Patent ID: 7221688

Claim:
A method for processing a composite digital audio broadcasting signal including an analog modulated portion in a central frequency band and digitally modulated portions in upper and lower sidebands with respect to the central frequency band, the method comprising the steps of: wideband filtering the composite digital audio broadcasting signal to produce a first intermediate frequency signal; narrowband filtering the composite digital audio broadcasting signal to produce a second intermediate frequency signal; simultaneously processing the first intermediate frequency signal to retrieve a digitally modulated version of program material from the first intermediate frequency signal, and processing the second intermediate frequency signal to retrieve an analog modulated version of the program material from the second intermediate frequency signal; making a determination of the quality of the digitally modulated version of the program material; and using the quality determination to select the analog modulated version of the program material, the digitally modulated version of the program material, or a combination of the analog modulated version of the program material and the digitally modulated version of the program material as an output signal.