Abstract: A method is provided to calibrate a monitor photodiode that measures the optical output power generated by an optoelectronic transceiver module that includes a burst mode laser diode. The method includes disabling the power control loop that controls an average optical output power generated by the laser diode during a laser burst. A series of logic zero signals is applied to a data input of the transceiver module and the logic zero level of the optical signal generated by the burst mode laser diode while applying the series of logic zero signals is measured. The logic zero bias level applied to the laser diode is adjusted until the measured logic zero level of the optical signal reaches a first desired value. While maintaining the optical signal at the first desired value, a first value of a current generated by the monitor photodiode in response to optical energy received from a back facet of the laser diode is stored.

Abstract: Methods are described for identifying a dominant impairment on a communication channel impaired by an interference issue. The methods include systematic examination of total power loading, systematic examination of signal power reduction, statistical examination of communication channel noise power, and systematic examination of interleaver effectiveness. Each relates to automatically diagnosing and characterizing distortion-based interference issues by monitoring the performance of a communication channel during a testing procedure. These methods enable a technician or engineer to remotely diagnose distortion-based interference issues relatively quickly without having to use external test equipment and without having to deploy technicians to various locations within the cable plant. A system by which these methods can be implemented is also disclosed.

Abstract: A hung call system includes a memory storing samples of voice data from packets for a VoIP call. A voice activity detector detects whether the stored voice data includes a voice from one or more parties to the call. A processing circuit determines whether the voice activity detector detects the voice, and the processing circuit facilitates release of the call if the voice activity detector does not detect the voice for a predetermined period of time.

Abstract: A method and system of encoding and decoding digital video content. The digital video content comprises a stream of pictures which can each be intra, predicted, or bi-predicted pictures. Each of the pictures comprises macroblocks that can be further divided into smaller blocks. The method entails encoding and decoding each picture in said stream of pictures in either frame mode or in field mode.

Abstract: The present invention discloses a system and method for providing a rate control to an encoder, e.g., a H.264/MPEG-4 AVC compliant encoder. Specifically, the rate control method computes a target rate for a segment, where the segment comprises at least one slice of macroblocks. In turn, a target rate is computed for the at least one slice of macroblocks from the target rate for the segment. In turn, a quantization parameter (QPj) is computed for a macroblock (j) of the macroblocks from the target rate for the at least one slice. Finally, the macroblock (j) is encoded in accordance with said quantization parameter (QPj).

Abstract: Methods and apparatus are provided for allocating bandwidth among members of two statistical multiplexing groups having overlapping members. At least two groups of such services having overlapping members are defined. The members of a first one of the groups consume a first bandwidth and the members of a second one of the groups consume a second bandwidth. A total bandwidth of all the members of the groups together is restricted to be no more than a total available bandwidth. In order to accomplish this, the members of the first and second groups are statistically multiplexed based on bandwidth requirements of members common to both said first and second groups.

Abstract: Existing key encryption approaches are extended by using overlapping portions of encrypted information. Another provision inserts one or more bits of data to ensure correct encryption/decryption. The inserted data can also be used for authentication.

Abstract: Logical channels in a network are automatically be configured by using measured network parameters. The measured network parameters are determined in cooperation with the network elements without interruption of active communication services. The network parameters include upstream or downstream modulation error ratio (MER), upstream or downstream signal to noise ratio (SNR), upstream or downstream microreflections, upstream transmit level, downstream receive power level, cable modem type (DOCSIS 1.0,1.1,2.0), functional capabilities (e.g., VoIP, 256QAM, etc), network element location with in a cable plant (e.g., node location or amplifier cascade depth), network element manufacturer, or type of services provided by the network element (including telephony versus data). An interactive display is provided to an operator which enables analysis of communication parameters, including modulation profiles and channel performance.

Abstract: A cable television system automatically locates set-top terminals within the system with respect to the specific equipment through which the set-top terminal communicates with the system controller. This location of the terminal is used to configure the terminal to operate properly within the system and with respect to its physical location and to improve the overall operating efficiency of the system. Identifying the location of terminals can also facilitate better trouble-shooting and characterization of the cable plant by providing logical and physical network topology information. Each terminal's attributes are also registered with the system controller. The controller can also effect automatic configuration of set-top terminals purchased through a retail outlet and installed by consumers.

Abstract: A method and system manages and controls the download of programming, i.e., code objects, to a set-top terminal connected to a cable television system so as to prevent disruptions to service that may arise if only some of the objects specified are successfully downloaded and might, therefore, function improperly or conflict with existing applications. When the message to download new or additional code objects lists two or more objects to be acquired, the set-top terminal will only enable and execute downloaded objects if all the listed objects are successfully acquired. If only some of the objects the terminal has been instructed to download are acquired, those downloaded objects may either be purged or stored in memory without being enabled and executed. The system operator may specify in the message instructing the terminal to acquire new objects, whether the listed objects must be implemented as a group or not at all.

