Presentation player

Image display device

The invention relates generally to a digital interactive switching system which, on request of a subscriber, can send out still video images, optionally with an accompanying audible message, and relates in particular to a display device that receives a digital packet stream via a conventional CATV distribution power line, converts the digital packages into the selected video presentation with accompanying audio message and forwards this presentation to the requesting subscriber via a previously assigned output channel in a standard CATV distribution.

Different types of connection systems are commonly used to provide voice, data and video connection services to subscribers. In particular, interactive cable television systems have been developed to distribute information to subscriber television sets on demand. One such system relates to a shopping service in which subscribers make purchases in an electronic mall at home. This system differs from home shopping channels in that it allows subscribers to select which products or services they want to see on their screens using a home installed subscriber set such as a telephone or collective subscriber keypads. In operation, the subscriber selects a channel and requests a connection to a remote location by dialing a predetermined telephone number, or gains access through a subscriber return channel. Once the system has identified the subscriber, its screen begins to show video stills, with associated audible information if necessary, and lists of electronic stores are displayed with products or services that the subscriber may want to view in detail for can postpone further considerations and complete a purchase by simply touching buttons on a dial pad telephone following instructions on the screen. A main frame auxiliary computer controls the flow of information in the system.

This sales service uses a cable television community service network to distribute the video presentations and associated audio messages as requested by the subscribers. A device known as a frame storage unit holds the video and audio portions of a representation at various points in the community network. Each of these locations serves a small group of participants. The function of each frame storage unit is to capture the video images intended for the participants assigned to the particular frame storage unit. The frame storage unit captures a video image which is addressed for an associated subscriber and converts the image into storable form. Then the frame storage unit determines which audio message belongs to the video picture, bundles the audio and video messages together by time division multiplexing the video part on one channel and frequency division multiplexing the audio part on another channel, and puts the result in the subscriber distribution cable. The composite signal sent out by the frame storage unit appears as a normal television picture on the subscriber's television set.

The audio and video signals processed by the frame storage unit are in an analog format. This is in contradiction to the display devices envisaged by the present invention which receive and process both the video and audio portions of displays in digital format. The associated device multiplexes both video and audio onto a single channel.

There are numerous advantages of the device according to the invention over the known frame storage unit. The display device enables the interactive connection system to operate a larger number of participants than the known system, since the audio and video signals are time-division multiplexed on one channel. In addition, the digital processing of these signals results in improved resistance to distortion, improved fidelity of the sound and improved ability to preserve the image of a representation intact. An additional advantage of digital processing is an increase in the frequency spectrum of the communal systems intended for broadcasting the audio / video service. '

The digital processing and time division multiplexing of audio and video signals by the display device according to the invention thus offer significant advantages over the frame storage unit which is used in other interactive connection systems.

It is an object of the present invention to provide a video and audio display apparatus of the character described which can be used in a digital interactive connection system for delivering still and motion video presentations with associated television quality audio to on-demand subscribers a more accurate reproduction of the original signals is to be achieved, thus enabling a virtually new interactive connection system for the distribution of products and services to subscribers.

This object is achieved with a display device for use in an interactive connection system in which subscribers can select from a variety of video / audio displays for viewing on their televisions. The video / audio presentations are sent in the form of digital information packets to a large number of display devices that are strategically distributed in the vicinity of a large number of participants. Each digital package sent to the presentation devices is uniquely addressed to a requesting participant.

The display device contains a converter, a control part and at least one participant aid. The converter is tuned to a fixed frequency narrowband control channel that sends out tuning information. This tuning information causes the converter to be tuned to a broadband channel in which it monitors a stream of digital information including the digital packets which represent the selected video / audio presentations. For further processing, the converter records the digital packets clearly addressed to predetermined requesting subscribers.

