Abstract: A speech signal has its characteristics extracted and encoded (16), transmitted over a limited-data-rate path (18) and is decoded (20) and synthesized (22) at the receiving end. The characteristics include line spectral frequencies (LSF), pitch and jitter. The LSF are extracted by autoregression, and split-vector quantized (SVQ) in a single frame, and, in parallel, in blocks of two, three and four frames. The SVQ codes have equal length and are evaluated for distortion in conjunction with a threshold. The threshold is varied in such a manner as tend to select for transmission those codewords which maintain a constant data rate into a transmit buffer. A single-bit jitter bit, and encoded pitch value, are product coded with the selected LSF codeword, and all are transmitted over the data path (18) to the receiver. The receiver decodes the characteristics, and controls a pitch generated (1226) in response to the pitch value and a random pitch jitter in response to the jitter bit.

Abstract: A downward compatible full-duplex ethernet transceiver associated with either the hub or the remote node in an ethernet local area network (LAN) includes generator circuitry for generating a full-duplex-capability signal indicating its full-duplex capability for transmission over a link of the LAN and detector circuitry for detecting transmission of such a signal from the transceiver with which it is communicating across the link of the LAN. The detector circuitry responds to the full-duplex-capability signal by sending a full-duplex enable signal to an ethernet controller configured according to the present invention. An ethernet controller contains circuitry responsive to the full-duplex-enable signal to disable transmission deferral in response to a carrier-sense signal generated by the transceiver. The full-duplex-capability indicator portion may comprise an extra pulse following an Nth link-integrity pulse after a delay of from about 2 to about 7 microseconds.

Abstract: A sharp phase variation of a clock is suppressed when master/slave status of a first and second communication device is changed over. The first and second communication devices respectively include clock selection circuits and clock production circuits for producing a synchronous clock from the selected clock, respectively, and supply the selected clock as the synchronous clock to the other communication device which is a mating-side device. One of the first and the second communication devices is a reference selection side and becomes a slave side, and the other device is a mating synchronous clock selection side and becomes a master side. Respective data signals from the communication devices are bit multiplexed in a multiplexing device on the basis of the synchronous clock.

Abstract: In a telecommunications network having a plurality of intelligent nodes interconnected by multiple communication channels, alternate paths and spare channels are set up for restoring traffic disrupted by failure to one or more of the communications channels. The alternate paths may be set up irrespective of the number of custodial node pairs, also referred to as leader/follower or sender/chooser pairs, that could simultaneously be involved in the restoration operation. The interconnected nodes have bi-directional working and/or spare channels. There is stored at each node in the network participating in the recovery operation a spare channel manifest for each of the leader/follower combinations. The first end node, or leader node, of every identified failed channel initiates a request message for each disrupted working channel to set up an alternate path.

Abstract: Within a desired service area, multiple transmitters at separately located sites simultaneously broadcast the same multi-channel, multi-program signal. Broadcast waves from the transmitters propagate throughout substantially overlapping portions of the service area. Obstructions in the service area, e.g. mountains, buildings, trees, etc., may block reception from one or more of the transmitters at certain sites. However, at most receiving sites, the receiving antenna can receive a clear line-of-sight transmission from at least one and often two or more of the transmitters. Each broadcast channel carries a multiplexed digital data stream containing packets of information for a plurality of programs, e.g. television programs. A shared antenna system, typically including multiple receiving antennae aimed at a plurality of the transmitters, supplies received signals to terminals in a plurality of living units.

Abstract: At a transmitting end, frequencies used to a construct a digital signal are substantially removed from an analog signal by a notch filter circuit to produce an interim signal which is then combined with the digital signal as by combining to produce a composite analog signal that is transmitted to a receiving end. At the receiving end the frequencies used to construct the digital signal are substantially removed from the composite analog signal by a notch filter circuit. In this way the digital signal can be transmitted simultaneously with the analog signal without errors that could be introduced by the analog signal, and with only a slight change to the frequency spectrum of the analog signal. In a second embodiment, the system provides clear and error free continuous transmission of digital signals over an analog channel simultaneously with an analog signal by periodically analyzing the analog signal and, during any given period, transmitting the digital signals in open bands, i.e.

Abstract: In methods and apparatus for processing a speech signals comprising a plurality of successive signal intervals, each signal interval containing no speech sounds is classified as a noise interval, and LPC coefficients are calculated for each noise interval based on the samples of that noise interval and on the samples of a plurality of preceding signal intervals. When noise intervals encoded using LPC coefficients calculated as described above are reconstructed, the subjectively annoying "swishing" or "waterfall" effects encountered in conventional LPC speech processing systems are reduced or eliminated.

Abstract: An arrangement for modulating orthogonal signals with an analog signal or a digital information signal. In either event, the information signal is partitioned into component signals which respectively modulate an associated one of the orthogonal signals. The analog signal has a predetermined bandwidth and may be represented by samples generated at no less than a predetermined rate. The component signals derived from this analog signal, on the other hand, may be represented by samples generated at a rate which is less than the predetermined rate. Apparatus is incorporated which detects a predetermined event which, in turn, determines whether the orthogonal signals are modulated by the analog or digital information signal. The value of the latter signal may be known at any time, such as when the digital information signal is a training sequence, or may be unknown. The foregoing modulation arrangement can also incorporate privacy or encryption schemes.

Abstract: A traffic shaper in a packet communication apparatus receives packets and immediately calculates a departure time for each received packet, using designated bandwidth allocation parameters. The packets are stored in a packet memory according to their calculated departure times. When each departure time arrives, the packets that have been stored for that departure time are transferred to an output queue. Packets are output in sequential order from the output queue.

