY +32V 2 SUBORDINATE POWER SUPPLY MODULATOR READINGS +2.
Module 4549 8VSB Modulator The 8VSB modulator automatically recognizes the incoming transport stream as either SMPTE310M or ASI. The transport stream input utilizes the BNC connector located on the rear panel of the unit. The modulated output signal of this module is composed by two IF orthogonal carriers termed; signals (I) and (Q). The central frequency of the 8VSB modulated IF signal is 18.83339MHz. The signal processing and modulation performed on this module follows the ATSC recommendation A/53 E.
Module 4407 60W UHF band multistage amplifier The IF modulated signal (previously converted into UHF) is amplified by a 60W UHF amplifier. This amplifier uses transistors built with LDMOS technology operating in a class AB configuration, which provides excellent efficiency and linearity. The RF OUT connector of the unit provides the high power RF output. RF Output monitoring Module 4407 detects the direct and reverse RF power present on the RF OUT connector of the unit.
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. Warns of excessive temperature of the 60W amplifier.
AT7120 External Interfaces Fig.1.2: AT7120 Front View AT7120 Owner Manual Rev. 1.
ASI/SMPTE310M Transport Stream Input External 10MHz Reference Input ID Tag Internal DB-9 Not Used (DB-9) RS232 Hyper-terminal Interface Power Switch Main Fuse GND Hot Air Outlets AC Power Cord RF Output Connector Fig.1.3: AT7120 Rear Panel View AT7120 Owner Manual Rev. 1.
AT7120 - Modules and Parts Displacement RF Power Amplifier Module 4407 DC Fan Filter CIM6646 Memory Card & Interface CIP 8437 LCD Screen CIM3004 8VSB Modulator & Master Clock Module 4549 DC/DC Converter Module 4567 Up Converter Module 4492 Ref. 10MHz OCXO Module 4281 Fuse & GND Key Pad CIM3003 Digital Control Card CIM3297/CIP8231A +32V Power Supply Module 4401 Power Switch Fig.1.4: AT7120 Modules and Parts displacement AT7120 Owner Manual Rev. 1.
AT7120 - 120W ATSC UHF Transmitter - Technical Specifications Table XX: AT7120 Technical specifications Electrical Main Consumption Power Factor Correction, FPC. Signal Input 220 VAC, bi phase, 50-60 Hz.
Section 2 – Control Set Functional Description The digital control is responsible for all management of AT7120 transmitter. This unit Monitors and assures the system is operating within acceptable parameters and provides user control access via key pad located on the front panel, or via RS232 hyper-terminal. Its main attributions are: Warns of signal lock failure of the PLL in the up-converter. Warns of excessive temperature of the 60W amplifier.
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. Figure 2.2, below, shows a detailed schematic of CIP8231 including connector pin layout.
AT7120 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 PIN 1 – CON-7 – CIP8358 – MOD. 4549 – 8VSB MODULATOR PIN 3 – CON-2 – CIP8357 – MOD. 4549 – 8VSB MODULATOR Owner Manual Rev. 1.
designation identifying the unity and software version. The unit contains firmware control software that allows the operating system software to be updated as needed. In case of substitution of the CI-4 or the entire PCB CIP8231, it is mandatory to provide the factory, prior to replacement, the programming identification number that is clearly indicated on CI-4. All the available analog parameter information from the system is sent to connector CON-9 on the CIP8231 board.
Lack of lock voltage of the PLL at the Up-converter - Module 4492. Excessive temperature of the 60W UHF amplifier - Module 4407 – (above 65ºC). Excessive reverse power (above +4V at CON-9). Overflow of the FIFO register in the 8VSB modulator (communication between microcontroller and modulator). Failure of synchronization of the transport data (MPEG) stream Presence of non-programmed hardware (a false alarm may present during the warm-up phase of the equipment).