The controller receives the uniquely addressed digital packets from the converter and sends each of these packets to a previously assigned subscriber aid in accordance with the unique packet address. This means that each display device processes the digital packets that are addressed for certain participants. In particular, each participant aid within a display device is in turn responsible for processing the digital packets of certain participants. The subscriber assistance receives the digital packets and converts them into analog formatted (in the USA for example NTSC formatted) video / audio representations, which are then sent out to the requesting subscriber.

The invention is explained in more detail below with reference to the drawing, for example; in this shows:

FIG. 1 shows a block diagram of a digital interactive connection system which, in connection with a cable community reception network and the display device of the type according to the invention, supplies participants with still image presentations in television quality,

Figure 2 is an exploded block diagram of the display device shown in Figure 1,

Figure 3 is an exploded block diagram of the

Display device converter from Figure 2, and

FIG. 4 is an exploded block diagram of FIG

Participant help from Figure 2.

In FIG. 1, the display device 54 according to the invention is used in conjunction with a digital interactive cable television system 10. In operating the system 10, a subscriber uses a dial tone keypad 12 to communicate with the system 10. The signals emitted by the telephone device 12 are carried over conventional telephone lines to a local operating center (LOC) 11 of the system, which operates with local area network technology. In the LOC 11, the tone signals of the telephone device 12 are picked up by a voice network interface (VNI) 14. If these audio signals are normal broadcasts in the speech area, they are fed to the VNI 14 in analog form and recognized by it and decoded into ASCII characters, which are recognized by a transfer circuit 16. As soon as the audio signals are received by the VNI 14 and converted into digital signals, the VNI 14 also transforms the digitized wave signals into a through the transfer6

Circuit 16 recognized protocol. The VNI 14 can, for example, be a special circuit from Summa Four, Inc. with the designation Specialty Digital Switch Model No. SDS-1000, in which a predetermined number of outgoing telephone lines are available in order to bridge any incoming subscriber calls to service representations. Regardless of whether the audio signals are in digital or analog form, the output signal of the VNI 14 is passed on to a first local area network (LAN) 18 through the intermediary of the transfer circuit 16. In FIG. 1, the VNI 14 is arranged within the LOG 11, but according to the invention it can also be possible for the VNI 14 to be accommodated at some other location.

The network topology of the first LAN 18, ie the physical configuration of the network, is known as the ring topology.

With a ring topology, all devices in the network are connected by a single connecting cable in a circular or ring shape. Signals are passed from one device to another around the ring. When a signal moves around the ring, each device on the LAN electronically detects whether the incoming message is intended for that device. If so, the device processes the signal; if not, the device normally regenerates the signal and sends it on to the next device in the ring.

Network access identifies the individual processes that allow every device in the network to communicate and receive data. The network access method used in the LAN 18 is commonly known as token passing. A token is a special bit pattern that is constantly passed on in the ring network. Every device in the network has to wait until it receives the character before it can send its message, it puts the character back into the network, and this is then passed on to the next device in the network. If a device has no message to send, it lets the character pass to the next device in the network. With that, possession of the sign is permission to send a message.

The transmission medium connecting the devices on LAN 18 can be either broadband or baseband coaxial cable. The baseband coaxial cable carries only one signal at a time, but the signal travels at a high speed in the region of 10 bits / s. Some method, of which there are a very large number, is used to allow many devices to have access to LAN 18 at the same time.

The devices contained in the LAN 18 include a large number of single-board or single-chip computers, each with a special function for operating the subscribers, as well as RAM memory, a clock generator and I / O devices (input / Output facilities). The single-board computers each have specialized application programming or software and are each connected to a transfer circuit that establishes the connection to the LAN 18. In addition to the single-board computers, the LAN also has a large database 28 which is commonly referred to as a disc farm. Digital information is stored in the database disk units which is video representations of goods or services. In general, these video presentations include television-quality still images or text information, text information may also be superimposed on a still image, or any other combination thereof. These video presentations can be accompanied by an audio message, and they are then referred to here as video / audio presentations. Any of these stored video / audio presentations can be saved upon request during

- 8 of a connection to the system 10 can be viewed (and listened to) by a subscriber. Path information is also stored in the database 28, which describes the paths to be followed in the display, and also information about participants. Typically, the companies that offer goods or services to such subscribers develop some structure of video / audio presentations that result in an electronic warehouse.

