Interactive home information system

ES 2 207 635 T3

DESCRIPTION

Interactive domestic information system. Technical field

The present invention relates to cable television systems, specifically those capable of bidirectional communications with the user.

Background of the invention

Bandwidth problems have long restricted the ability of cable television systems to provide information services to subscribers. Although a coaxial cable system may allow a cable system operator to provide, for example, 50 television channels, each 6 MHz wide, with a total bandwidth of 300 MHz, this total bandwidth is insufficient. to allow a device where each subscriber can have, in addition to these 50 channels, an interactive information service that operates independently of the interactive information services to all other subscribers and provides full color video, typical motion picture or television, and sound.

The reason for the insufficient bandwidth is evident from the demands placed on the system. Typically a subscriber in a cable system obtains information services over a communication path that begins at the headend, proceeds on one of several typical lines, then one of several feeders, and then one of several taps. Each feeder can have, for example, fifty or more subscribers, and each main line could serve a hundred or more feeders. The result is that 5000 subscribers per line is not atypical. Thus, simply providing a private one-way information service, and nothing more, to each of these 5,000 subscribers would require the line to carry 5,000 different signals, each using about 6 MHz of bandwidth, and would require only one bandwidth 30 GHz line, which is almost two orders of magnitude higher than that provided by a typical coaxial cable system.

The use of fiber optic lines can help provide additional bandwidth, but to the extent that secondary coaxial cable lines and feeders are used in a hybrid fiber-cable system, bandwidth limitations can continue to pose problems. . Although video compression schemes can help to put bandwidth requirements within more practical limits, each subscriber would have to be provided with their own decompression unit.

Another problem is how to deal with the switching and computational demands at the headend to provide separate and private information service potentially to hundreds of thousands of subscribers simultaneously.

One document suggests using a portion of the cable system bandwidth to provide the most popular channels universally to all subscribers and to supply the remaining services to individual buses on a demand-only basis. Large, D., "Tapper Fiber Vs Fiber-Reinforced Coaxial CATV Systems: A Comparison of Evolutionary Paths", Draft, 4/8/89, pages 16 and following. A three-level distributed switching system was proposed, with a switch at the head end to switch between hubs, one at each hub to switch between distribution lines, and a third-level “interdiction circuit” to select the service for each dwelling. . No architecture was proposed for such a scheme, and the author noted that "considerable development effort will be required." Id., Page 19. Furthermore, the author observes that his scheme poses a problem for the subscriber when using the system, because most channels will be accessed normally using the television tuner while switched services must be accessed by first tuning a channel from available switching, then using an auxiliary communications device to control said channel. "Since customers have historically objected to complications created by cable companies in accessing services, this can be a potential problem." Id., P. twenty.

EP-A-0 477 786 describes a system in which a regional processing center receives and distributes information to nodes located close to users. Each node receives an identical copy of information from the regional processing center through a host computer. Users receive information and interact directly with the node.

Summary of the invention

The present invention is set forth in the appended claims.

Brief description of the drawings

These and other aspects of the invention will be more readily understood by reference to the following detailed description taken with the accompanying drawings, in which:

Figure 1 is a schematic of an interactive television information system according to a preferred embodiment of the present invention, showing relationships with national and regional processing centers.

Figure 2 is a schematic showing how a multi-header system with fiber optic interconnection can be used to provide interactive television service in accordance with an embodiment of the invention.

Figure 3 is a diagram showing an embodiment similar to that shown in Figure 2, but in which a headend can have wireless communication with subscribers.

Figure 4 is a diagram showing a mixed fiber optic and coaxial cable system according to a preferred embodiment of the present invention.

Figure 5 illustrates the general architecture of the signal flow to the outdoors and bidirectional control in a system according to a preferred embodiment of the present invention.

Figure 6 illustrates how the architecture of a system similar to that of Figure 5 uses controls to handle a wide range of information services in analog and digital formats and distribution devices.

Figure 7 provides more detail of the system of Figure 6.

Figure 8 shows the signal processing aspects of the system of Figure 7.

Figure 9 shows detail of the divider and combiner of figure 7.

Figure 10 shows the assignment of frequency bands in the express lines of Figure 9.

Figures 11A-11D show the structure of a chassis according to a preferred embodiment of the presen2

ES 2 207 635 T3 The invention to support multimedia controllers (MMCs) and modulator cards that constitute components of the system illustrated in figure 7.

Figure 12 illustrates the structure of analog MMC and modulator cards for the chassis of Figure 11.

Figure 13 illustrates the structure of the preferred embodiments of the audio subsystems for the MMCs of Figures 12 and 14.

Figure 14 illustrates the structure of digital MMC and modulator cards for the chassis of Figure 11.

Figure 15 illustrates the structure of the data communication link at the head (node) of the system of Figure 7.

Figure 16 illustrates the structure of the encoder / modulator of Figure 12.

Figure 17 illustrates the structure of the video processor of Figure 16.

Figure 18 illustrates the structure of the synchro generator and scraper timing section of Figure 16.

Figure 19 illustrates the structure of the audio processor section of Figure 16.

Figure 20 illustrates the structure of the rf upconverter section of Figure 16.

Figure 21 illustrates the structure of a scrambler for use with the modulator of Figure 16.

Figure 22 illustrates the startup data timing used in connection with the scraper of Figure 21.

Figure 23 illustrates the structure of a decoiler suitable for use in a home interface controller according to a preferred embodiment of the present invention to decode a video signal that has been scrambled by a system according to Figure 21.

Figure 24 illustrates an alternative scrambling system.

Figure 25 illustrates a decoiler system for video use that has been scrambled by the system according to Figure 24.

Figure 26 illustrates the input and output structure of a home interface controller according to a preferred embodiment of the present invention.

Figure 27 illustrates one embodiment of the controller of Figure 26.

Figures 28 and 29 illustrate embodiments of digital decompression and multimedia versions of the controller of Figure 26.

Figure 30 illustrates an alternative embodiment of the system of Figure 7 in which the node is arranged in a feeder.

Figure 31 shows the bandwidth usage in a system according to Figure 30.

