Abstract: An apparatus for and a method of transmitting analog return signals in a digital return path of a cable television system (CATV) is disclosed. In one embodiment, at a node of the CATV system, an analog CATV return signal is converted to a stream of digital samples at approximately 100 MHz. Signals outside of a desired frequency band are removed with a digital filter having predetermined filter coefficients. The resulting stream of digital samples is up-sampled to generate another stream of digital samples at a rate that is four times the center frequency of a predetermined frequency band. The resulting stream is then punctured to generate yet another stream with a data rate that is lower than 100 MHz. Zero samples are removed, and the remaining digital samples are serialized and converted to optical signals for transmission via an optical medium of the CATV return path. A reverse process at a hub or head end of the CATV return system restores the signals of the desired frequency band.

Abstract: A switch router and one or more gateways incorporating a diagnostic and calibration system that performs RF characterization of an underlying cable plant. The switch router is connected at a point of insertion or point of distribution and each gateway is located downstream, such as at corresponding subscriber locations. The switch router and each gateway sends a test signal with known characteristics and power level, and the receiving device determines noise level and power loss for the corresponding downstream and upstream channel pair. The power loss information is used to calibrate the power level of the transmitters. The noise levels are used to determine if the selected modulation schemes employed for normal communications is realizable. A frequency analysis, such as FFT or the like, is performed on the upstream test signal spectrum to derive valuable frequency information for the upstream channel or the entire upstream bandwidth.

Abstract: A hybrid amplifier and regenerator (HAR) device is designed for use in a communications network for carrying downstream traffic in a forward frequency band and for carrying upstream traffic in a reverse frequency band spaced from the forward frequency band and below the forward frequency band. The hybrid amplifier and regenerator (HAR) device comprises an analog amplifier for amplifying the downstream traffic and a digital regenerator. The digital regenerator comprises mapping circuitry for mapping digital upstream traffic carried in at least one ramp band which is part of the reverse frequency band to digital upstream traffic carried in at least one express band which is also part of the reverse frequency band but spaced from the at least one ramp band, and an express band transmitter for transmitting digital upstream traffic from the mapping circuitry in the at least one express band.

Abstract: A Cable Television (CATV) digital return link system that provides dedicated, high-speed, full-duplex and point-to-point connections between users and the head end system is disclosed. The CATV digital return link system includes return path transmitters, intermediate hubs and a head end hub coupled to each other via a network of fiber optics cables. The return path transmitters are each coupled to a relatively large number of users via a local CATV-subtree. Signals from cable modems are transmitted via the local CATV-subtree to the return path transmitters for transmission to the head end. A number of users are individually and directly connected to the return path transmitters. Data from these directly connected users is transmitted to the head end via the network of fiber optics cables in conjunction with the RF data from the subtree. Likewise, data from the head end to these directly connected users is transmitted in the forward path direction using the digital return link system.

Abstract: An information delivery system includes receiving platforms to receive data communicated from a transmitting source according to a unidirectional transfer protocol over a link. At least some receiving platforms process the received data to determine if a portion of expected data is missing. If so, a receiving platform is able to generate and send a request for the missing data according to a supplemental protocol that is separate from the unidirectional transfer protocol. The transmitting source is able to receive the request for missing data and to retransmit the missing data. The data may include ancillary information (e.g., enhancement data) associated with audio/video content (e.g., television content). By adding the supplemental protocol to enable requests for missing data, a unidirectional transfer protocol that is not reliable is made reliable as a mechanism is provided to ensure receipt of the transmitted data.

Abstract: A data transmission system is proposed, for example for video-on-demand, internet or multimedia applications, in which a number of subscribers in a building are connected to a central server through at least in part twisted pair cables within the building. Compensation for the channel distortion caused by the use of twisted pair cables is provided by the use of pre-emphasis filters in the outgoing data lines from the server. The required coefficients for the pre-emphasis filters are established by first characterizing the distortion properties of a channel by the use of a test signal.

Abstract: A system in which a personal computer sends messages into a TCP/IP network using a conventional dial-up link and downloads data from the TCP/IP network using a high-speed one-way satellite link. A preferred embodiment uses a conventional SLIP provider to connect to the TCP/IP network and uses a commercial software TCP/IP package that has a standard driver interface. A spoofing protocol compensates for the long propagation delays inherent to satellite communication.

Abstract: An HPF for blocking an upstream signal and passing a downstream signal, an LPF for blocking the downstream signal and passing only an upstream data signal, a directional coupler for branching, and a high frequency relay for forming a through line are built in a shielded package integrally as a high frequency module, so as to restrain noise produced by a digital circuit from interfering. This enables the analogue circuit of the high frequency module and the other digital circuits to be built integrally in a network interface module mounted in a cable television set-top box. In addition, a single tuner is used for both analogue and digital signals. In doing so, the switching of an AGC voltage is problematic, which is done by an AGC switching circuit. With a network interface module mounted in a cable television set-top box, the circuit arrangement can be hence simplified, and improvements can be made on cost, size and power consumption.

