US 5,418,559 AGranted

Multi-channel television converter for conventional and interactive signals

AssigneeAT&T Corp.

InventorDonald E. Blahut

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Abstract

One or more channels in a multi-channel cable television distribution system is used for the transmission of interactive television (ITV) signals in the form of packetized digital information from the cable system headend to subscribers. A converter at each subscriber location is connected between the cable system and the subscriber's television receiver. Such converter contains a receiver for the ITV channels. Control packets in the ITV signals are addressed to individual converters to enable the receipt of one or more virtual channels by a converter. The converter decodes and expands the packetized digital information in such enabled channels and generates a conventional video signal, which is transmitted to the subscriber's television receiver on one of the channels used for the ITV signal from the headend, replacing the packetized digital information. The remaining channels from the cable system are forwarded to such television receiver unaltered. Thus, all cable-ready features of the subscriber's television receiver are usable. In alternate embodiments of the invention, the video signal generated by the converter is derived from one or more sources. Examples of such sources are an additional receiver adapted to receive a conventional television signal from the cable system and local text or symbol generators.

Claims8

Dependent claims

A converter for use in a signal distribution system having a plurality of distribution channels, at least one of said distribution channels carrying digital signals in the form of a set of packets, said set of packets being related to a set of virtual channels by an identification of a virtual channel contained in each packet of the set of packets, the remainder of said distribution channels carrying other signals, which comprises:

an input circuit for connecting said converter to said signal distribution system,
a first receiver connected to said input circuit for receiving said channels carrying digital signals and retrieving said packets,
a first memory for storing the identity of one of said virtual channels,
means for comparing the virtual channel identification in each retrieved packet with said stored identity in said first memory and for selecting those of said packets in which said virtual channel identification matches said stored identity,
means for decoding said selected packets to generate a decoded signal,
a second memory for storing the identity of one of said distribution channels carrying other signals,
a second receiver connected to said input circuit for receiving said other signal in the distribution channel whose identity is stored in said second memory,
means for selecting between and/or combining said other signal from said second receiver and the decoded signal from said decoding means,
an output circuit for connecting said converter to a receiver,
means for connecting said input circuit to said output circuit and blocking at least one of distribution channels carrying digital signals without affecting said distribution channels carrying other signals, and
means connected to said combining means and said output circuit for inserting the output of said selecting and/or combining means into said output circuit in one of said blocked distribution channels.

8 more elements

Dependencies are inferred from the claim text.