04718106 is referenced by 207 patents and cites 6 patents.

A technique for surveying an audience. A portable signal detector unit picks up audible sounds reproduced by a radio set from signals transmitted by a given radio station. Among the broadcast signals is one unique to that particular station. The unit includes means capable of identifying that signal to automatically electronically record the fact that the station is being listened to by the carrier of the unit.

Title
Survey of radio audience
Application Number
6/862107
Publication Number
4718106
Application Date
May 12, 1986
Publication Date
January 5, 1988
Inventor
Lee S Weinblatt
797 Winthrop Rd., Teaneck, 07666
NJ, US
Agent
Frishauf Holtz Goodman & Woodward
IPC
H04B 17/00
View Original Source