• Title/Summary/Keyword: Advanced television systems committee

Search Result 70, Processing Time 0.02 seconds

An Interference Canceller-based Digital On-Channel Repeater to Improve Feedback Channel Estimation and RFP Performance (귀환 채널 추정 및 RFP 성능을 개선한 간섭 제거 기반의 동일 채널 중계기)

  • Choi, Soocheol;Cho, Kiryang
    • Journal of Broadcast Engineering
    • /
    • v.21 no.2
    • /
    • pp.261-267
    • /
    • 2016
  • In this paper, Method for the phase distortion compensation timing offset and DC eliminator for the pilot component estimation and removal, transmitted and received signal correlation in the delay scheme DAB interference cancellation based on the same channel for using for estimating the feedback signal based on a between for removal for the timing offset compensation It proposes a repeater. This was applied to the ATSC system. The on-channel repeater of the proposed interference cancellation based on the interference removing capability is improved in interference signal is 20dB greater than the primary transmission signal environment via the return channel estimation and improve performance RFP. Accordingly, it was confirmed by simulation that good signal is sent out with the improvement of the ability of the repeater.

Design of Synchronization and T-STD Model for 3DTV Service over Hybrid Networks

  • Yun, Kugjin;Cheong, Won-Sik;Lee, Gwangsoon;Li, Xiaorui;Kim, Kyuheon
    • ETRI Journal
    • /
    • v.38 no.5
    • /
    • pp.838-846
    • /
    • 2016
  • The objective of digital broadcasting has evolved from providing a plain video service to offering a realistic visual experience. Technologies such as 3DTV and UHDTV have been suggested to achieve this new objective by providing an immersive and stereoscopic visual experience. However, owing to the high bandwidth requirements of such services, the broadcasting industry has faced a challenge to find a new transport mechanism for overcoming the bandwidth limitation. The standardization organizations, the Advanced Television Systems Committee, Digital Video Broadcasting, and Telecommunications Technology Association, have been working on the integration of broadcasting and a broadband network (IP) to resolve the bandwidth issue of realistic video services. This paper introduces a frame-level timeline synchronization and transport system target decoder model for providing a stable 3DTV service over a hybrid network. The experimental results indicate that the proposed technologies can be successfully adopted as a reference model in a broadcast-broadband hybrid 3DTV service and other IP-associated hybrid broadcasting services.

Effective identification of dominant fully absorbing sets for Raptor-like LDPC codes

  • Woncheol Cho;Chanho Yoon;Kapseok Chang;Young-Jo Ko
    • ETRI Journal
    • /
    • v.45 no.1
    • /
    • pp.7-17
    • /
    • 2023
  • The error-rate floor of low-density parity-check (LDPC) codes is attributed to the trapping sets of their Tanner graphs. Among them, fully absorbing sets dominantly affect the error-rate performance, especially for short blocklengths. Efficient methods to identify the dominant trapping sets of LDPC codes were thoroughly researched as exhaustively searching them is NP-hard. However, the existing methods are ineffective for Raptor-like LDPC codes, which have many types of trapping sets. An effective method to identify dominant fully absorbing sets of Raptor-like LDPC codes is proposed. The search space of the proposed algorithm is optimized into the Tanner subgraphs of the codes to afford time-efficiency and search-effectiveness. For 5G New Radio (NR) base graph (BG) 2 LDPC codes for short blocklengths, the proposed algorithm finds more dominant fully absorbing sets within one seventh of the computation time of the existing search algorithm, and its search-effectiveness is verified using importance sampling. The proposed method is also applied to 5G NR BG1 LDPC code and Advanced Television Systems Committee 3.0 type A LDPC code for large blocklengths.

Method of Delivering DASH Segments based on MMTP for Re-use of DASH Contents under MMT Broadcasting Environment (방송을 위한 MMT 환경에서의 DASH 콘텐츠 사용을 위한 MMTP 기반 DASH segment 전송 방안)

  • An, Hyomin;Kang, Dongjin;Kim, Kyuheon
    • Journal of Broadcast Engineering
    • /
    • v.22 no.5
    • /
    • pp.548-559
    • /
    • 2017
  • Recently, various high-quality AV services such as UHDTV have begun to increase as broadcasting technology evolves, and various broadcasting standards have been defined. Among the various broadcasting standards, there are representative delivery technologies which are DASH/ROUTE and MMTP. DASH/ROUTE and MMTP are adopted as delivery standards for UHD broadcasting in south Korea, currently. DASH segment and MPU are segmented units including media data, which are delivered via DASH/ROUTE and MMTP, respectively. In this paper, we analyzed structure of DASH segment and MPU and propose a verification system which enables converting DASH segments to MPUs and delivering them via MMTP.

