EN 50083-9:2002
(Main)Cable networks for television signals, sound signals and interactive services - Part 9: Interfaces for CATV/SMATV headends and similar professional equipment for DVB/MPEG-2 transport streams
Cable networks for television signals, sound signals and interactive services - Part 9: Interfaces for CATV/SMATV headends and similar professional equipment for DVB/MPEG-2 transport streams
1.1 General Standards of the EN 50083 series deal with cabled distribution systemsnetworks for television signals, sound signals and interactive multimedia signalsservices including equipment, systems and installations • - for headend -reception, processing and distribution of television and sound and television signals and their associated data signals and • - for processing, interfacing and transmitting all kinds of signals for interactive multimedia signalsservices using all applicable transmission media. They cover aAll kinds of systemsnetworks like • - CATV-systemsnetworks, • - MATV-networks and SMATV-systemsnetworks, • - iIndividual receiving systemsnetworks and all kinds of equipment, systems and installations installed in such systemsnetworks, are within this scope. The extent of theseis standardsization work is from the antennas, special signal source inputs to the headend or other interface points to the systemnetwork up to the system outlet or the terminal input, where no system outlet exists. The standardization of any user terminals (i.e. tuners, receivers, decoders, multimedia terminals etc.) as well as of any coaxial and optical cables and accessories therefor is excluded. 1.2 Specific scope of this part 9 This standard describes physical interfaces for the interconnection of signal processing devices for professional CATV/SMATV headend equipment or for similar systems, such as in uplink stations. Especially this document specifies the transfer of DVB/MPEG-2 data signals in the standardized transport layer format between devices of different signal processing functions. RF interfaces and interfaces to telecom networks are not covered in this document. In addition references are made to all other parts of EN 50083 series (Cabled distribution networks systems for television signals, and sound signals and interactive services) and in particular for RF, video and audio interfaces to part 5: "Headend equipment“. For connections to telecom networks a special Data Communication Equipment (DCE) is necessary to adapt the serial or parallel interfaces specified in this document to the bitrates and transmission formats of the public Plesiochronic Digital Hierarchy (PDH) networks. Other emerging technologies such as Connectionless Broadband Data Services (CBDS), Synchronous Digital Hierarchy (SDH), Asynchronous Transfer Mode (ATM) etc. can be used for transmitting MPEG-2 Transport Streams (TS) between remote locations. ATM is particularly suitable for providing bandwidth on demand and it allows for high data rates.
Kabelnetze für Fernsehsignale, Tonsignale und interaktive Dienste - Teil 9: Schnittstellen für CATV-/SMATV-Kopfstellen und vergleichbare professionelle Geräte für DVB/MPEG-2-Transportströme
Réseaux de distribution par câbles pour signaux de télévision, signaux de radiodiffusion sonore et services interactifs - Partie 9: Interfaces pour les têtes de réseaux pour antennes communautaires, antennes collectives par satellite et matériels professionnels analogues pour les flux transport DVB/MPEG-2
Cable networks for television signals, sound signals and interactive services - Part 9: Interfaces for CATV/SMATV headends and similar professional equipment for DVB/MPEG-2 transport streams
General Information
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Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Cable networks for television signals, sound signals and interactive services - Part 9: Interfaces for CATV/SMATV headends and similar professional equipment for DVB/MPEG-2 transport streamsKabelnetze für Fernsehsignale, Tonsignale und interaktive Dienste -- Teil 9: Schnittstellen für CATV-/SMATV-Kopfstellen und vergleichbare professionelle Geräte für DVB/MPEG-2-TransportströmeRéseaux de distribution par câbles pour signaux de télévision, signaux de radiodiffusion sonore et services interactifs -- Partie 9: Interfaces pour les têtes de résaux pour antennes communautaires, antennes collectives par satellite et matériels professionnels analogues pour les flux transport DVB/MPEG-2Cable networks for television signals, sound signals and interactive services -- Part 9: Interfaces for CATV/SMATV headends and similar professional equipment for DVB/MPEG-2 transport streams33.060.40Kabelski razdelilni sistemiCabled distribution systemsICS:Ta slovenski standard je istoveten z:EN 50083-9:2002SIST EN 50083-9:2003en01-december-2003SIST EN 50083-9:2003SLOVENSKI
STANDARDSIST EN 50083-9:19991DGRPHãþD
EUROPEAN STANDARD
EN 50083-9 NORME EUROPÉENNE EUROPÄISCHE NORM
December 2002 CENELEC European Committee for Electrotechnical Standardization Comité Européen de Normalisation Electrotechnique Europäisches Komitee für Elektrotechnische Normung
Central Secretariat: rue de Stassart 35, B - 1050 Brussels
© 2002 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 50083-9:2002 E
ICS 33.060.40 Supersedes EN 50083-9:1998
English version
Cable networks for television signals,
sound signals and interactive services Part 9: Interfaces for CATV/SMATV headends and similar
professional equipment for DVB/MPEG-2 transport streams
Réseaux de distribution par câbles destinés aux signaux de radiodiffusion sonore, de télévision et aux services interactifs Partie 9: Interfaces pour les têtes
de résaux pour antennes communautaires, antennes collectives par satellite et matériels professionnels analogues pour les flux transport DVB/MPEG-2
Kabelnetze für Fernsehsignale, Tonsignale und interaktive Dienste Teil 9: Schnittstellen
für CATV-/SMATV-Kopfstellen und vergleichbare professionelle Geräte
für DVB/MPEG-2-Transportströme
This European Standard was approved by CENELEC on 2002-07-01. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the Central Secretariat has the same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United Kingdom.
