Axcera DT325B Instruction Manual Download Page 14

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350-Watt VHF LB Digital Transmitter

Chapter 1, Introduction

DT325B, Rev. 0

1-9

ABBREVIATIONS/ACRONYMS

Alternating Current

AFC

Automatic Frequency Control

ALC

Automatic Level Control

Amplitude modulation

AGC

Automatic Gain Control

AWG

American wire gauge

BER

Bit Error Rate

Bandwidth

Direct Current

D/A

Digital to analog

Decibel

dBm

Decibel referenced to

1 milliwatt

dBmV

Decibel referenced to

1 millivolt

dBw

Decibel referenced to 1 watt

FEC

Forward Error Correction

Frequency modulation

Hertz

ICPM

Incidental Carrier Phase

Modulation

I/P

Input

Intermediate Frequency

LED

Light emitting diode

LSB

Lower Sideband

MPEG

Motion Pictures Expert Group

O/P

Output

PLL

Phase Locked Loop

PCB

Printed circuit board

QAM

Quadrature Amplitude

Modulation

Summary of Contents for DT325B

Page 1: ...INSTRUCTION MANUAL DT325B 350 Watt Digital VHF Low Band Transmitter AXCERA LLC 103 FREEDOM DRIVE P O BOX 525 LAWRENCE PA 15055 0525 USA 724 873 8100 FAX 724 873 8105 www axcera com info axcera com...

Page 2: ...emote Connections 2 9 CHAPTER 3 INSTALLATION AND SETUP PROCEDURES 3 1 Site Considerations 3 1 3 2 Unpacking and Installation of the Cabinet and Trays 3 4 3 3 Input and Output Connections to the Transm...

Page 3: ...odule Replacement 5 1 5 3 VHF Amplifier Tray 5 1 5 3 1 AGC Control Board 5 1 5 3 2 Phase Shifter Board 5 2 5 3 3 Filter Amplifier Board 5 2 5 3 4 VHF Low Band Amplifier Board 5 2 5 3 5 Overdrive Prote...

Page 4: ...er Amplifier Chassis Assembly Front View 2 1 2 2 Rear view Driver Amplifier Chassis Assembly 2 9 3 1 1 kW Minimum Ventilation Configuration 3 4 3 2 Front and Rear view Driver Amplifier Chassis Assembl...

Page 5: ...tter Device Data Access Screen 3 10 3 7 Menu 13 Transmitter Configuration Access Screen 3 10 3 8 Menu 20 Error List Display Screen 3 10 3 9 Menu 30 Transmitter Device Details Screen 3 10 3 10 Menu 30...

Page 6: ...es that make up the tray 1 2 Assembly Designation Numbers Axcera has assigned assembly numbers Ax designations such as A1 where x 1 2 3 etc to all assemblies modules and boards in the system These des...

Page 7: ...duct until becoming familiar with the equipment If in doubt refer all servicing questions to qualified Axcera service personnel Replacement Parts When replacement parts are used be sure that the parts...

Page 8: ...hip under normal use and service for a period of one 1 year from the date of shipment from Axcera s plant when operated in accordance with Axcera s operating instructions This warranty shall not apply...

Page 9: ...TS TO THE SYSTEM RADIO FREQUENCY RADIATION HAZARD MICROWAVE RF AMPLIFIERS AND TUBES GENERATE HAZARDOUS RF RADIATION THAT CAN CAUSE SEVERE INJURY INCLUDING CATARACTS WHICH CAN RESULT IN BLINDNESS SOME...

Page 10: ...with one hand and push down on his forehead with the other This opens the airway Sometimes doing this will let the person breathe again by himself 3 If he is still not breathing begin rescue breathing...

Page 11: ...TT 90 60 100 000 100 KILOWATTS 80 50 10 000 10 KILOWATTS 70 40 1 000 1 KILOWATT 60 30 100 1 HECTROWATT 50 20 50 47 17 20 43 13 10 1 DECAWATT 40 10 1 1 WATT 30 0 77 137 7 07V 0 1 1 DECIWATT 20 10 67 12...

Page 12: ...0 8327 Canadian gallon fluid ounce fl oz milliliters ml 29 57353 British Thermal Unit watt W 0 2930711 per hour Btu hr horsepower hp watt W 746 NOMENCLATURE OF FREQUENCY BANDS FREQUENCY RANGE DESIGNAT...

Page 13: ...350 Watt VHF LB Digital Transmitter Chapter 1 Introduction DT325B Rev 0 1 8 RETURN LOSS VS VSWR 1 001 1 01 1 1 2 0 VSWR 0 10 20 30 40 50 60 70 R E T U R N L O S S dB...

Page 14: ...ndwidth DC Direct Current D A Digital to analog dB Decibel dBm Decibel referenced to 1 milliwatt dBmV Decibel referenced to 1 millivolt dBw Decibel referenced to 1 watt FEC Forward Error Correction FM...

Page 15: ...AC input line of 220 VAC at 40 amps that connects to the AC Distribution Panel which distributes the AC through AC power cords to the VHF exciter driver chassis and the VHF amplifier tray The DT325B...