Abstract: A method and apparatus for providing an opportunistic data capability for an existing statistical multiplexing encoder platform, such as a multi-channel video data encoder. An Opportunistic Data Processor (ODP) is provided as a plug-in card or an external device that can be interfaced with an existing multi-channel encoder. The ODP communicates with a Quantization Level Processor (QLP) and Packet Multiplexer (PM) in the multi-channel encoder as if it was just another channel encoder. The ODP implements a special rate control scheme by encoding data and sending it to the PM only when a global Quantization Level (QL) indicates that spare bandwidth is available. Spare bandwidth is assumed to be available when the global QL is less than a threshold value. Moreover, the OPD sends a bandwidth need parameter to the QLP, as do the other channel encoders.

Abstract: The performance of a multiphase and/or multiple amplitude receiver, such as a 64/256 quadrature amplitude modulation (QAM) receiver, is improved in the presence of single and multiple echoes. A moving window adaptive decision feedback equalizer (DFE) is provided according to the adaptive equation Cn(k+1)=Cn(k)−&Dgr;·W(k)·En(k)·Xn(k), where &Dgr; (delta) is the step size, Cn(k) is the tap value of tap n for the k symbol, En(k) is the error output at the symbol k, Xn(k) is the received signal for pre-cursor taps (FFE) and past decision output for post-cursor taps (DFE), and W(k) is the sliding window function at symbol k. In the adaptation process, some coefficients are fixed while other taps are being adapted. In particular, the adaptation is focused on a group of taps which correspond to received echoes.

Abstract: Session Inter-Device (SID) mobility networks (50, 100, 150) are described in which a seamless transfer of a communication session from a first device (56. 106, 116) to a second device (66, 116, 166) can be achieved without interrupting the active session. According to the SID mobility network (50), the transfer can be accomplished by transferring away from the Transferring Node or first device (56) the IP address associated with the active session (58) so that the network (50) will route the session to the desired Target Node or second device (66). The Transferring Node (56) transfers its IP address (58) to the Agent (60) and stops requesting data packets addressed to its IP address (58). The Agent (60) then begins to request and eventually receive the packets addressed to the Transferring Node's IP address (58). The Agent (60) then transfers the packets to the Target Node (66).

Abstract: Session Inter-Device (SID) mobility networks (50, 100, 150) are described in which a seamless transfer of a communication session from a first device (56. 106, 116) to a second device (66, 116, 166) can be achieved without interrupting the active session. According to the SID mobility network (50), the transfer can be accomplished by transferring away from the Transferring Node or first device (56) the IP address associated with the active session (58) so that the network (50) will route the session to the desired Target Node or second device (66). The Transferring Node (56) transfers its IP address (58) to the Agent (60) and stops requesting data packets addressed to its IP address (58). The Agent (60) then begins to request and eventually receive the packets addressed to the Transferring Node's IP address (58). The Agent (60) then transfers the packets to the Target Node (66).

Abstract: An upconverter unit for a cable television system upconverts multiple channel signals from a common intermediate frequency to a VHF or UHF signal ready for transmission to subscribers. The two-stage upconverter provides a first stage in which different channel signals are upconverted to different frequencies which are spaced apart by same frequency difference characteristic of different channels in the cable system. A second stage of the upconverter uses a common oscillator signal to convert the various channel signals from the first stage to the frequencies at which they will be transmitted over the cable system.

Abstract: A method and apparatus for detecting a hardware configuration in a digital terminal, and, in response, selecting a corresponding executable software path for initializing the hardware. All terminals in a digital communication network, such as a television network, are provided with a single common set-top firmware/software object that contains all software components required to run on all hardware platforms. The total amount of software needed at the terminals is reduced over prior art schemes since the common software object includes software that is common to the different hardware component types only once, instead of providing a different object for each hardware type which results in duplication of the common software. The software from the software object can execute on platforms with different hardware components and circuits. This provides freedom to the network operator to select terminals with reduced cost components, e.g., from different manufacturers.

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 novel method and apparatus for scrambling a television signal includes using a synchronization separator to separate a synchronization signal from an input audio-visual signal. The synchronization signal is then used to regulate an oscillator producing an audio carrier signal. In this manner, the audio-visual signal is transmitted without the component synchronization signal rendering it useless to a conventional television receiver. The descrambler and descrambling method of the invention involve removing the audio carrier signal from the scrambled signal and using the audio carrier signal to generate the color sub-carrier signal and a vertical time frame reference signal necessary to synchronize the transmitted audio visual signal for display.