Foreword
This European Standard was prepared by CENELEC Technical Committee TC 209, "Cable networks for television signals, sound signals and interactive services" on the basis of EN 50083-9:1998 and a draft amendment to which was submitted to the Unique Acceptance Procedure.
The amendment was approved by CENELEC on 2002-07-01 to be published as part of a third edition of EN 50083-9.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement
(dop) 2003-07-01 – latest date by which the national standards conflicting
with the EN have to be withdrawn
(dow) 2005-07-01
Annexes designated "normative" are part of the body of the standard. Annexes designated "informative" are given for information only. In this standard, annexes A and B are normative and annexes C, D, E, F and G are informative. __________
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Contents Page 1 Scope.5 1.1 General.5 1.2 Specific scope of this part 9.5 2 Normative references.6 3 Terms, definitions and abbreviations.7 3.1 Terms and definitions.7 3.2 Abbreviations.8 4 Interfaces for MPEG-2 data signals.9 4.1 Introduction.8 4.2 Synchronous parallel interface (SPI).12 4.3 Synchronous Serial Interface (SSI).17 4.4 Asynchronous Serial Interface (ASI).17 Annex A (normative)
Synchronous Serial Interface (SSI).18 Annex B (normative)
Asynchronous Serial Interface (ASI).28 Annex C (informative)
8B/10B tables.36 Annex D (informative)
Implementation guidelines and clock recovery from the
Synchronous Serial Interface (SSI).40 Annex E (informative)
Implementation guidelines and deriving clocks from the
MPEG-2 packets
for the ASI.44 Annex F
(informative)
Guidelines for the implementation and usage of the
DVB Asynchronous Serial
Interface.48 Annex G (informative)
Bibliography.53 Figures Figure 1 - Protocol stack for 188 byte packets.10 Figure 2 - Protocol stack for 204 byte packets.10 Figure 3 - Packet structure of 188 byte packet.10 Figure 4 - Packet structure of 204 byte packet.10 Figure 5 -
System for parallel transmission.12 Figure 6 - Transmission format with 188 byte packets.13 Figure 7 - Transmission format with 204 byte packets
(188 data bytes and 16 dummy bytes).13 Figure 8 - Transmission format with RS-coded packets (204 bytes; 188 data bytes
and 16 valid extra bytes) as specified in EN 300 421.13 Figure 9 - Clock to data timing (at source).14 Figure 10 - Line driver and line receiver interconnection.15 Figure 11 - Idealized eye diagramme corresponding to the
minimum input signal level.16 Figure A.1 - Example of cascaded interfaces.18 SIST EN 50083-9:2003
Figure A.2 - Coaxial cable-based synchronous serial transmission link (SSI type).19 Figure A.3 - Fibre-optic-based synchronous serial transmission link (SSI type).19 Figure A.4 - Pulse mask for logical 0.22 Figure A.5 - Pulse mask for logical 1.23 Figure A.6 - Biphase Mark encoding.26 Figure B.1 - Coaxial cable-based asynchronous serial transmission link (ASI type).28 Figure B.2 - Fibre-optic-based asynchronous serial transmission link (ASI type).29 Figure B.3 - Serial link Layer-0 reference points.30 Figure B.4 - Coaxial transmitter test circuit.31 Figure B.5 - Transmitter eye diagramme for jitter.32 Figure B.6 - Spectral width of transmitter.33 Figure B.7 - Transmission format with data packets (example for 188 bytes).35 Figure B.8 - Transmission format with data bursts (example for 188 bytes).35 Figure D.1 - Connection of the adapter modules.40 Figure D.2 - Example of implementation of an emitting module.41 Figure D.3 - Example of implementation of a receiving module.42 Figure D.4 - Example of implementation of a flexible data rate receiving module for SSI. Figure E.1 - ASI link with output clock from following application or alternative with
clock recovery.44 Figure E.2 - Phase Locked Loop for clock generation.45 Figure F.1 - Abstract ASI transmission model.48 Figure F.2 - Random aperiodic transport stream rate and buffer utilisation.50 Figure F.3 - Deterministic aperiodic transport stream rate and buffer utilisation.50 Tables Table 1 - Mandatory and optional packet lengths.11 Table 2 - Contact assignment of 25 contact type D subminiature connector (ISO 2110).17 Table A.1 - Transmitter output characteristics.21 Table A.2 - Receiver input characteristics.21 Table A.3 - Optical characteristics for SSI links.24 Table B.1 - Electrical characteristic specifications for ASI link.31 Table B.2 - Chromatic dispersion requirements.32 Table B.3 - Optical characteristic specifications for ASI link.33 Table C.1 - Valid data characters.36 Table C.2 - Valid special characters.38 Table C.3 - Delayed code violation example.39 Table E.1 - Analysis of 10 kHz clock generating loop, ± 50 µs jitter.46 Table E.2 - Analysis of 10 kHz clock generating loop, ± 2 ms jitter.47
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1 Scope 1.1 General Standards of EN 50083 series deal with cable networks for television signals, sound signals and interactive services including equipment, systems and installations • for headend reception, processing and distribution of television and sound signals and their associated data signals and • for processing, interfacing and transmitting all kinds of signals for interactive services
using all applicable transmission media.