Figure 32 shows the general architecture of the signal flow destined for the outside and the bidirectional control in a system according to the embodiment of figure 30.

Figures 33 and 34 illustrate the use of the channel menu system in accordance with a preferred embodiment of the invention.

And Figures 35-41 illustrate the use of the carousel menu system and how the invention in a preferred embodiment provides user interaction.

Detailed description of specific realizations

For the purposes of the present description and the following claims, unless the context requires otherwise, the terms "cable television environment" and "cable television system" include all integrated systems for the provision of television services. information to subscribers for use in connection with their televisions. These include conventional cable television systems that use coaxial cable for distribution primarily of broadcast and pay television programming, cable television systems that use fiber optics and fiber-optic-coaxial cable mix, as well as other media for service distribution. information to subscribers. Likewise, unless the context requires otherwise, the term "information service" includes any service capable of being provided to a viewer that has an interface that allows (but does not necessarily require) interaction with a cable provider facility. , including, but not limited to, an interactive information service, video on demand, locally sourced service, community events service, regular broadcast service, etc. "Television communication" means to provide an information service by means of a television information signal. A "television information signal" is any signal that can be used by a television for video display, regardless of shape, including a standard NTSC modulated rf carrier, an MPEG-compressed digital data stream, or any other format. "Interactive television service" means an information service that uses an interface that provides two-way communication with a cable provider facility. When a node is said to be in an "interactive mode", it means that the node is providing an information service to the home interface controller; the home interface controller can, but does not have to, supply data to the node about what information service to provide.

Figure 1 shows the relationship of a cable television system according to the present invention with regional and national processing systems. A headend 11 is in communication with multiple nodes 12 which in turn communicate with converter-decoder units 13, which are hereinafter referred to as "home interface controllers." Each of these home interface controllers has a user-operable remote control 14. Each headend 11 may obtain items for use in providing an information service from a regional processing center 15, which in turn may obtain some information services from a national processing center 16. The information services may include a wide range of offerings, such as classified advertising services, newspapers, advertising, television catalog orders, video on demand or near video on demand, etc. Information services that are conventional television network programming can also be distributed from national and regional processing centers.

Figure 2 is a schematic showing how a multi-header system with fiber optic interconnection can be used to provide interactive television service in accordance with an embodiment of the invention. A pair of fiber optic cables 21 and 22 provide information services in the right and left directions (for

ES 2 207 635 T3 redundancy in case of cable break) from the superheader 28 to client headends 24 serving several cities 23. In turn, the superheader can obtain conventional broadcasting services as well as interactive information services from the receiver by satellite 27, and other information services from servers 25 of regional processing centers, as well as WAN and inter-central (IXC) facilities 26. Each client header 24 may contain an interactive service node, designated herein by the ISX trademark, a trademark of ICTV, the assignee hereof.

Figure 3 is a schematic showing an embodiment similar to that shown in Figure 2, but in which a headend 24 can have two-way wireless communication using transceiver 31 facilities with subscribers. A transceiver facility 31 may include a high gain antenna system 31a that communicates with a transceiver 36 coupled to a television 37 at each subscriber position. The antenna system 31a radiates rf signals fed by the transmitter 31b; the antenna 31a also receives signals from the subscriber transceivers and feeds them to the receiver 31c. Transmitter 31b and receiver 31c are linked to fiber optic receiver 32 and fiber optic transmitter 33 respectively, which in turn communicate with headend 24 over fiber optic 34 and 35.

Figure 4 is a diagram showing a mixed fiber optic and coaxial cable system according to a preferred embodiment of the present invention. In this embodiment, fiber backbones 42a carrying broadcast programming and conventional cable go to optical receiver 43a, from which coaxial lines 44A (express line A), 44B (express line B), and 44C (express line C) derive regular cable television programming signals. Each express line has a first portion of bandwidth that carries these non-interactive information television services which are substantially identical in nature and in bandwidth allocation among all express lines.

An interactive fiber line 42b in FIG. 4 carries desired interactive information services in the outward direction, which are not provided by the main fiber lines 42a, and these information services are fed to the optical receiver 43b. As will be shown in more detail in FIG. 9, the electrical output of the optical receiver 43b includes information services in separate spectral portions for each of the express lines A, B, and C. This output is supplied to hub splitter 46. Information services for each express lines A, B, and C are then transferred to common spectral portions by hub splitter 46, and then fed to designated lines, where they are coupled. to conventional signals by couplers at positions 45a, 45b, and 45c on lines 44a, 44b, and 44c, respectively. It should be noted that although the information services for each of these lines occupy similar spectral regions, their information content differs, since the information content of the information services on line A is supplied on request to the interface controllers. domestic interface controllers served by line A, content on line B is supplied on request to home interface controllers served by line B, and the content on line C is delivered on demand to home interface controllers served by line C. Thus, a second portion of bandwidth of each express line carries on-demand television information services established by usage by subscriber part of home interface controllers using the line for service.

The incoming data path from each express line 44A, 44B, and 44C is from a divider at each of positions 45a, 45b, and 45c, respectively, to the hub combiner 47. Incoming data, such as outgoing interactive television information services, on each of the express lines occupy similar spectral regions, although the data on each express line has a different information content that reflects the particular demands made by the interface controllers. domestic using each particular express line. The incoming data from each line is shifted in frequency by the hub combiner 47 in a manner described in more detail in connection with Figure 9 to cause the data from these lines to occupy separate spectral regions, and the combiner 47 output feeds the optical transmitter 42c. Optical transmitter 43c feeds fiber optic line 42c to provide a common line return path, for all home interface controllers served by express lines 44A, 44B, and 44C, for interactive headend 41.

Figure 5 illustrates the general architecture of the outbound signal flow in a system according to a preferred embodiment of the present invention. In the super header, for example, item 28 in Figure 2, various sources of information services are available from satellites, antennas, servers, and gateways, and are routed to subscribers via routing switches 52. A portion of these information services may, although not necessarily, be provided to all subscribers as a non-interactive basic service. Routing switches 52 feed appropriate modular multimedia controllers 53 (MMCs) that can provide appropriate processing to supply the service in question to each subscriber. Cards configured differently are used depending on the nature of the information service. When the information service is interactive, an individual MMC 53 is assigned on a demand basis to each requesting home interface controller, which is in data communication with MMC, and the MMC provides interactive information television service. Post switches 54 switch the MMC outputs to appropriate modulators 55, which in turn are grouped so that their outputs feed rf combiners used for each fiber optic 57 transmitter and associated fiber optic 58. As item 59 indicates, bi-directional control is exercised , to be explained in more detail below, about the flow of signals destined for the outside from end to end.

