Gigawave US RMTX 2025 Users manual
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.
RMT RACK MOUNT TRANSMITTER
OPERATORS MANUAL
Copyright 2005 Gigawave Limited
UNUM-RMTX-0100 Issue 2 page 1 of 38
CONTENTS
1 GENERAL SAFETY INFORMATION....................................................................................3
1.1 Health and Safety ..................................................................................................................4
1.2 Maximum RF Power Density Limits...................................................................................5
1.3 Issue Status ...........................................................................................................................5
2 INTRODUCTION.......................................................................................................................6
3 SPECIFICATIONS....................................................................................................................7
4 OVERVIEW OF RMT TRANSMITTER..................................................................................8
5 FRONT PANEL CONTROLS................................................................................................10
6 REAR PANEL CONNECTIONS ...........................................................................................11
6.1.1a Video for digital transmit section (BNC connectors)..........................................11
6.1.1b Video for analogue transmit section (BNC connector)......................................11
6.1.2 Analogue audio for Digital Transmit section (XLR connectors).......................11
6.1.3 Digital audio for Digital Transmit section (XLR connectors).............................12
6.1.4 Analogue audio for Analogue Transmit section (XLR connectors) .................12
6.1.5 Power Connector.....................................................................................................12
6.1.6 RF O/P ......................................................................................................................12
6.1.7 User Data..................................................................................................................13
6.1.8 Remote Monitoring and Control............................................................................13
7 CIRCUIT DESCRIPTIONS....................................................................................................14
7.1 Audio / Video Encoder........................................................................................................14
7.2 COFDM Modulator..............................................................................................................16
7.3 Analogue Transmitter Module...........................................................................................16
7.4 Power Amplifier ...................................................................................................................21
8 CONFIGURING THE TRANSMITTER ................................................................................22
8.1 Status Monitoring ................................................................................................................22
8.2 Top Level Menu...................................................................................................................22
8.3 Operational menu - MPEG2 mode...................................................................................23
8.4 Engineering Menu – MPEG2 mode.................................................................................24
8.5 Operational Menu – ASI mode..........................................................................................25
8.6 Engineering Menu – ASI mode.........................................................................................26
8.7 Operational Menu – Analogue mode...............................................................................27
8.8 Engineering Menu – Analogue mode ..............................................................................27
9 PREPARING FOR OPERATION..........................................................................................34
10 System Remote Monitoring and Setup................................................................................36
Appendix A - RMT MPEG Encoder Paramet er Sets.................................................................37
Appendix B - Table of non-hierarchical bit rates........................................................................38
UNUM-RMTX-0100 Issue 2 page 2 of 38
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.
Switch off supplies before removing covers or disconnecting any RF cables, and before
inspecting damaged cables or antennas.
Avoid standing in front of high gain antennas (such as a dish) and never look into the open
end of a waveguide or cable where RF power may be present.
Users are strongly recommended to return any equipment that requires RF servicing to
Gigawave.
WARNING- GaAs / BeO Hazard : Certain components inside the equipment contain Gallium
Arsenide and Beryllium Oxide that are toxic substances. Whilst safe to handle under normal
circumstances, individual components must not be cut, broken apart, incinerated or
chemically processed. In the case of Beryllium Oxide, a white ceramic material, the principal
hazard is from the dust or fumes which are carcinogenic if ingested, inhaled or entering
damaged skin.
Please consult your local authority before disposing of these components.
CAUTION- Tantalum Capacitors : When subjected to reverse or excess forward voltage,
ripple current or temperature these components may rupture and could potentially cause
personal injury.
CAUTION : This system contains MOS devices. Electro-Static Discharge (ESD) precautions
should be employed to prevent accidental damage.
This device complies with part 15 of the FCC Rules. Operation is subject to the following two
conditions: (1) This device may not cause harmful interference, and (2) this device must
accept any interference received, including interference that may cause undesired operation.
FCC Part 15.21
Changes or modifications not expressly approved by the party responsible for compliance
could void the user's authority to operate the equipment.
NOTE: The manufacturer is not responsible for any radio or TV interference caused by
unauthorized modifications to this equipment. Such modifications could void the user's
authority to operate the equipment.
UNUM-RMTX-0100 Issue 2 page 3 of 38
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:
PT. GR
D = √
in which D = safe working distance (metres)
PT = transmitter or combiner power output (watts)
GR = antenna gain ratio = anti log (gain dBi ÷10)
w = power density (watts/square metre)
The RF power density value is determined by reference to safety guidelines for exposure of
the human body to non-ionising radiation. It is important to note that the guidelines adopted
differ throughout the world and are from time-to-time re-issued with revised guidelines. For
Gigawave use, a maximum power density limit of 1w/m² is to be applied when calculating
minimum safe working distances.
