Abstract: A method and system for optimizing performance in a data-over-cable system. The method includes determining parameters for data transmission on an upstream channel of the data-over-cable system, and negotiating use of the parameters. A measurement is made of a signal-to-noise ratio (“SNR”) on the upstream channel. Associated with the SNR and a target packet-error-ratio (“PER”) are parameters that provide optimal data throughput. The parameters, such as symbol rate, type of modulation, or amount of error correction, are used to construct a message that is sent to the cable modems. The message instructs the cable modems to reconfigure themselves to transmit according to the parameters. The reconfiguration helps ensure optimal performance.

Abstract: The present invention comprises a device which may be attached to a cable ground block (62) such that the level and type for signal emitted through the upstream flow of the signal, from a residence or business (59), may be determined along with the location of the source of ingress of any such signals. The invention, further includes a device (10) to transmit a signal of predetermined frequency towards a residence, such the source of errant signal ingress may be determined. Further, a method of causing the transmission of the signal at a predetermined time, measurement of the signal and determination of the source of the ingress of the signal is provided.

Abstract: A cable modem uses a CATV network as an information transfer medium. To a cable modem proper that is connected by way of a coaxial cable to a CATV network, an expansion unit is attached that has a wireless LAN function that permits wireless communication with an information processing terminal. The expansion unit is removably attached to the cable modem proper by use of a plug and connector.

Abstract: The present invention encompasses a method and apparatus for detecting and characterizing one or more ingress events in the return band and creating a time/frequency map based on the detection of the ingress events. The time/frequency map is further characterized by marking frequency bands with ingress level above a predetermined threshold with a “1”. The time/frequency time map may be used to determine when and which return frequency band has exceeded a predetermined threshold, and to distinguish between a narrowband ingress event and a wideband ingress event. When such characterization has been made, the return path may be attenuated or disconnected at a communications gateway device located at or substantially near the subscriber location. By disconnecting the return path or attenuating the return path signal at or near the subscriber location, the ingress may be reduced and locations which are the cause of severe ingress may be effectively isolated.

Abstract: The present invention encompasses a method and apparatus for ingress detection and attenuation. When a determination is made that the level of ingress in a return frequency band has exceeded a predetermined threshold, the return path is attenuated or disconnected at a communications gateway device located at or substantially near the subscriber location. By disconnecting the return path or attenuating the return path signal at or near the subscriber location, ingress is reduced and locations which are the cause of severe ingress are effectively isolated. This allows for a high degree of reliability to be maintained on the return path, and insures that critical services like cable telephony can be provided.

Abstract: A technique is disclosed for selectively adjusting the power and/or frequency of cable modems without relying solely on the most recent measurement of these values to determine whether a change is necessary. Rather, it considers multiple recent measurements and from these makes its assessment. In one approach, the technique employs an average of the recent measurements to determine whether a change in power or frequency is necessary. There are actually at least three determinations that can make use of multiple recent measurements. These include (1) determining whether the signals are fluctuating to an extent that requires a special adjustment technique, (2) determining whether an adjustment is necessary (using the special technique), and (3) determining how large of an adjustment is necessary.

Abstract: The present invention concerns an ingress noise control system and an ingress noise blocking device which are used in a cable system to suppress ingress noise. In the cable system providing two-way communication using different frequency bands for transmission of upstream and downstream signals, the ingress noise control system includes, within a distribution unit, a two-way amplification unit, etc. provided in an upstream signal transmission path, a synchronous detection controller 6 for synchronously detecting the upstream signal transmitted from terminal equipment and separated by a low-pass filter 4 in a second separation filter 2, a gate switch circuit 5 which is turned on by the synchronous detection controller 6 to pass the upstream signal only when the upstream signal is synchronously detected, and an indicator 7 for indicating the on/off state of the gate switch circuit 5.