The control board also sends the operational channel information to program the PLL circuit at CIP8388, which will then synthesize the local oscillator frequency required to create the desired channel. During normal operation the CIP8231 continuously manages the PLL of module 4492. 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 the absence of this signal, the power supply - Module 4401 - will stop supplying the +32 volt line, which feeds the 60W UHF amplifier - Module 4407. The other voltages remain present if the transmitter is operational. Serial communication RS232 The access to CIP8231 board is through a PC that has the Windows Hyper Terminal. At the rear panel of the transmitter there is a DB9 connector - tag as RS232- which is linked to connector CON-10, located at CIP8231 board.
Section 3 – 8VSB Modulator and Master Clock Module 4549 Introduction The Module 4549 is composed by an 8VSB MODULATOR including an IF pre-correction circuit board (CIM3510) and the MASTER CLOCK UNIT, CIP8358. Each one of 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. 8VSB IF Modulated - 18.
General Functional Description Module 4549 consists of 2 printed circuit boards. This section describes the 8VSB modulator only; the Master Clock is described in the next section. The two boards are physically located below each side of the top covers, as shown on the figure above. CIP8412 board - 8VSB Modulator/Pre-corrector The CIP8412 is part of the Module 4549. The 8VSB modulator process the transport stream (TS) that carries up to 4 broadcast programming signals including, audio, video and data.
The benefit of working with two orthogonal carriers is: the possibility to implement corrections on nonlinear 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.
This oscillator signal is squared by a Schmitt-trigger circuit with amplitude equal to 0-3.3 volts. This square wave provides the master clock signal that synchronizes all the digital circuits of this system, except the control signals. Fig.3.3: CIP8358 master clock – block diagram CIP8358 board – general functional description: The 172.16MHz frequency is synthesized via a PLL, a VCO and a DDS circuit. There are two possible 10MHz signals but the external reference takes priority over the internal.
Section 4 – IF/UHF up-converter Module 4492 Introduction The module 4492 performs the following basic functions: This module translates the incoming I and Q IF carriers from the 8VSB modulator, to the desired FCC/UHF channel. Controls the RF output power of the exciter. The desired channel is entered via the keypad and the LCD display in the factory. Channel changes are not allowed by the end user. 2 x LO sample (I) IF input Ref. 10MHz input (Q) IF input RF Output Fig.4.1: Module 4492, RF connections.
The LO frequency is divided by two, to reduce the phase noise level by 6dB 10MHz internal reference oscillator, technology OCXO, (Oven Controlled Crystal Oscillator) Uses hybrid amplifiers with 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 requir
The already modulated IF carrier I and Q feed the 2 inputs of the up-converter – Module 4492. The output signal of this module is a FCC/6MHz/UHF channel (14-69). Besides this main function, it also controls the potential overdrive into the final 60W amplifier. The up-conversion circuit consists of an orthogonal mixer fed by the IF carriers, I and Q respectively with a fixed center frequency and 6 MHz bandwidth. The mixer converts the IF signal using the local oscillator CW (Carrier Wave) signal.
PCB CIM3442 – UHF Mixer The mixing operation translates the IF modulated signal frequency up to the assigned UHF broadcasting channel, the operation utilizes the orthogonal pair of signals (I-, I+) and (Q-,Q+) allowing rejection of one side band, and the oscillator itself. The rejection is around 40dB, facilitating the post filtering steps. Right after the mixing operation, the RF broadband signal is (VHF and UHF) amplified 10dB under a typical 2dB roll-off characteristic.
adjustments are performed by the trim pots: TPO-1, TPO-2, TPO-3, and TPO-4. Voltage range of +1.4V to +1.6V should be present on the following test points. TPO-1: readings on L17 TPO-2: readings on L18 TPO-3: readings on L19 TPO-4: readings on L20 Once the first set of adjustments is completed, the fine tuning adjustment should be performed. It is necessary to connect the spectrum analyzer to the UHF RF output of the sub-module 4453.