Important Note: It must be remembered that any transmitting equipment radiating power at
frequencies of 100 kHz and higher, has the potential to produce thermal and athermal effects
upon the human body.
To be safe:
a) Operators should not stand or walk in front of any antenna, nor should they allow
b) Operators should not operate any RF transmitter or power amplifier with any of its
Worked examples
Antenna Transmitter Power
Type Gain (dBi) Gain Ratio 2W 4W 10W 30W
OMNI
HELIX
PARABOLIC
DISH
4π.w
anyone else to do so.
covers removed, nor should they allow anyone else to do so.
4 2.5 1 1 1.5 2.5
20 100 4 5.6 9 15.5
35 3,162 22.5 32 50 87
MINIMUM SAFE DISTANCE (METRES)
UNUM-RMTX-0100 Issue 2 page 4 of 38
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. Guidelines for Limiting Exposure to Time-varying Electric, Magnetic & Electromagnetic
Fields (up to 300 GHz) published in 1998 by the Secretariat of the International Commission
on Non -Ionising Radiation Protection (ICNIRP).
Both documents define guideline RF power density limits for "Controlled" and "Uncontrolled"
environments. An uncontrolled environment is defined as one in which the person subjected
to the RF radiation may be unaware of and has no control over the radiation energy received.
The uncontrolled environment conditions can arise, even in the best regulated operations and
for this reason the limits defined for the uncontrolled environment have been assumed for the
Gigawave recommended limit.
Documents a) and b) also show the RF power density guidelines to be frequency dependent.
Different power density / frequency characteristics are presented in the two documents. To
avoid complexity and to avoid areas of uncertainty, Gigawave recommends the use of a
single power density limit across the frequency range 100 kHz to 300 GHz. The 1w/m² power
density limit we recommend satisfies the most stringent of the guidelines published to date.
Footnote: The IICNIRP document may be freely downloaded from the internet at
www.icnirp.de/emfgdl (PDF file), the IEEE standard is available on loan from Essex County
Library on payment of a search fee.
1.3 Issue Status
Issue Date Changes
Issue 1 30th September 2005 first issue
Issue 2 27th October 2005 second issue – revised menu drawings
UNUM-RMTX-0100 Issue 2 page 5 of 38
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. The unit features a comprehensive range
COFDM modulation formats (QPSK 16QAM, and 64QAM) and the MPEG coding format may
be set directly from the front panel control keys and LCD display.
The transmitter comprises a 19” inch rack mount (2 ‘U’) unit that contains both a digital and
an analogue section, with common power supplies and an RF power amplifier.
The digital section of the transmitter comprises an audio encoder, video encoder and COFDM
modulator. The analogue section comprises an integral FM modulator for one video channel
with two associated audio channels.
The RMT transmitter is most commonly used with a separate power amplifier for high power
ENG applications.
At the receive site a range of Gigawave analogue/digital receivers may be used. For example
the PTV (analogue)/PTV-D (digital) receivers are one box portable receivers and the MVL
(analogue)/MVL-D2 (digital) are two box rugged portable systems offering the features of triax
remoting. Alternatively, the complementary RMR switchable analogue/digital rack mounted
receiver may be used. Please consult the separate manual for information detailing the
operation of receivers.
