05630203 is referenced by 79 patents and cites 14 patents.

A surveying technique transmits a combined signal made up of a programming signal and a surveying signal, both of which are in the audible range. The surveying signal is uniquely coded to identify a signal source such as a radio station or television channel. At the receiver, the surveying signal is separated from the programming signal and then modified so as to be reproduced outside the audible range for detection by a portable unit worn by a person being monitored for his listening and/or viewing habits. The detection of the inaudible survey signal by the portable unit identifies the signal source to which the person was tuned.

Technique for surveying a radio or a television audience
Application Number
Publication Number
Application Date
January 12, 1993
Publication Date
May 13, 1997
Lee S Weinblatt
797 Winthrop Rd., Teaneck, 07666
Frishauf Holtz Goodman Langer & Chick P C
H04B 17/00
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