Section 5 – UHF ATSC Exciter Module 4407 General Functional Description Module 4407 has high linearity solid performance for TV signals across the entire UHF band. This module was developed to operate in two UHF bands including: • LOW BAND (LB): channels 14 to 44 • HIGH BAND (MB): channels 45 to 53 A single PCB is used for the two bands of UHF listed above. The components of the PCB determine which UHF bands in which the Module 4407 operates.
The trimpot TPO-2 adjusts VGS of T2 and, consequently, the drain bias current (ID) of this transistor. This adjust is made by measuring the loss of voltage in resistor R18 (2 x 10Ω/5W in parallel), as the voltage is adjusted to 1V, which corresponds to 1A in the ID. Note: Because this is Class A stage, the measurement of T2’s drain current must be the same with or without input RF signal in the module. Trimmer C32 adjust the gain associate with T2 and is optimized for the highest value possible.
The detector circuit for direct power is basically composed by diode D2B, the operational amplifier CI4B and the trimpot TPO-4 that fine adjusts the detected DC level. The detected voltage will be displayed at pin 5 of the connector CON-9 at CIP8231 board. The reverse RF power reading is performed by diode D2A, the operational CI-4A and for trimpot TPO5, which adjusts the level of reading measured at pin 2 of connector CON-5.
AT7120 +15V +15V RF INPUT -5 a +3dBm CI-3 +12V REGULATOR +12V +12V T2 S1 T3 TEMPERAT URE ALARM CI-2 TPO-3 VGS Adjust of T3 MRF373 +12V REFLECT ED POWER READING CI-4A DIRECT POWER READING DC AMPLIFIER CI -4B TPO-5 Reading Adjus t of Ref.
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.
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. TPO-1 trimmer adjusts the VGS to the T1 transistor. Adjusting the VGS1, also adjusts the quiescent current (automatic adjustment of the T1 transistor’s current).
power supply the alarm voltage is interlinked to pin 4 of connector CON-4 and finally, sent to the control unit. The loss of this voltage means that the temperature on Module 4442 exceeded 65˚C and in this situation the control unit will order the subordinate power supply to send +28V to the correspondent Module 4442.
Board CIP8431 – Adjustment Procedure The tests on Module 4442 can be done with the output points connected to the rest of the RF structure of the equipment, or with the output connected to a coaxial charge 50Ω/100W (minimum) that has a good response in UHF TV (470MHz to 860MHz). However, whatever is the use of Module 4442, it is important to make the adjustments with the module RF output connected to a coaxial charge. Never operate Module 4442 without making sure its output is properly charged.
5. To adjust T2’s quiescent current, slowly adjust trimpot TPO-2 clock wise until T2 is set, when then some loss in voltage, few mV, will be observed. Continue adjusting TPO-2 until its voltage measures 60mVdc, what translates to a drain current of 900mA for the BLF861A transistor Notes The BLF861A transistor is type Gemini; this means there are two identical transistors inside the capsule. That is why one trimpot was omitted when balancing the VGS voltage.
Section 7 – Power Supply Module 4401 General Functional Description Power supply - Module 4401 - is the switching type, configured in the topology of half bridge, having overall efficiency above 80%. Module 4401 is responsible for the generation and distribution of following voltage DC: +32V FIXED +32V RE-CONNECTABLE +18V -18V +9V Module 4401 can be connected to the electric AC network of 120Vac or 240Vac, according with internal jump positions. Module 4401 is self-protected against DC short-circuit.
The resistances R1 and R2 are the loads for the capacitors C9 and C10 when the power supply is powered ON. R3 and R4 provoke a fast discharge of C9 and C10 when the power supply is OFF. The control of the switching function over the PWM modulator is performed by the components TF-3, D5, D6, D7, R9, T3, C20, C18 and C46. Switch and Power The switching function over the DC input voltage is performed by MOSFETs, T1 and T2.
This event takes the output of the comparator to a low level and will trigger a timer formed by CI-2, R26 and C28 that will shut down, inhibiting the switching process. The electrical current readings are detected over the power resistors (R44, R45, R36, R40, and R38) and amplified by op-amps end of scale (4V), proportional to the nominal current of each output.
