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This standard is developed in accordance with the rules given in GB/T 1.1-2009
This standard supersedes GB/T 26683-2011 General Specification for Digital Terrestrial Set-Top Box. Besides editorial changes, this standard technically differs from GB/T 26683-2011 mainly as follows:
——"Symbols" are added to “Terms, Definitions, Symbols and Abbreviations” (see 3.2);
——"working mode 8", "working mode 9" and "working mode 10" are added to the requirements of RF demodulation and channel decoding;
——In relation to RF demodulation and channel decoding requirements, "Suppression of Two-Path Echo" (see 5.2.16), "Suppression of Three-Path Echo" (see 5.2.17), "Suppression 1 of Channel Disturbance under Fixed Receiving Conditions" (see 5.2.18), "Suppression 2 of Channel Disturbance under Fixed Receiving Conditions" (see 5.2.19), "Suppression of Single Frequency Interference" (see 5.2.20) and "Other Multiple-Path Model" (see 5.2.21) are added;
——In relation to video decoding characteristic, the requirement that "the set-top box shall be able to decode the code stream with the frame rate of 25Hz and aspect ratio of 4: 3 or 16: 9 as specified in GB/T 20090.2-2006" (see 5.3.2.1 of Edition 2011) is deleted; "the set-top box shall decode the code streams that correspond to the frame frequency of 25 Hz and pixel aspect ratios 4:3 and 16:9 as specified in GB/T 20090.16 and shall comply with SJ/T 11594.1-2016" and "the set-top box may normally decode the video streams as specified in other mainstream video encoding standards" are added (see 5.3.2.1);
——In relation to audio decoding characteristic, the requirement that "set-top box shall have the function of decoding layer MPEG -1 in GB/T 17975.3- 2002 or the digital audio stream specified in GB/T 22726-2008, and may have the function of decoding digital audio stream or other digital audio stream specified in ETSI TS 102 366" (see 5.3.2.2 of Edition 2011) is deleted; "the set-top box shall decode the digital audio streams that correspond to GB/T 22726 and shall comply with SJ/T 11594.2-2016" and "the set-top box may normally decode the audio streams as specified in other mainstream audio encoding standards" (see 5.3.2.2) are added;
——"Conditional access" (see 5.3.6 of Edition 2011) is deleted;
——"Digital Content Protection Requirements" (see 5.4 of Edition 2011) is deleted;
——Appendix G (Informative) Conditional Access Interface (see Appendix G of Edition 2011) is deleted;
——Annex B (Informative) (see Annex B), Annex C (Normative) Multipath Channel Model (See Annex C), Annex D (Informative) Other Multipath Channel Model (see Annex D) are added.
Attention is drawn to the possibility that some of the content of this standard may be the subject of patent rights. The issuing body of this document shall not be held responsible for identifying any or all such patent rights.
This standard was proposed by the Ministry of Industry and Information Technology of the People's Republic of China.
This standard is under the jurisdiction of the Technical Committee for Standardization of Audio, Video and Multimedia Systems and Equipment (SAC/TC 242).
The previous edition of the standard replaced by this standard is as follows:
——GB/T 26683-2011.
General Specification for
Digital Terrestrial Set-Top Box
1 Scope
This standard specifies function and performance requirements, measuring methods, inspection rules, marking, packaging, transportation and storage for the digital terrestrial set-top boxes (hereinafter referred to as "set-top boxes") supporting the digital terrestrial television receiving function as specified in GB 20600-2006.
This standard is applicable to digital terrestrial set-top boxes and is the main basis for product design, production type approval and inspections.