Abstract: In a cable network system of this invention, GSUs are installed in almost all subscriber residences. A G-STB or a G-MDM is set for a subscriber who wants to receive bidirectional services. Alternatively, an NGA is attached to an existing N-STB or N-MDM. The presence of an upward transmission signal from an in-home device is monitored in the G-STB, the G-MDM, or the NGA. While the upward transmission signal is detected, a transmission indication signal is supplied to the GSU. Only while the transmission indication signal is detected, the GSU sets a gate switch in an ON state. On the other hand, while no transmission indication signal is detected, the GSU keeps the gate switch in an OFF state.

Abstract: A system for synchronizing the upstream burst transmission in a cable system to a time specified by the cable head end is disclosed. The system includes a free running counter within a cable modem (CM) or network interface unit (NIU), along with logic to capture the value of this free running counter at the time a frame of MPEG-2 SYNC data arrives, to create a time tag stored in memory. A computer within the cable modem or network interface unit has access to the time tags in memory and the contents of a time synchronization message from the head end, also stored in memory. The computer contains a program to calculate the value of the local counter that corresponds to a time to transmit commanded by the cable system head end. The system includes logic within the CM or NIU to initiate an upstream burst transmission when the value of the local counter becomes equal to a calculated value, thus causing the cable modem to initiate its upstream burst transmission precisely at the time commanded by the head end.

Abstract: A cable television system (100) includes forward and reverse paths. Reverse path circuitry within an optical node (400) of the system (100) receives reverse analog electrical signals from subscriber equipment (140) and generates therefrom a multiplexed reverse digital optical signal. The reverse digital optical signal is transmitted over a fiber optic cable 420 to a cable television hub (430), the reverse path portion of which includes no active circuitry. The hub (430) multiplexes the reverse digital optical signal with other reverse digital optical signals from other nodes to generate one or more forwarded digital optical signals at a hub output, wherein generation of the one or more forwarded digital optical signals requires only passive devices in the reverse path of the hub (430).

Abstract: A communications system includes forward and reverse paths. Reverse path circuitry within an optical node of the system receives reverse analog electrical signals from subscriber equipment and generates therefrom a multiplexed reverse digital optical signal. A coupling node combines digital optical signals and/or RF signals from an optical node or from coaxial cable, respectively. The combined digital optical signal is transmitted over a fiber optic cable to a cable television hub, the reverse path portion of which includes no active circuitry. The hub multiplexes the digital optical signal with other digital optical signals from other nodes to generate one or more forwarded digital optical signals at a hub output, wherein generation of the one or more forwarded digital optical signals requires only passive devices in the reverse path of the hub.

Abstract: A cable TV system, which is arranged to permit a transmission of signals in the return direction from local networks (10), included in the system, to a head end (11) of the system within a predetermined carrier frequency band, serving for the transmission of signals in said direction, comprises means (11′, 23) for monitoring the system in respect of disturbances occurring within said carrier frequency band. Said monitoring means (11′, 23) comprise detector means (32, 33, 34, 35) within each local network (10) which are arranged to compare the energy level of signals occurring within said carrier frequency band with at least one predetermined reference level and to generate logic signals, depending upon the result of said comparison, and memory means (36) within each local network (10) which are arranged to store information about time intervals during which said energy level exceeds said reference level, derived from the values of said logic signals at different times.

Abstract: A method and an apparatus transmit and receive information in a cable TV network including at least one base station connected to a branching cable network, branching from the base station to at least two subscribers, provided with transmitters. A unique carrier frequency is assigned to each of the subscriber's transmitters, the carrier frequencies being orthogonal. Signals from the subscriber's transmitters are transmitted simultaneously, received in the base station as a broadband signal, and separated using a common algorithm.

Abstract: An interactive television channel is described which includes a programming center, a master control center, a distribution center such as a satellite broadcast center or cable head end, a customer site, and a commerce server. A broadcast signal is received via a “set-top box” such as a cable connection or a DBS integrated receiver-decoder at the customer site, which supplies video and audio signals to a conventional television receiver. When a viewer tunes to the interactive music channel, the television receiver screen displays a window in which content, such as a music video, is playing. Also displayed on the screen is a surrounding matte comprising a high-quality professionally produced graphic identifying the channel. In addition, the screen displays one or more “sensitive” areas to which the viewer may direct a cursor using a remote control. By directing the cursor to a sensitive area, the area becomes highlighted.

