The information contained in this manual remains the property of Gigawave and may not be used, disclosed or reproduced in any other form whatsoever without the prior written permission of Gigawave.
CONTENTS 1 GENERAL SAFETY INFORMATION ....................................................................................3 1.1 Health and Safety..................................................................................................................4 1.2 Maximum RF Power Density Limits ...................................................................................5 1.3 Issue Status ................................................................................................................
1. GENERAL SAFETY INFORMATION The information that follows, together with local site regulations, must be studied by personnel concerned with the operation or maintenance of the equipment, to ensure awareness of potential hazards. WARNING- RF Power Hazard : High levels of RF power are present in the unit. Exposure to RF or microwave power can cause burns and may be harmful to health.
1.1 Health & Safety Exposure to Non Ionising (RF) Radiation/Safe Working Distances The safe working distance from a transmitting antenna may be calculated from the relationship: D= √ PT. GR 4π.
1.2 Maximum RF Power Density Limits The RF Radiation Power Density limit figure recommended by Gigawave is based upon guideline levels published in: a. IEEE standard C95.1 1999 - IEEE Standard for Safety Levels with respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz. b.
2. INTRODUCTION This manual is to be used in conjunction with the RMT rack-mount switchable analogue/digital transmitter. When in digital mode the RMT offers significant features including ASI and component video inputs together with 4 audios (analogue, AES digital or SDI embedded). The Gigawave RMT transmitter is designed for permanent rack-mounted applications, such as ENG truck/vehicle or fixed link applications.
3. Frequency Band Frequency Selection Transmit Power Digital Specifications Modulation Modulation Modes Data Rate Bandwidth Encoding Options Latency Video Input Audio Input ASI Data Input Aux Data Input Analogue Specifications Modulation Deviation Spurious Bandwidth Video Input Audio Input Audio Subcarriers General Power Requirement Size Weight Environmental SPECIFICATIONS 1.97 – 2.
4. OVERVIEW OF RMT TRANSMITTER Motherboard SHF Power Amplifier Modulator Module Encoder Module RF switch Analogue Transmitter Module Front Panel Module The RMT transmitter comprises seven main modules or assemblies:1. Motherboard. This board accommodates the digital encoder and modulator boards, as well as providing DC, signal and I2C communications routing to/from all other modules. 2. Encoder module.
5. Power Amplifier. This module accepts the analogue or digital RF signal at a level of – 10dBm (nominal) and amplifies the signal to a level of 500mW (+27dBm) nominal. 6. Analogue transmitter module. This module accepts an analogue composite video signal (NTSV) plus up to 2x analogue audio signals (line level) and uses conventional FM modulation techniques to produce an RF signal complete with audio sub-carriers at the required RF frequency. 7. Front panel module.
5. FRONT PANEL CONTROLS Front panel view of the RMT Rack Mount Transmitter The front panel of an RMT transmitter comprises quantity 2x 2-way switches (On/Off and Analogue/Digital), 1x 10-way rotary switch (BAS channel number), six push button switches (used to navigate the various RMT menus) and an LCD display.
6. REAR PANEL CONNECTIONS RMT Rear Panel layout showing all connections 6.1.1a Video for Digital Transmit Section (bnc connectors) Connectors for either SDI digital, composite analogue or component analogue (Y/C or YUV) video or ASI transport stream. Selected via front panel keypad. 75Ω BNC connectors (female) 6.1.1b Video for Analogue Transmit Section (bnc connector) Connector for composite video input. 75Ω BNC connector (female) 6.1.
6.1.3 Digital Audio for Digital Transmit Section (XLR connectors) The two channels of AES EBU stereo digital audio are connected via two 3pin XLR Female Connectors. The connectors are designated Ch1 and Ch2. Pin 1 2 3 Ground Live/ +ve Return/ -ve 6.1.4 Analogue Audio for Analogue Transmit Section (XLR connectors) Line Level/ 600Ω balanced Z The two channels of analogue audio are connected via two 3pin XLR Female connectors. The connectors are designated Ch1 and Ch2.
6.1.7 User data (future option) Connector Type: 7 pin LEMO connector EGG.1B.307.CLN User data selectable as RS485 or RS232 (future option) Pin 1 2 3 4 5 6 7 RS232 CONNECTIONS RS485 CONNECTIONS Not Used Not Used User Data Not Used Ground Not Used Not Used Not Used Not Used User Data (-ve) Not Used Ground Not Used User Data (+ve) 6.1.
7.
• Audio Analogue to Digital Converter, 48kHz, 24 bit. Four high impedance analogue inputs. The channels are first buffered by a variable gain stage to cater for either Mic or Line level inputs. A switchable 20dB stage is also included to cater for low level Mic inputs. The audio channels are then converted into digital signals and passed to the MPEG2 Encoder. • Audio SDI de-embedder. Extracts digital audio from the SDI stream • MPEG2 Encoder. Compresses the video and audio.