One embodiment of single board computers connected to LAN 18 are, for example, Model No. iSBC 36/100 or Model iSbc 186/100 manufactured by Intel Corp of Santa Clara, California. The computers are designated according to their function in the LAN 18, and so one can see circuit connection aids 20, route aids 22, subscriber aids 24 and cashier aids 26 in FIG. While the aids 20, 22, 24 and 26 are each identified by a single functional task, it is also possible within the scope of the present invention for each aid to have appropriate programming so that each aid device changes its functions depending on the requirements in the system 10 can. During a circuit connection of a subscriber to the system 10, a circuit connection aid 20 will be dedicated to serving a particular subscriber. The number of interconnection aids 20 in any LOC 11 depends on the number of subscribers served by the LOC 11 and accordingly any number of interconnection aids 20 in the range of 100 to 2000 units in a LOC 11 is possible.

The outgoing message from the VNI 14 is transferred by the transfer circuit 16 to one of the plurality of switching connection aids 20. The transfer circuit 16 forwards an incoming subscriber call to any free switching connection aid 20. The switching connection aid 20, like all other aids in the LAN 18, is connected to the LAN 18 by means of a transfer circuit. In this case, each individual aid does not necessarily have to be connected to a transfer circuit, as shown in FIG.

The switch connection aid 20 processes the message by translating or converting it to some logical signal that the other aids understand and then passes the signal to the LAN 18 for further processing by the other aids. The switching connection aid 20 thus interprets the digital signal representing a key on the push-button telephone 12 and sends a command or sends commands to the other aids in the LAN 18. These commands contain the participants' requirements for selected displays.

The route aid 22 contains a dynamic RAM memory of such a size that in any case sufficient information can be stored to enable the subscriber to walk through accessible display structures. The information stored in the route aid 22 defines the routes between the displays in any display structure. Since the route aid 22 contains a dynamic RAM memory, it only stores route information that is useful at a particular point in time when connecting with a subscriber. The dynamic RAM memory of the route aid 22 typically has a size of approximately 10 Mbytes of RAM. This means that the route aid 22 cannot store all of the information given by a specific client of the display system in its memory. As already mentioned, this information is stored in the disk memories of the database 28.

In the operation of the system 10, the subscriber designates the Dar10

Position or the representations he wishes to view by pressing dial keys on the dial key telephone device 12. The digital signals which represent the pressed telephone keys are processed by the switching connection aid 20 and addressed for the route aid. The route aid 22 fetches the route data from the database 28 which are required at this point in time in order to carry out movements in the display network in accordance with the requirements of the subscriber. If the subscriber requests information within a particular presentation structure, the dynamic memory only stores such route information which is concerned with this section of the display network that could be requested by the subscriber at the particular point in time during the subscriber connection. If the subscriber moves in the display structure while the connection continues, the route information in the dynamic memory will change in accordance with the subscriber's walk in the structure. According to this route information stored in the dynamic memory and from the interpretation of the digital signals of the switching connection aid 20, the route aid 22 determines which representations stored in the database 28 are selected by the subscriber and sends a signal via the LAN 18 so that the database 28 can display the requested representations Sends participants.

The subscriber information aid 24 stores information about the subscribers connected to the system 10. The information pertaining to each subscriber includes his telephone number, his personal identification number and identifies a display device which is intended to receive the displays requested by the subscriber. As will be explained in more detail later, the display device receives and stores the displays requested by the subscriber and forwards them to him.

