SIST ETS 300 748 E1:2003
(Main)Digital Video Broadcasting (DVB); Framing structure, channel coding and modulation for MVDS at 10 GHz and above
- Abstract
Modulation and channel coding system for the distribution of digital multi-programme Television (TV)/High Definition Television (HDTV) by Multipoint Video Distribution Systems (MVDS) in the 40 GHz band. The System described in this ETS is based on that described in ETS 300 421 for 11/12 GHz satellite services. It allows the same consumer Integrated Receiver Decoder (IRD) to be used for either service, when used with a Low Noise Block (LNB) down-converter for the appropriate frequency band. The frequency band 40,5 to 42,5 GHz has been harmonised within CEPT under Recommendation T/R 52-01. The System however, is applicable to other frequency bands above 10 GHz. The System uses Quaternary Phase Shift Keying (QPSK) modulation and concatenated error protection strategy based on a convolutional code and shortened Reed-Solomon (RS) code. The System is suitable for use on different MVDS transmitter bandwidths. Compatibility with Moving Pictures Experts Group-2 (MPEG-2) coded TV services (see ISO/IEC IS 13818-1), with a transmission structure synchronous with the packet multiplex, is provided. Exploitation of the multiplex flexibility allows the use of the transmission capacity for a variety of TV service configurations, including sound and data services. All service components are Time Division Multiplexed (TDM) on a single digital carrier.
- Status
- Published
- Publication Date
- 30-Nov-2003
- Current Stage
- 6060 - National Implementation/Publication (Adopted Project)
- Start Date
- 01-Dec-2003
- Due Date
- 01-Dec-2003
- Completion Date
- 01-Dec-2003
- Mandate
- T-304
SIST ETS 300 748 E1:2003 is the Slovenian adoption of ETS 300 748 Edition 1, a European Telecommunications Standard for Digital Video Broadcasting (DVB) over Multipoint Video Distribution Systems (MVDS) at 10 GHz and above. It specifies the framing structure, channel coding and modulation used to carry MPEG-2 coded TV, HDTV, sound and data services, mainly for DVB system designers, MVDS equipment makers, and network operators.
What does SIST ETS 300 748 E1:2003 specify?
SIST ETS 300 748 E1:2003 specifies the transmission system for digital multi-programme Television (TV) and High Definition Television (HDTV) distribution over MVDS. The standard is built around a common DVB baseband and channel-coding approach so that equipment can be aligned with the related satellite service family and support compatible consumer Integrated Receiver Decoder (IRD) use with the appropriate Low Noise Block (LNB) down-converter.
The scope covers use in the 40 GHz band and says the system is also applicable above 10 GHz. It describes a single-carrier Time Division Multiplex (TDM) arrangement, while also noting that the system can be used in multi-carrier Frequency Division Multiplex (FDM) applications.
The document is organized into five main clauses and five annexes:
| Annex | What it covers |
|---|---|
| Annex A | Normative signal spectrum at the modulator output |
| Annex B | Informative conceptual system description |
| Annex C | Informative examples of bit rates versus MVDS transmitter bandwidth |
| Annex D | Informative examples of possible use of the system |
| Annex E | Informative bibliography |
Clause 2 lists normative references. Clause 3 defines symbols and abbreviations. Clause 4 describes the transmission system, and Clause 5 gives error performance requirements.
What are the key requirements of SIST ETS 300 748 E1:2003?
SIST ETS 300 748 E1:2003 defines a complete DVB-style chain from the MPEG-2 transport multiplexer to the MVDS channel. In practice, that means a designer has to implement the same functional sequence and keep the signal format compatible across different manufacturers.
System chain and modulation
Clause 4.1 requires transport multiplex adaptation, randomization for energy dispersal, outer Reed-Solomon coding, convolutional interleaving, inner punctured convolutional coding, baseband shaping, and modulation. The system uses Quaternary Phase Shift Keying (QPSK) with concatenated error protection, which matters because the link is designed for high power efficiency in millimetric-band MVDS rather than maximum spectrum efficiency.