Figure 6 illustrates how the architecture of a system similar to that of Figure 5 can handle a wide range of information services in analog and digital formats and distribution devices. A super headend 28 can obtain some information services by means of a television reception only system (TVRO) 61a and downlink 62a, as well as by line 61b using, for example, T1 or T3 bands or digital protocols

ES 2 207 635 T3

ATM and gateways 62b. Superheader 28 provides information services 64 via switch 65 to headend 11. These information services may include video on demand, near video on demand, and multimedia presentations. They are supplied under the general control of control manager 62c over control bus 63a. A central database for all subscribers about the types of service subscribed and the terms for the provision of services can be maintained on the server 64a, and the provision of services to the subscribers is verified and controlled by the service manager 63 on the control bus 63a. The control manager also has supervisory control on bus 63a over input switch 66 to header 11. This switch 66, which has an input from the output switch 65 of the super header 28, feeds the analog MMCs 67a for analog signals in conventional formats and the digital MMCs 67b for signals in digital formats. The MMC outputs are then subjected to modulators for appropriate frequency translation (item 68a) and distribution 68b over the cable network to subscribers having analog converters 69a or digital converters 69b. The interactive information service is enabled by the network administrator 66a, which maintains bi-directional data communication over the gateway 66b with each of the converter types 69a and 69b.

Figure 7 provides more detail of a system according to Figures 4-6. The information sources 51 coming from the superheader 28 feed its switch 65, the output of which is directed to the header 11, which contains, in a node 77, the input switch 66 that feeds a series of MMCs, whose use is assigned based on request. As described in connection with FIG. 4, conventional cable broadcast channels are routed over fiber optic trunk 42a to express lines 44A, 44B, and 44C. A fiber interactive line 42b carries interactive channels (here called "virtual channels" for reasons that will be described below) to splitter 46 for coupling at 45a, 45b, and 45c to express lines 44A, 44B, and 44C. Combiner 47 takes incoming data from each of the express lines to supply it over the common fiber data line 42c to the node at the headend. Analog television information signals from appropriate analog CMMs are muddled at 73a and modulators at 73b, while digital television information signals from appropriate digital CMMs are processed by combining them into a QAM (Quadrature Amplitude Modulation) signal. ) composed before going to modulators in 73b. In this embodiment (as opposed to the otherwise similar embodiment of Figure 5), the modulators are preferably capable of modulating a carrier that can be tuned by the network manager 66a, such that any given modulator can be configured to handle better the demands placed on the system. (In Figure 5, the modulators are associated with carriers at dedicated frequencies, and the inputs to the modulators are changed by switch 54). Depending on the capacity of the cable system and the information services to be provided, some cable broadcast channels 72 may alternatively be offered, over path 72a to MMCs, as on-demand information services provided by node 77. (Such an approach may conserve bandwidth at cable distribution plant 68b or allow subscribers to make more offers). Additionally, path 72a allows interactively operating MMCs to allow a subscriber to overlap otherwise conventional cable television programming. The outputs of elements 73b are then combined by combiner 73 and fed to interactive line 42b. Cable distribution plant 68b includes bridge amplifiers 74, feeders 74a, feeder amplifiers 74b, and cable drops such as 75a, 75b, and 75c serving dwellings 76a, 76b, and 76c.

The information services can be offered to a subscriber by virtual channels in which the channel number changes for different interactive information services, although the various information services can be provided by a fixed frequency input to the set-top box, making the subscriber set-top box control data that the headend provides a different information service when the subscriber appears to change the channel. This feature is described in more detail below.

The modular structure of node 77 and the layout of the distribution plant 68b allow to simultaneously serve homes, such as 76a, with a conventional converter, 76b with a digital converter-decoder that has MPEG decompression, and 76c with a digital converter-decoder It has multimedia capability achieved with a domestic central processing unit. Each home has a home interface controller that operates as part of the set-top box configured as described below.

Figure 8 shows the signal processing aspects of the system of Figure 7. This figure does not show the distribution system, and therefore applies equally to telephone or cable distribution architectures. An analog MMC 82a at the node at head end 11 will typically remove, under the control of a central processing unit (CPU), a television information signal in digital form from switch 66 and then decompress the signal, subject it to frequency translation. appropriated by a modulator and will be provided by the distribution system to homes where a conventional converter-decoder in block 81a can allow the signal to be demodulated for television viewing. A digital MMC 82b at the node at the head 11 also operates under the control of a CPU, but it does not need to decompress the signal. The signal is subjected to appropriate frequency translation and then distributed to the home. In the home, in block 81b, the signal is demodulated and decompressed in the set-top box for television viewing. In the case of digital set top boxes in the home, it is necessary to provide primarily frequency translation to the head node, which is achieved by the gateway card 82c, and the converter-decoder of block 81c includes the CPU for the processing of the signal from the headend.

Figure 9 shows detail of splitter 46 and combiner 47 of Figures 4 and 7. The signals fed to splitter 46 include spectral regions for television information signals 91A to be 5

ES 2 207 635 T3 information-on-demand services for subscribers served by an express line 44A and for outgoing data 95A to provide interactive service to these subscribers. Similarly, there are spectral regions for television information signals 91B for information-on-demand services for subscribers served by express line 44B and for outgoing data 95B to provide interactive service to these subscribers; also television information signals 91C for information-on-demand services for subscribers served by express line 44C and for outgoing data 95C to provide interactive service to these subscribers. The signals in these spectral regions are subjected to frequency translation such that corresponding bands 92A, 92B, and 92C on each of the express lines 44A, 44B, and 44C, respectively, carry television information signals for information-on-demand services to subscribers served by these lines. Frequency translation is also used so that the corresponding bands 94A, 94B, and 94C carry outgoing data (downstream) to provide interactive service to these subscribers on each of the express lines 44A, 44B, and 44C, respectively. As explained above in connection with Figure 4, conventional cable channels occupy corresponding bands (here represented as element 90) on each of the express lines.