Fig.6.
(RD) +32V (OR) +32V REL CON15 CON14 (BL) +18V CON13 CON12 (GR) +9V (WH) GND (BK) -18V * CON11 TPO-8 TPO-9 CON10 WH) GND CON9 CON8 TPO-6 TPO-3 ** Adjustment reading output current +18V TPO-4 ** Adjustment reading output current +9V TPO-5 Adjustment reading output voltage +32v TPO-6 ** Adjustment reading output voltage +32V RESTART TPO-7 Adjustment reading output voltage -18V TPO-8 Adjustment reading output voltage +18V TPO-9 Adjustment reading output voltage +9V CI-2 .
MODULE 4401 – Technical Specifications FEATURE SPECIFICATION INPUT AC VOLTAGE 90 TO 140VAC / 180 TO 250VAC SWITCHING FREQUENCY 50kHz LINE REGULATION BETTER THAN 2% FOR ALL OUTPUTS +32V / 10A OUTPUTS NOMINAL VOLTAGES +18V / 1A AND CURRENTS -18V / 1A +9V / 1A RIPPLE 300mV (+32V) 120mV (+18V / +9V) 80mV (-18V) LOAD REGULATION BETTER THAN 2% FOR +32V BETTER THAN 25% FOR +18V, -18V, +9V EFFICIENCY BETTER THAN 80% OUTPUT OVER CURRENT LIMIT 30% UPPER NOMINAL VALUE RESTART VOLTAGE HIGH LEVEL: > 3.
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 AT7120 Owner Manual Rev. 1.
Section 8 – DC/DC Converter Module 4567 General Functional Description This 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: 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 AT7120 +5.0V (CON-2/3) Owner Manual Rev. 1.
Section 9 – Memory Interface Module 3535 General Functional Description CON-4 and CON-10 at the modulator – Module CIM3510 – 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 nonlinear pre-correction. Fig.8.
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. 2 Navigation and Signals 2.1 Keypad and Display 2.1.
2.2 Display The display navigation works as follows: The cursor must be located on the first character of each function to access that function It is then activated by pressing the yellow “ENTER” key MEASURES NXT SETUP ESC During the navigation, special functions will appear in the display to assist the user, these are: ESC – Used to return to the previous menu NXT – Used to access the next screen CLEAR – Used to clear old alarms 2.
3.2 Measurement Screen 1 [Measures ] MEASURES NXT SETUP ESC [Esc] POWER NXT P.SUPPLY ESC [Power ] FWD. PWR.: RFL. PWR.: [P.Supply ] W W +32V: + +18V: + V V V + 9V: + -18V: - V V I1: A [Up and Down Keys ] ALC STATUS: ALC R.V: P.A. TEMPERATURE: [Enter Key ] AT7120 Owner Manual Rev. 1.
3.3 Measurement Screen 2 TR.STR. STATUS NXT SOFTWARE ESC [Tr.Stream ] DATA PACKETS RATE: Mbps [Status ] PASSWORD ON: [Up and Down keys ] NULL PACKETS RATE: Mbps PILOT LEVEL: FIFO OCCUPATION: % CHANNEL: TRANSPORT STREAM: LO N.I: LO N.Q: [Enter Key] [Software ] mV mV TX.BAL.I: PHASE I: SOFTWARE: VERSION: TX.BAL.Q: PHASE Q: DPD SCALE : DPD ACTIVE: AT7120 Owner Manual Rev. 1.
3.4 Configuration Screen MEASURES NXT ESC [Wrong Password and TYPE PASSWORD: [Esc] SETUP Enter Key ] [Correct Password and Enter Key ] WRONG PASSWORD ! NXT YES PREV ESC TYPE PASSWORD: [Yes] ENABLE PASSWORD: YES NO [Enter Key] TYPE PILOT LEVEL: TYPE CHANNEL: FACTORY SETUP TYPE LO NULL I: TYPE LO NULL Q: TYPE AMPLITUDE I: TYPE PHASE I: TYPE AMPLITUDE Q: TYPE PHASE Q: TYPE DPD SCALE: DPD ACTIVE: YES ALC. R.V.: POWER : NO [V] [W] TYPE CONFIG.: [Enter Key ] AT7120 Owner Manual Rev. 1.
