DRM frame
In Digital Radio Mondiale( DRM), messages and data are multiplexed into a DRM superframe. The resulting superframe structure consists of the Main Service Channel( MSC), the Fast Access Channel( FAC) and the Service Description Channel( SDC).
The Main Service Channel corresponds to a channel composed of up to four audio or data streams. The Fast Access Channel is one of two multiplex channels. It contains information about the signal bandwidth and other parameters that enable the receiver to start decoding. The second multiplex channel is the Service Description Channel. It contains information about the decoding specification of the Main Service Channel as well as alternative ways of receiving the same data.
Such a DRM frame consists of 15 OFDM symbols and has a duration of 400 ms. Three 400 ms frames each form a DRM superframe.