Incoming data (upstream) for interactive service is handled by the hub combiner in reverse. The data initially occupies corresponding bands 93A, 93B, and 93C on lines 44A, 44B, and 44C, and is frequency translated by combiner 47 such that incoming data from main line 44A occupies a first spectral region 96A, the incoming data from main line 44B occupies a second spectral region 96B, and incoming data from main line 44C occupies a third spectral region 96C.

Figure 10 shows the frequency band assignment on express lines 44A, 44B and 44C. The return data in band 93 occupies the region of 15-18 MHz. Data downstream in band 94 occupies the region above channel 4 in the range of 72-76 MHz. Television information signals for interactive service in band 92 they are located above the assignment 90 for conventional cable broadcast channels. However, these frequency assignments are merely illustrative. Furthermore, television communications and data communications between the node and the subscriber's home can be achieved in a wide variety of formats. Instead of putting each television information signal on a separate carrier at a separate frequency on express lines 44A, 44B, and 44C, for example, the signal could be delivered as a compressed digital data stream on a time-sharing basis or as addressed packets. In fact, data communications in both directions (inward to the node and outward to the home interface controller) according to a preferred embodiment of the invention use interval ALOHA protocols, so that data communications use addressed packets.

Figures 11A-11D show the structure of a chassis according to a preferred embodiment of the present invention to support multimedia controllers (MMCs) and modulator cards that constitute components of the system illustrated in Figure 7. A rack 112 in Figure 11A supports the switch 66 of Figure 7 along with the MMCs and encoder and modulator cards 73a and 73b of Figure 7. The MMCs and other cards are mounted in rows 114 of frame 112. Each row of cards is supported in a chassis 113 shown in Figure 11D. The MMCs (called processor line cards in Figure 11B and processors in Figure 11D) connect to the left rear portion of chassis 113, and the encoder and modulator cards connect to the right front portion of the chassis. The central vertical element 115 of the chassis provides on both sides buses for digital and RF communication, as well as power for the cards that are mounted on both sides of the chassis. Chassis 113 mounts to rack 112 so that processor line cards 67 face the reader in FIG. 11A. It can be seen from the code letters in Figure 11a for the card types listed in Figure 11B that a wide range of specialized CMMs can be employed for the system to provide a wide range of information services over a wide range. of formats. Thus, MMCs for movies only (A) (providing, for example, decompression of stored movies digitally compressed in MPEG format) can be used to obtain multimedia presentations using software that uses the Intel 486 microprocessor (B) or the Intel Pentium microprocessor ( C), or using 3DO or SGI formats (D and E). Digital CMMs are also provided (configured with a corresponding modulator as suggested in item 82b of figure 8) (item F), as well as various communication cards including some with Live Sync (which allow interactive overlaps in broadcast programming) ( G) and that allow Homev-Home communications (whereby subscribers in two or more homes can communicate interactively, for example, in a computer game) (H) and gateway cards (I). (Live Sync and Home-v-Home are trademarks of ICTV Inc., the assignee hereof).

Figure 12 illustrates the structure of an analog MMC 125 and a scrambling-modulator card 126 for the chassis of Figure 11. The MMC includes a video subsystem 121 and an audio subsystem 122 that operate under the control of the CPU 127 and the line. control 128 from network manager 66a of FIG. 7. Line 128 is also in communication with sources of information services, which receive decompression by block 121b and are mixed in the video effects and mixer module 121d. Module 121d also receives input from graphic digital-to-analog converter 121c (providing, among other things, display for subscriber interaction) using RAM / ROM storage data 121a and control / content bitstream data obtained over the line. 128. TV tuner 129 also provides video signals from conventional cable television channels on line 72a to module 121d. The RGB / YUV output from module 121d is supplied to modulator scrambler card 126. Module 121d also receives a composite sync signal input from scrambler / encoder 123 for use in providing a system timing reference to the video overlap.

The audio subsystem 122 in Figure 12 has a

ES 2 207 635 T3 coupling to TV tuner 129 (again represented in this subsystem for convenience of reference) to provide audio signals from conventional cable television channels on line 72a to a mixer 122e, which also receives signals from background music source 122b, tactile feedback source 122c (for use in connection with subscriber remote control 14 in interactive television service), and digital program source 122d, which obtain control and content data on line 128. The MTS stereo audio output of mixer 122e is then supplied to modulator 124 of card 126.

The scrambler-modulator card 126 takes the RGB input from the video subsystem 121 and the encryption control signal from the CPU 127 to provide a scrambled video output to the modulator 124. The audio output from the mixer 122e of the audio subsystem 122 is fed directly to the modulator 124. The frequency of the carrier being modulated is determined by the network administrator's control over line 128.

The structure of the digital MMC and modulator cards 141 and 142 shown in figure 14 is similar to that of the analog cards in figure 12. The outputs of the TV tuner and digital to analog graphic converter are mixed as in figure 12. However, instead of decompressing the digital video source before feeding it to the mixer module 121d, the compression is maintained here and sent directly to the MPEG mixer 144a as the MPEG 2 source. The analog output of mixer 121d is compressed by compression encoder 144, which also receives MTS audio output. The output of the compression encoder serves as source 1 input to the MPEG 144a mixer. This MPEG output is then sent to encoder 143 and modulator 124. MPEG mixing at block 144a is achieved by recognizing that the overlapping graphics data from the digital-to-analog converter 121c provides video content that does not change rapidly, and therefore can be implemented by having the mixer affect only the I-frame picture elements. in the MPEG compression scheme with respect to the overlapping content. (The MPEG compression scheme is described in “CCube CL450 Development Kit User's Guide”, December 14, 1992, Chapter 2, available from C-Cube Microsystems, Milpitas, California, incorporated herein by reference) . The MPEG mixer 144 includes a device for supplying the MPEG encoded digital signal from source 1 to a buffer; a device for extracting from the source 2 image elements of frame I of digital signal to be overlapped; and a device for overlapping the I-frame picture elements of the source 2 digital signal onto the corresponding regions of the I-pictures of the source 1 digital signal. The mixer does not allow the other image types in the source 2 signal to modify portions of the I image resulting from mixing.

