05412720 is referenced by 427 patents and cites 68 patents.

An interactive cable television system having a plurality of feeder servers, a plurality of home interface controllers and a feeder port. Home interface controllers are each equipped with a radio frequency input and a data communications link with a receiver and transmitter in the feeder port. A node control in communication with the feeder port determines whether a home interface controller is active and then assigns a feeder server to it. The feeder server provides one of a plurality of information signals from a headend depending on a selection input. Digitally compressed video signals are provided at the headend. The digitally compressed video signals can be provided by a modulator means at a carrier frequency greater than the upper frequency limit for carrying analog television signals with acceptable quality on the cable system.

The cable television system may make use of a scrambler that maintains the chrome subcarrier on a sync-stripped output signal at all times including the period of vertical retrace. The sync-stripped output signal is modulated at a first carrier frequency and the sync-signal is modulated at a second carrier frequency. A corresponding decoder is provided for receiving scrambled signals and restoring the sync-signal to restore the television signal.

Title
Interactive home information system
Application Number
589205
Publication Number
5412720
Application Date
May 1, 1992
Publication Date
May 2, 1995
Inventor
W Leo Hoarty
Morgan Hill
CA, US
Agent
Bromberg & Sunstein
Assignee
ICTV
CA, US
IPC
H04M 7/167
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