All kinds of networks like • CATV-networks, • MATV-networks and SMATV-networks, • Individual receiving networks and all kinds of equipment, systems and installations installed in such networks, are within this scope.
The extent of this standardization work is from the antennas, special signal source inputs to the headend or other interface points to the network up to the system outlet or the terminal input, where no system outlet exists.
The standardization of any user terminals (i.e. tuners, receivers, decoders, multimedia terminals etc.) as well as of any coaxial and optical cables and accessories therefor is excluded. 1.2 Specific scope of this part 9 This standard describes physical interfaces for the interconnection of signal processing devices for professional CATV/SMATV headend equipment or for similar systems, such as in uplink stations. Especially this document specifies the transfer of DVB/MPEG-2 data signals in the standardized transport layer format between devices of different signal processing functions.
RF interfaces and interfaces to telecom networks are not covered in this document.
In addition references are made to all other parts of EN 50083 series (Cable networks for television signals, sound signals and interactive services) and in particular for RF, video and audio interfaces to part 5: "Headend equipment“.
For connections to telecom networks a special Data Communication Equipment (DCE) is necessary to adapt the serial or parallel interfaces specified in this document to the bitrates and transmission formats of the public Plesiochronic Digital Hierarchy (PDH) networks. Other emerging technologies such as Connectionless Broadband Data Services (CBDS), Synchronous Digital Hierarchy (SDH), Asynchronous Transfer Mode (ATM) etc. can be used for transmitting MPEG-2 Transport Streams (TS) between remote locations. ATM is particularly suitable for providing bandwidth on demand and it allows for high data rates.
2 Normative references This European Standard incorporates by dated or 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 European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies.
EN 50083
Cable networks for television signals, sound signals and interactive services
EN 50083-1 1993 Part 1: Safety requirements + A1 1997 + A2 1997
EN 50083-2 2001 Part 2: Electromagnetic compatibility for equipment
EN 50083-3 2002 Part 3: Active wideband equipment for coaxial cable networks
EN 50083-4 1998 Part 4: Passive wideband equipment for coaxial cable networks
EN 50083-5 2001 Part 5: Headend equipment
EN 50083-6 1997 Part 6: Optical equipment
EN 50083-7 1996 Part 7: System performance + A1 2000
EN 50083-8 2002 Part 8: Electromagnetic compatibility for networks
EN 60793-2-10 2002 Optical fibres - Part 2-10: Product specifications - Sectional specification for category A1 multimode fibres (IEC 60793-2-10:2002)
EN 60793-2-50 2002 Optical fibres - Part 2-50: Product specifications - Sectional specification for class B single-mode fibres (IEC 60793-2-50:2002)
EN ISO/IEC 13818-1 1997 Information technology - Generic coding of moving pictures and associated audio information - Part 1: Systems
(ISO/IEC 13818-1:1996)
EN ISO/IEC 13818-9 2000 Information technology - Generic coding of moving pictures and associated audio information - Part 9: Extension for real-time interface for systems decoders
(ISO/IEC 13818-9:1996)
EN 300 421 1997 Digital Video Broadcasting (DVB) - Framing structure, channel coding and modulation for 11/12 GHz satellite services
EN 300 429 1997 Digital Video Broadcasting (DVB) - Framing structure, channel coding and modulation for cable systems
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EN 300 473 1997 Digital Video Broadcasting (DVB) - Satellite Master Antenna Television (SMATV) distribution systems
ETR 290 1997 Digital Video Broadcasting (DVB) - Measurement guidelines for DVB systems
IEC 60169-8 1978 Radio frequency connectors - Part 8: RF coaxial connectors with inner diameter of outer conductor 6,5 mm (0,25 in) with bayonet lock - Characteristic impedance 50 Ω (type BNC)
IEC 60793-2 series Optical fibres - Part 2: Product specifications
IEC 60874-14 1993 Connectors for optical fibres and cables - Part 14: Sectional specification for fibre-optic connector - Type SC
ISO 2110 1989 Information technology - Data communication, 25 pole DTE/DCE interface connector and contact number assignments
ISO/IEC 14165-111 1) Information technology - Fibre Channel - Part 111: Physical and signalling interface (FC-PH)
ITU-R Rec. BT.656-4 1998 Interfaces for digital component video signals in 525-line and 625-line television systems operating at the 4:2:2 level of recommendation ITU-R BT.601
ITU-T Rec. G.654 2002 Characteristics of cut-off shifted single-mode optical fibre and cable
ITU-T Rec. G.703 2001 Physical/electrical characteristics of hierarchical digital interfaces
ITU-T Rec. G.957 1999 Optical interfaces for equipments and systems relating to the synchronous digital hierarchy
3 Terms, definitions and abbreviations
3.1 Terms and definitions
3.1.1
headend equipment which is connected between receiving antennas or other signal sources and the remainder of the cable distribution system to process the signals to be distributed
NOTE
The headend may, for example, comprise antenna amplifiers, frequency converters, combiners, selectors and generators.