I i

Μ - 11 Typically, the help 24 is only active during part of any subscriber connection. During the operation of the system 10, the switching connection aid 20 queries the subscriber information aid 24 for the information relating to a subscriber. The aid 24 then fetches the requested information and sends it to the circuit connection aid 20, which stores this information in its memory. Since the switching connection aid 20 is active during the entire connection of the subscriber, there is no need to ask the aid 24 for information during the remainder of the subscriber's connection.

The cashier aid 26 processes all information relating to the subscriber's purchases of goods or services. For example, the cashier assistant 26 asks the subscriber how he would like to pay for purchases. If the subscriber chooses a credit card as a means of payment, the cashier 26 provides access to the identification number of the subscriber's credit card in the database 28 and sends a corresponding message to a corresponding service so that the subscriber's credit card is charged with the purchase. Another function of the cashier's aid 26 is to notify the trading companies participating in the demonstration and sale of the purchases so that the goods are appropriately brought to the participant on the way.

Purchasing information can either be sent to the client in real time (on-line) or it can be stored at the cashier's 26 and passed on to a client at a later point in time. For example, all purchases made during a certain time can be stored by the cashier aid 26 in a memory data folder (file) and are then collected at the end of the period (in batches) and sent to the various clients for further processing. The cashier aid 26 can also describe the means with which the purchased goods are delivered to the subscriber. This means that the assistance instructs the client whether the goods and how they should be brought to the participant, or whether the participant will pick them up at the client's shop.

A second LAN 30, also with a ring topology, is connected to the database 28 in order to transmit the digital signals which represent the video / audio presentations to a community TV reception system. The transmission of a single video image requires amounts of information of around 30 to 50 kbytes. Since a large number of bytes of digital information are required to represent the image portion of the display, a second LAN 30 is necessary as it can accommodate a greater amount of digital information at a higher speed than the first LAN 18. In order to meet this requirement, the transmission means of the second LAN 30 is a broadband connection, preferably an optical fiber cable with a few optical fibers which represent a larger bandwidth than the first LAN 18, which transmits a few 100,000 information bits / s with a coaxial cable.

A channel assistant 32 receives subscriber control information from the first LAN 18 and information representing selected video presentations from the second LAN 32 to route a broadcast to a receive community headend 38. Transfer circuits 34 and 36 couple the channel aid 32 to the first LAN 18 and the second LAN 30, respectively. The channel aid 32 contains a microprocessor, a RAM memory with a few Mbytes, an encoder with debugging and a modulator. The video, audio and control information received by the channel aid 32 is converted and modulated into a high speed digital stream suitable for transmission over a cable television network. The channel aid also establishes the order in which the information is sent to the shared cable network and performs forward debug encoding to ensure the reliability of transmission through the cable television network.

Typically, a LOC 11 serves approximately 5,000 to 10,000 subscribers, depending on the location. Each LOC 11 can communicate with other LOC circuits via a gateway 40 which in turn connects via a very high speed transmission medium such as broadband transmission or a communications satellite. The gateway 40 contains a microcomputer with a memory of at least several Mbytes and is connected to the first LAN 18 and the second LAN 30 through interface circuits 42 'and 44, respectively. When connected to other LOC circuits, the LOC 11 can request information, for example video / audio presentations, which cannot be found in its own database 28, and can in turn meet the requirements of other LOC circuits.

In a typical cable television network with a common receive end head 38, trunk cables 46 extend from end head 38 as the primary signal path. A plurality of nodes 48 are provided along the trunk cables 46. A bridge amplifier 49 (see Figures 2, 3 and 4) is generally located at each node 48 to amplify the video / audio representations and route them along a secondary cable 50 to the respective subscriber's home 52. According to the invention, a display device 54 is arranged at each node 48, which device supplies at least one secondary cable 50 with signals. Eight possible secondary cables 50 are connected to display device 54 in Figure 2, and only one such secondary cable is shown as actually being used. A connection connection 56 to a connection cable 58 extends along each secondary cable 50 into the apartment 52 of the corresponding subscriber and is connected there to a television set 60. Each subscriber cable 58 is typically a coaxial cable.