Abstract: An adaptive data stream filter removes narrowband interference from the CATV return path prior to these paths being combined in the network. A method for removing narrowband interference from the CATV return path detects potential narrowband interference in real-time and adapts a filter to remove this potential narrowband interference. An exemplary embodiment of the above method uses previously created filters that are combined based on detected interference in an adaptive manner to continually adapt to new interference sources. Another exemplary embodiment of the above method calculates new filter coefficients for the data stream filter based on detected interference. In another embodiment, two filters are operated in a ping-pong manner for each band of interference identified as above threshold. This enables updating of one filter while another filter is performing the data stream filter operation.

Abstract: A method and apparatus providing channel management in a broadcast receiver. The method includes estimating an intensity and a signal-to-noise ratio (SNR) of broadcast signals received via a plurality of physical channels (PCT channels) in a channel memory mode, determining reception quality of the respective plurality of PCT channels, in consideration of both the estimated intensity and SNR of the broadcast signals, and assigning the plurality of PCT channels to a virtual channel (VCT channel) according to a predetermined rule with respect to a reception quality of the plurality of PCT channels.

Abstract: Provided are a system and method for modifying detected radio frequency (RF) leak information in a cable television system. In one example, the method includes identifying a leak location and a leak magnitude in the cable television system using a detection system. A predefined range value may be automatically identified based on the leak location, where the range value is used to define an approximate distance between the cable television system and the detection system. The leak magnitude may then be modified based on the range value.

Abstract: An arrangement for the reduction of noise transmitted in the return direction fron a local cable TV network (10) comprises an input (14), an output (16), means (21) for evaluating signals incoming at the input (14), and blocking means (17) controllable by said evaluation means (21). Said blocking means are formed by a reprogrammable digital signal processing unit (17), which is connected to the input (14) via an analog-to-digital converter (19) and which is arranged to generate digital output signals corresponding to portions of the incoming signals, depending upon the existing programming of the signal processing unit (17) and the result of the evaluation of the incoming signals effected by the evaluation means (21), and to deliver said digital output signals to a digital-to-analog converter (24) connected to the output (16).

Abstract: Cable modems are provided for measuring a noise signal power level on the upstream side of the cable network. The cable modem may be configured to make the signal power measurements at a variety of frequencies and at a selected bandwidth during a specified test time period responsive to a request received from the cable network. Methods and systems are provided for identifying a noise signal source on a cable network including specifying a time window for measurements, the desired measurements and the cable modems from which measurements are desired when the need to initiate a test to identify a noise source is detected. Tests may be initiated based on noise signal measurements by individual cable modems or by the cable services provider which indicate an unacceptable noise level. In addition, the reliability of the test measurements may be improved by not allowing any transmissions on the upstream side during the concurrent test window while cable modems are making the requested measurements.

Abstract: An adaptive high pass filter is used to reduce signal noise such as that occurring on a CATV upstream carrier. A signal detector senses a lowest active frequency on a CATV transmission. A high pass filter is then adjusted to cut off transmissions at frequencies below the lowest active frequency. This reduces ingress noise present in the upstream channel.

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 optic 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. The return path transmitters include circuitry for digitally processing the RF data from the subtree prior to transmitting the RF data to the head end.

Abstract: A method for decreasing upward-joining-noise in an upward-signal-inputting position of a center device includes the steps of: measuring a noise level of each of a plurality of upward signals supplied from a plurality of transmission lines; determining whether the measured noise level of each upward signal is low enough or not; and based on a determination result, controlling and adjusting a level of each upward signal. Therefore, the level of an upward signal, for which the noise level of the upward signal is determined to be low enough, is adjusted higher but still kept at a level low enough not to interfere with upward signals from other transmission lines.

Abstract: A method and apparatus for reducing delay distortion of upstream transmissions in a cable television (CATV) distribution plant. Upstream transmission in a CATV distribution plant, i.e., from the customer premises toward the head-end, is made difficult by delay distortion caused by diplexing filters used in bi-directional amplifiers and other components in the CATV distribution plant. A database storing information relating to each cable modem (CM) in the CATV distribution plant is maintained, and the delay distortion for each upstream transmission is calculated using information queried from the database. Delay distortion in the upper portion of the upstream bandwidth in a CATV distribution plant is preferably minimized by assigning CMs having a transmission path that causes relatively minimal delay distortion to the upper portion of the upstream bandwidth.

