DRM update

DRM Development Sep 96 – Informal meeting between 5 broadcast-related organizations Apr 97 – 1 st formal meeting of Digital Radio Mondiale TM (DRM TM ) 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 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 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

Analogue Vs Digital

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)

Spectral Band Replication

Digital Multiplex AudioDataControl signal MSCFACSDC Multiplex

World wide field test

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: – IBOC: MPEG: mpeg.telecomitalialab.com ETSI Web site: