main service channel (DAB, DRM) (MSC)

InDigitalAudio Broadcast(DAB) and Digital Radio Mondiale( DRM), the audio data is multiplexed with additional data for data services to form a data stream.

1. In Digital Audio Broadcast, this DAB multiplex of the audio data and the data services is called the Main Service Channel( MSC) and, together with the Fast Information Channel( FIC), forms the complete DAB data stream. In the Main Service Channel, the audio data is transmitted in up to 64 subchannels and also contains program-associated data ( PAD) and non-program-associated data( NPAD). The audio data itself is encoded using the Musicam process, which is standardized as MPEG-1 Audio Layer-2 (MP2). In these subchannels, digital audio broadcasting transmits, for example, traffic information or data with the IP protocol.
   

   DAB data stream, graphic based on Fraunhofer IIS

   The transmission capacity of these MSC subchannels can be increased in steps of 8 kbit/s, making transmission rates of 8 kbit/s up to 1.2 Mbit/s theoretically possible for digital audio broadcast.
2. In Digital Radio Mondiale (DRM), the Main Service Channel (MSC) contains the audio data to be transmitted and additional accompanying data.
   

   Structure of the multiplexed superframe of Digital Radio Mondial (DRM)

   The MSC channel is multiplexed with the Fast Access Channel ( FAC) and the Service Description Channel( SDC) to form a transmissionframe. A transmission frame from the DRM multiplex takes 400 ms.