Abstract: The upstream performance characteristics of a network are measured by looping a signal through both the downstream and upstream paths of the network. Test equipment may be located at a headend of the network and configured to transmit a signal downstream to a remotely located loopback device that redirects the signal in the upstream path to the test equipment. The upstream characteristics may be predominant in the analysis of the return signal because the downstream path may be relatively free from noise.

Abstract: A system, method and apparatus for coordinating the operation of channel quality assessment and analysis and ingress filtering of an active channel in a cable modem system.

Abstract: The present invention provides an apparatus and method for reducing the amount of ingress noise that is present in the reverse path of a two-way communication network. The present invention employs intelligent dynamic switches (200) that determine whether desirable reverse signals are present at that point in the network. If so, the reverse signals, which also probably include some amount of ingress noise, are allowed to pass further upstream. If no desirable reverse signals are present at that point in the network, the IDS (200) blocks the transmission of any reverse signal further upstream, thereby blocking the transmission of any ingress signals. Although ingress noise is allowed to travel upstream with desirable reverse signals, the performance of the overall network is improved because ingress signals are blocked at various points in the network, thereby reducing the total amount of cumulative ingress noise signals that would otherwise be present in the network.

Abstract: Apparatus, methods, and computer program products for utilizing a frequency channel determined to be unacceptably noisy by finding a cleaner, narrower bandwidth within the frequency channel. Initially data is received on a frequency channel at a CMTS, specifically an upstream receiver, and by a narrow bandwidth detector, connected to a processor also used by components in the CMTS. The narrow bandwidth detector performs a Fast Fourier Transform (FFT) on the frequency channel thereby creating multiple FFT points within the frequency channel. A clean bandwidth for transmitting data within the frequency channel is identified where the clean bandwidth is derived from a subset of FFT points from the full set of FFT points. The subset of FFT points are contiguous points that have a noise level below a predetermined noise threshold.

Abstract: A cable television system (400) includes a transmitter (200) for generating a digital optical signal (204) and a receiver (300) for receiving said digital optical signal and converting it to an analog signal. The transmitter (200) includes a processor (238) for processing inputs and generating a gain/loss parameter which is applied via a gain/loss amplifier (250) to an incoming analog signal (232). The modified digital signal received by the digital optical receiver (300) decodes the applied gain/loss parameter at a converter (325) and applies the information to the output analog signal via a gain/loss amplifier (330).

Abstract: In transmitting the analog video signal via a coaxial cable, a transmission apparatus side is not provided with an emphasis characteristic which is the inverse to the frequency attenuation characteristic of the coaxial cable. In stead, an emphasis is applied by a preemphasis circuit on the transmission side, on the basis of an emphasis curve of a frequency band characteristic curve having an inverse characteristic to a frequency band characteristic curve of a detected signal which is obtained when transmitting a modulated signal without a preemphasis to the coaxial cable and conducting synchronous detection on a receiving apparatus side by using an oscillation frequency having the same frequency as that of a carrier used at the time of modulation.

Abstract: At transmission of a digital modulated wave between a digital set top box and a digital TV, favorable transmission with little picture quality deterioration and noise is realized without employing a coaxial cable.

Abstract: A supervisory communications device, such as a headend device within a cable communications network, monitors and controls communications with a plurality of remote communications devices, such as cable modems, throughout a widely distributed network. The supervisory device allocates bandwidth on the upstream channels by sending MAP messages over its downstream channel. A highly integrated media access controller integrated circuit (MAC IC) operates within the headend to provide lower level DOCSIS processing on signals exchanged with the remote devices. The enhanced functionality of the MAC IC relieves the processing burden on the headend CPU and increases packet throughput. The enhanced functionality includes header suppression and expansion, DES encryption and decryption, fragment reassembly, concatenation, and DMA operations.

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: The present invention comprises a device which may be attached to a cable ground block (62) such that the level and type for signal emitted through the upstream flow of the signal, from a residence or business (59), may be determined along with the location of the source of ingress of any such signals. The invention, further includes a device (10) to transmit a signal of predetermined frequency towards a residence, such the source of errant signal ingress may be determined. Further, a method of causing the transmission of the signal at a predetermined time, measurement of the signal and determination of the source of the ingress of the signal is provided.

