Abstract: The generation and upstream transmission of voice packets in an HFC network is controlled by including a synchronization circuit in the broadband terminal interface unit. The synchronization circuit is used to generate the timing signals for the codec, DSP and host microprocessor so that as the host microprocessor receives an upstream grant, the remaining components will assemble and forward the packets in synchronization with the grant.

Abstract: A method to reduce the amount of bandwidth used in the transmission of digitized voice packets is described. The method is used to reduce the number of transmitted packets by suspending transmission during periods of silence or when only noise is present. The system determines if a background noise update is warranted based on human auditory perception factors instead of an artificial limiter on excessive silence insertion descriptor packets. The system searches for characteristics in the perceptual changes of background noise instead of analyzing speech for improved audio compression. The invention weighs factors affecting the perception of sound including frequency masking, temporal masking, loudness perception based on tone, and auditory perception differential based on tone.

Abstract: A modem-based echo cancellation enhancement for digital communications networks is provided. The effects on echo cancellation of non-linearity in a far end echo path in a digital telephone system are reduced by introduction of non-linearities into the near end signal prior to generation of the echo cancellation signal. Near end signal is sampled after linear to PCM conversion. A PCM to linear conversion is added prior to the echo canceler. The near end delay line can be provided between the converters to delay the signal as PCM samples, thereby reducing delay line memory requirements.

Abstract: A method for detecting synchronization loss of the trellis minimum path metric in V.34 modem communications. The invention detects synchronization loss due to bit inversions in trellis decoding in transmitted digital frames due to a periodic inversion pattern that is used for superframe synchronization. The method provides synchronization loss detection by finding the ratio of moving averages for a series of data blocks to the average of a series of inverted 4D symbols located periodically in the beginning and center of received data frames.

Abstract: A message-based memory system for Digital Signal Processor (DSP) storage expansion has a shared memory device connected to a number of DSPs through a packet communication bus. Each of the DSPs has a packet bus interface interconnected to the packet bus; and a messaging unit connected to the packet bus interface. The memory device interconnected to the packet bus can provide shared memory space for the DSPs to increase the amount of memory available to each DSP. The memory device can also be utilized to provide access to common information such as shared data or shared programing that may need to be run by multiple DSPs. The DSPs and the memory device communicate through the packet bus interface by generating packetized read and write requests.

Abstract: The transport of ABCD bits in a digital packet network is facilitated by the inclusion of the ABCD bits into the RTP header of the digital packets. The ABCD bits are first placed in the unused bits of the RTP header. Redundancy of the previous ABCD bits, when applicable, is achieved by restricting the size of fields in the header to reserve space for redundant ABCD bits. The ABCD bits are placed in the reserved portions of restricted header fields.

Abstract: A system and method for reducing or eliminating degradation in voice transmission quality resulting from repeated or sequential compression and decompression of voice packets over one or more packet networks. When a voice connection is established between two parties on separate packet networks, the signal is often passed through a PBX and/or over PSTN lines, with the occurrence of two tandem low-bit-rate codecs used to transfer the signal and introducing degradation of voice quality. This situation arises frequently in voice-over-packet applications. The situation can also arise when a call is forwarded from one place to another. The present invention reduces the degradation associated with the transport of voice data and thereby improving the voice quality by removing one of the tandem codecs.

Abstract: An asymmetric modem communications system achieves high speed data transfers through a telephone network that includes both digital and analog communications mediums. In general, the system includes means for concurrently communicating first and second signals, respectively, in opposite directions along the connection between the communications devices and modems for modulating the first and second signals with different modulation techniques. The communications occur in full duplex manner. In a possible implementation, a digital modem is interfaced to a digital network. The digital network is connected with a coder/decoder (codec). The codec is interfaced with a two-wire analog telephone connection, sometimes referred to as a copper loop. The telephone connection is interfaced with an analog modem. Both the digital and analog modems have a transmitter and a receiver.

Abstract: An asymmetric modem communications system achieves high speed data transfers through a telephone network that includes both digital and analog communications mediums. In general, the system includes means for concurrently communicating first and second signals, respectively, in opposite directions along the connection between the communications devices and modem for modulating the first and second signals with different modulation techniques. The communications occur in full duplex manner. In a possible implementation, a digital modem is interfaced to a digital network. The digital network is connected with a coder/decoder (codec). The codec is interfaced with a two-wire analog telephone connection, sometimes referred to as a copper loop. The telephone connection is interfaced with an analog modem. Both the digital and analog modems have a transmitter and a receiver.

Abstract: A method of discriminating noise and voice energy in a communication signal. A signal is measured in a plurality of block periods, which are sampled to obtain a measurement of the block energy value for the signal. The blocks are compared to a noise threshold and to a voice threshold to discriminate between noise and voice. The thresholds for noise and voice are periodically updated based on the minimum and maximum energy levels measured for block energies. In a preferred embodiment, the voice energy threshold and noise energy threshold values are updated according to a formula where the revised thresholds are based upon a factor of the minimum and maximum energy levels of the current block and the most recent past block and the average energy of the previous blocks. Updating of threshold levels allows for more accurate estimation of noise and voice during changes in either noise, voice or both to avoid missclassification of noise and/or voice.

Abstract: An asymmetric modem communications system achieves high speed data transfers through a telephone network that includes both digital and analog communications mediums. In general, the system includes means for concurrently communicating first and second signals, respectively, in opposite directions along the connection between the communications devices and modems for modulating the first and second signals with different modulation techniques. The communications occur in full duplex manner. In a possible implementation, a digital modem is interfaced to a digital network. The digital network is connected with a coder/decoder (codec). The codec is interfaced with a two-wire analog telephone connection, sometimes referred to as a copper loop. The telephone connection is interfaced with an analog modem. Both the digital and analog modems have a transmitter and a receiver.