Figures 13A-13C illustrate the structure of the preferred embodiments of the audio subsystems for the MMCs of Figures 12 and 14. In these embodiments, a mixer 122e is provided and, controlling its operation, a CPU 131, which can, but it does not have to be the same as CPU 127 of Figures 12 and 14. CPU 131 of Figure 13A operates in association with a synthesizer 133. The bit streams contained in line 128 may include digitally compressed audio that is decompressed by block 135. These embodiments also have an off-air tuner 132, which may, but does not have to, be the same as tuner 129 of the figures. 12 and 14. Other digital audio formats, represented herein covered by digital-to-analog converter 134, also fall within the scope of use of these embodiments. Instead of the synthesizer 133, a second decompression unit 135a (FIG. 13B) can be provided, and likewise, instead of the digital-to-analog converter 134, a third decompression unit 135b can be provided.

Figure 15 illustrates the structure of the data communication link at the head end (node) of the system of Figure 7 with subscriber home interface controllers located downstream. The outgoing data leaves the gateway 66b via line 153a where it leaves via the interactive fiber line 42b. Incoming data enters gateway 66b via line 155a from common return line 42c. Outgoing data is output from rf modulators 153 using frequency shift coding (FSK) via encoders 152, and incoming data is input via rf demodulators 155 using FSK detectors. The communications processing of the data is handled by the communications processor 151 under the control of a compatible PC having microprocessor 156a, ROM 156b, and RAM 156c. Control can be further managed by a network transceiver 157. The interval ALOHA protocol used in a preferred embodiment for incoming and outgoing data communications requires that each home interface controller be assigned an address for data packets that are used in communication with the node. When a subscriber causes his home interface controller to select a virtual channel, the node's network manager 66a is alerted accordingly. The network administrator 66a, upon determining that a given home interface controller is intended to be used for interactive television service (that is, that the given home interface controller should be put into an interactive mode), allocates additional communication bandwidth. data for data communication with the particular home interface controller, to establish on a demand basis the data communications bandwidth used by the particular home interface controller.

Depending on the nature of the information service selected by the subscriber when selecting a particular virtual channel, an appropriate MMC is assigned by the network administrator66a on a demand basis to serve the subscriber home interface controller while in interactive mode. In the case of many types of interactive television service, the home interface controller will have exclusive use of the assigned MMC, a "private line" to it over the data communications link, and the interactive line 42b. However, in the case of near-video-on-demand, multiple home interface controllers can share the same length of time on a movie, for example, and these subscribers would have a "shared line" to the MMC.

As described in more detail below, appropriate MMCs can be used to provide

ES 2 207 635 T3 overlaps or other graphics on the television screen when the home interface controller is properly equipped.

Figure 16 illustrates the structure of the encoder / modulator 126 of Figure 12. It includes a video processor 164 that has an RGB / YUV input and produces a scrambled NTSC video output on line 123d. The video processor has inputs from the scrambler / clock generator timing block 163, including a 3.58 MHz color subcarrier on line 163d, burst flag on line 163c, invert control on line 163b, and sandcastle pulses on the 163rd line. The scrambler / sync generator timing block 163 has inputs including free run / sync generator selection and encryption control 123c from CPU 127, and provides composite sync output on line 123a. The scrambler / sync generator timing block 163 also provides an MTS subcarrier reference signal on line 123e to audio processor 162. The audio processor 162 includes standard MTS stereo audio inputs for left, right, and secondary audio program. The NTSC video signal jumbled on line 123d along with the MTS composite audio output from the audio processor 162 is used to modulate a carrier at a desired frequency (set by the network manager 66a of Figures 6 and 7) by the upstream rf converter. 161.

Figure 18 illustrates the structure of the scrambler / sync generator timing block 163 of Figure 16. It is used to generate a series of overlap sync and scramble timing signals that are either synchronized to or from an external CATV signal. inherently stable mode. The TV tuner 129 of FIG. 12 further includes a demodulator 186 in FIG. 18 and a sync splitter 185. The sync splitter includes conventional cable television video output bare horizontal sync on line 181a and frame replacement signal on line 182c. The bare horizontal sync signal on line 181a forms a reference to phase lock a 3.58 MHz oscillator in color subcarrier lock block 181, the output of which is provided on line 163d. The signal on line 163d is divided to provide a horizontal reference signal on line 182d. The signal on line 182d provides a reference to phase lock the generation of sync signals by sync generator block 182. This block provides composite sync and blanking signals on lines 182a and 182b, as well as frame sync, horizontal sync, burst flag, and MTS subcarrier reference on lines 184a, 184b, 163c, and 123e respectively. Block 182 provides frame sync and horizontal sync signals to cryptology block 184. It also provides composite sync and composite erase signals to mode logic block 183. Cryptology block 184 and mode logic block 183 operate cooperatively with each other to produce sandcastle pulses on line 163a in the manner described below in connection with Figure 21. Sandcastle pulses are used to provide NTSC video jumbled in the manner also described below in connection with Figure 21.

FIG. 21 illustrates an implementation of scrambling by cryptology block 184 of FIG. 18 in cooperation with mode logic 183 and video processor 164. Scrambling is accomplished by removing substantially all sync pulses from the NTSC signal. Then infrequent horizontal pulses (at least once per frame, two fields per frame) and randomly spaced (sand castles) are reintroduced. The effect of such jumble is to prevent the standard NTSC receiver from obtaining horizontal and vertical sync lock with the incoming signal. This produces fast horizontal and vertical reappearance of the image. During the intervals when the removed sync signals were present before, the scrambler fixes the video to a near white level. As a result, when the video signal tends toward levels corresponding to black, the receiver frequently interprets this video content as a sync signal, with the additional effect that the horizontal reappearance and vertical reappearance are aperiodic.

