METHOD OF ESTIMATING DIGITAL AUDIO AVAILABILITY FOR SUPPLEMENTAL AUDIO PROGRAMS IN HD RADIO BROADCAST

摘要

A radio signal processing circuit comprises multiple audio blend channels, an audio decoder, a program selector and a blending circuit. The audio blend channels are configured to receive digital audio packets for multiple supplemental audio programs. Each audio blend channel includes an audio blend buffer and a signal quality metric circuit. The signal quality metric (SQM) circuit configured to determines an audio quality indicator for the digital audio packets of the program and indicates availability of the program according to the audio quality indicator regardless of whether the program is selected for play. The program selector configured to provides digital audio packets from a selected audio blend channel to the audio decoder to produce a digital audio signal. The blending circuit blends the digital audio signal produced for the selected audio blend channel with a signal representing silence according to the audio quality indicator for the audio blend channel.