DRM update

1
DRM update
2
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

3
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 DRMs on-air system. The
  document is called ETSI TS 101 980 V1.1.1

4
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

5
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

6
Digital AM System

• DRM
• Europe (LW, MW SW)
• Tx on same band, different channels.
• Simulcast is underway
• MPEG4, QAM OFDM

7
IBOC Spectrum
Fig 1 AM Hybrid IBOC Spectrum
Fig 2 AM All digital IBOC Spectrum
8
IBOC Spectrum
Fig 1 AM Hybrid IBOC Spectrum
9
IBOC Spectrum
Fig 2 AM All digital IBOC Spectrum
10
DRM Spectrum
11
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

12
DRM Field Test

• Phase 2B
• Dec 2000, broadcast in MF and LF bands.
• 2001, transmission from Canada to Madagascar
  (13000km)

13
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

14
DRM Field Test Commend

• BBC Compliance testing and specification
  validation ? Clear, Complete and Unambiguous

15
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

16
Features

• Wider coverage due to improved S/N
• Alternative frequency switching and Single
  Frequency Network
• Value added services
• Program labels
• Text messages

17
Impact

• Modification of existing transmission equipment
  is needed
• New digital receivers is needed
• Slightly reception improvement with existing
  output power
• Better sound quality

18
Coming Up

• OFTA invite RTHK to conduct a DRM trial test in
  Peng Chau at 810 kHz

19
Analogue Vs Digital
20
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

21
Technical Info

• Audio
• MPEG4 Advanced Audio Coding (AAC) Spectral Band
  Replication (SBR) ? compressed audio 20kbps /
  channel
• RF
• QAM ODFM (similar to DAB)

22
Spectral Band Replication
23
Digital Multiplex
Audio
Data
Control signal
MSC
FAC
SDC
Multiplex
24
World wide field test
25
World wide field test
26
Countries with DRM Members
27
16 QAM Constellation
Change in amplitude and phase
28
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.

29
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

30
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

31
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