3.5 Alarm Screen ALARMS NXT REMOTE ESC [Alarms ] CURRENT [Esc] PAST ESC [Current ] NXT [Past] [Esc] [Esc] ESC NXT CLR. ALL ESC 4 Initialization When the equipment is initially switched on, the screen backlight lights automatically and the message “LOADING”… is displayed, indicating the load process of the modulator has begun.
4.1 MEASURE MENU The measure menu allows access to the general equipment configuration parameters; power levels, TS feed and status, qualification of passwords, cancellation of the L.O signal., rejection of image frequency signal, level of scale, activation of look up tables (LUTs) for pre-distortion and the name and version of the installed software on the central microcontroller. Navigation through these screens is done by pressing the keys UP and DOWN.
To have access to the P.SUPPLY screen the sequence of screens are: M E A S U R E S S E T U P N X T E S C Access MEASURES P O W E R N X T P . S U P P L Y E S C Access P.SUPPLY Use the key “UP and DOWN” to move between screens. +32V: + +18V: + V V + 9V: + -18V: + V V I1: A To return to the previous screen press the key UP. To return to the option P.SUPPLY press “ENTER”. 4.1.3 MENU ESC Pressing ESC returns the cursor to the previous screen. 4.1.
Select NXT and press ENTER 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 Select TR.STR and press ENTER DATA PACKETS RATE: Mbps NULL PACKETS RATE: Mbps FIFO OCCUPATION: % TRANSPORT STREAM: To return to the previous screen press the UP key. To return to the TR.STR options press ENTER. 4.1.6 MENU STATUS 4.1.6.
Below is the sequence necessary for this option: Select STATUS and press ENTER 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 PASSWORD ON: 4.1.6.2 Amplitude level of the ATSC Pilot carrier This is a numerical value relative to the carrier pilot level. PILOT LEVEL: <+511 TO -2048> Access to the STATUS menu can be via the far left option or from the PASSWORD ON screen: following viewing the programmed level press the UP and DOWN keys to navigate to other STATUS screens.
4.1.6.4 DC voltage level adjustment for the cancellation of the L.O signal This level indicates the voltage programmed in the Up Converter for the cancellation of the local oscillator signal. LO N.I.: and LO N.Q. <0.00 to 49.75 mV>: To have access to this menu, select the option STATUSCHANNEL, press UP and DOWN key CHANNEL: LO N.I: LO N.Q: mV mV 4.1.6.5 Rejection of the frequency image The following are numerical values related to the amplitude and phase signal for rejection of the image frequency. TX.
4.1.6.7 Qualification of pre-distortion tables DPD ACTIVE: YES – indicates the signal pre-distortion tables are active DPD ACTIVE: NO - - indicates the signal pre-distortion tables are not active. TX.BAL.Q: PHASE Q: DPD SCALE : DPD ACTIVE: 4.1.6.8 Name and version of software This menu indicates the name and the version of recorded software in the central microcontroller. This information must be provided to the factory in the case of any maintenance request. SOFTWARE: < ATXXXX > VERSION: < X.
UP and DOWN keys edit the digits. The “ENTER” key transmits the value of the password to the control system. It is only possible to leave this screen after entering the numerical password. If the correct password is entered, access to the SETUP options is available. If the incorrect password is entered, the following is message is shown “WRONG PASSWORD” and the equipment returns automatically to the main options menu.
It is only possible to leave this screen after entering the numerical password. TYPE PASSWORD: 4.2.2.2 < ENABLE PASSWORD? > This option allows the qualification or not of the password programmed in SET NEW PASSWORD option. YES: confirms the requirement of the password to have access to the SETUP options menu. NO: Indicates that no password is required to have access to the SETUP options menu. ENABLE PASSWORD: YES NO 4.2.2.
