Abstract: A Communication Gateway is capable of operating in broadband telephony networks having different Cable Modem Termination System and Call Agent implementations. The Communication Gateway has a set of parameters for use in defining the different implementations. Based on a selected implementation of the different implementations, values for parameters of the set are input into the Communication Gateway. The inputted values are stored. The Communication Gateway operates in the selected implementation using the stored values.

Abstract: A method of reducing noise and ingress in cable return paths is disclosed in which the return frequency spectrum is divided into two regions; one frequency region being for transmissions from in-home devices such as television settops and personal computers, and another frequency region being for transmissions from communications devices called coaxial termination units located between the drop cable and the home coaxial wiring. By locating blocking filters between the drop cable and home coaxial wiring, undesirable signals emanating in the home in the second part of the return spectrum are prevented from entering the cable return system. The location of the blocking filter reduces the noise in the second part of the return spectrum substantially and allows the establishment of reliable telecommunications services on the cable return in such second part of the return spectrum.

Abstract: A method and apparatus are provided for receiving a packet stream having fixed length packets. Data carried in the packet stream is selectively processed for output to a computer. A packet identifier filter selects particular packets from the recovered packet stream. A computer disk controller receives the packets selected by the filter and manages the transfer of packet data from the packets to and from a buffer. A data bus is coupled to the disk controller for communicating the packet data from the buffer to the computer. A data compression stage prior to the disk controller compresses packets from the recovered packet stream in order to provide a gap between data carried by successive packets to be provided by the disk controller. In this manner, a low cost disk controller chip can be used to control the buffering of data in a cable or satellite television modem that provides, e.g., Internet access.

Abstract: The integrity of a group of secure processing elements in a communication system is ensured with a validation scheme. Member elements are checked by adjacent members to determine whether a member has been tampered with or operatively removed from a group. If a member is found to be untrustworthy, propagation of group characteristic information to that member will be halted. The group characteristic information defines the group, and is required by each group member in order to function. The untrustworthy member is therefore effectively exiled from the group. An efficient network topology minimizes inter-member message traffic while maintaining group robustness.

Abstract: A control unit provides unified control of various consumer electronic appliances such as a television, video cassette recorder, and home stereo system through remote control (e.g., infrared) signals. A receiver portion of an interface module positioned over the built-in remote control signal receiver of the appliance intercepts signals from a hand-held remote control operated by a user. The signals are routed to a control unit (such as a set-top television converter) where control logic determines a desired control action. A corresponding control action signal is routed back to a transmitter portion of the interface module and is received by the built-in remote control signal receiver of the appliance to be controlled, thereby resulting in the desired control action. The apparatus provides additional functions and increases user convenience and access to video, audio, and data signals provided via a cable television, direct satellite broadcast or similar service provider.

Abstract: Apparatus and methods are provided for implementing an interactive program guide on an information network. A plurality of database pages are communicated over the information network. Each page corresponds to a time slot over which events are available on the network. Schedule data for each event to be included in the interactive guide is inserted into the database page for the time slot during which the event is to be provided. The database pages are transmitted via the information network at a transmission rate selected to enable the recovery of a particular database page within a predetermined acquisition time limit, for retrieval of schedule data for the time represented by that page. Schedule information for a current time period can be provided in a trickle data stream with future scheduling information provided in a demand data stream. The demand data stream is transmitted at a substantially higher rate than the trickle data stream.

Abstract: A resonantly enhanced external electro-optic modulator reduces required drive power. The modulator has a coupling structure that efficiently couples power from a feed line into the resonator and eliminates the need for a terminal impedance. The modulator can be driven by a RF signal that is designed to suppress Stimulated Brillouin Scattering (SBS) in a long haul, high power fiber optic link, such as that used to transmit analog CATV signals. The modulator can also be used to depolarize an optical signal. A ring resonator includes a portion located outside the active area of the modulator in order to provide a space-efficient structure. The ring resonator can include one or more coaxial cable portions that are tuned to provide resonance at one or more frequencies that are matched to the input RF drive signal.

