DRM update

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 an

d 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 fro

m 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

AM Mod

DRMMod

Amp

Amp

Audio

RF (single carrier)

RF (multi-carrier)

Audio

QAM

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

Encoder Decoder

X(f) Y(f)

freqfreq

Audio In Audio Out

X7~15KHz

Digital Multiplex

Audio Data Control signal

MSC FAC SDC

Multiplex

World wide field test

World wide field test

Countries with DRM Members

72 DRM-Members from 27 countries, 2002

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