The ABU undertakes wide ranging activities reflecting the current needs of the members. These activities are implemented by the Secretariat's Technical Department. Providing technical information to the members is a major activity of the Technical Department. The activity takes various forms including the publication of the ABU Technical Review and regular distribution of clippings containing a selection of the most useful papers published in technical journals worldwide. Recenty they published the "Digital Radio Guide". It's give the introduction about the digital radio. Total number of pages 118. You will more info from the following link
http://www.abu.org.my/public/documents/DRG-2007-Final.pdf