added to read as follows: Subpart C-Digital Audio Broadcasting § 73.401 Scope. This subpart contains those rules which apply exclusively to the digital audio broadcasting (DAB) service, and are in addition to those rules in Subparts A, B, C, G and H which apply to AM and FM broadcast services, both commercial and noncommercial. * * * * * § 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.