Abstract: The present invention comprises a memory management system employed in a settop terminal which utilizes memory available at the headend of a CATV system through a bidirectional CATV network to augment the memory resident within the settop terminal. The system includes a memory management unit that monitors the software application running on the settop terminal microprocessor, pre-fetches blocks of the program from the headend and stores these blocks in resident memory. The memory management unit manages the limited pool of settop terminal memory by dividing it into segments large enough to hold a single program block. Program blocks are fetched from the headend as needed by the microprocessor, and segments of memory containing program blocks not likely to be used are reused. The system provides sufficient read-ahead capability to ensure that the microprocessor has enough executable code to process at all times. The location of the memory is completely transparent to the microprocessor.

Abstract: An MPEG transport packet stream or the like is modified to provide concatenated synchronization bytes at an output of an interleaver receiving the modified packet stream. A conventional sync byte located in a first transport packet is replaced with a first substitute sync byte. A conventional sync byte located in a conventional sync byte position of a second transport packet is deleted. Another byte from the second transport packet is moved to the position of the deleted sync byte to open a desired byte position in the second transport packet. A second substitute sync byte is inserted into the desired byte position. The first and second transport packets and the desired byte position are selected to provide the first and second substitute sync bytes at locations in the modified packet stream where the first substitute sync byte will be concatenated with the second substitute sync byte at the output of the interleaver.

Abstract: A method and apparatus are provided for generating a digital signature that authenticates information of a plurality of different information groups. Information from each group is hashed to produce a separate hash key for each group authenticating the information in that group. Particular combinations of the hash keys are hashed together to produce at least one combined hash key. Each of the hash keys is ultimately combined in a predetermined order with all other hash keys via the combined hash keys to produce the digital signature in a manner that authenticates the information of all of the information groups. The digital signature is reproducible without access to all of the information groups authenticated thereby. Instead, information from a first information group is provided together with a set of hash keys and combined hash keys embodying authenticated information from the other groups.

Abstract: An N-bit, byte-wise data randomizer uses a linear feedback shift register arrangement where each register stage stores N-bits. In this manner, a pseudorandom sequence can be generated based on a nonbinary primitive polynomial over a finite field of any desired length. In a specific disclosed embodiment, the primitive, degree three trinomialf(x)=x.sup.3 +x+.alpha..sup.3over the finite fieldF.sub.128 =F.sub.2 ?.alpha.!/(.alpha..sup.7 +.alpha..sup.3 +1)is implemented.

Abstract: Error recovery is provided for isochronous data ("isodata") obtained from a data stream. Isodata transport packets are monitored to locate isodata presentation time stamps (PTSs). The presentation of isodata from a buffer is synchronized to a system time clock (STC) using timing information derived from the PTSs. Discontinuity errors between said isodata transport packets are identified and, if a discontinuity of no more than one packet is identified, a write pointer of the buffer is advanced by a suitable number of bits to compensate for the discontinuity, while maintaining the synchronization of the presentation with respect to the STC.

Abstract: Apparatus processes mixed YUV and color palettized video signals for display on an interlaced NTSC or PAL television receiver by storing first and second fields of one or more sprites in a graphic memory. Each sprite is stored as YUV or color palettized data and given a priority. A higher priority sprite overwrites pixel data of sprites of a lower priority when sprites overlap. First and second adjacent horizontal lines of pixel data in the first and second fields, respectively, are concurrently stored in respective first and second double buffers of a pixel assembly buffer during each line period. A delay buffer and the first and second double buffers generate first, second, and third adjacent horizontal lines, respectively, of pixel data at the output of the pixel assembly buffer while third and fourth adjacent horizontal lines of pixel data are inputted to the first and second double buffers.