The transmission frame is synchronous with the MPEG-2 transport packets. For the reader, this means the modulator and demodulator have to preserve packet timing and sync-byte handling so that downstream MPEG-2 processing can lock correctly.
Packet randomization and framing
Clause 4.4.1 requires the MPEG-2 transport stream to be randomized with a Pseudo Random Binary Sequence (PRBS) based on the polynomial given in the standard. The sync byte of the first packet in each group of eight is inverted, and the remaining sync bytes in that group are left unrandomized.
In practice, this is done to improve transition density and avoid an unmodulated carrier when the input is absent or non-compliant. The reader needs to implement the same packet grouping and sync-byte treatment so the receiver can de-randomize and synchronize reliably.
Outer coding and interleaving
Clause 4.4.2 specifies a shortened Reed-Solomon code, RS(204,188, T = 8), applied to each randomized transport packet. It also defines convolutional interleaving with depth I = 12 and requires sync bytes to stay in branch 0 of the interleaver.
This matters because the outer code and interleaver are what turn short bursts of errors into correctable patterns. A manufacturer needs to keep the packet structure, interleaver depth, and sync-byte routing aligned with the defined framing so the receiver can de-interleave and decode without losing packet boundaries.
Inner coding options
Clause 4.4.3 allows a rate 1/2 convolutional code with constraint length K = 7 and punctured code rates of 1/2, 2/3, 3/4, 5/6 and 7/8. The puncturing pattern is defined in the clause’s table.
In practice, this gives the operator a trade-off between protection and capacity. A service planner chooses the code rate to match available MVDS transmitter bandwidth and the required robustness, while the receiver has to be able to try the allowed rates until lock is obtained.
Baseband shaping and spectrum control
Clause 4.5 requires Gray-coded QPSK with absolute mapping and square-root raised cosine filtering with roll-off factor 0.35. Annex A then defines the output spectrum template and group-delay mask for the modulator.
This is important for transmitter design and compliance testing. The modulator must fit the spectral mask, and the receiver filter has to complement the transmit shaping so that intersymbol interference stays controlled.
Error performance target
Clause 5 sets the modem performance target in an IF loop using BER versus E_b/N_0 limits for each inner code rate. The standard also defines Quasi-Error-Free (QEF) as less than one uncorrected error event per transmission hour.
For the reader, this is the acceptance criterion for link design and testing: the chosen code rate must meet the required performance at the specified noise level if the service is to behave as intended.
What terms does SIST ETS 300 748 E1:2003 define?
- Multipoint Video Distribution System (MVDS) - the distribution system targeted by the standard for carrying digital TV services over high-frequency radio links.
- Integrated Receiver Decoder (IRD) - the consumer receiver used to decode the incoming service, with compatibility considered across the related DVB family.
- Low Noise Block (LNB) down-converter - the front-end unit used with the receiver for the relevant frequency band.
- Moving Pictures Experts Group-2 (MPEG-2) - the source coding and transport format used for compatible TV services.
- Quaternary Phase Shift Keying (QPSK) - the modulation method used on the MVDS channel.
- Forward Error Correction (FEC) - the coding approach used to improve link robustness before reception.
- Quasi-Error-Free (QEF) - the service quality target corresponding to very low residual error at the MPEG-2 demultiplexer input.
Who uses SIST ETS 300 748 E1:2003?
SIST ETS 300 748 E1:2003 is used by MVDS transmitter and receiver designers, broadcast equipment manufacturers, and system integrators. It is also relevant to broadcasters and service providers planning digital TV, HDTV, sound, and data delivery over high-frequency MVDS links.
Test laboratories use it to check spectrum shape, coding behavior, and error performance. Network planners and buyers use it to compare equipment based on the same modulation, framing, and coding rules.
Which standards are used with SIST ETS 300 748 E1:2003?