Page 16: ...al is returned FAULT red or green Red indicates that a problem has occurred in the transmitter The transmitter will be Muted or placed in Standby until the problem is corrected DC OK red or green Gree...

Page 17: ...e channel mask filter so that its linear distortions can be seen When a nonlinear adaptive equalizer is being calculated the transmitter sample is taken before the channel mask filter so that the dist...

Page 18: ...tector Voltage Level and also the VSWR Cutback protection if the Reflected Power level increases above the preset level Two voltages 28 VDC from the internal switching power supply and 12 VDC from the...

Page 19: ...vel of the tray 1 to 3 VDC Power Supply Reads the voltage from the switching power supply 28 VDC S1 Switch Meter Current Uses Switch S2 to indicate the current of transistor devices Selects the curren...

Page 20: ...ter 2 5 System Operation When the transmitter is in operate as set by the menu screen located on the Control Monitoring Module the 32 VDC stage of the Power Supply in the Control Monitoring Module is...

Page 21: ...tering Standby Mode Similar to the operate mode the standby mode is entered various different ways These are A low on the Remote Transmitter Stand By line Depressing the STB key on selected front pane...

Page 22: ...have been designed to function even if covered with dust a heavy buildup of dust dirt or insects will affect the cooling of the components This could lead to a thermal shutdown or the premature failu...

Page 23: ...ect drawing and Table 2 9 TB30 and TB31 are 18 position terminal blocks that are removable from their sockets to make connections easier Just grasp and pull connector straight out After connections ar...

Page 24: ...he transmitter power is to be raised RMT Power Lower TB30 9 Discrete Open Collector Input A pull down to ground on this line indicates that the transmitter power is to be lowered RMT System Reflect Po...

Page 25: ...cale factor is 100 0 80V NOTE The RMT RF System Interlock at TB30 5 provides the customer with a means of connecting the transmitter to protection circuits for the loads thermal switches combiners or...

Page 26: ...and without excessive humidity An ideal environment will require temperature in the range of 40 F to 70 F throughout the year reasonably low humidity and a dust free room This is rarely attainable in...

Page 27: ...certain conditions 3 Do not isolate the front of the transmitter from the back with the thought of air conditioning only the front of the unit Cooling air is drawn in at the front of all transmitters...

Page 28: ...ters should not rely on the internal blower to exhaust cooling air at elevations above 4000 feet For external venting the air vent on the cabinet top must be increased to an 8 diameter for a 50 W 100...

Page 29: ...stem driver amplifier chassis and VHF amplifier tray also the harmonic filter bandpass filter couplers and the installation material from the crates and boxes Remove the straps that hold the cabinets...

Page 30: ...t of the AC junction box mounted near the upper right hand rear portion of the cabinet terminals 1 and 2 220 VAC and terminal 3 chassis ground See Figure 3 3 Figure 3 3 AC Input Box Assembly Check tha...

Page 31: ...F Loop Thru Output 50O J10 BNC External 10 MHz Reference Input From Axciter 50O J12 BNC NOT USED MPEG Input 50O J13 BNC Downconverter IF Output To Axciter 50O J68 J15 BNC Digital IF I P From Axciter 5...

Page 32: ...s the output power level is being checked observe the LCD screen reading in the Reflected Power position If the Reflected Power is very high above 10 a problem may exist with the output coaxial lines...

Page 33: ...when the DC outputs that connect to the modules in the transmitter are present 3 4 2 Front Panel LCD Screen for the Driver Amplifier Chassis Assembly A 4 x 20 display located on the front of the Cont...

Page 34: ...ter is in Standby the OPR characters appear in the lower right By pushing the right most button located under the display the operator will place the Transmitter in Operate When the transmitter is in...

Page 35: ...display returns to Menu 10 Main Screen If the key is activated the display returns to Menu 12 the Transmitter Device Data Access Screen Table 3 8 Menu 20 Error List Display Screen This screen of the...

Page 36: ...TION STATUS RUNNING N A MEASURED SIGNAL TO NOISE 32 6dB N A PLL STATUS LOCKED N A SMTE310 INPUT STATUS OK N A DEMOD FUNCTION STATUS OK N A FX VERSION 1 013 N A Axciter Details NB VERSION 0 029 N A D C...

Page 37: ...ange is made to a screen within the Set Up Menus when you go to the next menu a new screen asks if you accept the change or want to return to the previous menu to reconsider the changes made To accept...

Page 38: ...nu 40 5 Transmitter Set up Serial Address Screen This screen allows the user to set the serial address of the transmitter The default address is 5 This value and all other set up parameters are stored...

Page 39: ...the fault is not fixed the transmitter will enable measure power and if above this value plus five percent it will again shut down for five minutes If the system s reflected output power exceeds the...

Page 40: ...the split connects to J4 The AC line 2 input connects from J1 3 to the F2 fuse The AC line 2 input after the F2 fuse is split with one line connected back to Jack J1 at Pin 5 which becomes the AC Line...