Performance Improvement of Frequency Synchronization in ATSC DTV System using Signal Power at Both Edges of Spectrum (ATSC DTV 시스템에서 스펙트럼 양끝의 신호전력을 이용한 주파수 동기 성능 개선)

  • Song Hyun Keun;Lee Joo Hyung;Kim Jae Moung;Eum Ho Min;Kim Seung Won
    • Journal of Broadcast Engineering
    • /
    • v.10 no.1 s.26
    • /
    • pp.31-42
    • /
    • 2005
  • ATSC DTV system uses FPLL block for acquiring the frequency synchronization. Because the FPLL uses only the pilot signal, the frequency convergence range becomes narrower and it takes a more time to acquire the frequency synchronization as the pilot is distorted. And the spectrum shape around the pilot makes an asymmetric convergence range between the positive frequency offset and the negative frequency offset. This paper proposes the algorithm that requires the Installation of the fitters at the both edges of a VSB spectrum and uses the signal power that passes these filters. The proposed algorithm complements the problems of the asymmetric convergence range and overcomes the performance degradation due to the distortion of a pilot level.

Performance Improvement of Terrestrial DTV Receivers Using Frequency-domain Equalization (주파수 영역 등화를 이용한 지상파 DTV 수신 성능 개선)

  • Son Sang-Won;Kim Ji-Hyun;Kim Hyoung-Nam
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.31 no.4C
    • /
    • pp.351-363
    • /
    • 2006
  • The 8-VSB modulation, the transmission standard for the terrestrial digital television(DTV) of the Advanced Television Systems Committee(ATSC), suffers from multipath fading because it conveys information on the amplitude. To solve this problem, decision feedback equalizers(DFE's) have been commonly used in terrestrial DTV receivers. However, under severe channels, such as a 0 dB ghost channel or a single frequency network (SFN) channel, the DFE shows unstable convergence due to the error propagation caused by decision errors. Instead of unstable time-domain DFE schemes, by proposing a frequency-domain direct-inversion equalization method, we try to guarantee stable equalization and achieve low symbol error rates. To secure the existence of a channel inverse, channel-matched filtering and noncausal filtering are carried out prior to equalization. Simulation results show that the proposed method performs much better than existing DFE schemes in terms of both the stability and the symbol error rate.

Blind Decision Feedback Equalizer with a Modified Trellis Decoder for ATSC DTV Receivers (ATSC DTV 수신기를 위해 변형된 트렐리스 복호기를 사용하는 블라인드 판정 궤환 등화기)

  • 박성익;김형남;김승원;이수인
    • Journal of Broadcast Engineering
    • /
    • v.8 no.4
    • /
    • pp.481-491
    • /
    • 2003
  • We present a near-optimal blind decision feedback equalizer (DFE) for Advanced Television Systems Committee digital television (DTV) receivers. By adopting a modified trellis decoder (MTD) with trace back depth of 1 for the decision device In the DFE, we obtain a hardware-efficient near-optimal blind DFE approaching to the optimal DFE which has no error propagation. The MTD uses absolute distance instead of Euclidean distance for computation of a path metric, resulting. In reduced computational complexity. Comparing to the conventional slicer, the MTD shows outstanding performance improvement of decision error probability and is comparable to the original trellis decoder using Euclidean distance. Reducing error propagation in the DFE leads to the improvement of convergence performance in terms of convergence speed and residual error. Simulation results show that the proposed blind DFE performs much better than the blind DFE with the slicer.

The Development of Multimedia Player Platform for Terrestrial Digital Multimedia Broadcasting (DMB) (지상파 이동 멀티미디어방송용 멀티미디어 재생기 개발)

  • 기명석;서정일;강경옥
    • Journal of Broadcast Engineering
    • /
    • v.8 no.4
    • /
    • pp.465-472
    • /
    • 2003
  • In this paper we propose the structure of MPEG-4 multimedia player platform for Terrestrial Digital Multimedia Broadcasting (DMB) Service. Korea will launch DMB service at next 2004 you based on Eureka-147 Digital Audio Broadcasting (DAB) Service System. This new mobile multimedia broadcasting services provide not only high quality digital audio broadcasting services, but also various multimedia data broadcasting services including high quality video. For the sake of MPEG-4 Systems technologies, it will provide an interactive service to users in the near future. Therefore it terminal shall have various functionalities as well as playing audio-visual contents. However there is no precedence standard for such mobile interactive multimedia broadcasting system. Therefore it is very import to provide the multimedia player platform of DMB service for accelerating the development process of commercial terminal and providing a direction of next DMB terminal structure.