Abstract: Packet production by a digital signal processor (DSP) is synchronized with modem transmission opportunities in a cable network. The cable modem computes the average waiting time a packet spends waiting to be transmitted by the modem. The DSP re-syncs transfer of packets to the modem by using this average waiting time minus a small amount sufficient to account for the maximum anticipated propagation delay, as the amount to delay the transmission of its next packet to the cable modem. This invention is a mechanism for re-synchronization that is largely independent of any propagation delays inherent in the hardware architecture.

Abstract: A method of estimating background noise in a signal. The signal is divided into blocks of equal predetermined length. The minimum energy of the signal during the length of each block is determined. The minimum energy determined for the current block is compared to a previous determination of minimum energy. If the current minimum energy exceeds a predetermined maximum energy level, the current block minimum energy is discarded and the previous determination remains unchanged. If the current block minimum energy is below the previous determination, the previous estimate is reduced by the difference between the previous determination and current minimum energy. If the current energy is above the previous determination but below the maximum, the previous estimate is increased by half of the difference between the current energy and the previous estimate. The increase factor may also be adjusted to increase the current estimated energy level by a factor of any amount between and including 0 and 1.

Abstract: The present invention provides network management of a network or multiple networks, using a Web client, and including multimedia and hypermedia capability. The present invention provides a unified, remote, graphical, transparent interface for Web users, working at a Web client, to a variety of managed networks. The present invention receives requests from a Web client forwarded by a Web server and interacts with the managed networks and their associated objects to obtain information. The present invention then converts this information in real time to hypermedia document format in HTTP and HTML, and transmits this information to the Web client via the Web server, appearing to the client as if the information received were a Web file ab initio. This permits a Web user to manage multiple networks and access multiple networks via a single Web client, thus providing a unification of the management interface for dissimilar managed networks, and devices.

Abstract: A method and system whereby a network management control center can monitor and control point-to-point remote satellite communication links without a physical connection between the remote satellite control modems and the network management control center. This method and system provides greater efficiency with reduced costs through rapid reconfiguration of remote satellite control modems. The method and system can actively cause either remote satellite control modem to terminate link transmission, which allows the network management control center to establish a maintenance link with the other remote satellite control modem, through a local satellite control modem. The maintenance link is used to modify operating parameters of the remote satellite control modem. Once parameters are changed at the first remote satellite control modem, the process is repeated for the other remote satellite control modem.

Abstract: The invention provides a method for speech coding using Code-Excited Linear Prediction (CELP) producing toll-quality speech at data rates between 4 and 16 Kbit/s. The invention uses a series of baseline, implied and adaptive codebooks, comprised of pulse and random codebooks, with associated gain vectors, to characterize the speech. Improved quantization and search techniques to achieve real-time operation, based on the codebooks and gains, are also provided.

Abstract: A narrow band RF carrier acquisition method suitable for Demand Assigned Multiple Access (DAMA) networks having multiple narrow band carriers operating with channel frequency spacing that may be less than the frequency uncertainty on the link. The present invention uses a variable database of active narrow band carrier frequency assignments for the ground stations in the system, which, together with a knowledge of the approximate magnitude of the frequency errors, can be exploited to allow a receiving ground station to optimize the process of narrow band carrier frequency acquisition. The optimization employs alternative procedures depending upon different acquisition circumstances, thereby allowing the receiving ground station to utilize the optimal acquisition method under any given set of circumstances, where the circumstances are individual and changing for each ground station in the system but are known and communicated from a system database.

Abstract: A rob bit compensation system improves the accuracy of digital signals received from and transmitted to a digital network, such as a telephone network, that employs rob bit signaling (RBS) wherein the network periodically robs a bit for its own use. The system can be employed within a digital modem or a coder/decoder (codec), each of which is interconnected with the digital network that periodically robs a bit every nth frame, where n is, for example, 6 or 24. The system can be implemented in association with the receive subsystem of the digital modem or in the communications paths within the codec associated with receiving data from the digital network. The system includes a compensation control utilized to detect when a least significant bit (LSB) of a particular frame of data consistently exhibits a certain logic state, either a mark (logical 1) or a space (logical 0). When an LSB of a particular frame does consistently exhibit the certain logic state, then the particular frame is considered an RBS frame.

Abstract: An asymmetric modem communications system achieves high speed data transfers through a telephone network that includes both digital and analog communications mediums. In general, the system includes means for concurrently communicating first and second signals, respectively, in opposite directions along the connection between the communications devices and modems for modulating the first and second signals with different modulation techniques. The communications occur in full duplex manner. In a possible implementation, a digital modem is interfaced to a digital network. The digital network is connected with a coder/decoder (codec). The codec is interfaced with a two-wire analog telephone connection, sometimes referred to as a copper loop. The telephone connection is interfaced with an analog modem. Both the digital and analog modems have a transmitter and a receiver.

Abstract: A system and method is presented for multi-dimensional scheduling, unscheduling, and control of resources using a database approach. Indivisible resources, percentage divisible resources, and range divisible resources are scheduled, unscheduled, and controlled. Resources in telecommunication systems are scheduled, unscheduled, and controlled. Resources in satellite telecommunication systems are scheduled, unscheduled, and controlled.