05839050 is referenced by 41 patents and cites 38 patents.

A remote radio listenership monitoring system including a digitally tuned scanning receiver disposed in an area adjacent to automobiles carrying radio receivers which radiate intermediate frequency signals corresponding to the frequency being amplified by that radio receivers, the receiver utilizes a narrowed filter scheme to sense the presence of an intermediate signal of a predetermined power level and rapidly polls a plurality of selected target frequencies. The system compiles target "hits" in a local memory device to create a database for that local unit. Periodically, the databases are transferred to a central processing station where individual local unit databases are compiled into a comprehensive report. Communication between the remote local units and the central processing station may be accomplished through a hard wired or cellular link. Updates to the system software and new target frequency data are transferred back to the remote units by the central processing station.

Title
System for determining radio listenership
Application Number
385482
Publication Number
5839050
Application Date
July 16, 1997
Publication Date
November 17, 1998
Inventor
George Chambers
Abilene
TX, US
Karl Baehr
Albuqurque
NM, US
Agent
Brian McCormack
Assignee
Actual Radio Measurement
NM, US
IPC
H04B 7/00
View Original Source