A method of processing a digital radio broadcast signal in a digital radio receiver comprising: (a) determining a plurality of current correlation sample values representative of a time delay between samples in an analog audio sample stream and samples in a digital audio sample stream of the same audio program; (b) determining a current inversion status between the samples in an analog audio sample stream and samples in a digital audio sample stream, the inversion status indicating if the waveform of the analog audio sample stream is phase inverted with respect to the waveform in the digital audio sample stream; (c) updating a delay history and an inversion status history; (d) checking the current correlation sample values for consistency with a first confidence threshold by checking if the current correlation sample values are greater than the first confidence threshold; (e) if consistency is found in step (d), determining if each of a first plurality of values in the delay history is consistent within a predetermined range of the current correlation sample values by determining if each of the first plurality of values in the delay history lies within the predetermined range of the current correlation sample values; (f) if consistency is found in step (e), determining if each value in the inversion status history is consistent with the current inversion status by determining if each value in the inversion status history agrees with the current inversion status; (g) if the consistency is found in step (f), allowing blending of an output to the digital audio sample stream; otherwise repeating steps (a) through (g) using different samples in the analog audio sample stream and different samples in the digital audio sample stream. (a) determining a plurality of current correlation sample values representative of a time delay between samples in an analog audio sample stream and samples in a digital audio sample stream of the same audio program; (b) determining a current inversion status between the samples in an analog audio sample stream and samples in a digital audio sample stream, the inversion status indicating if the waveform of the analog audio sample stream is phase inverted with respect to the waveform in the digital audio sample stream; (c) updating a delay history and an inversion status history; (d) checking the current correlation sample values for consistency with a first confidence threshold by checking if the current correlation sample values are greater than the first confidence threshold; (e) if consistency is found in step (d), determining if each of a first plurality of values in the delay history is consistent within a predetermined range of the current correlation sample values by determining if each of the first plurality of values in the delay history lies within the predetermined range of the current correlation sample values; (f) if consistency is found in step (e), determining if each value in the inversion status history is consistent with the current inversion status by determining if each value in the inversion status history agrees with the current inversion status; (g) if the consistency is found in step (f), allowing blending of an output to the digital audio sample stream; otherwise repeating steps (a) through (g) using different samples in the analog audio sample stream and different samples in the digital audio sample stream.