LDMOS - UHF TV AMPLIFIER AUTV/1500LD Users manual 50
This page is intentionally blank 51
_______________________________________________________________________________________________ Section 1 - Information Contents: 1.1 Description 1.
AUTV/1500LD LDMOS - UHF TV AMPLIFIER 1.1 DESCRIPTION The AUTV/1500LD is an amplifier operating into Band IV-V for common amplification process of the Vision and Sound carriers. The amplifier has been designed to offer to the customer high performances, high reliability and greater simplicity in his operation and maintenance procedures. The amplifiers modules employ all solid state LDMOS technology in order to obtain high gain, wideband performances, very good linearity, reliability and high efficiency.
1.2 TECHNICAL CHARACTERISTICS RF GENERAL PROTECTION THR. 54 Frequency range Output power Video/Sound power ratio Out stage technology Vision-Sound amplification I.M.D. (-8, -10, -16dB) Standards Spurious and harmonics level RF Output impedance RF Output connector 470 - 860MHz 1300W PEP 10/1 Solid State LDMOS Common Better than -54dB G, K, N In compliance with CCIR rec.
This page is intentionally blank 55
_______________________________________________________________________________________________ Section 2 - Installation Contents: 2.1 Operating environment 2.2 Preliminary operations 2.3 Telemeasuring socket connections 2.4 RS232, RS485 and AGC socket connections 2.
2.1 OPERATING ENVIRONMENT You can install the apparatus in a standard component rack or on a suitable surface such as a bench or desk. In any case, the area should be as clean and well-ventilated as possible. Always allow for at least 2 cm of clearance under the unit for ventilation. If you set the apparatus on a flat surface, install spacers on the bottom cover plate. If you install the apparatus in a rack, provide adequate clearance above and below.
When the apparatus is put within a combined system it is directly connected to the input splitting and output combining systems. Before fully powering the apparatus, check that the output connections of the coaxial cable to the antenna system are working. In order to this it is possible to check the indication of the reflected power at low power levels. Only if the SWR indication on the display is 0, the output power can be slowly increased.
PIN N° SIGNAL TYPE IN / OUT FUNCTION 1 GND - - 2 Digital Output 0V = Normal 5V = AGC Alarm 3 Digital Output 0V = Normal 5V = AGC Alarm 8 Analog Output FWD Power 9 Analog Output FWD Power AGC - DB9 Socket 2.5 PREVENTIVE MAINTENANCE To ensure maximum performance and minimum repair trouble, we strongly recommend you to follow the below stated headlines for preventive maintenance: 1. check antenna installation and ground connection at regular intervals; 2.
Front panel 60 5 2 1 6 3 4 DESCRIPTION 1 LCD Display 2 Function keys 3 Status LEDs 4 RF Monitor connector 5 Main switch 6 RS232 Socket
Rear panel 1 Breaker 2 Power supply socket 3 Auxiliary socket 4 Fuse 5 RS485 Socket 6 AGC Socket 7 Telemeasure socket 8 RF Input connector 9 RF Output connector 5 6 7 8 9 4 2 3 1 DESCRIPTION 61
_______________________________________________________________________________________________ Section 3 - Operation Contents: 3.1 Operation 3.2 Display 3.
3.1 OPERATION At startup, after initial image, the display shows the main screen with the RF powers as in Figure 1: Figure 1: Main screen The user may turn on and off the amplifier by means of the switch on the front panel. The control board turns on all the power supplies, the exciter (if any), and internal cooling fans.
3.2 DISPLAY The control board is provided with a modern pixels graphic display with blue background. Normally it always shows a title bar (on the top line) and a status bar (on the bottom line). The title bar, see Figure 2, shows the name of the amplifier (TV Amplifier) and the current time. If the amplifier is a single unit coupled externally with other units in a high power transmitter, the title bar shows the amplifier number (slave address) too.
Figure 4: Main menu The display only shows three items at a time: all the items can be scrolled by the UP and DOWN arrow keys. Any item can be chosen by selecting it and pressing the RET key. Menu entries with an arrow on the right open sub-menus when chosen. Thus there is a hierarchical structure as in Figure 5. To go back from a submenu to the previous menu, press the ESC key. If the ESC key is pressed in the main menu, the RF powers screen is accessed.
- RF Powers This is the main screen showing the RF powers of the amplifier: forward power, reflected power, unbalances, if any. For forward power a level bar is displayed. See an example in Figure 1. - Power Supply This screen shows all the signals coming from the power supply. To check the next (previous) power supply press the UP (DOWN) key. For each power supply, the two voltages, the two absorbed currents and the status (ON or OFF) are shown.
In case of alarm, the value of the measure which caused the alarm is saved into the log. In case of alarm still existing after five turning-on attempts, the parameter is marked as FAILED. Table 2 is the list of all the events which can be logged.
