Coverage, DRM Digital Radio Mondiale

DIGITAL RADIO GUIDE

TERRESTRIAL TRANSMISSION SYSTEMS - ISSUES

broadcasters can be expected to have significant flexibility in determining when and how to phase out the analogue portion of the IBOC signal all together.

In addition, the simulcasting of audio material in some IBOC systems, while done primarily to facilitate time diversity, can also mitigate the undesired digital receiver behaviour experienced in cases of severe signal obstructions or extreme cases of interference. In these cases, systems without time diversity (such as Eureka 147) exhibit what is called a "cliff effect" failure, in that the audio signal is perfect one second, and completely gone ("muted") the next. In a simulcast IBOC system, the existence of the "backup" analogue signal for purposes of time diversity has the added effect of eliminating the cliff effect failure mode, since in those cases the receiver will blend to analogue and the audio program, while degraded, will not go away all together, and is likely to remain with the listener throughout the impairment.

These developments are at a relatively early stage and their viability has to be assessed, but the work carried out to date is encouraging. The audio quality achievable with simulcasting remains to be established.

(2)DRM (Digital Radio Mondiale)

Two types of simulcast are present in the DRM design. The first is confined to a 9 or 10 kHz channel. Half the channel is used for an analogue signal capable of envelope detection (in order that a conventional AM radio receiver can demodulate the signal). The other half is a DRM digital signal that requires digital demodulation. The second technique requires 18 or 20 kHz of 2 adjacent channels where one channel contains standard AM and the other contains either a 4.5/5 or 9/10 kHz DRM signal.

For Regions 2 and 3 the simulcast solution is potentially much simpler as the Long and Medium Wave bands have been allocated 18/20 KHz channels. In Region 3 the 18 kHZ allocation is also protection against night time sky wave interference.

4.5.3Coverage

The move from analogue to digital transmission raises important questions under the heading ”coverage.”

One of the main differences between analogue and digital broadcasts is the mode of failure when the received signal starts to fail. It happens at the edge of the service area and at locations within the coverage footprint where the signal strength is affected by shadowing or interference. When the signal strength reduces, analogue reception is often described as degrading “gracefully.” By contrast, a digital signal will at some point fail suddenly and completely. Whilst usually robust in areas of generally poor analogue reception, the digital signal gives little indication as it approaches a point of failure.

Within a defined coverage area, the service availability from analogue and digital services will be affected by the type of receiver (fixed, mobile or portable), by the type of environment (urban, rural), and by the topography. It is also a function of the transmission frequency and the system performance.

COFDM signals (such as those used in the Eureka 147, DRM and AM and FM IBOC schemes) have characteristics which facilitate the planning of single frequency networks

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.