SIST ETS 300 748 E1:2003 is built around several named references:
- ISO/IEC 13818-1 - provides the MPEG-2 transport system that the MVDS chain adapts and preserves.
- ETS 300 421 - the related DVB satellite-service framing and channel-coding system that this ETS says it is based on.
- ETS 300 429 - listed in the bibliography as a related DVB cable-system standard.
- IESS No. 308 - used as the basis for the output spectrum template in Annex A.
- Forney, G.D. on burst-correcting codes - the interleaving approach in Clause 4.4.2 follows this method.
What does the SIST ETS 300 748 E1:2003 document contain?
The document includes the system block description, the packet randomization procedure, the Reed-Solomon framing and interleaving scheme, the punctured convolutional code definitions, and the QPSK shaping rules. It also includes interface definitions between the MPEG-2 multiplex, the RF chain, and the receive installation.
Annex A provides a spectrum mask and group-delay mask for modulator output checking. Annex C and Annex D give worked examples for bandwidth planning and service configuration, including tables and figures that relate symbol rate, bit rate, transmitter bandwidth, and expected carrier-to-noise behavior.
Get Certified
Connect with accredited certification bodies for this standard
ANCE
Mexican certification and testing association.
Intertek Slovenia
Intertek testing, inspection, and certification services in Slovenia.
LNE (Laboratoire National de Métrologie et d'Essais)
French national laboratory for metrology and testing.
Sponsored listings
Frequently Asked Questions
SIST ETS 300 748 E1:2003 is a standard published by the Slovenian Institute for Standardization (SIST). Its full title is "Digital Video Broadcasting (DVB); Framing structure, channel coding and modulation for MVDS at 10 GHz and above". This standard covers: Modulation and channel coding system for the distribution of digital multi-programme Television (TV)/High Definition Television (HDTV) by Multipoint Video Distribution Systems (MVDS) in the 40 GHz band. The System described in this ETS is based on that described in ETS 300 421 for 11/12 GHz satellite services. It allows the same consumer Integrated Receiver Decoder (IRD) to be used for either service, when used with a Low Noise Block (LNB) down-converter for the appropriate frequency band. The frequency band 40,5 to 42,5 GHz has been harmonised within CEPT under Recommendation T/R 52-01. The System however, is applicable to other frequency bands above 10 GHz. The System uses Quaternary Phase Shift Keying (QPSK) modulation and concatenated error protection strategy based on a convolutional code and shortened Reed-Solomon (RS) code. The System is suitable for use on different MVDS transmitter bandwidths. Compatibility with Moving Pictures Experts Group-2 (MPEG-2) coded TV services (see ISO/IEC IS 13818-1), with a transmission structure synchronous with the packet multiplex, is provided. Exploitation of the multiplex flexibility allows the use of the transmission capacity for a variety of TV service configurations, including sound and data services. All service components are Time Division Multiplexed (TDM) on a single digital carrier.
Modulation and channel coding system for the distribution of digital multi-programme Television (TV)/High Definition Television (HDTV) by Multipoint Video Distribution Systems (MVDS) in the 40 GHz band. The System described in this ETS is based on that described in ETS 300 421 for 11/12 GHz satellite services. It allows the same consumer Integrated Receiver Decoder (IRD) to be used for either service, when used with a Low Noise Block (LNB) down-converter for the appropriate frequency band. The frequency band 40,5 to 42,5 GHz has been harmonised within CEPT under Recommendation T/R 52-01. The System however, is applicable to other frequency bands above 10 GHz. The System uses Quaternary Phase Shift Keying (QPSK) modulation and concatenated error protection strategy based on a convolutional code and shortened Reed-Solomon (RS) code. The System is suitable for use on different MVDS transmitter bandwidths. Compatibility with Moving Pictures Experts Group-2 (MPEG-2) coded TV services (see ISO/IEC IS 13818-1), with a transmission structure synchronous with the packet multiplex, is provided. Exploitation of the multiplex flexibility allows the use of the transmission capacity for a variety of TV service configurations, including sound and data services. All service components are Time Division Multiplexed (TDM) on a single digital carrier.