The adjustment has the following potential values: < 0.00 to 49.75 mV >. TYPE LO NULL I: 4.2.2.6 < SET LO NULL Q? > This menu allows the DC voltage adjustment for “nulling” the “Q” signal from the local oscillator (intermodulation in the Up-Converter. The adjustment has the following potential values: < 0.00 to 49.75 mV >. TYPE LO NULL Q: 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.
4.2.2.9 < SET TX BAL. AMP. Q? > This menu allows the adjustment of the “I” balance of the image rejection signal in the 8VSB modulator. range of values: < 00000 to 32767 >. TYPE AMPLITUDE Q: 4.2.2.10 < SET PHASE Q? > This menu allows the adjustment of the “Q” phase signal amplitude of image rejection signal in the 8VSB modulator. range of values: < 00000 to 32767 >. TYPE PHASE Q: 4.2.2.
The power value displayed on this screen is a value fed directly from the output of the reflectometer and is the same value that is provided to the ALC s (Automatic Level Control) system circuit. The system allows for a certain flexibility of adjustment by providing at the same time the power level display in order to verify the actual power level. It is not recommended to adjust for very low values of ALC voltage as this may cause the power to become unstable. For higher ALC values (above 1.
< ALARMS LIST START! > < OVER FIFO! > < MPEG LOSS! > < DWR. NOT PROGRAMMED! > < TEMPERATURE! > < LOCK CLOCK! > < LOCK LO! > < OUTPUT POWER ZERO! > < REFLECTED POWER! > < ALARMS LIST END! > Below shows the screens necessary to display the CURRENT alarms menu: MEASURES NXT SETUP ESC Select NXT and press ENTER ALARMS NXT REMOTE ESC Select ALARMS and press ENTER CURRENT PAST ESC Select CURRENT and press ENTER NXT ESC 4.3.2 PAST MENU This menu displays the past or old alarm messages, i.e.
The current alarm messages are updated when entering the PAST MENU. To update the list, you must leave the menu and then return to the ALARMS menu using the ESC option and then access the PAST menu option again. Option NXT shows the next alarm message. If there are no alarm messages it will read as follows: < ALARMS LIST START! > < ALARMS LIST END! > Option CLR. ALL erases all the old alarm messages. These messages are also erased when the equipment is turned off. Option ESC returns to the previous screen.
4.4 Remote Menu It allows the display of the parameters to be configured in the Windows® Hyper-terminal emulator in order to connect a computer with an RS232 port and have access to the configuration and monitoring of the equipment. 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).
PROPERTIES OF COM4 Configuration of Port Bits per Second Bits of data Parity Bits of Parity Flow Control 19200 8 None 1 None To access the data of the equipment and to bring up to date the screens in the Hyper-terminal use ENTER on the keyboard. Screen 1 indicates some measurements, states 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.
(Typical example of screen shot) (Typical example of screen shot) To configure the parameters of screen 3 the characters in 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.
(Typical example of screen shot) AT7120 Owner Manual Rev. 1.
Annex B – Checking the RF Power LDMOS Transistors All 3 main RF transistors on the module 4407 are LDMOS technology type. The manipulation of these transistors requires some special care, for instance, avoiding manual bare finger direct contact with the parts. Instead, prioritize the usage of metal parts tools and grounded care procedures. Gate-to-ground conductance test With the transistors in place, it is possible with a digital multimeter to perform this test.
Annex C – Typical Final Test Reports Results Out of Channel Emissions AT7120 Owner Manual Rev. 1.
Frequency Response and Group Delay Carrier Phase Noise AT7120 Owner Manual Rev. 1.
Digital Modulation Error Rate AT7120 Owner Manual Rev. 1.
Conducted Spurious Emissions AT7120 Owner Manual Rev. 1.
