Patent ID: 9025773
Filing Date: 2015-05-05
Classification: G10L,H04H

Abstract:
1. A method of undetectable blending of a Digital Audio Broadcast transmission first audio source and a Frequency Modulate transmission second audio source comprising the steps of: calculating an average envelop value of the first audio source over a time span Ts as follows: DAB audio=DAB_Left+DAB_Right, DAB_envelope=ABS[DAB_audio], and DAB_Envelope_Avg=(1−α)*DAB_Envelope_Avg+α*DAB_envelope, where: DAB_Left is a left channel of the first audio source; DAB_Right is a right channel of the first audio source; and α is selected whereby Ts*(1−α)/α˜0.1; downsampling the average envelop value of the first audio source; calculating an average envelop value of the second audio source over the time span Ts as follows: FM_audio=FM_Left+FM_Right, FM_envelope=ABS[FM_audio], and FM_Envelope_Avg=(1−α)*FM_Envelope_Avg+α*FM_envelope, where: FM_Left is a left channel of the second audio source; and FM_Right is a right channel of the second audio source; downsampling the average envelop value of the second audio source; calculating a gain adjustment for the first audio source; calculating a gain adjustment for the second audio source; applying gain adjustment to the second audio source; calculating a time delay between the first audio source and the second audio source; calculating a Quality of Service (QOS) indicator for said first and second audio source using quality indicators provided by said audio sources; blending the first audio source and the second audio source offset by the calculated time delay based upon the Quality of Service indicator.