3.1.2
Satellite Master Antenna Television system (SMATV) a system which is designed to provide sound and television signals to the households of a building or group of buildings
1) In preparation SIST EN 50083-9:2003
NOTE
Two system configurations are defined in EN 300 473 as follows: - SMATV system A, based on transparent transmodulation of QPSK satellite signals into QAM signals to be distributed to the user - SMATV system B, based on direct distribution of QPSK signals to the user, with two options:
- SMATV-IF distribution in the satellite IF band (above 950 MHz)
- SMATV-S distribution in the VHF/UHF band, for example in the extended S-band (230-470 MHz)
3.1.3
Biphase Mark
a line code which ensures DC balance, easy clock recovery and polarity freedom
3.1.4
Transport Stream includes one or more programs with one or more independent time bases into a single stream. The Transport Stream is designed for use in environments where errors are likely, such as storage or transmission in lossy or noisy media.
3.1.5
Transport Packet a packetized element of the Transport Stream. The packets are either 188 bytes or in case of using Reed Solomon FEC 204 byte in length
3.1.6
DVALID a signal which indicates in the 204 byte mode of a Transport Stream that the empty space is filled with dummy bytes
3.1.7
PSYNC A flag which indicates the beginning of a packet
3.2 Abbreviations
8B/10B
eight to ten bit conversion ACCP
Accumulated Phase ACCT
Accumulated Time ASI
Asynchronous Serial Interface ASI-C
Asynchronous Serial Interface on coacial cable ASI-O
Asynchronous Serial Interface on opticaL fiber ATM
Asynchronous Transfer Mode BER
Bit Error Rate CBDS
Connectionless Broadband Data Services DFB
Distributed Feedback DJ
Deterministic Jitter DVALID
data valid DVB
Digital Video Broadcast FC
FIBRE Channel FEC
Forward Error Correction FIFO
First In First Out FWHM
Full Width Half Max IEC
International Electrotechnical Commission ISO
International Standards Organisation ITU-R
International Telecommunication Union Radiocommunication ITU-T
International Telecommunication Union Telecommunication LF
Low Frequency SIST EN 50083-9:2003
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LVDS
Low Voltage Differential Signalling MPEG
Motion Picture Experts Group MSB
Most Significant Bit NA
not applicable NRZ
Non-Return-to-Zero NTSC
National Television System Committee PAL
Phase Alternation Line PCR
Program Clock Reference PDH
Plesiosynchronic Digital Hierarchy PLL
Phase Lock Loop PMD
Physical Medium Dependent PSYNC
Packet Synchron QAM
Quadrature Amplitude Modulation QPSK
Quarternary Phase Shift Keying RB
Receiver Buffer RD
Running Disparity RIN
Relative Intrinsic Noise RJ
Random Jitter RS
Reed Solomon rx-clk
receiver clock SDH
Synchronous Digital Hierarchy SMPT
Society of Motion Picture and Television Engineers SPI
Synchronous Parallel Interface SSI
Synchronous Serial Interface SSI-C
Synchronous Serial Interface on coacial cable SSI-O
Synchronous Serial Interface on optical fiber TB
Transmission Buffer Tr
rise-time TS
Transport Stream tx-clk
transmission clock UNC
Unified National Coarse Thread
NOTE
Only the abbreviations used in the English version of this part of EN 50083 are mentioned in this subclause. The German and the French versions of this part may use other abbreviations. Refer to 3.2 of each language version for details.
4 Interfaces for MPEG-2 data signals 4.1 Introduction This subclause describes possible interfaces for devices transmitting or receiving MPEG-2 data as transport packets, such as QPSK demodulators, QAM modulators, multiplexers, demultiplexers, or telecom network adapters.
This specification is similar to EN 300 429 and EN 300 421.
NOTE
Both standards describe a first functional block representing the MPEG2 source coding and multiplexing as standardised in EN ISO/IEC 13818-1, a second functional block representing the channel adaptation, whereas an interface in between shall be based on MPEG2 transport stream specification as per EN ISO/IEC 13818-1.