In accordance with the present invention, display device 54 is a cable television outdoor system device approximately the size of a common common reception bridge amplifier and generally has the same power and mounting requirements as such a bridge amplifier. In its broadest sense, the display device is a frequency-moving broadband receiver with a very fast data demodulator that is tuned by a narrowband fixed-frequency control channel. The purpose of the display device 54 is to receive a stream of digital packets representing the video / audio displays from the head end 38 of the communal receiving system, to convert those digital packets to video / audio displays and to convert certain video / audio displays to predetermined output channels to send participants to be requested. Each display device 54 processes only those digital packets which represent video / audio displays which are requested by subscribers assigned to this display device 54. In this way, the digital packets representing video / audio representations requested by a subscriber are addressed to the special display device 54 which is dedicated to the task of processing the video / audio representation for the subscriber.

According to FIG. 2, the display device 54 contains at least one and up to eight subscriber aids 62. The subscriber aid 62 can only be available for a single subscriber and can be installed in an apartment in a subscriber device, but will typically serve a small group of subscribers together according to usage criteria . Any single participant of a predetermined group can

Achieve access to a subscriber assistance 62 by dialing the number of the LOC 11 and entering his wishes. When a subscriber has made use of the services of a subscriber assistance 62, no other subscriber in the same group can use the subscriber assistance until the first subscriber has finished. The number of participants or simultaneous users for whom a single display device 54 was installed depends firstly on the number of participant aids 62 in the device 54, secondly on the acceptance of the average number of orders by the participants assigned to each participant support 62 and thirdly on the number of participants to be selected Output channels available to the LOC 11 for broadcasting the video / audio presentations on the cable television network.

The display device in FIG. 2 contains eight subscriber aids 62, but the present invention does not stipulate that more than one output channel frequency can possibly also be reachable for two or more subscriber aids. Typically, the display device 54 will be installed in the vicinity of an intermediate or bridge amplifier 49 and serves one to eight simultaneous users who are served by one to eight secondary cables 50. The relevant number of secondary cables 50, which proceed from a display device 54, is determined by design criteria, which relate firstly to the number of apartments that are served by the CATV feeder cable in question, secondly to the channel distribution in the local CATV system and thirdly to considerations relating to the local installation and availability of systems.

In addition to the subscriber aids 62, each display device 54 further includes a subscriber aid controller 64 and a display device converter 66. The choice of configuration of any display device 54 depends on the servicing needs of the area in which the display device 54 is installed.

The display device converter 66 is tuned to a fixed frequency narrowband control channel to in turn tune itself to a broadband channel for receiving the digital packets representative of the video / audio presentations. In other words, the converter 66 receives tuning information over the narrowband control channel and, as a function of this information, tunes itself to the indicated broadband channel which carries the stream of digital packets sent out by the LOC 11. This automatic tuning arrangement allows display converter 66 to select the correct channel, demodulate the signal to form a digital stream suitable for local processing, perform forward error correction, and determine whether the packetized information in the monitored digital stream is intended for a subscriber aid 62 housed in the same display 54 is. Thus, display device converter 66 is a variable frequency broadband receiver with a high speed data receiver tuned by a narrow band fixed frequency control channel.

As shown in FIG. 2, the output signal from the display device converter 66 is transmitted to the subscriber assistance controller 64. The subscriber assistance controller 64 is a monitoring device that routes signals from the display device transducer 66 to the appropriate subscriber assistance 62. That is, the subscriber assistance control 64 determines which subscriber assistance 62 is intended to receive the information present in packets. This information, which is present in packets, contains video and audio packets, which each represent the video or audio component of the display and also a display rule. The representation rule determines when and during what length of time the subscriber aid 62 is to send out video images with associated audio signals that represent a specific video / audio representation. The operation of the subscriber aid 62 includes the implementation of a digital-to-audio conversion of the video / audio representation, the use of graphic information made up of ASCII characters, the mixing in of background music and the transmission of the video / audio representations the assigned output channels in a compatible format (eg NTSC format, PAL format or SECAM format) for viewing by the requesting subscriber.

