Abstract: A transmitter for transmitting a plurality of digital signals through a plurality of channels, the channels having a predetermined total allocated bitrate, includes a plurality of encoders each associated with one channel, a multiplexer for receiving the encoded digital signals and for transmitting the encoded signals as a stream of data, and operable for adjusting the distribution of the bitrate allocation between and among the encoded signals, and a processing device for providing an indication of a target quality and an actual quality for each channel and for causing the multiplexer to repeatedly adjust the distribution of the bitrate allocation in response to differences between the indicated actual quality and the indicated target quality for each channel so as to equalize differences between the actual and target quality across at least some of the channels.

Abstract: Packets from multiple packet streams are transmitted in an output stream having substantially equally spaced packets using a scheduler which spaces the packets based upon the input stream speeds of the various input streams as well as the bandwidth of the transmission channel. Such a scheduler advantageously spaces the packets so that the maximum distance between two filled slots is never more than twice the minimum distance between any two filled slots. Such a system also advantageously allows the computation of the slot locations to be precomputed when the slots are initially allocated to streams, thereby allowing the scheduler to efficiently compute slot locations while the scheduler is receiving the input streams.

Abstract: In a video/audio coding and multiplexing method, coding of multimedia data including video data and audio data is implemented as a software program operating on a multitask operating system, and video/audio coded and multiplexed information in which video/audio synchronization is realized in specified time units is obtained. In this method, coded video information and coded audio information are temporarily stored in a video buffer and an audio buffer, respectively. A video/audio synchronization means creates time and information using video block rate information which is created on the basis of the coded video information and stored with the coded video information. According to the time information, a coded video read-out means and a coded audio read-out means read the coded video information and the coded audio information from the respective buffers, and the video/audio synchronization means performs video/audio multiplexing.

Abstract: An asynchronous transfer mode (ATM) based very-high-bit-rate subscriber line (VDSL) communication system includes an optical ring having a plurality of multiplexers. An information provider is connected to the optical ring via a first one of the multiplexers. The information provider includes an ATM core switch operable with the first one of the multiplexers for transmitting data and video signals on to the optical ring and for receiving data signals from the optical ring. Each of a plurality of central offices is connected to the optical ring via a respective one of the multiplexers. Each of the central offices includes an ATM edge switch operable with the respective one of the multiplexers for receiving video and data signals from the information provider via the optical ring and for transmitting data signals to the information provider via the optical ring. The information provider communicates with the central offices through a single optical ring.

Abstract: In a communication system between a CS concentrator 50-1 concentrating lines of PHS radio base stations 10-1 to 10-N and being located in a remote area and a subscriber terminal device 60 in a PHS exchange, by multiplexing two call control groups of (14B+D+C) channels on a 2M primary-group transmission line, a PHS system is constructed which uses the 2M primary-group transmission line with a good channel operating efficiency.

Abstract: Digitally compressed video/audio bit streams, when transmitted over digital communication channels such as digital subscriber loop (DSL) access networks, ATM networks, satellite, or wireless digital transmission facilities, can be corrupted due to lack of sufficient channel bandwidth. This invention describes schemes to ensure lossless transmission of bit streams containing pre-compressed video signals within the communication channels. The schemes herein comprises a rate conversion system that converts the bit rate of a pre-compressed video bit stream from one bit rate to another, and that is integrated with a digital communication channel, and a means to convey the maximum channel transmission rate to the rate conversion system to allow satisfactory transmission of the bit stream from the input of the rate converter through the transmission facility.

Abstract: The system is formed by at least a base station (SR1, SR2, . . . ) intended to relay information signals having variable rates between a plurality N (N.gtoreq.1) of mobile stations (M1, M2, . . . ) linked thereto and a nodal station (K, K', . . . ), this system comprising a first time-division multiplex link between the N mobile stations and the base station and a second time-division multiplex link (L1, L2, . . . ) between the base station and the nodal station, the first multiplex link comprising time intervals for containing the information of each mobile station, the second multiplex link comprising time intervals for the information relating to all the mobile stations. There is provided that:the time intervals of the first link contain n binary elements assigned according to the information bit stream,the time intervals of the second link are organized in frames of M words of n binary elements,and M is close to a multiple of N.

Abstract: Multiplexing and demultiplexing are commonplace for an efficient bandwidth utilization in telecommunications. SRTS (Synchronous Residual Time Stamp) technique is widely used for timing recovery in processing of digital signal streams. The bit stuffing is also prevalent for various purposes, one being rate adjustment. The invention performs the SRTS technique entirely digitally to monitor the rate of slower speed signal streams in relation to the rate of a higher speed stream. The digital implementation permits the use of context switching for processing a plurality of digital signal streams. As the result, hardware requirement is greatly reduced.

Abstract: An apparatus, system, and method for compressing and coding audio and/or video data by the MPEG2 system or the like, multiplexing the same, and transmitting the resultant data via a digital line. When generating a transport stream for transmitting a PES packet of the MPEG2 system, the amounts of the compressed video data and the compressed audio data are defined as whole multiples of the amount of the transport packet (188 bytes) of the MPEG2 system, thereby to bring the boundary of the frame cycle of the audio and/or video data and the boundary of the transport packet into coincidence. Where the amount of data is arbitrary, calculation etc. of the offset value which becomes necessary at the scheduling is made unnecessary.