The function of the channel modulator/demodulator is to adapt the signal to the characteristics of the transmission channel: satellite, terrestrial or cable as specified in the DVB base line documents.
Also the case where data signals are transmitted to or from a headend via a telecom network or if a headend serves to insert data signals into such networks is considered to be covered by the generic channel modulator / demodulator functional block. The interface parameters valid for this network have to be met. For the latter reference is made to ITU-T G.703 for Plesiochronic Digital Hierarchy (PDH) networks. 4.1.1
Application requirements In order to avoid any unnecessary processing at transmitting or receiving station of an interface in certain applications, it is considered an application requirement that the interface supports 204 byte packet length in such cases, in addition to or instead of the 188 packet lengthas specified in EN ISO/IEC 13818-1. These two cases are identified in the protocol diagrams of Figures 1 and 2 where also the scope of this specification is delineated. The relevant associated packet structures are illustrated in Figures 3 and 4.
transmission mediumlower protocollayersMPEG2 TS packet(188 bytes)
MPEG2 TSpacket (188bytes)optionalextra data(16 bytes)transmission mediumlower protocollayersConversion to204 byte packets
Figure 1 - Protocol stack for
Figure 2 - Protocol stack for
188 byte packets 204 byte packets
NOTE
Shaded areas identify the scope of this standard
187 databytes (MPEG2 TS packet)1Sync byte Figure 3 - Packet structure of 188 byte packet
1Sync byte187 databytes (MPEG2 TS packet) plus 16 extra
Figure 4 - Packet structure of 204 byte packet
4.1.2 Interfaces Three interfaces and two serial transmission media are specified as follows:
• SPI (Synchronous Parallel Interface); • SSI-C (Synchronous Serial Interface on coaxial cable); • SSI-O (Synchronous Serial Interface on optical fibre); • ASI-C (Asynchronous Serial Interface on coaxial cable); • ASI-O (Asynchronous Serial Interface on optical fibre).
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Each of these interfaces feature a BER such that FEC is not required for reliable data transport.
The synchronous parallel interface is specified to cover short or medium distances, i.e. for devices arranged near to each other. Subclause 4.2 describes the definitions for such a parallel interface derived from ITU-R Recommendation BT.656-4. Flags are provided to distinguish 188 byte packets from 204 byte packets, and to signal the existence of valid RS bytes. Note that the interface as such is transparent to the RS bytes.
The synchronous serial interface (SSI) which can be seen as an extension of the parallel interface, is briefly introduced in subclause 4.3 and described in detail in annexes A and D. The packet length and the existence of valid RS bytes are conveyed through suitable coding mechanisms.
Subclause 4.4 introduces the Asynchronous Serial Interface (ASI). Details of the ASI are provided in annexes B and E. The ASI is configurable to either convey 188 byte packets (which is mandatory) or optionally 204 byte packets.
4.1.3 Packet length and contents
Each of the interface specifications can be used to convey either 188 byte packets or 204 byte packets in order to enable selection of the appropriate interface characteristics dependent on the kind of equipment to be interconnected. Which packet sizes are mandatory and which are optional is specified in Table 1.
Table 1 - Mandatory and optional packet lengths
Data packet carrying capability Interface 188 bytes 204 bytes (with 16 dummy bytes) 204 bytes (with 16 RS bytes) SPI transmitter O M O
receiver M
M M SSI transmitter O M O
receiver M
M M ASI transmitter M O O
receiver M O O M
mandatory
O
optional
In case the data stream is packetised in 188 byte packets and the interface is configured to convey 204 byte packets, the extra packet length can be used for additional data. The contents of the 16 bytes in this extra packet length are not specified in this standard. One application could be the transmission of 16 RS bytes associated with the preceding transport package. 4.1.4 Compliance For an equipment to be compliant to this standard it is sufficient for the equipment to show at least one instance of at least one of the interface specifications as introduced in 4.1.2 and specified in detail in subsequent subclauses of this standard, while at least the mandatory packet sizes as indicated in 4.1.3 shall be supported. SIST EN 50083-9:2003
4.1.5 System integration The interfaces specified in this standard define physical connections between various pieces of equipment. It is important to notice that various parameters which are important for interoperation are not specified in this standard. This is intentional as it leaves maximum implementation flexibility for different applications. In order to facilitate system integration equipment suppliers shall provide the following information about the characteristics of the interfaces in their equipment:
• Interface type (SPI, SSI-C, SSI-O, ASI-C, ASI-O); • Supported packet length (188 bytes, 204 bytes, both); • Maximum input jitter (jitter measured as specified in EN ISO/IEC 13818-9); • Output jitter (jitter measured as specified in EN ISO/IEC 13818-9); • Minimum input data rate (rate measured as specified in EN ISO/IEC 13818-1); • Maximum input data rate (rate measured as specified in EN ISO/IEC 13818-1).
Some of these parameters may not be applicable to certain types of equipment. If all relevant parameters are provided by equipment suppliers, the proper functioning of the complete system can be ensured.
