A system for peak-to-average-power ratio (PAPR) reduction of a frequency shifted plurality of digital broadcast signals taking into account the combined signal peaks in order to transmit the signals more efficiently in a single broadcast transmission system. The PAPR algorithm takes into account a rotating constellation phase offset for the shifted signals corresponding to the amount of applied frequency shift. In the case of a dual sideband In-Band-On-Channel (IBOC) signal typically used in conjunction with an FM carrier in the center, the sidebands can be interleaved to create a new IBOC signal definition and take the place of the FM carrier for an all-digital transmission that is backward compatible with IBOC receivers allowing for a gradual migration to all digital broadcasting.