Abstract: A transmitter (305) for transmitting reverse optical signals in a broadband communications system (300) that includes a converter (320) for digitizing the analog RF signals and a carrier-detect circuit (330) coupled to the converter (320) for detecting when digital RF signals are present at the output of the converter (320). When the carrier-detect circuit (330) detects digital RF signals, the carrier-detect circuit (330) allows the digital RF signals to be transmitted upstream through the broadband communications system (300). A digital network (310) then combines the received digital RF signals with other digital RF signals from additional transmitters (305). The combined digital signals are then provided to a receiver (315) that includes a converter (335) for returning the digital RF signals to analog RF signals and then providing the analog signals to a headend for further processing.

Abstract: A method of transmitting TV signals and bidirectional telephone communication signals on a single optical fiber, existing telephone twisted pair infrastructure, and existing coaxial cable infrastructure. In addition to allowing the downstream transmission of television channels as well as bidirectional telephone communication, the single optical fibers also provides for the upstream travel of television related signals while requiring minimal changes of the existing infrastructure.

Abstract: The distributed broadband cable modem termination system centralizes the point to multi-point function of the downstream signaling while simultaneously localizing the multi-point to single point functions of the upstream signaling. The upstream broadband cable termination segment of the broadband cable modem termination system is located at a different layer of the broadband cable network from the downstream broadband cable modem termination segment of the broadband cable modem termination system. By splitting the broadband cable modem termination system functions into separable and independently operable upstream and downstream functions, network deployment is optimized for a number of reasons. The downstream and upstream functions scale independently so the system can selectively add capacity where needed in the direction needed independent of the capacity in the reverse direction.

Abstract: A circuit arrangement for combining signals in a cable set-top box or television receiver. An out-of-band upstream amplifier and a cable modem upstream amplifier have their outputs combined at a combiner before being passed to the cable through a diplexer. The output of the diplexer provides incoming signals for an in-band tuner, a cable modem tuner and an out-of-band tuner that can be passed through a low noise amplifier before passing through a three-way splitter to divide the signals to each of the tuners.

Abstract: A data delivery system including a transmodulator for converting Internet data modulated using a first modulation protocol to Internet data modulated using a second modulation protocol and a receiver for receiving the Internet data modulated using the second modulation protocol via a transmission link.

Abstract: Docket: D2459 A system and method for increasing the performance of a digital return path in a hybrid-fiber-coax television system using baseband serial optical transport, receives an analog composite return path waveform at a comparator input to a digital return transmitter that includes an A/D converter and a first nonlinear processor. A first processing function is applied to a signal output from the comparator at the first nonlinear processor and the processed signal is forwarded to the A/D converter which converts the processed signal to generate a quantized output signal of a sequence of digital words whose value represent analog signal samples. The quantized digital signal is output to an output of the digital return transmitter and to a feedback loop including a D/A converter, which converts the quantized digital signal to an analog feedback signal and forwards the analog feedback signal to a second processor.

Abstract: A method and apparatus for identifying an appropriate video signal path is provided for delivery of video-on-demand (VOD) data to a subscriber in a VOD system. The signal path may be a portion of an hybrid fiber optic and cable (HFC) network so that other signal paths in the HFC network may service subscribers in other areas. Because each path need not service every area, the total bandwidth provided by the VOD server need not be provided to every area so that the bandwidth provided to each area can be commensurate with the needs of that area. When a subscriber requests VOD programming, the identification received by the subscriber's terminal from the VOD server is returned to the server along with the request. From the identification, the VOD server may determine the area in which the requesting subscriber is located and the VOD server may then transmit the requested programming to the area in which the subscriber is located for reception by the subscriber.

Abstract: The invention relates to the transmission of digital data which can be processed to generate video, audio and/or auxiliary data for television programmes and related information. As part of the data transmission a data stream of Out of Band (OOB) data is typically transmitted. However this requires additional components to be provided in the broadcast data receivers (18). The present invention allows for the transcoding and reformatting of data at the broadcast location (2) which allows the transmission of data between the broadcast location (2) and the broadcast data receivers (18) without the need for an OOB tuner and/or modem to be provided at the broadcast data receiver.

Abstract: The following patent relates to an overall hardware configuration that produces an enhanced spatial television-like viewing experience. Unlike normal television, with this system the viewer is able to control both the viewing direction and relative position of the viewer with respect to the movie action. In addition to a specific hardware configuration, this patent also relates to a new video format which makes possible this virtual reality like experience.