Page 41: ...t low on pin 20 by either the programming port or the external watchdog IC U2 a FET Q1 inverts the reset signal to a high that connects to the control lines of U5 an analog switch The closed contacts...

Page 42: ...transfer to the display is wired for read and write control RB1 is the connector to a Rabbit Semiconductor RCM4300 This Ethernet enabled controller polls the U1 microcontroller on the same serial line...

Page 43: ...forward biased current will flow from ground through the LED the transistor and the current limiting resistors in the collector to the 12 VDC source The effected LED will light With the LED control l...

Page 44: ...is Assembly The RF output from the upconverter at the upconverter RF output jack J23 a BNC connector The RF is cabled to the S input Jack on the A10 2 Way Splitter One output of the splitter connects...

Page 45: ...ccurs the AGC Control Board generates a Fault Output at J1 which is connected to J4 on the Filter Amplifier Board The Fault cuts back the RF Signal level using the Pin Diode Attenuator Circuit located...

Page 46: ...that consists of CR1 and U1A The gain of amplifier U1D is controlled by detector gain pot R11 which is set to 4 VDC as measured at TP1 The set output of U1D is connected to the comparator IC U1B The t...

Page 47: ...level is combined with the AGC reference inputs at J2 and J6 2 which produces the AGC output at J1 which connects to the automatic level control circuit on the Filter Amplifier Board for the output p...

Page 48: ...d by the jumper from TB1 5 to TB1 6 to the Phase Shifter Board the Filter Amplifier Board and the Overdrive Protection Board The Current Metering Board also supplies sample outputs of the operating cu...

Page 49: ...he Tray as set by R60 VSWR Cutback on the AGC Control Board is cutback to maintain a 20 Reflected Output level The Red LED DS4 VSWR Cutback located on the front panel remains lit until the Reflected l...

Page 50: ...R38 which adjusts the gain of U2C The output of U2C is split and connected to J5 6 and J5 5 DC O P 3 The 12 VDC needed for the operation of Op Amps U1 and U2 enters the board at J5 10 The voltage is...

Page 51: ...Upconverter and Controller Power Supply can then be gently pulled from the unit After removal of the failed module slide the replacement module in place and make certain it connects to the backplane b...

Page 52: ...resistor on the Filter Amplifier Board and adjust R13 for 25 Volts Using Ohms Law E I x R E 250 mA x 1 E 250 mV 5 3 4 A2 A1 VHF Low Band Amplifier Board 1198 1605 Appendix D This board has 20 dB of ga...

Page 53: ...located on the AGC Control Board Then adjust R59 VSWR Cutback Adjust located on the AGC Control Board until DS4 the Red VSWR Cutback LED mounted on the front panel lights This sets up the VSWR Cutback...

Page 54: ...e number entered until the monitored reading is 1 5 Volts 5 5 2 Setting up of the Overdrive Threshold On the Axciter Upconverter Downconverter Screen set the Overdrive Threshold to 1 7 Volts by select...

Page 55: ...ng the Driver AmplifierChassis NOTE Do not adjust R38 on A4 the Triple Peak Detector Board 1159713 It is factory set for 7 to 8 VDC typical AGC Reference to the VHF Amplifier Tray and any readjustment...

Page 56: ...APPENDIX A DT325B SYSTEM SPECIFICATIONS...

Page 57: ...he companion upconverter The upconverter provides a pre correct ed output directly to the high gain final power amplifier modules three PAs in the 1000W unit The entire package is housed in a single 1...

Page 58: ...mber of PAs 1 2 3 4 5 6 Input Power Line Voltage Volts 1 208 or 240 10 Power Requirements Single Phase 50 or 60 Hz Size H x W x D 69 x22 x34 69 x44 x34 OperationalTemperature Range 0 to 50 derate 2 C...

Page 59: ...APPENDIX B SYSTEM DRAWINGS...

Page 60: ...350 Watt Digital VHF LB Transmitter Appendix B System Drawings DT325B Rev 0 B 1 DT325B DT325B Transmitter w Axciter Interconnect 1311143 Triple Peak Detector Board Schematic 1160522...

Page 61: ...APPENDIX C EXCITER DRIVER CHASSIS ASSEMBLY DRAWINGS...

Page 62: ...LX Schematic 1310081 NOTE Information and drawings on the Axciter Modulator Tray 1305842 and the Upconverter Module 1310226 and Downconverter Module 1311157 are found in the separate Axciter Manual E...

Page 63: ...APPENDIX D VHF LOW BAND AMPLIFIER TRAY DRAWINGS...

Page 64: ...Overdrive Protection Board Schematic 1198 3601 Phase Shifter Board Schematic 1198 3602 VHF Low Band Amplifier Board Schematic 1198 3605 VHF Filter Amplifier Board Schematic 1198 3606 3 Way Splitter B...

Page 65: ...50 Watt Digital VHF LB Transmitter Appendix D VHF LB Amplifier Tray Drawings DT325B Rev 0 D 2 AGC Control Board Schematic 1306481 400 Watt VHF Amplifier Assembly 1304348 Delta RF Data Sheet P400 VHF L...

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