Abstract: A random access memory of a digital video decompression processor is mapped to enable the reconstruction of successive video frames of pixel data represented by a compressed video bitstream. A FIFO buffer is provided in the RAM for the compressed video bitstream. A first luminance anchor frame buffer and a first chrominance anchor frame buffer are provided for storing a full frame of luminance data and a full frame of chrominance data for a first anchor frame used to predict B-frames. A second luminance anchor frame buffer and second chrominance anchor frame buffer are provided for storing a full frame of luminance data and a full frame of chrominance data for a second anchor frame used to predict the B-frames. A first B-frame luminance buffer is provided in the RAM and sized to store less than 100% of the amount of luminance data in a first B-frame field. A second B-frame luminance buffer is provided in the RAM and sized to store at least 100% of the amount of luminance data in a second B-frame field.

Abstract: Audio data is processed from a packetized data stream carrying digital television information in a succession of fixed length transport packets. Some of the packets contain a presentation time stamp (PTS) indicative of a time for commencing the output of associated audio data. After the audio data stream has been acquired, the detected audio packets are monitored to locate subsequent PTS's for adjusting the timing at which audio data is output, thereby providing proper lip synchronization with associated video. Errors in the audio data are processed in a manner which attempts to maintain synchronization of the audio data stream while masking the errors. In the event that the synchronization condition cannot be maintained, for example in the presence of errors over more than one audio frame, the audio data stream is reacquired while the audio output is concealed.

Abstract: A method and apparatus are provided for achieving synchronization and detecting errors in a data stream such as an MPEG-2 transport packet stream. In an MPEG embodiment, the MPEG sync word is removed and replaced with a parity code that is used at the decoder for both synchronization and error detection. A syndrome calculator in the decoder can be implemented using a unique one bit in, one bit out FIR filter. Codewords used to generate the parity code can be provided by a linear block code that is a dual of a shortened cyclic code.

Abstract: A method and apparatus are provided for communicating VBI user information for digital television. A syntax is provided which allows the transport of closed captions, non-realtime video, sampled video and AMOL. Non-realtime video can be used to transport various types of data, such as a vertical interval test signal (VITS) through the system at full resolution. The provision in the syntax of a count for each type of VBI user information enables the adjustment of a digital television data stream to accommodate variable amounts and types of such information without space being reserved in advance. The provision of a priority number in the syntax enables decoders to discard VBI user information priorities which are not supported by the particular decoder.

Abstract: A phase modulator is provided in an externally modulated, feed-forward linearized, analog cable television (CATV) link for reducing fiber-induced composite second order (CSO) distortion components. The system is compatible with existing commercially available modulators. CSO distortion is caused, in part, by self-phase modulation of the transmitted signal in the fiber optic link. The problem is particularly prevalent when data is transmitted at a wavelength other than the minimum dispersion wavelength of the fiber. Moreover, CSO distortion increases with the length of the fiber optic link and with the optical intensity modulation index of the primary modulator of the link. The phase modulator modulates an optical signal which is provided to the primary modulator in accordance with an optical phase modulation index k of an RF data signal to be transmitted.

Abstract: An injection molding apparatus includes a nozzle which is directly connected to a mold for injecting a molding material into the mold. The mold defines at least one cavity in the shape of a element to be molded and at least one gate passage, each gate passage interconnecting a separate cavity with the nozzle. The shape of the gate passage permits a rapid curing of any residual molding material, and permits separation of the mold and the nozzle before the molding material in each cavity is cured. The nozzle is then used for a subsequent procedure or molding process while the molding material in the cavity cures. The nozzle defines a first bore and a second bore arranged longitudinally in sequence, and a side hole for introducing the molding material into the first bore. The nozzle includes a first plunger which is selectively reciprocally movable in the first bore, and a second plunger which is selectively reciprocally movable in the second bore and in a central bore defined in the first plunger.

Abstract: A semiconductor device, which has a silicon body that includes at least one planar p-n junction that intersects a surface of the body, uses a multilayer arrangement that includes a first layer of thermally grown silicon dioxide, a second layer of Chemical-Vapor-Deposited (CVD) silicon nitride, a third layer of CVD oxygen-rich polysilicon, and a fourth layer of CVD silicon dioxide to passivate the junction. Common metallization contacts both the diffused region of the planar junction and the oxygen-rich polysilicon.