The function of the display device converter 66 is to determine and tune the frequency band within the CATV spectrum in which the digital information stream resides, convert and monitor this information for processing and handling details as required to video / audio - Deliver representation to requesting participants. This function of the display device converter 66 will be more apparent from the description of its constituent parts below.

As seen in Figure 3, the display device converter 66 includes a fixed frequency receiver 68 which is continuously tuned to a predetermined narrowband control channel within the CATV spectrum. This narrowband control channel with a width of 10 kHz or less, for example, contains the information required for the converter 66 to control the display device 54. The receiver 68, which is permanently tuned to the control channel, transmits digitally coded information at a rate of approximately 9600 bit / s to a demodulator 70 designed in VLSI. At this speed, approximately 100 million destination addresses can be controlled with simultaneous forward error correction, display format variants and a number of diagnostic Missing. After the demodulator 70 performs forward error correction, it forwards the signal to a receiver controller 72 which contains handling and editing commands including scripted product display instructions, video / audio package determinations, diagnostic reporting schedules and the location of subscriber information screens.

The frequency of the selected high speed input channel is sent by the receiver controller 72 to a frequency variable broadband receiver 74. The receiver 74 tunes to the channel determined by the receiver controller 72. The signal in the selected channel is sent by the receiver 74 to a demodulator 76, the demodulator 76 converts the analog signal into a digital bit stream, carries out a forward correction and sends the digital packets thus obtained to the receiver controller 72 Display device 54 selected digital packages and transferred to the subscriber assistance control 64.

The subscriber assistance controller 64 sends the information digital packets to one of the subscriber aids 62 present in the display device 54 in accordance with the address information contained in the digital packet. Each subscriber aid 62 in a display device 54 is responsible for processing the digital information packets which are intended for subscribers assigned to this display device.

In FIG. 4 it can be seen that the information packets transmitted by the subscriber assistance control 64 are received by a small CPU 78 in the subscriber assistance 62 and are stored in a read / write memory area 80 (RAM memory). The CPU 78 determines which of the information packets is an explanation packet and then uses the explanation in that packet to determine how the video and audio packets are combined with graphical information in real time for viewing by the subscriber. The rule packages also determine the fidelity and duration of background and upper deck tones, as well as the arrangement of video images on the screen and the duration of these presentations together with the added visible text. In addition, the regulation packages can define an automatic sequence of audio / video sequences when a special subscriber requirement is met. If an error is detected during the preparation of a product presentation sequence, the subscriber error control 64 uses a replacement message from the local read / write memory in order to provide the requesting subscriber with information or instructions. '

The rule packets, depending on whether they contain video or audio information or both, are transmitted from the CPU 78 to a video expander 82 and / or an audio expander 84. The video expander 82 contains facilities for graphic overlays, as well as functions for reversing the process which is defined by a video compression algorithm. The audio expander 84 decompresses the audio packets and converts them to real-time sounds. The video and audio packets are also handled by video processor 86 and audio processor 88, respectively. After expanding and lining up the video and audio information, it is used to modulate a CATV channel that can be selected by the subscriber by means of an output modulator 90, a frequency-moving transmitter that sends the compiled display to the requesting subscriber in the appropriate format (NTSC, SECAM or PAL) the frequency assigned by the CPU 78. Accordingly, the requested video / audio presentations are played to the requesting participants via the display device 54 on the previously assigned output channels.

An illustrative embodiment of the present invention has been described in detail with reference to the drawings, but it is to be kept in mind that the invention is not limited to this embodiment and various changes and modifications are possible for those skilled in the art without departing from what is claimed To deviate from the protection area.