UNUM-RMTX-0100 Issue 2 page 6 of 38
Frequency Selection
Audio Subcarriers
Power Requirement
3. SPECIFICATIONS
Frequency Band 1.97 – 2.50GHz band
As per US BAS allocation (current and future plans)
Transmit Power 500mW nominal
Digital Specifications
Modulation COFDM DVB-T 2k
Modulation Modes QPSK, 16QAM, 64QAM
1
FEC:
/2 2/3 3/4 5/6 7/
Guard interval:
8
1
/32 1/16 1/8 1/
4
Data Rate 4.98 to 31.7 Mbit/s
Bandwidth 8MHz (7 & 6MHz options available)
Encoding Options MPEG 2: 4:2:0/4:2:2 high quality video (DVB standard)
Latency Selectable to less than 2 frames minimum, Tx to Rx
Video Input Digital: SDI 270Mbit/s
Analogue: YUV, Y/C
or Composite (NTSC/PAL)
Audio Input Digital AES/EBU 2 x stereo
Digital SDI embedded
Analogue 2 x stereo / 4 x mono inputs, mic/line selectable
ASI Data Input ASI transport stream, 188/204/byte, automatic selection of burst,
byte or packet mode
Aux Data Input Aux. RS232 data (optional)
Analogue
Specifications
Modulation FM
Deviation Adjustable to current and future BAS channel plans
Spurious Better than –60dBm
Bandwidth 8MHz (7 & 6MHz options available)
Video Input Analogue: Composite (NTSC)
Audio Input Analogue: 1 x stereo / 2 x mono inputs, line level
Factory pre-set to 4.83 and 5.80MHz. Programmable +/- 100kHz
via front panel
General
11-18VDC (Digital mode = 3A at 12VDC, Analogue mode = 2A at
12VDC)
Size 19 inch rack mount x 2’U’. Depth = 350mm
Weight 6.0kg
Environmental Safe use: -20° to +50°C
To spec: -10° to +45°C
Altitude: 4500m
Humidity: 95% long term
Specifications may alter at the discretion of Gigawave or to meet customer specific requirements.
UNUM-RMTX-0100 Issue 2 page 7 of 38
SHF Power
Encoder
Modulator
Front Panel
RF switch
Analogue
4. OVERVIEW OF RMT TRANSMITTER
Motherboard
Amplifier
Transmitter
Module
Module
Module
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. This module accepts all signals provided for digital transmission
and uses MPEG2 encoding/multiplexing techniques to produce a digital transport
stream for the modu lator module
3. Modulator module. This module accepts the digital transport stream from the
encoder module and uses digital COFDM modulation techniques to produce a digital
RF signal and the required RF frequency
4. RF switch. This switch is controlled via the front panel and is used to select either the
RF signal from the digital modulator module or from the analogue transmitter module.
UNUM-RMTX-0100 Issue 2 page 8 of 38
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. This module contains a microprocessor plus six push buttons
and an LCD display for overall monitoring and control of the RMT transmitter.
UNUM-RMTX-0100 Issue 2 page 9 of 38
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.
Also fitted are three LEDs – ‘DC’ (Green), ‘Status’ (bi-colour green/red) and ‘Local’ (bi-colour
green and amber)
On/Off Switch Down for Off, up for On
Digital/Analogue switch Down= Analogue transmission, Up = Digital transmission. Please
note that this function can also be controlled via the push buttons and RMT menus.
Channel Rotary, 0-10. 1= BAS channel 1, 2 = BAS channel 2, etc to 0 =
BAS channel 10. Please note that the BAS channels can be switched between the ‘current’
plan and the ‘new’ plan via the push buttons and RMT menus. The exact frequency selected
by either method is shown on the top menu page on the LCD display.
‘DC’ LED Lit green whenever a correct DC voltage is presented to the RMT
transmitter. This LED will be lit irrespective of whether the unit is switched ‘on’ or ‘off’.
Status LED Stable Green indicates that the RMT is functioning correctly. A
flashing green light indicates that the RMT is functioning correctly but that no video signal is
present whilst the unit is switched into ‘digital transmission’ mode. A stable red light indicates
that the unit has an alarm condition.
Local LED Indicates whether the ‘channel’ and ‘analogue/digital’ switching
controls are being accepted from the front panel rocker switches or from the push button
menu. Green light = rocker switch operation, amber light = push button menu operation.
Full details of the push button menu structure can be found in section 8.
UNUM-RMTX-0100 Issue 2 page 10 of 38
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)
6.1.2 Analogue Audio for Digital Transmit Section (XLR connectors)
Line / Mic Hi Z
The four channels of analogue audio are connected via four 3pin XLR Female connectors.
The connectors are designated Ch1, Ch2, Ch3 and Ch4. These inputs can be independently
selected for Line or Mic level inputs with adjustable gain, via the front panel keypad
Pin
1 Analogue Ground
2 Ch1/ A / Left +ve
3 Ch1/ A / Left -ve
UNUM-RMTX-0100 Issue 2 page 11 of 38
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 Ground
2 Live/ +ve
3 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.
Pin
1 Analogue Ground
2 Ch1/ A / Left +ve
3 Ch1/ A / Left -ve
6.1.5 Power Connector
Connector Type: 4 pin XLR connector (male)
Input range: 11 to 18V DC nominal
Pin Function
1 +12VDC
2 Not Used
3 Not Used
4 0V
6.1.6 RF O/P
Connector Type: 50? ‘N’ type (female)
UNUM-RMTX-0100 Issue 2 page 12 of 38
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