SIST ETS 300 748 E1:2003 is classified under the following ICS (International Classification for Standards) categories: 33.170 - Television and radio broadcasting. The ICS classification helps identify the subject area and facilitates finding related standards.
SIST ETS 300 748 E1:2003 is associated with the following European legislation: EU Directives/Regulations: 2005-01-1864; Standardization Mandates: T-304. When a standard is cited in the Official Journal of the European Union, products manufactured in conformity with it benefit from a presumption of conformity with the essential requirements of the corresponding EU directive or regulation.
SIST ETS 300 748 E1:2003 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
SLOVENSKI STANDARD
01-december-2003
Digitalna videoradiodifuzija (DVB) – Struktura okvirov, kodiranje kanalov in
modulacija za MVDS na 10 GHz in nad 10 GHz
Digital Video Broadcasting (DVB); Framing structure, channel coding and modulation for
MVDS at 10 GHz and above
Ta slovenski standard je istoveten z: ETS 300 748 Edition 1
ICS:
33.170 Televizijska in radijska Television and radio
difuzija broadcasting
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EUROPEAN ETS 300 748
TELECOMMUNICATION October 1996
STANDARD
Source: EBU/CENELEC/ETSI JTC Reference: DE/JTC-00DVB-20
ICS: 33.060.20
Key words: DVB, digital, video, broadcasting, MPEG, TV, multipoint, radio
European Broadcasting Union Union Européenne de Radio-Télévision
Digital Video Broadcasting (DVB);
Framing structure, channel coding and modulation
for MVDS at 10 GHz and above
ETSI
European Telecommunications Standards Institute
ETSI Secretariat
Postal address: F-06921 Sophia Antipolis CEDEX - FRANCE
Office address: 650 Route des Lucioles - Sophia Antipolis - Valbonne - FRANCE
X.400: c=fr, a=atlas, p=etsi, s=secretariat - Internet: secretariat@etsi.fr
Tel.: +33 4 92 94 42 00 - Fax: +33 4 93 65 47 16
Copyright Notification:
No part may be reproduced except as authorized by written permission. The copyright and the
foregoing restriction extend to reproduction in all media.
© European Telecommunications Standards Institute 1996.
© European Broadcasting Union 1996.
All rights reserved.
Page 2
ETS 300 748: October 1996
Whilst every care has been taken in the preparation and publication of this document, errors in content,
typographical or otherwise, may occur. If you have comments concerning its accuracy, please write to
"ETSI Editing and Committee Support Dept." at the address shown on the title page.
Page 3
ETS 300 748: October 1996
Contents
Foreword .5
1 Scope .7
2 Normative references.7
3 Symbols and abbreviations .8
3.1 Symbols .8
3.2 Abbreviations .8
4 Transmission system .9
4.1 System definition.9
4.2 Adaptation to MVDS transmitter characteristics .10
4.3 Interfacing .10
4.4 Channel coding.10
4.4.1 Transport multiplex adaptation and randomization for energy dispersal.10
4.4.2 Outer coding (Reed-Solomon), interleaving and framing.11
4.4.3 Inner coding (convolutional) .12
4.5 Baseband shaping and modulation.13
5 Error performance requirements.15
Annex A (normative): Signal spectrum at the modulator output.16
Annex B (informative): Conceptual System description.18
Annex C (informative): Examples of bit rates versus MVDS transmitter bandwidth .20
Annex D (informative): Examples of possible use of the System.21
Annex E (informative): Bibliography.22
History.23
Page 4
ETS 300 748: October 1996
Blank page
Page 5
ETS 300 748: October 1996
Foreword
This European Telecommunication Standard (ETS) has been produced by the Joint Technical Committee
(JTC) of the European Broadcasting Union (EBU), Comité Européen de Normalisation ELECtrotechnique
(CENELEC) and the European Telecommunications Standards Institute (ETSI).
