FMeXtra is a system which enables FM-stations to broadcast extra digital radio programs besides their regular signal. The system makes use of existing, so called lift capacity, which is presently not being used by most broadcasters, although it is available and usable. Within the technical standard used in Europe it is possible to broadcast one or two extra digital stereo channels besides the regular analogue signal. These channels are added to the FM-signal similar to the way RDS-information is being added. To be able to receive FMeXtra one needs a radio set suitable for these digital programs, for example the radio set as shown here. Additional models are expected to be available soon. Figure 1 - FMeXtra Aruba receiver The migration from FM to FMeXtra can be compared to the change from black-and-white to colour television. So the migration will take place in phases, with the analogue standard remaining operational as before. After all FMeXtra does not interfere with the existing FM services!

FM broadcasts are made up of several signals that are added together into a multiplex MPX signal as shown in the figure below. Even though you can't hear most of them directly, some of these signals may already be familiar, such as the stereo pilot which, when present, often shows up as "ST" on the radio display. FMeXtra uses additional inaudible signals known as sub carriers. The amount of bandwidth available for FMeXtra's sub carrier signal depends upon the individual station's configuration - whether it is broadcasting mono audio or stereo audio, and whether or not there are already existing other sub carrier signals. FMeXtra is designed to be flexible and to accommodate many possible configurations. In a typical stereo FM signal.