The sandcastles are reintroduced into a pseudo-random position in each consecutive frame, determined by the vertical random number generator 212 in FIG. 21. The line counter 214 is synchronized by horizontal synchronization displayed on line 184b, and is reset by pulses. frame sync on line 184 each frame. The line counter 214 stores a new number from the vertical random number generator 212 each time a frame reset pulse is received. When the line counter 214 has counted to zero from the stored number, it triggers the timing pulse generator 216 to send a pulse to mode logic control 183. Occasionally, on command of the load / count line 212a, the timing pulse generator 216 is caused to produce sand castles on a plurality of successive lines. A command from the load / count line 212a also triggers the loading of a previously stored start value (loaded from line 211a) from the buffer register 211 to the vertical random number generator 212 and the horizontal random number generator 215. The startup value and load / count numbers on lines 211a and 212a are supplied by CPU 127 of Figure 12 at the command of the network administrator initially each time an MMC is assigned to serve a particular home interface controller. and then whenever the home interface controller reports on the data communications link that it has lost synchronization. Additionally, CPU 127 may be programmed to generate new start values ​​and load / count numbers according to any desired strategy to resist unauthorized re-bypass efforts.

Each sandcastle pulse looks like the sum of the composite blanking and composite sync signals. Therefore, the shape of the sandcastle pulse is such that when added in the adder 172 of Figure 17 with suppressed sync video, the result is a signal that has a normal NTSC blanking period once per frame, and furthermore, the normal blanking period occurs on pseudo-randomly located lines in successive frames. The sandcastle pulses appear on line 163a from the logic controller of

ES 2 207 635 T3 mode 183. Therefore, the composite sync signals 182a and the composite blanking signals 182b are summed and gate-switched by the mode 183 logic control upon receipt of pulses from the timing pulse generator 216 as described above. The width of the timing pulse generator signal along line 184c, which controls the duration of the sandcastle pulse, is equal to the horizontal blanking period.

Analogously to the operation of the vertical random number generator, the horizontal random number generator 215 outputs a pulse at pseudo-random line intervals. Each pulse is the duration of the active video portion of a horizontal line, and is fed through input 163b to cause video processor 164 to produce entire horizontal lines that have inverted video.

Figure 17 illustrates the structure of the video processor 164 of Figures 16 and 21. Block 171 shows an RGB / YUV to NTSC converter that receives conventional inputs (including RGB / YUV, 3.58 MHz color subcarrier, and burst) but in this case, no sync or blanking input signals are missing. The converted output is standard NTSC with the exception that all timing information is suppressed. Inverter 173, under control of pulses present on line 163b, reverses video on a line-by-line random basis in the manner previously described in connection with Figure 21. The output of the inverter is then added at adder 172 with the sandcastle pulses to produce the jumbled NTSC waveform described above.

Figure 23 illustrates the structure of a decoiler suitable for use in a home interface controller according to a preferred embodiment of the present invention to decode a video signal that has been scrambled by a system according to Figure 21. It will be recalled in connection with Figure 21 that the start value and load / count numbers in lines 211a and 212a are supplied by the CPU 127 of Figure 12 at the command of the network administrator initially each time an MMC is assigned. to serve a particular home interface controller. The same start value is also supplied to the home interface controller and stored in buffer register 231. Each time a new start value is loaded into the scraper's buffer register 211, the same start value is loaded into the unwinder's buffer register 231. The value in register 231 remains in the register until it is synchronized to the vertical and horizontal pseudo-random number generators 232 and 235 respectively by a pulse from the timing pulse detector 238. The relative timing of the startup data, and the load / count pulses, and the appearance of sand castles in the jumbled NTSC video are shown as items 221, 222, and 223 of Figure 22.

Timing pulse detector 238 checks for incoming jumbled video on line 238a. The timing pulse detector 238 produces a clock pulse when it detects the plurality of pulses produced in the scrambled NTSC video when the scrambler in FIG. 21 received a load / count pulse on line 212a. (In this way the timing pulse detector produces the generation of one pulse at a time with respect to the received jumbled signal which corresponds generally to the appearance of the load / count pulse when the original signal was being jumbled). The clock pulse from the timing pulse detector then causes the stored start value to be loaded into the pseudo-random number generators 232 and 235.

Timing pulse generator 238 also detects the appearance of single sandcastle pulses, and these are used to trigger the load of line counter 234 and resetting of timing generator 237. This generator is phase locked to burst color and thus makes the necessary sync signals reconstruct an unwound NTSC signal. The composite sync and composite blanking signals from generator 237 feed sand castle adder 2331 to produce a complete series of sand castles for each line and the entire NTSC frame structure. The output of the adder 2331 goes to the sandcastle complement generator 233, which gates the input each time a sandcastle occurs on the jumbled video input line 238a. Therefore, the output of the sand castle plug-in generator is a series of sand castles that lacks a sand castle each time, and only each time, that a sand castle is present in the jumbled video signal. This output is fed to decoder / amplifier 236, where it is added with the scrambled video signal to produce an output that has a sand castle on each line and is therefore an unscrambled NTSC video signal.

Analogously to the function of the inverter control on line 163b of Figures 21 and 17, the horizontal pseudo-random number generator 235 produces an inverter control signal on line 235a, which produces a pulse in time corresponding to the production of a pulse by the horizontal pseudo-random number generator 215. This control signal on line 235a produces a second inversion (and therefore restoration) of the previously inverted video line produced by inverter 173 of FIG. 17. The result is fully restored NTSC video on line 236a.

Figure 19 illustrates the structure of the audio processor section 162 of Figure 16. The left and right audio inputs of the audio subsystem 122 are supplied to the sum-difference matrix 191. The sum L + R output on line 191a is subjects to the low pass filter 1921 and the pre-emphasis filter 1923. Similarly, the LR difference on line 191b is subjected to the low-pass filter 1922 and the dbx compressor 1924 and the compressor output is fed to a dual balance mixer 193. The MTS subcarrier reference signal on line 123e is subjected a frequency division by divisor 195, and also frequency division by a divisor by two 196. The output of the first divider 195 is band-pass filtered by element 1971, and the resulting output is supplied to the dual balanced mixer, to produce a double sideband suppressed carrier signal on line 193a. This signal is summed by the adder 194 with the pre-emphasized L + R signal on line 1923a and the subcarrier signal SAP; the latter is supplied by the SAP subcarrier generator 198, to which the SAP signal of the audio subsystem 122 is supplied. This produces a composite BTSC signal on line 162a, which is supplied to the rf converter

ES 2 207 635 T3 upstream 161 described in figure 16.

