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Explore the development of DRM technology, field testing progress, and its impact on the broadcasting industry. Learn about DRM's standards and features, comparison with other digital systems, and key milestones. Discover how DRM enhances sound quality, coverage, and services. Stay updated on the latest trials and technical specifications, including the transition from analog to digital broadcasting. Access valuable information on official websites for further research.
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DRM Development • Sep 96 – Informal meeting between 5 broadcast-related organizations • Apr 97 – 1st formal meeting of Digital Radio MondialeTM (DRMTM) • Mar 98 – 20 broadcast-related organizations signed the MOU in Guangzhou, as a first step to the official inauguration
DRM Development • Apr 2001 – DRM's has gained approval by ITU-R's members. The recommendation is now referenced as ITU-R BS.1514 and under standardization process. • Sept 2001 – the European Telecommunications Standards Institute (ETSI) published the technical standard for DRM’s on-air system. The document is called ETSI TS 101 980 V1.1.1
DRM Development • Nov 99 – Evaluation group carried out field test • 2002 – DRM is an international consortium of 72 broadcasters, network operators, manufacturers • 2003 – DRM is scheduled to launch
Digital AM System • iBOC • USA (MW) • In Band On Channel system, analog and digital Tx on same channel • Wider BW requirement than DRM • MPEG2 & OFDM
Digital AM System • DRM • Europe (LW, MW & SW) • Tx on same band, different channels. • Simulcast is underway • MPEG4, QAM & OFDM
IBOC Spectrum Fig 1 – AM Hybrid IBOC Spectrum Fig 2 – AM All digital IBOC Spectrum
IBOC Spectrum Fig 1 – AM Hybrid IBOC Spectrum
IBOC Spectrum Fig 2 – AM All digital IBOC Spectrum
DRM Field Test • Phase 1 • Nov 1999 ~ Mar 2000, point to point SW and MF transmission. • Transmission path testing. • Phase 2A • Jul ~ Aug 2000 • Audio quality and reliability test
DRM Field Test • Phase 2B • Dec 2000, broadcast in MF and LF bands. • 2001, transmission from Canada to Madagascar (13000km)
DRM Field Test • Latest Test • 12 June 2002, Long-term DRM tests from Deutsche Welle and Radio Netherlands Bonaire, Netherlands Antilles are continuing. • The latest phase involves simulcast (analog/digital) mode. • Carrier frequency: 15530kHz
DRM Field Test Commend • BBC – Compliance testing and specification validation Clear, Complete and Unambiguous
Features • Reinvigorate the use of frequency bands below 30 MHz – Short-Wave, Medium-Wave and Long-Wave • Improve sound quality, FM-like with the AM reach • Reduce interference by digital technique
Features • Wider coverage due to improved S/N • Alternative frequency switching and Single Frequency Network • Value added services: • Program labels • Text messages
Impact • Modification of existing transmission equipment is needed • New digital receivers is needed • Slightly reception improvement with existing output power • Better sound quality
Coming Up • OFTA invite RTHK to conduct a DRM trial test in Peng Chau at 810 kHz
DRM System • Non proprietary, open standard • uses existing AM broadcast frequency bands, 9 –10 KHz channel • Support SFN • Not support analog receivers • Simulcast is underway
Technical Info • Audio: • MPEG4 Advanced Audio Coding (AAC) + Spectral Band Replication (SBR) compressed audio: 20kbps / channel • RF: • QAM & ODFM (similar to DAB)
Digital Multiplex Audio Data Control signal MSC FAC SDC Multiplex
72 DRM-Members from 27 countries, 2002 Countries with DRM Members
16 QAM Constellation Change in amplitude and phase
MPEG-2 AAC • a high quality audio coding standard for 1 to 48 channels at sampling rates of 8 to 96 kHz, with multi-channel and multilingual capabilities. • AAC works at bit rates from 8 kbit/s for a mono speech signal up to 160 kbit/s for very high quality. • Three profiles of AAC provide varying levels of complexity and scalability.
MPEG-4 AAC • Coding and composition of natural and synthetic audio objects at a very wide range of bit rates • The representation for synthesized sound can be derived from text data or so-called instrument descriptions
MPEG-2 AAC Vs MPEG-4 AAC • MPEG-4 AAC has all the tools and functions of MPEG-2 AAC plus the Noise Substitution tool, a Long Term Predictor as well as extensions to support scalability
Useful Web Site • DRM: • official website: www.drm.org • www.ist-radiate.com • IBOC: www.ibiquity.com • MPEG: mpeg.telecomitalialab.com • ETSI Web site: www.etsi.org