IN THE PRESENCE OF AN IBOC DIGITAL SIGNAL
R. McCutcheon · 1996
Certain types of VHF In-Band On Channel (IBOC) Digital Audio Radio (DAR) systems transport digital audio information on independent adjacent RF signals either side of the Host FM signal. In conventional FM stereo broadcasting, normal deviation of the carrier (modulation) does not significantly contribute to the recovered composite baseband noise floor in a receiver. During laboratory testing of IBOC DAR systems of the type utilizing the adjacent RF signals, modulation of the main analog channel caused an increase in the recovered composite baseband noise floor when the adjacent DAR signals were present.