Figure 20 illustrates the structure of the rf upconverter section 161 of Figure 16. The inputs include BTSC audio on line 162a and NTSC scrambling video on line 123d. The video input is supplied to a 2011 am modulator and the audio input is supplied to a 2012 fm modulator, and the respective modulator outputs are summed at adder 202. The adder output is passed in-band by filter 2031 and amplified by amplifier 2032. The amplifier output is mixed with the signal from the first local oscillator 2043, and the desired upper sideband is amplified and band-pass filtered by amplifier 2042 and filter 205. This intermediate frequency signal is then passed through amplifier 2051 and is mixed in mixer 2052 with a signal from a second local oscillator 2053 that is frequency agile (here a phase locked oscillator). The output is amplified (at amplifier 2053) and low-pass filtered by filter 2054, to remove the upper sideband, and the resulting signal is amplified by amplifier 2055 and provided as an output on line 161a. (This output is fed to the combiner 73 of Figure 7).

Figure 24 illustrates an alternative scrambling system. The system has an NTSC sync stripper 241 that supplies sync nude video to a mixer 243, which masks sync signals by supplying a chroma subcarrier at all times, including during horizontal and vertical retrace. Furthermore, the luminance signal is made to be present at all times.

These results are achieved by using the vertical and horizontal sync outputs of stripper 241 to provide an output from OR gate 2461 when either of both vertical and horizontal retrace signals is present. This output switches via switch 242 a pink noise luminance masking signal 2421 to mixer 53. This output is also affected by switch 247 by a pink noise signal from generator 2471 which is used in turn to modulate phase locked loop oscillator 244 to produce a chroma modulated subcarrier masking signal. This signal is subjected to an optional programmable phase delay 245 to produce a different phase shift of the signal during the color burst interval on a line-to-line basis according to a phase shift generated by the pseudo-random generator 2451. The signal from Composite sync output from stripper 241 is provided with an encrypted value for the current phase shift produced by generator 2451. The encrypted value is obtained from the DES encoder 248, and this encrypted value, a digital signal, is put into the signal during the vertical blanking interval as a binary pattern by the vertical blanking interval data encoder 249. The sync signal The composite is then subjected by delay 2491 to an optional variable time delay of a reference value that is also obtained from pseudo-random generator 2451. Naturally, a separate generator could be used, provided that the value obtained from such a generator is also encoded in the composite sync signal. This resulting jumbled composite sync signal is then supplied as an output. Thus, this system provides a continuously present chroma subcarrier, a continuously present luminance signal, and shifts the color burst by a random amount. Therefore, scrambling video is relatively difficult to unravel, without accessing the scrambling method.

Figure 25 shows a video descrambling system for descrambling the scrambled video according to a system as shown in figure 24. The jumbled video signal provided by line 259 is disabled during both vertical and horizontal retrace intervals by gate 251, thereby removing the masking signals that interfere with proper timing, and the proper timing signal, presented on line 2543. , is also added to mixer 253 to provide composite video output on line 2532. The jumbled timing present at input 258 is first used to provide the encrypted delay information (if an encrypted delay is used) that is decoded from the vertical blanking interval data by decoder 255 and decrypted by DES 256 decoder The jumbled sync signal is executed by programmable time delay 257 to provide a composite sync signal that is in phase with the video. Sync splitter 254 provides separate outputs for vertical and horizontal sync as well as a gate signal for the color burst. The vertical and horizontal sync signals are routed via the NI gate 2541 and the OR gate 2542, such that 251 turns off video during the vertical and horizontal retrace except during the color burst. The optional video decoder 252 separates the chroma subcarrier (in case it is phase-shifted), and the separated subcarrier is executed by optional programmable phase delays 2531 by an amount specified by the decrypted delay data to recover the original phase of the subcarrier. The resulting corrected subcarrier is mixed with the luminance and audio subcarrier and the composite sync signal by mixer 253 to provide a composite video signal unwound on line 2532.

Figure 26 illustrates the input and output structure of a home interface controller 13 according to a preferred embodiment of the present invention. The controller includes input and output connections 261 for rf cable television, a videocassette recorder interface 262, an expansion interface 263 (for obtaining baseband video; ports for printer, modem, and computer; and power line interface), infrared transmitter port 264 for communication with a conventional converter-decoder, video cassette recorder, and television, infrared receiver port for communication with the remote control 14, rf output 266 for communication with a receiver of television, and baseband outputs 267 for communication with a television screen.

Figure 27 illustrates an embodiment of the controller of Figure 26 suitable for analog television signal inputs. RF cable TV input 2711 feeds diplex filter 271, the high-pass section of which feeds TV information signals and data down to line 2712 and splitter 2714 for splitting between the RF VCR output at 2782, the VCR receiver. data control 2751 and tuner 272. The low-pass section receives communication10

ES 2 207 635 T3 data streams up from control data transmitter 2752 on line 2713. Tuner 272 switches between rf VCR output 2782 and television information signals on line 2712. The tuner output is switched feeds unwinder 373, which is branched by switch 2731. The sync generator block 2732 provides necessary sync signals to allow the overlap controller 2733 to function properly with the tuner output. The output of the overlap controller is fed directly to the baseband video output 267a, and the audio output of the tuner is routed via the volume control 2741 to the baseband audio output 267b. A channel 3 / channel 4 modulator 274 coupled to these baseband outputs provides rf output on line 266 to the subscriber television. Switch 2741 switches the television between the television information signals from the home interface controller and the rf output of the VCR. Data communications involving data receiver 2751 and transmitter 2752 are handled by data communications processor 275, and the flow of information is via data bus 279 to and from converter-decoder processor 276, infrared interface 2761 for remote control 14, overlap controller 2733, tuner 272, and volume control (set) 2741.