NOTE: The EBU/ETSI JTC was established in 1990 to co-ordinate the drafting of ETSs in the
specific field of broadcasting and related fields. Since 1995 the JTC became a tripartite
body by including in the Memorandum of Understanding also CENELEC, which is
responsible for the standardization of radio and television receivers. The EBU is a
professional association of broadcasting organizations whose work includes the co-
ordination of its Members' activities in the technical, legal, programme-making and
programme-exchange domains. The EBU has Active Members in about 60 countries
in the European Broadcasting Area; its headquarters is in Geneva *.
* European Broadcasting Union
Case Postale 67
CH-1218 GRAND SACONNEX (Geneva)
Switzerland
Tel: +41 22 717 21 11
Fax: +41 22 717 24 81
Digital Video Broadcasting (DVB) Project
Founded in September 1993, the DVB Project is a market-led consortium of public and private sector
organizations in the television industry. Its aim is to establish the framework for the introduction of
MPEG-2 based digital television services. Now comprising over 200 organizations from more than 25
countries around the world, DVB fosters market-led systems, which meet the real needs, and economic
circumstances, of the consumer electronics and the broadcast industry.
Transposition dates
Date of adoption of this ETS: 18 October 1996
Date of latest announcement of this ETS (doa): 31 January 1997
Date of latest publication of new National Standard
or endorsement of this ETS (dop/e): 31 July 1997
Date of withdrawal of any conflicting National Standard (dow): 31 July 1997
Page 6
ETS 300 748: October 1996
Blank page
Page 7
ETS 300 748: October 1996
1 Scope
This European Telecommunication Standard (ETS) describes the modulation and channel coding system
(denoted the "System" for the purposes of this ETS) for the distribution of digital multi-programme Television
(TV) / High Definition Television (HDTV) by Multipoint Video Distribution Systems (MVDS) in the 40 GHz
band. The System described in this ETS is based on that described in ETS 300 421 for 11/12 GHz satellite
services. It allows the same consumer Integrated Receiver Decoder (IRD) to be used for either service, when
used with a Low Noise Block (LNB) down-converter for the appropriate frequency band.
The frequency band 40,5 to 42,5 GHz has been harmonized within the European Conference of Post and
Telecommunications Administrations (CEPT) under Recommendation T/R 52-01. The System however, is
applicable to other frequency bands above 10 GHz.
The System uses Quaternary Phase Shift Keying (QPSK) modulation and concatenated error protection
strategy based on a convolutional code and shortened Reed-Solomon (RS) code.
The System is suitable for use on different MVDS transmitter bandwidths.
Compatibility with Moving Pictures Experts Group - 2 (MPEG-2) coded TV services (see
ISO/IEC 13818-1 [1]), with a transmission structure synchronous with the packet multiplex, is provided.
Exploitation of the multiplex flexibility allows the use of the transmission capacity for a variety of TV service
configurations, including sound and data services. All service components are Time Division Multiplexed
(TDM) on a single digital carrier.
This ETS:
- gives a general description of the System for MVDS digital TV transmission;
- specifies the digitally modulated signal in order to allow compatibility between pieces of equipment
developed by different manufacturers. This is achieved by describing in detail the signal processing
principles at the modulator side, while the processing at the receive side is left open to different
implementation solutions. However, it is necessary in this ETS to refer to certain aspects of
reception;
- identifies the global performance requirements and features of the System, in order to meet the
service quality targets.
2 Normative references
This ETS incorporates by dated and undated reference, provisions from other publications. These
normative references are cited at the appropriate places in the text and the publications are listed
hereafter. For dated references, subsequent amendments to or revisions of any of these publications
apply to this ETS only when incorporated in it by amendment or revision. For undated references the latest
edition of the publication referred to applies.
[1] ISO/IEC 13818-1 (November 1994): "Coding of moving pictures and associated
audio".