4.2 Synchronous parallel interface (SPI) This subclause describes an interface for a system for parallel transmission of variable data rates. The data transfer is synchronized to the byte clock of the data stream, which is the MPEG Transport Stream. Transmission links use LVDS technology, (for details concerning LVDS, see [2]) and
25 pin connections.
1811Data (0-7)ClockPSYNCTXRXDVALID
Figure 5 -
System for parallel transmission
The data to be transmitted are MPEG-2 Transport Packets with 188 or 204 bytes. In the case of the 204 byte packet format packets may contain a 16 bytes "empty space", a DVALID
Signal serves to identify these dummy bytes. A PSYNC flag labels the beginning of a packet. The data are synchronized to the clock depending on the transmission rate.
Equipment which implements the parallel interface shall support the three transmission formats as shown in Figures 6, 7 and 8.
4.2.1 Signal format The clock, data, and synchronization signals shall be transmitted in parallel: 8 data bits together with one (MPEG-2) PSYUNC singal and a DVALID signal which indicates in the 204 byte mode that the empty space is filled with dummy bytes. All signals are synchronous to the clock signal. The signals are coded in NRZ form. SIST EN 50083-9:2003
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syncPSYNC12186sync1187187Data (0-7)ClockDVALID
Figure 6 - Transmission format with 188 byte packets
syncPSYNC12186sync1187121616Data (0-7)ClockDVALID
Figure 7 - Transmission format with 204 byte packets (188 data bytes and 16 dummy bytes)
syncPSYNC12sync1203203202201Data (0-7)ClockDVALID
Figure 8 - Transmission format with RS-coded packets
(204 bytes; 188 data bytes and 16 valid extra bytes)
as specified in EN 300 421
Data (0-7):
Transport packet data word (8 bit: Data 0 to Data 7). Data 7 is the Most
Significant Bit (MSB).
DVALID:
active logic "1". Indicates valid data at the interface. It is constantly high in
the 188 byte mode. In the 204 byte mode a low logical state indicates not
to check the extra (dummy) bytes.
PSYNC: active logic "1". Indicates the beginning of a Transport Packet by
signalling the sync byte.
4.2.2 Clock signal
The clock is a square wave signal where the 0-1 transition represents the data transfer time. The clock frequency fp depends on the transmission rate.
• The Transport Packets are transmitted without insertion of additional bytes for RS coding or padding (packet length 188 bytes):
fp = fu / 8
• The Transport Packets are transmitted with insertion of additional bytes for RS coding or padding (packet length 204 bytes):
fp = (204 / 188) * fu / 8
The frequency fu corresponds to the useful bitrate Ru of the MPEG-2 transport layer. The clock frequency fp shall not exceed 13,5 MHz.
DataClocktdtTtiming reference for data and clock Figure 9 - Clock to data timing (at source)
Clock period:
Tfp=1 Clock pulse width: tTT=±210 Data hold time:
tTTd=±210
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4.2.3 Electrical characteristics of the interface
The interface employs eleven line drivers and eleven line receivers. Each line driver (source) has a balanced output and the corresponding line receiver (destination) a balanced input (see Figure 10). The line driver and receiver shall be LVDS-compatible, i.e. they shall permit the use of LVDS for their drivers or receivers. All digital signal time intervals are measured between the half-amplitude points.
Logic convention
The terminal A of the line driver is positive with respect to the terminal B for a binary 1 and negative for a binary 0 (see Figure 10).
SourceDestinationLinereceiverLinedriverTransmissionlineABA'B'Z
=t100 Ω Figure 10 - Line driver and line receiver interconnection
Line driver characteristics (source)
Output impedance:
100 Ω maximum Common mode voltage:
1,125 V to 1,375 V Signal amplitude:
247 mV to 454 mV Rise and fall times:
less than T / 7, measured between the 20% and 80%
amplitude points, with a 100 Ω resistive load. The difference
between rise and fall times shall not exceed T / 20.
Line receiver characteristics (destination)
Input impedance:
90 Ω to 132 Ω Maximum input signal: 2,0 V peak to peak Minimum input signal: 100 mV peak to peak
However, the line receiver shall sense correctly the binary data when a random data signal produces the conditions represented by the eye diagramme in Figure 11 at the data detection point.
Maximum common mode signal: ± 0,5 V, comprising interference in the range of 0 to 15 kHz (both terminals to ground).
Differential delay: Data shall be correctly sensed when the clock-to-data differential delay is in the range between ± T / 3 (see Figure 11). UminTminTminreference transition of clock Tmin =
T / 3,
Umin = 100 mV
Figure 11 - Idealized eye diagramme corresponding to the
minimum input signal level
4.2.4 Mechanical details of the connector
The interface uses the 25 contact type D subminiature connector specified in ISO 2110 with the contact assignment shown in Table 2.
Connectors are locked together with screw lock, with male screws on the cable connector and a female threaded posts on the equipment connector. The threads are of type UNC 4-40 [3]. Cable connectors employ pin contacts and equipment connectors employ socket contacts. Shielding of the interconnecting cable and its connectors shall be employed.
