Sec.  73.402   Definitions.

   (a) DAB. Digital audio broadcast stations are those radio stations licensed
   by  the  Commission and use the In-band On-channel (“IBOC”) system for
   broadcasting purposes.

   (b) In Band On Channel DAB System. A technical system in which a station's
   digital signal is broadcast in the same spectrum and on the same channel as
   its analog signal.

   (c) Hybrid DAB System. A system which transmits both the digital and analog
   signals within the spectral emission mask of a single AM or FM channel.

   (d) Extended hybrid operation. An enhanced mode of FM IBOC DAB operation
   which includes additional DAB subcarriers transmitted between the analog FM
   signal and the inner edges of the primary DAB sidebands.

   (e)  Primary  AM  DAB  Sidebands. The two groups of hybrid AM IBOC DAB
   subcarriers which are transmitted 10 to 15 kHz above carrier frequency (the
   upper primary DAB sideband), and 10 to 15 kHz below carrier frequency (the
   lower primary DAB sideband).

   (f) Multicasting. Subdividing the digital bitstream into multiple channels
   for additional audio programming uses.

   (g) Datacasting. Subdividing the digital bitstream into multiple channels
   for additional data or information services uses.