- RMS/Peak The control board can monitor both the RMS and peak powers, the first used in digital systems. The menu entry Settings RMS/Peak allows to choose the power to be displayed and monitored. This menu is present only in certain amplifiers. - Date/Time This screen allows to set the current date and time. The setting is changed by pressing the arrow keys, then pressing the RET key to move to the following value and eventually save the changes.
- Frequency (only for some Amplifiers) The forward and reflected RF powers is measured by means of a directional coupler. In order to compensate for the effect due to the sampling made by the coupler, it is possible to set the frequency by menu entry Settings Frequency. The setting can be changed by pressing the arrow keys. The changes made are saved by pressing the RET key or discarded pressing the ESC key. Set the video carrier frequency.
menu item Settings Interlock. When it is enabled, the status bar shows the lock symbol (see Figure 3), which is close if the interlock chain is closed (no alarm) or open if it is open (alarm). - Firmware Release The menu entry Settings Firmware Release allows to display the firmware version number and the hardware release of the amplifier. - Serial Number The menu entry Settings 70 Serial Number allows to display the serial number of the apparatus.
This page is intentionally blank 71
_______________________________________________________________________________________________ Section 4 - Diagram Contents: - Cable diagram - AUTV/1500LD Component layout - RF Section Block Diagram - MTF0070BR0 Amplifier module - Component list - SCH0192AR0 (200W UHF LDMOS Amplifier module) - SCH0223AR1 (Control board and display) - SCH0221AR1 (Amplifier interface) - SCH0215AR0 (Mains distribution board) - E0026 (1kW 32Vdc Switching power supply) 72
73
74
75
Component list MTF0070BR0 Amplifier module Part Name Code Description 00001 01041D 00221B 03207 SCH0192AR0 SCH0221AR0 SCH0248AR0 SCH0249AR0 SCH0250AR0 SCH0251AR0 SCH0252AR0 PN1091A 02402 02512 01400 01408 DET0726 DET0727 DET0728 DET0729 DET0730 DET0732 DET0734 DET0736 DET0807 DET0810 DET0811 DET0812 DET0819 DET0828 DET0839 08502 08527 0W 1206 SMD RESISTOR 2 1nF 1206 2% SMD CAPACITOR 2 75W 1206 1% SMD RESISTOR 2 HSMS-2802*L31 DIODE 2 200W UHF LDMOS AMPLIFIER MODULE 9 AMPLIFIER INTERFACE 1 8 WAY WILKINSO
This page is intentionally blank 77
200W UHF LDMOS AMPLIFIER MODULE SCH0192AR0 DESCRIPTION The RF module is an integrated TV linear amplifier designed for UHF band, this module employs push-pull LDMOS technology in order to achieve very good efficiency, high linearity and reliability. LDMOS transistors operate in AB class. It is a wideband amplifier over the full frequency, no adjustment is required for the channel change. The board includes RF section amplifier, bias circuit, protection circuit and matching networks.
- Curve response graphic Middle frequency 660MHz, span 500MHz, 2dB/div., reference to the arrow CALIBRATION PROCEDURE - Technical characteristics Power supply voltage Polarisation current Gain for low signal 32V (± 2%) 1.0 cold for each device (2A total), ± 0.
- Calibration steps STEP 1. Close the input and the output of the module by connecting them to a 50W W dummy load and connect the spectrum analyser through a directive sample, in order to look for self-oscillation of the module, if any (anyway the module has been designed so that it would not self-oscillate even if totally decoupled, without any input or output load). STEP 2.
capacitive trimmers, between the two pair of gates, as shown by the mounting plan. STEP 5. Connect serially a c.c. amperometer to the power supply, with scale starting from more than 5A (i.e. 10A). STEP 6. Power the module and check the MOSFET is not absorbing current; this means that the device is integral and working correctly. STEP 7.
Component layout SCH0192AR0 82
83
COMPONENT LIST SCH0192AR0 REF.
REF.
REF. DESCRIPTION ELETTRONIKA CODE B2 B3 B4 L1 L2 L3 L4 H1 H2 NTC1 NTC2 IC1 IC2 DZ1 DZ2 DZ3 DZ4 DL1 DL2 PN964AR3 COAX 2:1 BALUN COAX 4:1 BALUN COAX 4:1 BALUN 4 TURNS SILV. COP. WIRE 1.2mm WOUND ON OD 5mm 4 TURNS SILV. COP. WIRE 1.2mm WOUND ON OD 5mm ½ TURN COIL ½ TURN COIL HYBRID COUPLER 3dB 90° ANAREN HYBRID COUPLER 3dB 90° SAGE NTC 100KW PTH NTC 100KW PTH DG419DY DG419DY 15V SMD ZENER DIODE 15V SMD ZENER DIODE 6.8V SMD ZENER DIODE 6.
