Recent system developments

DIGITAL RADIO GUIDE

APPENDIX A: EUREKA 147

show that L Band can be used to provide indoor reception with a well designed terrestrial retransmission network. Canadian authorities consider L Band to be suitable for terrestrial digital radio services and are using only L Band for their Eureka 147 services. In the US, S Band has been used for terrestrial digital radio repeaters and GSM phones have been implemented at 1800 MHz and can provide adequate indoor reception.

Digital radio is likely to turn from a simple audio-only service, merely simulcasting existing analogue programmes, into a far more interactive and rich experience across several platforms including DAB, using scrolling text and on demand digital services. This section describes some technical developments of the Eureka 147 DAB system, as performed by the WorldDAB Forum.

As this section shows, the technical possibilities of DAB are practically unlimited. The challenge is to harness the technical developments and to restrict them reasonably to those for which an international consensus of broadcasters, manufactures and other players could be reached.

Multimedia Object Transport (MOT)

The MOT protocol allows the standardised transport of audio-visual information, such as still pictures and web pages. It can be used in the PAD and packet mode. MOT is particularly suitable for two applications: Broadcast Website (BWS) and Slide Show (SLS).

The basic principle of the MOT data carousels19 is that each file to be broadcast is divided into segments of equal length and then the segments for all files are repeated cyclically in the broadcast stream. Each segment is tagged with an identifier to say which file it belongs to and a segment number to identify which segment of the file it is. Segmenting the file in this way means that the system will still work in an error-prone channel because, even for large files, the minimum amount of data that must be received without error is just a segment rather than the whole file. If a segment is received in error, the receiver can just wait for the next time that segment is broadcast, and the file identifier and segment number allow the receiver to correctly reconstruct each file.

This on its own, however, is not sufficient; with a "sea" of segments, the receiver can reconstruct the files but cannot know either how to access them or how to manage them. What is needed is a "table of contents" for the carousel that contains a list of all the files contained within the carousel. With suitable version control applied to this "table of contents," it is possible to detect any change to the carousel simply by examining the version of the table of contents. If a file is changed, the version number for the file will change. This will, in turn, change the "table of contents," which will result in a change in its own version number. A simple comparison of the "table of contents" before and after the change allows the receiver to determine exactly what has changed, and to perform any cache management as appropriate.

19EN 301 234 V1.2.1 Digital Audio Broadcasting (DAB); Multimedia Object Transfer (MOT) protocol.

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Digital Radio specifications

The Grundig Digital Radio represents a significant advancement in radio technology, combining aesthetics, functionality, and a user-friendly interface. As a pioneer in the audio and electronics industry, Grundig has successfully integrated modern digital capabilities into its traditional radio design, appealing to both nostalgic listeners and tech-savvy users.

One of the standout features of the Grundig Digital Radio is its versatility in reception. With DAB+ (Digital Audio Broadcasting) technology, users can enjoy a wide array of radio stations with superior sound quality, free from the hiss and interference commonly associated with analog broadcasts. The inclusion of FM and AM bands ensures that listeners are not limited, providing access to local stations that may not yet have transitioned to digital.

The Grundig Digital Radio is designed with ease of use in mind. Its intuitive interface, often featuring a clear LCD display, allows users to navigate through stations and settings effortlessly. Many models also include a built-in tuner that automatically scans and presets available stations, simplifying the setup process. For those who appreciate personalization, some variants come equipped with customizable presets, allowing users to save their favorite stations for quick access.

Portability is another key characteristic of the Grundig Digital Radio. Many models are lightweight and come with built-in handles, making them ideal for on-the-go listening, whether it's in the garden, on the beach, or during a picnic. Battery options, alongside mains power, ensure that users can take advantage of their radios wherever they choose.

In terms of sound quality, Grundig utilizes advanced audio technologies to deliver rich and clear sound. Enhanced bass responses and treble controls allow users to fine-tune their listening experience to match their preferences. Furthermore, many models feature additional inputs, such as AUX and USB ports, enabling users to connect their smartphones or other devices, expanding their audio options.

Other notable characteristics include built-in alarms and timers, which make the Grundig Digital Radio a versatile companion for daily routines. Some models even support Bluetooth connectivity, allowing for seamless streaming from a variety of devices.

In summary, the Grundig Digital Radio embodies the perfect blend of traditional radio appeal and modern digital technology, offering versatility, ease of use, superior sound quality, and portability to meet the diverse needs of today’s listeners. Its well-thought-out features and user-friendly design make it an excellent choice for anyone looking to enhance their audio experience.