Editorial

DAB field trials in the urban jungle
George T. Waters

Digital Audio Broadcasting

First results of field tests with the DAB single frequency network in Bavaria
A. Lau, M. Pausch and W. Wütschner (2.2 MB)

This article presents a report on the DAB field test in the channel 12 single frequency network which forms one component of the Bavarian DAB Pilot Project.

Measurements results obtained using a specially-equipped monitoring van and computer software which has been specifically developed for mobile reception are compared with coverage predictions. The "gain" over individual transmitters, which is achievable in DAB SFNs, is demonstrated by way of an example.

The special features of coverage in mountainous regions are also discussed.

DAB field trials in Finland
V. Erkkilä and M. Jokisalo (213 KB)

The article describes the facilities recently installed for DAB field trials in VHF Band II, in Finland.

Preliminary results are given, together with some indications of specific aspects of DAB reception which will require more-detailed investigation.

A full-scale measurement campaign is due to begin in autumn 1994.

Field trials with a high-power VHF single frequency network for DAB – Measurement techniques and network performance
M.C.D. Maddocks, I.R. Pullen and J.A. Green (2.8 MB)

The advent of digital formats such as CD has created demand for uniformly high audio quality from radio, even in vehicles and for portable reception. The Eureka-147 DAB system has been designed specifically to meet these demands and the BBC is undertaking a major experiment to test the system and to gather data which will allow efficient planning of its transmitter network. As a basis for these tests, a network of four 1 kW e.r.p., VHF transmitters has been installed to cover the London area in England.

The results show wide-area coverage from the transmitter network which is in reasonable agreement with computer predictions. The results also provide quantitative values which can be used for coverage prediction and for international coordination of services. Finally, the performance of the system demonstrates a number of the benefits of the Eureka DAB system for mobile and portable reception.

Dynamic Range Control (DRC) and Music/Speech Control (MSC) – Programme – associated data services for DAB
W. Hoeg, N. Gilchrist, H. Twietmeyer and H. Jünger (659 KB)

There will always be the need for broadcasters to apply dynamic range compression to some types of programme material, either because of the limitations of the broadcasting medium or because of listeners' requirements.

The Eureka 147 DAB digital audio broad casting system enables broadcasters to transmit programmes with a relatively wide dynamic range, accompanied by a dynamic range control (DRC) signal which the listener may use to effect unobtrusive compression of the programme dynamics, if required. A music/speech control (MSC) signal, which is also transmitted, will enable the listener to balance the loudness of different types of programme according to taste.

The techniques used for the optional compression of programme dynamics in DAB may also be used to control the dynamic range of programmes unobtrusively for conventional VHF/FM broadcasting, but without control data being transmitted.

Portrait

Carlo Terzani (15 KB)