Abstract: Most cable television systems in the United States (over 75% as of this application) are structured for one-way only service between the cable headend and the user. With more and more services being introduced that require a two-way connection with the user (e.g. impulse-pay-per-view, home shopping, Internet access), it has become necessary for more and more cable systems to upgrade to a two-way capability at considerable cost and over a fairly long period of time. The typical short-term solution to the lack of two-way capability is to send request backlinks over he user's telephone line. The problem with this solution is that when used, it ties up the telephone line and requires an additional telephone connection to be located near the cable set-top-box or modem. A more practical solution is the hub centered backhaul invention described herein. With this invention, users can operate their cable systems as if they were two-way systems, with all available interactive capabilities available.

Abstract: In interactive television, a broadcaster may broadcast triggers to a great many receiver units prompting the receiver units to attempt to send requests to a single destination on the Internet at roughly the same time. Such a large number of simultaneous requests can give rise to throughput problems and server overload. A receiver unit in accordance with the invention, rather than immediately attempting to send a request, waits a period of time (for example, a random period) before sending the request so as not to overload the server. In one embodiment, a trigger is received on an interactive television receiver unit prompting the viewer to select an icon. If the viewer selects the icon, then a browser in the receiver unit retrieves a web page on the Internet identified by a URL in the trigger. The web page includes an indication of a destination, scheduling information, and a form area. The viewer enters user information in association with the form area.

Abstract: Interference and/or nonlinear distortions are reduced in a signal communicated from a transmitter to a receiver. To reduce interference, the transmitter is momentarily disrupted, during which time the receiver analyzes interference on the communication path to determine the frequency of at least one peak thereof. Information is communicated from the receiver to the transmitter identifying the frequencies of the interference peaks. Based on this information, the transmitter pre-distorts the signal to accentuate the signal magnitude at the identified frequencies. The pre-distorted signal is then communicated to the receiver, where it is filtered to attenuate the signal magnitude at the identified frequencies. An adaptive scheme periodically determines the interference peak frequencies. For nonlinear distortion cancellation (e.g., CSO/CTB), there is no need to disrupt the transmitter since the frequencies of the distortion are already known.

Abstract: The invention relates to a system for transmitting data between a distribution centre and a subscriber, this system transporting a useful signal to the subscriber and possessing a return path, characterized in that a carrier signal is transmitted in addition to the useful signal and in that the frequency of the signal transmitted over the return path is synchronized with the frequency of the carrier signal.

Abstract: A cable modem provides upstream data signals in a cable system on a return channel. The upstream data signals are provided in a 50-550 MHz frequency range and yet do not affect the picture quality associated with conventional cable television signals. The data is provided on vestigial sidebands associated with the cable television signals or during black periods associated with the cable television signals. The data can be modulated in accordance with quadrature amplitude modulation (QAM) techniques.

Abstract: A system for synchronizing one or more decoders with a network sync signal at a headend of a television communication network. The system allows decoders to transmit upstream messages synchronously in time slots which are defined according to the network sync signal, thereby improving system throughput. Identifying data is provided in a blanking interval (VBI or HBI) of one or more television signals to designate a horizontal scan line of the respective television signal which follows a reference point in the network sync signal by a predetermined delay. At each decoder, the identifying data is recovered, and the onset of the designated scan line can be used to signal the start of a transmission for the decoder. Preferably, the identifying data is provided in each television signal so the user is not forced to tune to a particular television channel to transmit a message. Various channel access protocols may be used, such as a session oriented protocol, or a synchronized ALOHA protocol.

Abstract: A communication signal adapter is connected between a portable satellite signal receiver/decoder and a wireless local area network (LAN) transceiver to enable wireless communication between the portable satellite signal receiver/decoder and a wireless LAN. The adapter includes a modem interface adapter and a communications processor that converts information, such as callback data and viewer statistical data, developed by the satellite signal receiver/decoder in a proprietary format, to a data format that is suitable for transmission via the wireless LAN transceiver and then provides the converted data to the wireless LAN transceiver for communication to the LAN.

Abstract: The present invention provides a method for combining a plurality of digital video signals, a plurality of digital data signals, a plurality of voice signals, and a plurality of upstream communications within a digital broadband headend. This digital broadband headend uses a common shared bus to optimize the resources used on a digital headend. More particularly, the method comprises providing a video interface for receiving the plurality of digital video signal, providing a data interface for receiving the plurality of digital data signals, and providing a voice interface for receiving the plurality of voice signals. The method then proceeds to process the plurality of digital video signals, digital data signals and voice signals. After this processing is completed by the digital headend, the plurality of digital video signals is communicated to at least one smart network interface module which is configured to buffer the plurality of digital video signals.

Abstract: An interactive information distribution system includes service provider equipment for generating an information stream that is coupled to an information channel and transmitted to subscriber equipment. The service provider also generates a command signal that is coupled to a command channel and transmitted to the subscriber equipment. The service provider also receives information manipulation requests from the subscriber via a back channel. A communication network supporting the information channel, command channel and back channel is coupled between the service provider equipment and the subscriber equipment.