Abstract: A system and method for creating and distributing virtual channels of digital video content. Initially, a first entity is enabled to acquire digital video content from one or more sources and store the digital video content into a database storage device. Next, the first entity is enabled to select digital video content and group the selected digital video content to form virtual specialty channels, each virtual specialty channel having content customized for a particular viewer base. The created virtual specialty channels are stored in the database storage device which is accessible by a second entity over a public communications network. The second entity comprises infrastructure for delivering virtual specialty channels to individual viewers over a broadband communications channel.

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: A local area network uses coaxial cable wiring for interconnection of terminal devices. A frequency selective network interface device is placed at the building point of entry or another point in the wiring to reflect network signals transmitted by terminal devices back into the building distribution to be received by other terminal devices. By reflecting network upstream signals back into the building as downstream signals, the network interface provides a path for terminal devices to transmit to and receive from other terminal devices.

Abstract: A method, device and system are provided for a physical layer for a CATV upstream channel. A group of features is provided to address increased capacity and robustness to noise, while at the same time keeping cost and complexity to a minimum. Other methods and systems are also provided.

Abstract: A CATV system in which a technician in the field requests via a field client that a node of the CATV system be tested for ingress. The CATV system includes a headend facility that is coupled to a CATV distribution network. The CATV distribution network includes a plurality of nodes through which upstream signals are transmitted to the headend facility. A method of ingress testing for use in the CATV system includes one step of receiving at the headend facility a first reverse telemetry signal transmitted by a first field client that is coupled to the CATV distribution network at a first location downstream from the headend facility. Another step of the method includes selecting at the headend facility a first test node from the plurality of nodes of the CATV distribution network, wherein the selection is based upon the received first reverse telemetry signal.

Abstract: Transitions among different upstream frequency channels in a cable television plant in order to transmit data occur while considering the noise level of the upstream frequency channel presently being used to transmit data. By taking into account the noise level of the presently used upstream frequency channel, the CMTS in a cable plant can make a more intelligent decision as to whether it is worthwhile changing the upstream frequency channel for a group of cable modems. A spectrum analyzer determines the noise level of a presently used frequency channel. A bit error rate for the present frequency channel is detected. The spectrum analyzer then determines whether the bit error rate exceeds a threshold value. Is so, it is then determined whether the noise level of the present frequency channel is greater than or less than the noise level of another frequency channel having the lowest noise level plus a buffer noise value.

Abstract: In a processing terminal, operational request information inputted from an operational request unit is transmitted as additional information to a communication unit of a CATV distributor. In the CATV distributor, the additional information is received in the communication unit, and when the additional information is the operational request information, an operational command generator generates operational command information corresponding to the operational request information. The operational command information is transmitted to a communication unit of a receiver through the communication unit. In the receiver, as the communication unit receives the operational command information for the receiver, an operating unit operates the receiver to perform the desired operation in response to the operational command information.

Abstract: A system for the removing of interference (ingress) in cable modems without reducing the data rate or changing the frequency of the signal. The invention comprises both, a variable band stop filter bank, and a non-linear equalization system. The band stop filter bank removes ingress while the equalization system, comprising of an inner and an outer equalizer, removes the distortion created by the band stop filtering. A spectrum monitor detects both the presence of ingress and its frequency, then feeds the data to a digital signal processor which calculates the distortion removal settings for the equalizers. No additional hardware of software is required in the users homes, but rather the invention is designed to be used solely at the head end and in addition to the basic Cable Modem Termination System.

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: 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 for locating the source of noise ingress into a CATV system return path by coupling a filter having a passband in the noise frequency bandwidth to the nodes between adjacent return path amplifiers. The filter is sequentially coupled to the nodes, working away from the CATV system headend. A signal level meter or the like monitors the effect on the noise of coupling the filter to the nodes. When a node is reached at which coupling of the filter to the node no longer has any effect on the signal level in the node, the source of the noise is isolated in the node immediately preceding the node under test.