2 Normative References
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 191 Packaging - Pictorial Marking for Handling of Goods
GB/T 2312-1980 Code of Chinese Graphic Character Set for Information Interchange—Primary Set
GB/T 2828.1-2012 Sampling Procedures for Inspection by Attribute—Part1: Sampling Schemes Indexed by Acceptance Quality Limit (AQL) for Lot-by-lot Inspection
GB/T 2829-2002 Sampling Procedures and Tables for Periodic Inspection by Attributes (Apply to Inspection of Process Stability)
GB/T 5465.2 Graphical Symbols for Use on Electrical Equipment—Part 2: Graphical Symbols
GB 8898 Audio, Video and Similar Electronic Apparatus—Safety Requirements
GB/T 9383 Sound and Television Broadcast Receivers and Associated Equipment—Immunity Characteristics—Limits and Methods of Measurement
GB/T 13000-2010 Information Technology—Universal Multiple-Octet Coded Character Set (UCS)
GB/T 13837 Sound and Television Broadcast Receivers and Associated Equipment—Radio Disturbance Characteristics—Limits and Methods of Measurement
GB/T 14960-1994 Technical Requirements and Methods of Measurement of Infrared Remote Control Radiation Unit for Television Broadcast Receivers
GB 17625.1 Electromagnetic Compatibility-Limits—Limits for Harmonic Current Emissions (Equipment Input Current ≤16A per Phase)
GB/T 17975.1 Information Technology - Generic Coding of Moving Pictures and Associated Audio Information—Part 1: System
GB/T 20090.16 Information Technology—Advanced Coding of Audio and Video—Part 16: Broadcasting Video
GB 20600-2006 Framing Structure, Channel Coding, and Modulation for Digital Television Terrestrial Broadcasting System (DTMB)
GB/T 22122-2008 Methods of Measurement of Surround Audio for Digital TV
GB/T 22726 Specification for Multichannel Digital Audio Coding Technology
GB 25957 Minimum Allowable Values of Energy Efficiency and Energy Efficiency Grades for Digital Television Adapters (Set-Top Boxes)
GB/T 26684-2017 Methods of Measurement for Digital Terrestrial Set-top Box
GB/T 26685-2017 Methods of Measurement for Digital Terrestrial Set-top Box
GB/T 26686-2017 General Specification for Digital Terrestrial Set-top Box
GB/T 28160-2011 Specification of Electronic Programme Guide for Digital Television Broadcasting
SJ/T 10514-1994 Technical Requirements and Methods of Measurement on Infrared Remote Control Unit for Television Broadcast Receivers
SJ/T 10919-1996 Packaging of Color Broadcasting TV Receivers
SJ/T 11324-2006 Terminology of Digital Television Receiving Equipment
SJ/T 11325-2006 Reliability Test Methods for Digital Television Receiver and Display Equipment
SJ/T 11326 Environmental Testing Methods for Digital Television Receiver and Display Equipment
SJ/T 11327-2006 Specification of Interfaces for Digital Television Receiving Equipment—Part 1: Interface of Radio Frequency
SJ/T 11329-2006 Specification of Interfaces for Digital Television Receiving Equipment—Part 3: Video Interface of Composite Video Blanking Synchronization
SJ/T 11330-2006 Specification of Interfaces for Digital Television Receiving Equipment—Part 4: Video Interface of S-Video
SJ/T 11331-2006 Specification of Interfaces for Digital Television Receiving Equipment—Part 5: Analog Audio Interface
SJ/T 11332-2006 Specification of Interfaces for Digital Television Receiving Equipment—Part 6: Analog Video Interface of RGB
SJ/T 11333-2006 Specification of Interfaces for Digital Television Receiving Equipment—Part 7: Interface of Video Component YPBPR
SJ/T 11594.1-2016 Technical Requirements and Measuring Methods for Audio and Video Decoding of Digital TV Receiving Terminal—Part 1: Video (AVS+)
SJ/T 11594.2-2016 Technical Requirements and Measuring Methods for Audio and Video Decoding of Digital TV Receiving Terminal—Part 2: Audio (DRA)
3 Terms, Definitions, Symbols and Abbreviations
3.1 Terms and Definitions
For the purpose of this standard, the terms and definitions established in SJ/T 11324-2006 and the following ones apply.
3.1.1
acceptable error free
a threshold of maximum uncorrected error events within the specified time while receiving signals
3.2 Symbols
tD,MAX: the maximum delay of 0dB echo withstandable to set-top box as specified hereby
3.3 Abbreviations
For the purposes of this standard, the following abbreviations apply.
AEF: Acceptable Error Free
C/N: Carrier-Noise ratio
ECM: Entitlement Control Message
EIT: Event Information Table
EIT p/f: EIT present/following
EMM: Entitlement Management Message
EPG: Electronic Program Guide
FS: Full Scale
HDTV: High Definition Television
LFE: Low Frequency Enhancement
MPEG: Moving Picture Experts Group
PID: Packet Identifier
PSI: Program Specific Information
QAM: Quadrature Amplitude Modulation
RF: Radio Frequency
SDTV: Standard Definition Television
SI: Service Information
UHF: Ultra High Frequency
VHF: Very High Frequency
Y/C: Luminance/Chrominance
4 General Requirements
4.1 Normal Service Conditions
Normal service conditions shall meet the following requirements:
Ambient temperature: 5℃~35℃;
Relative humidity: 25%~80%;
Atmospheric pressure: 86 kPa~106 kPa
Power supply: 220 V , [50×(1±2%)]Hz.
4.2 Graphical Symbols for Use on Equipment
Graphical symbols shall comply with the relevant requirements of GB/T 5465.2.
The graphical symbols that are not defined in GB/T 5465.2 are specified in product specification.
4.3 Appearance and Structural Requirements
Set-top boxes shall have tidy appearance, their surfaces shall be free from such defects as concave and convex marks, scratch, crack, burr and mold stain, and the surface coating shall be free from blistering, cracking or shedding, etc.
Metal parts shall be free from rust and other mechanical damages, and the potting compounds shall not spill over.
The operation of switches, keys and knobs shall be flexible and reliable, the parts and components shall be fastened without looseness. The integral machine shall have sufficient mechanical stability.
The text stating the functions and the marking of graphical symbols shall be correct, legible, right and firm, and the indication shall be correct.
4.4 Interface Requirements
See Table 1 for interface requirements.
