04258386 is referenced by 224 patents and cites 11 patents.

Apparatus for television audience analysis comprising means for monitoring a television receiver, means responsive to a monitored signal for storing information representative of channel identification and of the time at which a channel is selected and at which the selection of a channel is terminated, and means for reading the stored information periodically.

Title
Television audience measuring system
Application Number
5/955802
Publication Number
4258386
Application Date
October 30, 1978
Publication Date
March 24, 1981
Inventor
Shiu H Cheung
95B Robinson Rd., Hong Kong
HK
Agent
Kinzer Plyer Dorn & McEachran
IPC
H04N 7/00
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