Cable broadcasting system and the transmission center for on demand program services
First Claim
1. A transmission center for on demand television for communicating with subscribers and providing a plurality of television channels to subscribers, each channel being capable of carrying at least one image signal, the transmission center comprising:
- an image playback means for producing a plurality of image programs repetitively, each image program being simultaneously available in more than one version, the versions being identical except for being time-shifted in relation to one another;
a receiving means for receiving a demand for an image program from the subscribers;
a first selection means for selecting the image program demanded by the subscriber, the selected image program being one of the versions of the plurality of image programs repetitively produced by the image playback means;
a second selection means for selecting an available channel in a transmission line connecting the transmission center and a group of the subscribers to provide the selected image program to the subscribers as the image signal;
a signal processing means for enciphering the image signal of the selected image program, and subsequently modulating and multiplexing the enciphered image signal;
a transmission means for transmitting the image signal of the image program selected by the first selection means to the subscriber on the channel selected by the second selection means after the processing of the signal by the signal processing means; and
a notifying means for notifying the subscriber of the selected channel and a deciphering key for the image signal.
1 Assignment
0 Petitions
Accused Products
Abstract
The present invention provides a cable broadcasting system and the transmission center employed therein. In the transmission center, plural images are divided into several groups in the same kinds and each image in one kind is repeated not simultaneously so that they are outputted as independent plural image signals, and the image that the subscribers have requested is selected from those plural image signals which is enciphered, modulated, and multiplexed to be transmitted in optical transmission lines through an available channel to the subscribers, while the transmission channel is validated as well as the enciphered image signal is deciphered at the subscribers'"'"' end in order to enable the subscribers to watch the image they have requested.
152 Citations
23 Claims
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1. A transmission center for on demand television for communicating with subscribers and providing a plurality of television channels to subscribers, each channel being capable of carrying at least one image signal, the transmission center comprising:
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an image playback means for producing a plurality of image programs repetitively, each image program being simultaneously available in more than one version, the versions being identical except for being time-shifted in relation to one another; a receiving means for receiving a demand for an image program from the subscribers; a first selection means for selecting the image program demanded by the subscriber, the selected image program being one of the versions of the plurality of image programs repetitively produced by the image playback means; a second selection means for selecting an available channel in a transmission line connecting the transmission center and a group of the subscribers to provide the selected image program to the subscribers as the image signal; a signal processing means for enciphering the image signal of the selected image program, and subsequently modulating and multiplexing the enciphered image signal; a transmission means for transmitting the image signal of the image program selected by the first selection means to the subscriber on the channel selected by the second selection means after the processing of the signal by the signal processing means; and a notifying means for notifying the subscriber of the selected channel and a deciphering key for the image signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A cable television broadcasting system for providing a plurality of image programs for on demand television service to subscribers, the cable broadcasting system comprising:
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a plurality of transmission lines for enabling a transmission center to provide a plurality of image programs as image signals to the subscribers, the plurality of transmission lines comprising first transmission lines extending from the transmission center to a plurality of groups, each group having a plurality of subscribers, and second transmission lines in a tree network for connecting the first transmission line and the subscribers; the transmission center comprising; an image playback means for producing a plurality of image programs repetitively, each image program being simultaneously available in more than one version, the versions being identical except for being time-shifted in relation to one another; a receiving means for receiving a demand for an image program from the subscriber; a first selection means for selecting the image program demanded by the subscriber, the selected image program being one of the versions of the plurality of image programs repetitively produced by the image playback means; a second selection means for selecting an available channel in the first and the second transmission lines to provide the selected image program to the subscribers as the image signal; a signal processing means for enciphering the image signal of the selected image program, and subsequently modulating and multiplexing the enciphered image signal for transmission to the subscriber on the channel selected by the second selection means; a transmission means for transmitting the image signal of the image program selected by the first selection means, the image signal being transmitted on the channel selected by the second selection means to the subscriber after being processed by the signal processing means; and a notifying means for sending a notice to the subscriber of both a deciphering key for the image signal and the channel selected by the second selection means; an image signal receiving means provided to each subscriber for receiving the image signal transmitted from the transmission center; and a communication means provided to each subscriber for making a demand for an image program to the transmission center and for receiving a notice from the transmission center. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A transmission center for on demand television for communicating with subscribers and providing a plurality of television channels to subscribers, each channel being capable of carrying at least one image signal, the transmission center comprising:
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a plurality of transmission lines for connecting the transmission center with a plurality of distribution system sections, the distribution section comprising a delivery line connecting the subscribers to the transmission line, the delivery line arranged in a network so that the subscribers share the delivery line without the need for a delivery line dedicated to each subscriber; a receiving means for receiving a demand for an image program from the subscribers; an image playback means for producing a plurality of image programs, each image program being simultaneously available in more than one version, the versions being identical except for being time-shifted in relation to one another; an encoding means for encoding the plurality of image programs into a multiplexed signal; a first selection means for selecting, from the multiplexed signal, the image program demanded by the subscriber; a second selection means for selecting an available television channel in the distribution system section; a transmission means for transmitting the image program selected by the first selection means to the distribution system section on the channel selected by the second selection means; and a notifying means for notifying the subscriber of the selected television channel. - View Dependent Claims (20, 21)
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22. A cable television broadcasting system for providing on demand television service comprising:
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a plurality of distribution system sections to provide a plurality of television channels to subscribers, each channel being capable of carrying at least one image program, the system section comprising delivery lines which are arranged in a network such as a tree network so that the subscribers connected to the section share the same line without need for an individual delivery line dedicated to each subscriber; a plurality of receivers attached to the distribution systems and equipped with means used by the subscribers for making a demand for an image program and means for transmitting the demand to the broadcasting system; and a transmission center comprising; a plurality of transmission lines for connecting the transmission center with the distribution system sections; an image playback means for repetitively producing a plurality of different image programs, each image program being simultaneously available in multiple versions, the versions being identical except for being time-shifted in relation to one another with each succeeding version starting at a later time than the preceding version; an encoding means for encoding the plurality of image programs into a multiplexed signal; optical transmission means for transmitting the multiplexed signal; a first selection means for selecting, from the multiplexed signal, the image program demanded by the subscriber; a second selection means for selecting an available television channel in the distribution system section; a transmission means for transmitting the image program selected by the first selection means through the transmission line to the distribution system section on the channel selected by the second selecting means; and a notifying means for notifying the receiver of the selected television channel. - View Dependent Claims (23)
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Specification