Table 1
No. Interface type Requirement Technical requirement of interface
1 RF input Compulsory Comply with SJ/T 11327-2006.
2 RF loop output Optional Comply with SJ/T 11327-2006.
3 Composite video signal output Compulsory Comply with SJ/T 11329-2006.
Y/C output Optional Comply with SJ/T 11330-2006.
Y, PB and PR outputs HDTV compulsory; SDTV optional Comply with SJ/T 11333-2006.
R, G and B outputs Optional Comply with SJ/T 11332-2006.
4 Audio output (double-channel) Compulsory Comply with SJ/T 11331-2006.
5 D-subminiature 15-pin VGA output Optional Comply with SJ/T 11332-2006.
6 Digital video interface Optional To be determined
7 Digital audio interface Optional To be determined
5 Technical Requirements
5.1 General
The functional block diagram of digital terrestrial set-top box is as shown in Figure 1.
The digital terrestrial set-top box completes the conversion from radio-frequency signal input to terminal audio and video signals. Input radio-frequency signals, after demodulation and channel decoding, delivers the output transport stream to demultiplexing module for demultiplexing and, at the same time, outputs information, e.g. service information/program specific information (SI/PSI), electronic program guide (EPG), while output elementary stream is delivered to audio/video decoding module and then to baseband audio/video output.
Figure 1
5.2 Requirements of RF Demodulation and Channel Decoding
5.2.1 General
The performance requirements and functional requirements specified in this article refer to those in the case of acceptable error free (AEF). See Annex A for AEF requirements.
5.2.2 Frequency
5.2.2.1 Frequency range
The set-top box shall be able to receive radio-frequency signal on all channels in very high frequency (VHF) and ultra high frequency (UHF) bands. See Annex B for the frequency allocations of VHF and UHF bands.
5.2.2.2 Signal bandwidth
Each channel bandwidth is 8 MHz.
5.2.2.3 Frequency entrainment range
The set-top box shall be able to receive radio-frequency signals with frequency offset not exceeding ±150 kHz.
5.2.3 Working mode
The set-top box shall be able to receive and correctly demodulate at least the working mode 1~working mode 7 listed in Table 2. The set-top box applied in Single Frequency Network shall also support working mode 8~working mode 10.In this standard, the requirements of performance parameters are specified based on the modes listed in Table 2.
Foreword i
1 Scope
2 Normative References
3 Terms, Definitions, Symbols and Abbreviations
3.1 Terms and Definitions
3.2 Symbols
3.3 Abbreviations
4 General Requirements
4.1 Normal Service Conditions
4.2 Graphical Symbols for Use on Equipment
4.3 Appearance and Structural Requirements
4.4 Interface Requirements
5 Technical Requirements
5.1 General
5.2 Requirements of RF Demodulation and Channel Decoding
5.3 Decoding Requirements of Transport Stream
5.4 Performance Requirements of Baseband Video Output
5.5 Performance Requirements of Baseband Audio Output
5.6 Performance Requirements of Digital Audio Output
5.7 Functional Requirements
5.8 Performance Requirements of Remote Control and Remote-Control Transmitter
5.9 Power Supply Adaptability Requirements
5.10 Limit of Electromagnetic Compatibility
5.11 Safety Requirements
5.12 Reliability Requirements
5.13 Environment Test Requirements
5.14 Unpacking Inspection Requirements
5.15 Technological Assembly Inspection Requirements
6 Measuring Methods
6.1 Graphical Symbols for Use on Equipment, Appearance and Structure, Interface Inspections methods
6.2 Measuring Methods for RF Demodulation and Channel Decoding
6.3 Measuring Methods for Transport Stream Decoding Characteristics
6.4 Baseband Video Output Characteristic
6.5 Baseband Audio Output Characteristic
6.6 Digital Audio Output Performance
6.7 Function
6.8 Remote Performance and Remote Transmitter
6.9 Power Supply Adaptability
6.10 Limit of Electromagnetic Compatibility
6.11 Safety Inspection Method
6.12 Reliability Test Method
6.13 Environmental Test Method
6.14 Unpacking Inspection Method
6.15 Technological Assembly Inspection Method
7 Inspection Rules
7.1 Type Inspection
7.2 Acceptance Inspection
7.3 Routine Inspection
8 Marking, Packing, Transport and Storage
8.1 Marking
8.2 Packing
8.3 Transport
8.4 Storage
Annex A (Normative) Acceptable Error Free
Annex B (Informative) VHF and UHF Frequency Band Division of Radio & Television
Annex C (Normative) Multipath Channel Model
Annex D (Informative) Other Multipath Channel Model
Annex E (Informative) Function of Remote Transmitter
Annex F (Normative) Contents and Rejection Criteria of Unpacking Inspection
Annex G (Normative) Contents and Rejection Criteria of Technological Assembly Inspection
Annex H (Normative) Contents and Rejection Criteria of Performance Test at Normal Temperature
Annex I (Normative) Contents and Rejection Criteria of Environment Test