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Table 2 - Contact assignment of 25 contact type D subminiature connector
(ISO 2110)
Pin Signal line Pin Signal line
1 2 3 4 5 6 7 8 9 10 11 12 13 Clock A System Gnd Data 7 A(MSB) Data 6 A Data 5 A Data 4 A Data 3 A Data 2 A Data 1 A Data 0 A DVALID A PSYNC A Cable Shield 14 15 16 17 18 19 20 21 22 23 24 25 Clock B System Gnd Data 7 B Data 6 B Data 5 B Data 4 B Data 3 B Data 2 B Data 1 B Data 0 B DVALID B PSYNC B
4.3 Synchronous Serial Interface (SSI)
The Synchronous Serial Interface (SSI) can be seen as the extension of the parallel interface by means of an adaptation of the parallel format. SSI is synchronous to the Transport Stream which is transmitted on the serial link.
A detailed specification of the SSI is provided in annex A and guidelines for its implementation are provided in annex D.
4.4 Asynchronous Serial Interface (ASI)
The Asynchronous Serial Interface (ASI) is a serial link operating at a fixed line clock rate.
A detailed specification of ASI is provided in normative annex B. Implementation guidelines and deriving clocks from the MPEG-2 packets for ASI are provided in informative annex E. Guidelines for the implementation and usage of ASI are laid down in informative annex F.
Annex A
(normative)
Synchronous Serial Interface (SSI)
This annex describes a system for serial, encoded transmission of different data rates with a transmission rate equal to the data rate. It is based on a layered structure of MPEG-2 Transport Packets as a top layer (Layer-2), and a pair of bottom layers attached to physical and coding aspects (Layer-0 and Layer-1).
The SSI is based on a line rate directly locked to the transport rate. The SSI is functionally equivalent to the parallel interface since the Transport Packets can be transmitted either contiguously or separated by 16 bytes reserved for dummy bytes or extra bytes. Because the link and the TS are synchronous, the bit justification operation is not needed. The system shall be designed to fulfil the high stability requirements of the modulator clocks, even when several links are cascaded.
As an example, consider a signal which passes through several re-broadcast steps, such as the one depicted in Figure A.1.
In this chain, the last clock (that of the QAM modulator) is slaved to the encoder/mux clock via four
steps of clock regeneration circuits.
M U XPDH SDHR EM U XQAMInterfaces pointsQPSK MODQPSK DEMODQAMMODREMUXNETWORK ADAPTERMUX
Figure A.1 - Example of cascaded interfaces
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A.1 SSI transmission system overview
Figures A.2 and A.3 represent the primary components of this SSI method over copper coaxial cable and fibre-optic cable, respectively.
Figure A.2 - Coaxial cable-based synchronous serial transmission link (SSI type)
Figure A.3 - Fibre-optic-based synchronous serial transmission link (SSI type)
The main functions of the transmission system are described below.
Emission path
Data to be transmitted are presented in byte-synchronized form as MPEG-2 Transport Packets. The Transport Stream is then passed through a parallel-to-serial converter. The line data stream is locked to the TS data stream.
The serial signal is Biphase Mark encoded.
Fibre-OpticCable Continuous Byte-Synchronous Continuous Byte-Synchronous MPEG-2 TS Layer-1
Layer-0Layer-2 Parallel/Serial Conversion Biphase
Coding Amplifier/ Buffer Connector Serial/Parallel Conversion Amplifier/ Buffer Connector Optical Emitter Optical Receiver Clock Recovery BiphaseCoaxial Cable Continuous Byte-Synchronous Continuous Byte-Synchronous MPEG-2 TS Layer-1
Layer-0Layer-2 Parallel/Serial Conversion Biphase
Coding Amplifier/ Buffer Coupling/ Impedance Matching Connector Serial/Parallel Conversion Amplifier/ Buffer Coupling/ Impedance Matching Connector Clock Recovery BiphaseSIST EN 50083-9:2003
In the case of a coaxial cable application, the resulting signal is typically passed to a buffer/ driver circuit and then through a coupling network, which performs impedance matching and optionally galvanic isolation, to a coaxial connector. In the case of fibre-optic application, the serial bit stream is passed through a driver circuit which drives an optical transmitter (LED or LASER) which is coupled to a fibre-optic cable through a connector.
Reception path
The incoming data stream from the coaxial cable is first coupled through a connector and coupling network to a circuit which recovers clock and data. In case of fibre-optic transmission, a light sensitive detector converts light levels to electrical levels which then are passed to a clock and data recovery circuit.
Once the clock and data are recovered, the bit stream is passed to a Biphase Mark decoder. In order to recover byte alignment, a decoder searches in the serial stream for the synchronization word which is necessary to achieve the serial to parallel conversion.
Annex D provides further clarification of the characteristics of the SSI and implementation guidelines for clock and data recovery.
