DIGITAL RADIO GUIDE

APPENDIX A: EUREKA 147

Data Services

Each audio program contains PAD with a variable capacity (minimum 667 bps, up to 65 kbps) which is used to convey information together with the sound program. Typical examples of PAD applications are dynamic range control information, a dynamic label to display program titles or lyrics, speech/music indication and text with graphic features.

Additionally, general data may be transmitted as a separate service. This may be either in the form of a continuous stream segmented into 24 ms logical frames with a data rate of n x 8 kbps (n x 32 kbps for some code rates) or in packet mode, where individual packet data services may have much lower capacities and are bundled in a packet sub multiplex. A third way to carry independent data services is as a part of the Fast Information Channel (FIC) that carries multiplex control and service information. Typical examples of independent data services that could use the FIC are a Traffic Message Channel, correction data for Differential GPS and paging.

Some elements of Service Information (SI) data can also be made available to the listener for program selection and for the operation and control of receivers. For example, the name of a program service; the program type, title and language; transmitter identification and controls for switching to traffic reports, news flashes or announcements.

Number of audio services in a multiplex

Eureka 147 uses MPEG 1 Layer II and MPEG 2 Layer II audio compression standards and permits full data rate coding at the sampling frequency of 48 kHz and half data rate coding at the sampling frequency of 24 kHz. Half data rate coding is not fast enough to capture all of the information in a speech signal so this sampling rate is only used where some distortion.

Eureka 147 is capable of processing mono, stereo and dual channel (e.g., bilingual) programs. A range of encoded data rate options are available (8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160 or 192 kbps per monophonic channel). In stereophonic or dual channel mode, the encoder produces twice the data rate of a mono channel. The range of possible options can be utilised flexibly by broadcasters depending on the quality required and the number of sound programs to be broadcast.

A stereophonic signal may be conveyed in the stereo mode, or particularly at lower data rates in the joint stereo mode. This mode, typically used at 144 - 224 kbps, uses the redundancy and interleaving of the two channels of a stereophonic program to maximise the overall perceived audio quality.

The degree of error protection (and hence ruggedness) can also be varied to meet the needs of the broadcasters. In the case of audio services, five protection levels (1 to 5) have been specified in order to cater for a variety of applications. Level 5 affords the lowest protection and is designed for cable systems. It allows a high number of program services, but does not have the strong error protection necessary for operation in multipath environments. Protection Level 3 is better suited to mobile operation. To allow more flexibility in accommodating subchannels, Protection Levels 4 and 2 have also been introduced with somewhat weaker and stronger performance than Protection Level 3 (respectively). Protection Level 1 is suited to applications with a very high sensitivity to transmission errors while Protection Level 4 is intended for less demanding applications (for example services addressed to fixed receivers).

Table A.2 outlines the typical number of services that can be delivered for a selection of audio data rates for different levels of error protection.

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Grundig Digital Radio manual Data Services, Number of audio services in a multiplex

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.