Figures 28 and 29 illustrate embodiments of digital decompression and multimedia versions of the controller of Figure 26. The embodiment of Figure 28 is similar to that of Figure 27, except that a high-speed data receiver is also provided. speed 281 having an input connected to divider 2714. The output of the high speed receiver feeds the digital decompression module 282. This module has an audio output that feeds the mixer 283 along with the audio from tuner 272 and a video output that can be switched to the overlap controller 2733 by the switch 285, the other position of which makes the overlap controller 2733 get its video only. from the analog source as before.

The multimedia embodiment of Figure 29 represents a further improvement of the embodiment of Figure 28. In addition to the high-speed data receiver 281, there is a high-speed data transmitter 291. These communicate with the data bus 279 via an interface high speed data rate 292. Communication frequency control at these data rates is provided by frequency control block 2941. Audio mixer 295 operates under the control of sound microprocessor 2943. Additional effects are achieved by multimedia processor 2944, and overlap and effects block 2942.

Figure 30 illustrates an alternative embodiment to the system of Figure 7 in which node 302 is arranged on a feeder 74a, typically close to a bridge amplifier 74. In some embodiments where a bridge amplifier can serve a plurality of feeders, the node can equally serve home information controllers in each of these feeders. In this embodiment, the main line 301 feeds the express lines 44. Bridge amplifiers 74 are arranged in positions where feeders 74a are connected to lines 44. At a socket 303 is arranged the supply line 75 to a subscriber dwelling having a home interface controller 13 and remote control 14.

Figure 31 shows the use of bandwidth in a system according to that of Figure 30. The bandwidth is limited at node 302 by a low-pass filter so that digital carrier signals 319 in the bandwidth portion above the region 315 assigned to ordinary cable channels cannot reach the home interface controllers downstream of the node on feeder 74a. (Alternatively, the bandwidth can naturally be limited by the bridge amplifier 74, with the node in communication with line 44). The digital signals removed in bandwidth 319 can typically carry compressed digital television information, and those of these signals that may be required to serve downstream home interface controllers are obtained by node 302 and remodulated to provide interactive service of television downward on the same spectrum 317 used upward by digital signals 319. The decompression of the digital signals can be carried out in the node 302 or in the home interface controllers 13. Thus, the node 302 is able to use, for communication only, the home interface controllers 13 associated with its own group of feeders 74a, the interactive channel bandwidth 317 shown in FIG. 31. Each node can use this bandwidth region independently of the other nodes, because the signal transfer between nodes in the frequency spectrum portion 317 is small, and in any event it can be controlled between different nodes. Above the bandwidth used for non-interactive television signal management, including the system region 315, is the spectrum portion 317 used to carry interactive television information signals from the headend. Incoming back data communications are accomplished using the lower frequency band 316, with a high pass filter at each node to prevent the transfer of unwanted signals; fresh remodulated carriers are introduced into the node for upstream communications. Protective bands 318 are placed between bands 315 and 317 and between 316 and 315 to prevent interference. Each node 302 then achieves utilization of the relevant interactive television information signals to the subscribers associated with that node who have gained access to such signals.

Figure 32 shows the general architecture of the signal flow destined for the outside and bidirectional control in a system according to the embodiment of figure 30. In the feeders 74a node 302 is arranged, which can include an RF bus and tuners to demodulate signals from television information (which may include conventional cable television signals as well as interactive television signals) from the headend. An MMC 53 with related modulator, as in previous embodiments, is placed in direct communication with a home interface controller 13 on a demand basis, so that node 302 functions essentially the same way as node 77 when placed in the header.

Figures 33 and 34 illustrate the use of the channel menu system in accordance with a preferred embodiment of the

ES 2 207 635 T3 invention. Figures 33 and 34 apparently show different channels used for different information services, here TV programming (channel 31) and classified ads (channel 37), albeit in the manner previously described, the frequency at which the home interface control unit you receive information that has not changed. The term "different information service" used in this description and in the following claims can mean any information service in a way that appears to be different to the subscriber, including an interactive service in a different information area, or a different interactive service. , or a different broadcast television signal provided by the headend, etc.

Figures 35-41 illustrate the use of the carousel menu system and how the invention in a preferred embodiment provides user interaction. Figure 35 illustrates an embodiment of the carousel menu system according to the invention when an interactive information service has been selected. (In this case, the interactive service is classified ads). The carousel here shows three faces, one of which is a front face. The front face shows one or more menu options. The two side faces shown are previewed to visualize the obvious availability of other options if the carousel is rotated such that one of the side faces moves to the front position. By operating the overlap 2733 described in connection with Figures 27-29, or the video effects and mixer block 121d of Figures 12 and 14, a cursor can be moved on the television screen by the remote unit 14, and when the cursor overlaps the menu option of interest, the choice can be selected by pressing the appropriate button on the remote unit 14. Depending on the choice selected (and if secondary options are required by the area of ​​interest in the particular interactive information service), the carousel is shown momentarily rotated apparently in one direction or another, and then another set of options is made to appear in the front face, the flank side faces again showing in preview.

Figures 36 to 41 illustrate how interactive television service can be provided in accordance with a preferred embodiment of the invention. If TV programming has been selected (here channel 31), a grid portion is displayed, which can be scrolled on the screen to view the grid in its entirety. Figure 36 shows a portion of the grid display, which represents television programs as a function of channel and time for a given date and part of the day; and the date and part of the day can be selected by the subscriber.

Selecting "Smart TV" allows the subscriber to search for programs or other information service offerings in the manner illustrated in the following figures. The carousel options indicated in FIG. 37 allow the subscriber to find shows and movies by theme, by broadcast, or by actor. Other options allow the subscriber to program their favorite channels and find offers on the channels, or identify offers on a pay-per-view basis, or return to the grid in Figure 36. If the selection is made “by actor”, the alphabetical menu of figure 38 is presented. To find “Bogart” programming, the upper button “ABCDE” would be selected, producing the visualization of figure 39. Then, the button "B", and from the displayed list of actors whose names begin with "B", one could select "Bogart", and eventually produce the list and options represented in figure 40. One could, for example, choose to record Casablanca on June 24, producing the display of figure 41, including the choice to have other Bogart films notified in the future.