[2] Forney, G.D. IEEE Trans. Comm. Tech., COM-19, pp. 772-781, (October 1971):
"Burst-correcting codes for the classic bursty channel".
[3] Intelsat Earth Station Standards (IESS) No. 308, revision 6 (26 October 1990):
"Performance characteristics for Intermediate Data Rate (IDR) digital carriers".
Page 8
ETS 300 748: October 1996
3 Symbols and abbreviations
3.1 Symbols
For the purposes of this ETS, the following symbols apply:
α Roll-off factor
C/N Signal-to-Noise ratio
d Convolutional code free distance
free
E /N Ratio between the energy per useful bit and twice the noise power spectral
b 0
density
f Nyquist frequency
N
G ,G Convolutional code generators
1 2
g(x) RS code generator polynomial
I Interleaving depth (bytes)
I, Q In-phase, Quadrature phase components of the modulated signal
j Branch index of the interleaver
K Convolutional code constraint length
M Convolutional interleaver branch depth for j = 1, M = N/I
N Error protected frame length (bytes)
p(x) RS field generator polynomial
r In-band ripple (dB)
m
R Symbol rate corresponding to the bilateral Nyquist bandwidth of the modulated
s
signal
R Useful bit rate after MPEG-2 [1] transport multiplexer
u
R ' Bit rate after RS outer coder
u
T Number of bytes which can be corrected in RS error protected packet
T Symbol period
s
X,Y Di-bit stream after rate 1/2 convolutional coding
3.2 Abbreviations
For the purposes of this ETS, the following abbreviations apply:
AWGN Additive White Gaussian Noise
BB BaseBand
BER Bit Error Ratio
BSS Broadcast Satellite Service
BW BandWidth
CCITT International Telegraph and Telephone Consultative Committee (now ITU-T)
DTH Direct To Home
FDM Frequency Division Multiplex
FEC Forward Error Correction
FIFO First-In, First-Out shift register
FIR Finite Impulse Response
FSS Fixed Satellite Service
HEX Hexadecimal notation
HDTV High Definition TeleVision
IF Intermediate Frequency
IMUX Input Multiplexer - Filter
IRD Integrated Receiver Decoder
MPEG Moving Pictures Experts Group
MSB Most Significant Bit
MUX Multiplex
MVDS Multipoint Video Distribution System
OBO Output Back Off
OCT Octal notation
OMUX Output Multiplexer - Filter
P Puncturing
PDH Plesiochronous Digital Hierarchy
PSK Phase Shift Keying
PRBS Pseudo Random Binary Sequence
QEF Quasi-Error-Free
Page 9
ETS 300 748: October 1996
QPSK Quaternary PSK
R Randomized sequence
RF Radio Frequency
RS Reed-Solomon
SMATV Satellite Master Antenna Television
TBD To Be Defined
TDM Time Division Multiplex
TV Television
TWTA Travelling Wave Tube Amplifier
4 Transmission system
4.1 System definition
The System is defined as the functional block of equipment performing the adaptation of the baseband TV
signals from the output of the MPEG-2 transport multiplexer (see ISO/IEC 13818-1 [1]), to the MVDS channel
characteristics. The following processes shall be applied to the data stream (see figure 1):
- transport multiplex adaptation and randomization for energy dispersal;
- outer coding (i.e. Reed-Solomon);
- convolutional interleaving;
- inner coding (i.e. punctured convolutional code);
- baseband shaping for modulation;
- modulation.
The System functional description is given in annex B.
MVDS services at millimetric frequency bands are particularly affected by power limitations, therefore
ruggedness against noise and interference shall be the main design objective, rather than spectrum
efficiency. To achieve a very high power efficiency without excessively penalizing the spectrum efficiency, the
System shall use QPSK modulation and the concatenation of convolutional and RS codes. The convolutional
code is able to be configured flexibly, allowing the optimization of the system performance for a given MVDS
transmitter bandwidth (see annex C).