A.2 SSI configuration
A SSI interconnection physically consists of two nodes: a transmitting node and a receiving node. This unidirectional optical fibre or copper coaxial cable carrying data from the transmitting node to the receiving node is referred to as a link. The link is used by the interconnected ports to perform communication. Physical equipment such as video or audio compressors, multiplexers, modulators, etc., can be interconnected through these links. This SSI specification clause applies only to the point-to-point type link.
A.3 SSI protocol architecture description
The SSI protocol is divided into three architectural layers for purposes of development of the standard: Layer-0, Layer-1, Layer-2.
A.3.1 Layer-0: Physical requirements
The physical layer defines the transmission media, the drivers and receivers. The transmission uses Biphase Mark encoding.
This subclause provides specifications for SSI physical layer (Layer-0). Interfaces for coaxial and optical fibre applications are specified. The links are unidirectional point to point.
A.3.1.1 Coaxial cable Physical Medium Dependent (PMD) requirement
The nominal cable impedance shall be 75 Ω.
Considering that the transmission data rate is derived from the user data rate, longer links can be achieved for lower user data rates. The physical medium specified in this subclause has the following characteristics:
- Provides a means of coupling the SSI Layer-1 to the coaxial cable segment - Provides the driving of coaxial cable between a transmitter and a receiver - Specifies the type and grade of cable and connectors to be used in a synchronous
serial interface link.
- 21 - EN 50083-9: 2002
Electrical medium connector
The required connector shall have mechanical characteristics conforming to the BNC type.
NOTE
Due to its higher mechanical stability a 50 Ω BNC type connector according to IEC 60169-8 is recommended.
The electrical characteristics of the connector shall permit it to be used over the frequency range of the specified interface.
The following Table A.1 and Figures A.4 and A.5 give the requirements for the serial signal launched synchronously on the coaxial cable.
Table A.1 - Transmitter output characteristics
Pulse shape Conforming to masks shown in Figures A.4 and A.5. Peak to peak voltage 1 V ± 0,1 V Rise/fall time (10-90%) ≤ 4 ns Transition timing tolerance (referred to the mean value of the 50% amplitude points of negative transition) Negative transition:
± 0,2 ns Positive transition at unit interval boundaries: ± 1 ns Positive transition at mid interval:
± 0,7 ns Return loss (75 Ω) - 15 dB over frequency range 3,5 MHz to 105 MHz Maximum peak-to peak jitter at the output port 2 ns
The digital signal presented at the input port shall conform to Table A.2 and Figures A.4 and A.5 modified by the characteristics of the interconnecting coaxial pair. The attenuation of the coaxial pair shall be assumed to follow an approximate f law. The cable shall have a maximum insertion loss of 12 dB at a frequency of 70 MHz.
Table A.2 - Receiver input characteristics
Maximum attenuation at a frequency of 70 MHz assuming a f law - 12 dB Maximum peak to peak jitter at the input port 4 ns Return loss (75 Ω) - 15 dB over frequency range
3,5 MHz to 105 MHz
- 0,60- 0,55- 0,50- 0,45- 0,40 0,60 0,55 0,50 0,45 0,40NegativetransitionPositivetransition2,7 ns2,7 nsNominalzero levelVNominal pulseT2 ns2 ns0,2 ns0,2 ns1 ns1 ns2 ns2 ns(NOTE 1)(NOTE 1)(NOTE 1) 0,05- 0,05/4T/4T/2T/2T
NOTE 1
The maximum “steady state” amplitude should not exceed the 0,55 V limit. Overshoots and other transients are permitted to fall into the dotted area, bounded by the amplitude levels 0,55 V and 0,6 V, provided that they do not exceed the steady state level by more than 0,05 V. The possibility of relaxing the amount by which the overshoot may exceed the steady state level is under study.
NOTE 2
For all measurements using these masks, the signal should be AC coupled, using a capacitor of not less than 0,02 µF (for data rate = 70 Mbit/s), to the input of the oscilloscope used for measurements.
The nominal zero level for both masks should be aligned with the oscilloscope trace with no input signal. With the signal then applied, the vertical position of the trace can be adjusted with the objective of meeting the limits of the masks. Any such adjustment should be the same for both masks and should not exceed ± 0,05 V. This may be checked by removing the input signal again and verifying that the trace lies within ± 0,05 V of the nominal zero level of the masks.
NOTE 3
Each pulse in a coded pulse sequence should meet the limits of the relevant mask, irrespective of the state of the preceding or succeeding pulses, with both pulse masks fixed in the same relation to a common timing reference, i.e. with their nominal start and finish edges coincident. The masks allow for HF jitter present in the timing signal associated with the source of interface signal
When using an oscilloscope technique to determine pulse compliance with the mask, it is important that successive traces of the pulses overlay in order to suppress the effects of low frequency jitter. This can be accomplished by several techniques [such as a) triggering the oscilloscope on the measured waveform or b) providing both the oscilloscope and the pulse output circuits with the same clock signal]. These techniques require further study.
NOTE 4
For the purpose of these masks, the rise time and delay time should be measured
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