05065231 is referenced by 54 patents and cites 4 patents.

A circuit which receives RGB and composite video and provides both RGB and composite merged outputs. Merging of RGB signals occur where the input composite signal is converted to RGB; and also, merging occurs of composite signals where the input RGB is converted to a composite signal. The circuit is particularly useful in a video overlay application. Notch filters are used both in the video path and keying path. The notch filters are centered at frequencies equal to the dot clock frequency of the RGB divided by integers where the result of this division falls within the chroma subcarrier spectrum.

Title
Apparatus and method for merging input RGB and composite video signals to provide both RGB and composite merged video outputs
Application Number
249603
Publication Number
5065231
Application Date
February 1, 1991
Publication Date
November 12, 1991
Inventor
Laurence A Thompson
Saratoga
CA, US
Stephen G Perlman
Mountain View
CA, US
Michael R Moore
Folsom
CA, US
Paul E Greaves
Rancho Cordova
CA, US
Agent
Blakely Sokoloff Taylor & Zafman
Assignee
Apple Computer
CA, US
IPC
G09G 1/14
H04N 5/272
H04N 5/262
H04N 9/74
View Original Source