7.2 COFDM Modulator The normal scheme of COFDM modulation adopted by Gigawave for the RMT is 2k carriers with 8MHz RF bandwidth. The COFDM modulator has been designed to take its input from the MPEG2 encoder, or from an external ASI. This Transport stream is then modulated directly to the output frequency band (e.g. 2GHz). This method reduces the occurrence of inter-modulated harmonic frequencies and requires less upconverters The COFDM modulator RF output is via the SMB connector.
2. Convert two balanced line level (+9dBm 600 ohms) audio inputs to frequency modulated sub-carriers at nominally 4.83 and 5.8MHz. The independent operation of the two sub carriers is available via front panel control. The subcarrier frequencies can be adjusted over a +/- 100kHz range via front panel control, to facilitate regional and customer requirements. Video and R.F output circuit operation. The 75 ohm unbalanced video input is connected via board mounted SMB socket SK1.
These provide clock, data and latch enable inputs for the phase locked loop circuit IC6. (Also the common bus clock and data and separate latch enables for the two audio modulator PLL’s). The VCO R.F. output is attenuated and then split as described in the video and R.F. section above. The A.C. coupled R.F. sample is applied to IC6 RF input. The PLL has a reference frequency crystal (X2) oscillator of 8MHz.
The audio subcarrier frequencies can be adjusted via the front panel display and controls and switched on / off independently. The subcarriers are switched on via TR12, TR13. A logic ‘low’ level on PL1 pins 7 and 8 respectively switches on the A1 and A2 modulator oscillator circuits. Power supplies and monitoring The +12v input supply is filtered and regulated by IC7, +5v linear regulator.
Schematic layout of analogue transmitter module, RMT transmitter UNUM-RMTX-0100 Issue 2 page 20 of 38
7.4 Power Amplifier The function of the power amplifier is to amplify the signal from the COFDM modulator to a suitable level for transmission. The amplifier is required to be highly linear to accommodate the high order modulation modes employed for digital system operation, with very low distortion (low inter-modulation between carriers). The nominal output power is +27dBm (500mW) (band specific).
8. 8.1 CONFIGURING THE TRANSMITTER Status Monitoring The red/green ‘status’ LED on the front panel indicates the condition of the RMT, if a fault or warning exists the LED will indicate Red and the Status menu will indicate the nature of the fault / warning. During initialisation of the unit the Status LED will be off. 8.2 Top level Menu Six charts showing the menu trees of the RMT are included in this manual.
Top level and Current Operational State This is the display screen during normal operation of the RMT and indicates the Tx frequency (Channel number or Manual frequency), the current operating mode (analogue or digital), and the MPEG/COFDM parameters in use (digital operation). The B button is used to show other current parameters (digital = bit rate, encoder memory, video input mode, audio input mode, analogue = RF frequency, subcarrier frequencies).
Audio 2, 3, 4 Menus As Audio 1 Status Menu The status menu is used to confirm the condition of the RMT. If the Status LED is red indicating a fault or warning, the Status menu will indicate the nature of the problem.
The video input may be selected to CVBS/YC/YUV, analogue, or SDI digital, or internal test colour bars The Enter button allows the ? ? buttons to select the required value. The Enter button then stores the value and returns to the Main menu. In the event that BARS is selected, a sub menu allows ALT BARS, or 75%, or 100% BARS to be selected. Video Format The video format may be selected PAL or NTSC The Enter button allows the ? ? buttons to select the required value.
8.6 Engineering Menu – ASI mode The engineering menu is entered by pressing the ? and ‘C’ buttons simultaneously for 2 to 10 seconds, then releasing the ‘C’ button.
The Enter button allows the ? ? buttons to select the required value. The Enter button then stores the value and returns to the Main menu, after which the menu tree becomes appropriate to the mode selected (ASI or MPEG) 8.7 Operations Menu – Analogue mode Ch / Frequency Menu This menu is the same as the equivalent in the MPEG Operations menu Status Menu This menu is the same as the equivalent in the MPEG Operations menu 8.
Key: E = Enter E/C = Enter or Cancel A =? B = RMT – OPS MENU - DIGITAL MPEG ENCODER MODE ? CURRENT OPERATIONAL STATE B DIGITAL TX CH 1 2375 MHz QPSK ½ 1/32 ? /? FOR MAIN MENU Omitted when in Switch front panel control mode B ENC MEM 9 6.032086 Mbit/s PBMP4087-0009-00 NTSC CH/FREQ ? MAIN MENU MAIN MENU ? STATUS ENCODER B AUDIO 1 MIC ANALOG -3.0dB Video Input C/E 2.49200GHz ? MAIN MENU 2.
