DIGITAL RADIO GUIDE

TERRESTRIAL TRANSMISSION SYSTEMS - DAB

New receivers which appear on the market with the new codec will also be backwards compatible with the existing DAB-MPEG Audio Layer II in operation today for DAB services.

The main features for the new audio codec are described by WorldDAB as:

Latest MPEG-4 audio codec delivers exceptional performance efficiency;

More stations can be broadcast on a multiplex;

Greater station choice for consumers;

More efficient use of radio spectrum;

Lower transmission costs for digital stations;

New receivers backwards compatible with existing codec standard;

Current MPEG Audio Layer II services and consumers unaffected;

Compatible with existing scrolling text and multimedia services;

Robust audio delivery with fast re-tuning response time;

Optimised for live broadcast radio;

Broadcasters/regulators can select either standard MPEG Audio Layer II, or optional high efficiency advanced audio codec, or both, to suit their country needs.

The following is a brief explanation of how the new codec enhances the DAB standard.

The main Digital Audio Broadcasting specification (ETSI EN 300 401) defines how audio should be broadcast. “The DAB system uses MPEG Audio Layer II, suitably formatted for DAB transmissions. For 48kHz sampling frequency it uses ISO/IEC 11172-3 and for 24kHz sampling frequency it uses ISO/IEC 13818-3.”

For Layer II audio, two sampling rates are permitted, 48 kHz and 24 kHz. Each audio frame contains samples for 24 ms or 48 ms respectively and each contains the same number of bytes. The audio frames are carried in one or two respectively DAB logical frames. The draft technical specification now approved by ETSI defines the way that audio (programme) services are carried when using MPEG 4 HE AAC v2. For AAC, two transforms are specified. For DAB, only the 960 transform is permitted with sampling rates of 48 kHz, 32 kHz, 24 kHz and 16 kHz. Each AU (audio frame) contains samples for 20 ms, 30 ms, 40 ms or 60 ms respectively. In order to provide a similar architectural model to Layer II audio, simple synchronisation and minimal re-tuning delay (i.e. station selection, or “zapping” time), AUs are built into audio super frames of 120 ms which are then carried in five DAB logical frames. In order to provide additional error control, Reed Solomon coding and virtual interleaving is applied. The overall scheme is shown in Figure 4.3.

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Grundig manual Digital Radio Guide Terrestrial Transmission Systems DAB

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.