The system is suitable for single carrier per MVDS transmitter Time Division Multiplex (TDM) type
applications. It can also be used for multi-carrier Frequency Division Multiplex (FDM) type applications.
Video coder
Convolutional
RS (204, 188)
Audio coder code
MUX
adaptation
Conv.
Baseband
Outer
Inner QPSK
&
inter-
Data coder shaping
coder
coder modulator
2 energy
leaver
dispersal
n
Service components
to the RF
MVDS
Services
Channel
MPEG - 2
MVDS channel adapter
Source coding and multiplexing
Figure 1: Functional block diagram of the System
Programme
MUX
Transport
MUX
Page 10
ETS 300 748: October 1996
The System is directly compatible with MPEG-2 coded TV signals (see ISO/IEC 13818-1 [1]). The modem
transmission frame is synchronous with the MPEG-2 multiplex transport packets.
If the received signal is above C/N and C/I threshold, the Forward Error Correction (FEC) technique
adopted in the System is designed to provide a Quasi Error Free (QEF) quality target. The QEF means
less than one uncorrected error-event per transmission hour, corresponding to Bit Error Ratio
-10 -11
(BER) = 10 to 10 at the input of the MPEG-2 demultiplexer.
4.2 Adaptation to MVDS transmitter characteristics
MVDS transmitters of digital multi-programme TV services will use channels within band plans set according
to individual countries' planning and regulatory criteria and are required to provide compatibility with existing
digital cable and satellite services. The MVDS transmitter performance specification and, in particular, its
operating bandwidth will determine the data rates available to the service.
The symbol rate shall be matched to given MVDS transmitter characteristics. Examples based on computer
simulations for a hypothetical MVDS chain, not including interference effects, are given in annex C.
4.3 Interfacing
The System, as defined in this ETS, shall be delimited by the following interfaces given in table 1:
Table 1: System interfaces
Location Interface Interface type Connection
Transmit station Input MPEG-2 [1] transport from MPEG-2
multiplex multiplexer
Output 70/140 MHz IF to RF devices
Receive installation Output MPEG-2 transport to MPEG-2
multiplex demultiplexer
Input TBD from RF devices
(indoor unit)
4.4 Channel coding
4.4.1 Transport multiplex adaptation and randomization for energy dispersal
The System input stream shall be organized in fixed length packets (see figure 3), following the MPEG-2
transport multiplexer (see ISO/IEC 13818-1 [1]). The total packet length of the MPEG-2 transport Multiplex
(MUX) packet is 188 bytes. This includes 1 sync-word byte (i.e. 47 ). The processing order at the
HEX
transmitting side shall always start from the MSB (i.e. "0") of the sync word-byte (i.e. 01000111).
In order to comply with ITU Radio Regulations and to ensure adequate binary transitions, the data of the
input MPEG-2 multiplex shall be randomized in accordance with the configuration depicted in figure 2.
The polynomial for the Pseudo Random Binary Sequence (PRBS) generator shall be:
14 15
1 + X + X .
Loading of the sequence "100101010000000" into the PRBS registers, as indicated in figure 2, shall be
initiated at the start of every eight transport packets. To provide an initialization signal for the descrambler,
the MPEG-2 sync byte of the first transport packet in a group of eight packets is bit-wise inverted from
47 to B8 . This process is referred to as the "Transport Multiplex Adaptation".
HEX HEX
The first bit at the output of the PRBS generator shall be applied to the first bit (i.e. MSB) of the first byte
following the inverted MPEG-2 sync byte (i.e. B8 ). To aid other synchronization functions, during the
HEX
MPEG-2 sync bytes of the subsequent 7 transport packets, the PRBS generation shall continue, but its
output shall be disabled, leaving these bytes unrandomized. Thus, the period of the PRBS sequence shall
be 1 503 bytes.
Page 11
ETS 300 748: October 1996
The randomization process shall be active also when the modulator input bit-stream is non-existent, or
when it is no
...