Design of white tandem organic light-emitting diodes for full-color microdisplay with high current efficiency and high color gamut

  • Cho, Hyunsu;Joo, Chul Woong;Choi, Sukyung;Kang, Chan-mo;Kim, Gi Heon;Shin, Jin-Wook;Kwon, Byoung-Hwa;Lee, Hyunkoo;Byun, Chun-Won;Cho, Nam Sung
    • ETRI Journal
    • /
    • v.43 no.6
    • /
    • pp.1093-1102
    • /
    • 2021
  • Microdisplays based on organic light-emitting diodes (OLEDs) have a small form factor, and this can be a great advantage when applied to augmented reality and virtual reality devices. In addition, a high-resolution microdisplay of 3000 ppi or more can be achieved when applying a white OLED structure and a color filter. However, low luminance is the weakness of an OLED-based microdisplay as compared with other microdisplay technologies. By applying a tandem structure consisting of two separate emission layers, the efficiency of the OLED device is increased, and higher luminance can be achieved. The efficiency and white spectrum of the OLED device are affected by the position of the emitting layer in the tandem structure and calculated via optical simulation. Each white OLED device with optimized efficiency is fabricated according to the position of the emitting layer, and red, green, and blue spectrum and efficiency are confirmed after passing through color filters. The optimized white OLED device with color filters reaches 97.8% of the National Television Standards Committee standard.

Recent Developments in Space Law (우주법(宇宙法)의 최근동향(最近動向))

  • Choi, June-Sun
    • The Korean Journal of Air & Space Law and Policy
    • /
    • v.1
    • /
    • pp.223-243
    • /
    • 1989
  • The practical application of modern space science and technology have resulted in many actual and potential gains of mankind. These successes have conditioned and increased the need for a viable space law regime and the challenge of space has ultimately led to the formation of an international legal regime for space. Space law is no longer a primitive law. It is a modern law. Yet, in its stages of growth, it has not reached the condition of perfection. Therefore, under the existing state of thing, we could carefully say that the space law is one of the most newest fields of jurisprudence despite the fact that no one has so far defined it perfectly. However, if space law can be a true jurisprudential entity, it must be definable. In defining the space law, first of all, the grasp of it's nature iis inevitable. Although space law encompasses many tenets and facets of other legal discriplines, its principal nature is public international law, because space law affects and effects law relating intercourse among nations. Since early 1960s when mankind was first able to flight and stay in outer space, the necessity to control and administrate the space activities of human beings has growingly increased. The leading law-formulating agency to this purpose is the United Nation's ad hoc Committee on Peaceful Uses of Outer Space("COPUOS"). COPUOS gave direction to public international space law by establishing the 1963 Declaration of Legal Principles Governing the Activities of the States in the Exploration and Use of Outer Space("1963 Declaration"). The 1963 Declaration is very foundation of the five international multilateral treaties that were established successively after the 1963 Declaration. The five treaties are as follows: 1) The Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space including Moon and other Celestial Bodies, 1967. 2) The Agreement on the Rescue of Astronauts, the Return of Astronauts, and the Return of Objects Launched into Outer Space, 1968. 3) The Convention on International Liability for Damage Caused by Space Objects, 1972. 4) The Convention on Registration of Objects Launched into Outer Space, 1974. 5) The Agreement Governing Activities of States on the Moon and Other Celestial Bodies: Moon Treaty, 1979. The other face of space law is it's commercial aspect. Space is no longer the sole domination of governments. Many private enterprise have already moved directly or indirectly into space activities in the parts such as telecommunications and space manufacturing. Since space law as the public international law has already advanced in accordance with the developments of space science and technology, there left only a few areas untouched in this field of law. Therefore the possibility of rapid growth of space law is expected in the parts of commerical space law, as it is, at this time, in a nascent state. The resources of the space environment are also commercially both valuable and important since the resources include the tangible natural resources to be found on the moon and other celestial bodies. Other space-based resources are solar energy, geostationary and geosynchronous orbital positions, radio frequencies, area possibly suited to human habitations, all areas and materials lending themselves to scientific research and inquiry. Remote sensing, space manufacturing and space transportation services are also another potential areas in which commercial. endeavors of Mankind can be carried out. In this regard, space insurance is also one of the most important devices allowing mankind to proceed with commercial space venture. Thus, knowlege of how space insurance came into existence and what it covers is necessary to understand the legal issues peculiar to space law. As a conclusion the writer emphasized the international cooperation of all nations in space activities of mankind, because space commerce, by its nature, will give rise many legal issues of international scope and concern. Important national and world-community interests would be served over time through the acceptance of new international agreements relating to remote sencing, direct television broadcasting, the use of nuclear power sources in space, the regularization of the activities of space transportation systems. standards respecting contamination and pollution, and a practical boundary between outer space and air space. If space activity regulation does not move beyond the national level, the peaceful exploration of space for all mankind will not be realized. For the efficient regulation on private and governmental space activities, the creation of an international space agency, similar to the International Civil Aviation Organization but modified to meet the needs of space technology, will be required. But prior to creation of an international organization, it will be necessary to establish, at national level, the Office of Air and Space Bureau, which will administrate liscence liscence application process, safety review and sale of launch equipment, and will carry out launch service.

  • PDF