Abstract: A gateway as one example of a mutual connecting appraratus between networks virtually provides an address of a mini manufacturing automation protocol (miniMAP) device to a mechatronics network (ME-NET) device in plural devices forming a network so that the miniMAP device uniquely identifies the ME-NET device. These plural devices connected to respective networks can mutually transmit and receive data in a network environment in which the ME-NET device is connected to the miniMAP device or another ME-NET device. Conversely, an address of the ME-NET device may be virtually provided to the miniMAP device so that the ME-NET device uniquely identifies the miniMAP device. Further, for example, the plural devices may be constructed by ME-NET devices. In this case, one ME-NET device uniquely identifies another ME-NET device in the plural ME-NET devices by virtually providing a station address unused in this one ME-NET device to this another ME-NET device.

Abstract: A method of synchronizing a fixed access unit (16) into a time division multiple access (TDMA) system (10). The method includes the steps of receiving a first timing advance channel time slot (86) at the fixed access unit (16), sending a message advanced in time by an offset value over a second time slot (88), receiving an acknowledgment from the TDMA system (10) that the message was received, and advancing a subsequently transmitted communication based on the offset value.

Abstract: An ISDN interface unit interconnects a data processing unit, an ISDN, and an analog telephone and includes a DMA request signal generation circuit for generating a DMA request signal from an 8 kHz clock signal from an ISDN line. In accordance with the request signal, PCM coded data input from the ISDN line is transferred, using DMA, to a memory of the data processing unit or vice versa. Alternatively, the ISDN interface unit includes a code conversion circuit. Data stored in the data processing unit are converted to nonlinear PCM coded data and transmitted to the ISDN line or vice versa. Further, the ISDN interface unit includes communication functions for the digital signal and for the voice band signal, a control channel signal sent from the ISDN line is interpreted, and one of the communication functions can be selected.

Abstract: A method to be used in a Source Routed Bridged LAN by which access points maintain location information of mobile stations, and forward packets destined for mobile stations that have moved to another access point. This method resolves the problem that correspondent stations do not (timely) update the routing information to the mobile stations.

Abstract: All nodes on a malfunctioned communications circuit of a communications network are enabled to identify the location of the fault causing the circuit malfunction. Upon detecting an incoming signal impairment on the circuit, each node on the circuit first assumes that the failure is on the segment of the circuit immediately upstream thereof, and accordingly sends an identifier of that fault location to its downstream nodes. Each node periodically repeats sending its identifier to its downstream nodes. A node that has sent its identifier at least a predetermined number of times without receiving a similar identifier from another node upstream thereof or without having detected a normal signal during all that time is determined to have sent out an identifier that correctly identifies the fault location on the communications circuit.

Abstract: An improved technique for simultaneously performing bit synchronization and error detection of received digital data bursts in a time division multiplexed/time division multiple access (TDM/TDMA) system, such as that used in conjunction with low power portable digital telephony. With the improved technique both bit synchronization and error detection are performed simultaneously to thereby reduce latency in the transceiver. Since round-trip delay is reduced, echo suppression techniques may not be needed.

Abstract: In a data communication system (100) including infrastructure (101) arranged to communicate with a plurality of terminals (103) over a channel (109), a method of adaptable channel access practiced at a terminal (103) including determining an access priority value (303), responsive thereto ascertaining when the channel is available (305), and then executing a channel access attempt (307). The access priority value is determined with information received by the terminal or information available to the terminal.

Abstract: In radio communication system in which single frequency simultaneous transmission and reception is performed, a speech audio signal is divided by a predetermined time interval. A transmission time and a reception time are allotted in the predetermined time. A time-compressed signal is transmitted during the transmission time, and a time-compressed signal transmitted from other transceiver is received during the reception time and it is decompressed to the original length. The transmission time and the reception time are alternately repeated to transmit and receive the audio signals substantially simultaneously by a single frequency, and the audio signal is reproduced from the received signal. When communication with a telephone set is to be established, a DTMF signal is used as a dialing signal to call the telephone set from the transceiver. The DTMF signal is time-compressed and then transmitted along with the speech signal.

Abstract: A communication system comprising an Asynchronous Transmission Mode ("ATM") network and at least one demultiplexing device. The demultiplexing device receives information cells which include a header, containing the destination to which the cells are to be transmitted, and data. The demultiplexing device comprises at least one input access for receiving the cells, a plurality of output accesses, at least one network circuit, a plurality of service circuits and a common data line. The network circuit has an input access, a header analyzing element, a routing table and a combining element. At least one of the output accesses are assigned to each of the service circuits. The routing table produces a routing information signal which determines the destination to which the cells are to be transmitted. The combining element combines the information signal and the data and transmits the same on the common data line.

Abstract: An apparatus for controlling data transmissions in a communication network which includes a plurality of nodes connected to a common bus, each of said nodes having a communication processor with a memory and a bus control device associated with the processor.

Abstract: A double-talk detector for an echo canceller includes power estimators (60) and (62) which are utilized to measure the ERLE value in a calculator (64). This ERLE value is stored in a register (70) when it is the largest value generated. This register (70) is updated whenever a new and better ERLE occurs. A fraction of the value in register (70) is utilized as an input to a comparator (88), and then compared to the current ERLE value. If the current ERLE differs from the SERLE in register (70) an inhibit signal is generated for blocking the updates of an adaptive filter (40). The value stored in the register (70) is periodically decremented to reduce the value thereof. This decrement operation is performed in response to detection of an utterance from the far-end.