RMT – ENG MENU - DIGITAL MPEG ENCODER MODE ENGINEERING Enter Engineering mode by pressing C and E buttons together Key: E = Enter E/C = Enter or Cancel ? ENGINEER MENU CONTROL MODE ? E ENG MENU FW INVENTORY ENG MENU ? CHANNEL PLAN E CONTROL MODE FIRMWARE SWITCH CTRL FP AVR 0305-05 ? ENG MENU VIDEO INPUT E E/C ? ENG MENU VIDEO FORMAT ? ENG MENU AUDIO INPUT ? ENG MENU ASI/MPEG ENG MENU PROG CHANNELS E E E Select VIDEO INPUT VIDEO INPUT AUDIO INPUT Select PROG CHANNEL OLD PL
Key: E = Enter E/C = Enter or Cancel A =? B RMT – OPS MENU - ASI MODE =? B DIGITAL TX CH10 2.49200GHz 16QAM__2/3__1/32 B ASI DATA RATE 12.064171 Mbit/s ? OR ? MAIN MENU ? CH/FREQ MAIN MENU Omitted when in Switch front panel control mode E ? TX MODE MAIN MENU STATUS E E Video Input CH/FREQ Select Ch 1 2 .30000GHz Digital TX V CH/FREQ Ch 10 2 .30000GHz Select E/C Analog TX C/E NO TS Present YES TS Rate YES Synth Lock YES CH/FREQ Manual 2.
RMT – ENG MENU - ASI MODE ENGINEERING Enter Engineering mode by pressing C and E buttons together Key: E = Enter E/C = Enter or Cancel ENG MENU CONTROL MODE ? ENG MENU FW INVENTORY E ENG MENU CHANNEL PLAN E CONTROL MODE FIRMWARE SWITCH CONTROL FP AVR 0305-05 ? OR ? ? ? ENG MENU ? Modulation mode E E /C OLD PLAN ? OR ? QPSK ? Modulation mode CONTROL MODE FIRMWARE Select KEYPAD CONTROL ENC AVR 0301-02 NEW PLAN ? 16QAM ? Modulation mode FIRMWARE ENC FPGA 0101 -80 ENG MENU Cod
RMT – OPS MENU – ANALOGUE TX MODE Key: E = Enter E/C = Enter or Cancel A =? B =? CURRENT OPERATIONAL STATE B Subcarrier Freq AUDIO 1 4.830MHz AUDIO 2 5.800MHz ANALOG TX B CH 10 2. 49200 GHz ? /? FOR MAIN MENU ? OPS MENU Omitted when in Switch front panel control mode ? MAIN MENU ? CH/FREQ MAIN MENU TX MODE E MAIN MENU STATUS E CH/FREQ E Select C/E Ch 1 ? 2.49200GHz C/E Synth Lock YES Digital TX ? ? CH/FREQ Select Ch 10 Analog TX 2.
ENGINEERING Enter Engineering mode by pressing C and E buttons together RMT – ENG MENU – ANALOGUE MODE Key: E = Enter E/C = Enter or Cancel ENG MENU CONTROL MODE ? ENG MENU PROG CHANNELS E ENG MENU AUDIO 1 FREQ E CONTROL MODE PROG CHANNEL SWITCH CONTROL Ch 1 2.30000GHz ? OR ? ? ? ENG MENU AUDIO 2 FREQ E CHANNEL PLAN 5.80 0 OLD PLAN ? OR ? PROG CHANNEL KEYPAD CONTROL Ch 10 2 .
9. PREPARING FOR OPERATION EQUIPMENT PREPARATION Before leaving the equipment base to undertake an operation it is recommended that the following equipment checks be made.
The Receiving Equipment The RMT transmitter may be used with a variety of Gigawave digital receivers including § MVL-D series digital receiver, a two box radio offering the convenience of triax remoting § MVL-D series digital receiver with diversity reception control unit § MVL series analogue receiver, a two box radio offering the convenience of triax remoting § PTV-D series digital one box receiver § PTV series analogue one box receiver § Complementary RMR series rack-mounted switchable analogu
10. System Remote Monitoring and Setup Using a PC running Hyper Terminal or other terminal emulator, the RMT can be configured without the use of the operator controls and LCD display. The current configuration can also be obtained via this RS232/RS485 interface.
Appendix A RMT MPEG Encoder Parameter Sets Set Part Number Rate (Mbit/s) COFDM Mode MPEG 0 PBMP-40870008-10 PBMP-40870010-10 PBMP-40870006-10 PBMP-40870009-10 PBMP-40870009-08 PBMP-40870011-08 PBMP-40870010-08 PBMP-40870012-08 PBMP-40870012-02 PBMP-40870010-02 PBMP-40870009-02 PBMP-40870011-02 PBMP-40870009-00 PBMP-40870012-00 PBMP-40870011-00 PBMP-40870010-00 18.
Appendix B Table of DVB-T non-hierarchical bit rates Modulation Code rate QPSK 1/2 2/3 3/4 5/6 7/8 16-QAM 1/2 2/3 3/4 5/6 7/8 1/32 12.1 16.1 18.1 20.1 21.1 1/16 11.7 15.6 17.6 19.5 20.5 1/8 11.1 14.7 16.6 18.4 19.4 1/4 9.95 13.3 14.9 16.6 17.4 1/2 2/3 3/4 5/6 7/8 1/32 18.1 24.1 27.1 30.2 31.7 1/16 17.6 23.4 26.3 29.3 30.7 1/8 16.6 22.1 24.9 27.6 29.0 1/4 14.9 19.9 22.4 24.9 26.1 64-QAM UNUM-RMTX-0100 Bit rate (Mbit/s) at each guard interval (symbol fraction) 1/32 1/16 1/8 1/4 6.03 5.85 5.53 4.
