Patent ID: 6980769

Claim:
A method of determining a validity of a lookup table in a radio receiver, said lookup table including table entries for respective digital audio broadcast stations of a broadcast band transmitting to a geographical location, each table entry containing a respective station identification code and content-related information for presentation to a listener, said respective digital audio broadcast stations broadcasting a duplicative audio broadcast signal containing both a primary and a backup signal allocated over a frequency range of each of said respective digital audio broadcast stations, said backup signal containing a data signal providing said station identification code for said respective digital audio broadcast stations, said method comprising the steps of: tuning to a first designated frequency; receiving the backup data signal to determine a station identification code of a received station; if said backup data signal did not contain said station identification code, then receiving the primary data signal to determine the station identification code of said received station; comparing said station identification code of said received station with said station identification code in a table entry corresponding to said first designated frequency; tuning to a next designated frequency of a next received station; receiving a next backup data signal to determine a next station identification code of said next received station; if said next backup data signal did not contain said next station identification code, then receiving a next primary data signal to determine said next station identification code of said next received station; comparing said next station identification code of said next received station with said next station identification code in said next table entry corresponding to said next designated frequency; detecting an invalid table condition in response to a non-matching number of comparisons.