Abstract: A plurality of transmitters are multiplexed to a hub through clocked serial links. Timing problems that may arise when switching between links are eliminated with a system including a group serial receiver for each link for performing serial to parallel conversion of data sent over the serial link, outputing a group clock signal based on the serial clock signal, outputing parallel data clocked by the group clock signal, and determining a data enable signal from the serial link. A select signal for determining the serial link being read by the hub selects the corresponding group clock, parallel data, and data enable. A load control clocks the selected parallel data into a first-in, first-out buffer using the selected group clock when the selected data enable is asserted. When the selected data enable is not asserted, the load control is held in reset and, hence, is insensitive to irregularities in the selected clock signal due to switching between links. Data is clocked from the buffer by a local clock.

Abstract: An optimal multiplexing method is disclosed which allows buffers to be two packets in depth. For a plurality of buffers, with each buffer associated with a packetized data stream, packets are received at respective buffer input rates. The buffers are serviced at a service rate at least equal to a sum of the buffer input rates. For each buffer, once a full packet has been received therein, a time interval until that buffer is expected to reach its buffer depth is determined. The buffer having the least time interval is then serviced first, such that overflow of the buffers is avoided.

Abstract: A technique for performing a time slot interchange in a processor. The TSI process is surrounded by a multiplexing/demultiplexing circuit for converting a plurality of PCM highways into a single input serial data stream. The mux/demux circuit includes elastic stores to align frames and shift resisters to mux/demux with a minimum of delay. The TSI processor includes an input and an output buffered serial port, a pair of input buffers, one to receive even-numbered frames from the PCM highways and one to receive odd-numbered frames, and an output buffer. Data is read from the appropriate input buffer in a non-sequential fashion as commanded by the processor in accordance with information stored in connection arrays (address buffers). The data is then written to the output buffer sequentially. The timing of the reading and writing steps is optimized relative to free running buffered serial port pointers for each BSP to reduce the frame delay.

Abstract: A statistical multiplexing apparatus and method for generating and combining a plurality of encoded video bit streams. A storage device contains pre-stored a priori statistics indicative of the encoding complexity of the video signals from which the encoded video bit streams will be generated. The pre-stored a priori statistics may include inter-pixel differences in the same picture or between multiple pictures or pre-encoding a priori statistics generated during a preliminary encoding of the video signals. Examples of pre-encoding a priori statistics include the number of bits per picture at a given quantization level, an average quantization level, picture types, scene change locations and repeat field for one or more of the video bit streams. The video signals are applied to encoders which compress the signals in accordance with bit allocation decisions generated by a statistics computer.

Abstract: A multiplex type transmitting apparatus is arranged to have a plurality of slow signal receive/transmit sections for accommodating a counterpart for a SONET system or an SDH system, a multiplex separation converting section, and a receive/transmit section for a SONET system or SDH system fast signal.

Abstract: Techniques for determining an output rate for a bit stream, the output rate being determined by applying information read from the bit stream to a model of a receiver for the bit stream. The techniques are employed to construct a statistical multiplexer that multiplexes varying bit-rate MPEG-2 bit streams onto a satellite up-link. Minimum and maximum output rates for each MPEG-2 bit stream are determined such that neither a queue for the bit stream in the multiplexer nor the bit stream's decoder will underflow or overflow. The rates with regard to the decoder are determined using timing information read from the bit stream and a general model of an MPEG-2 decoder. The multiplexer first allocates each bit stream its minimum bandwidth and then allocates any remaining bandwidth to the bit streams in proportion to the difference between the minimum and maximum output rates for the bit streams, with no bit stream receiving more than its maximum output rate.

Abstract: A system for utilizing the available bit rate in a constrained variable bit rate channel is described. The system receives one or more encoded information streams, each having a variable bit rate. Rate control circuitry controls the rate of transmission of the encoded information streams so that the variable bit rate of the streams is transformed into a constrained variable bit rate, in which the variable bit rate is limited to a predetermined maximum value. A multiplexer multiplexes the encoded information streams for transmission over a channel. The channel may comprise a 6 MHz television channel. The multiplexer also multiplexes the encoded information streams with a secondary information stream for transmission over the channel. For purposes of multiplexer selection of information streams, the secondary information stream is assigned a lower priority than the encoded information streams.

Abstract: The present invention relates to a private branch exchange, a telecommunication system comprising such an exchange and methods of transmitting signals in subrate channels of a fullrate channel. The exchange comprises a switch control means, which allocates subrate traffic channels of the fullrate channel to voice and data, and a channel handling device (44), which comprises at least one voice channel means (66, 68, 70) connected to a respective channel input (22, 24, 26) and being arranged to compress signals appearing on this input (22, 24) or to pass at least part of each signal through unaffected. The compressed or passed signals are fed to a multiplexer (76), which multiplexes signals incoming from the voice channel means to outgoing signals for sending in a fullrate channel on a first telecommunication line (14). A demultiplexer (78) is also included for demultiplexing signals in a fullrate channel.

Abstract: A device for deriving an ancillary signal from a compressed digital video signal (e.g. MPEG), wherein the ancillary signal includes selected parts of the main signal, for example, the DC coefficients of I-pictures, or the unscrambled parts, which parts can be used for display in a (multi-) picture-in-picture television receiver, or as an "appetizer" in order to encourage the user to pay a subscription fee, is described. The ancillary signal can separately be recorded in digital video recorders so as to assist the user in finding the beginning of a scrambled program on tape. The ancillary signal can also be generated at the transmitter end and transmitted at a low bit rate. A decoder for decoding such an ancillary signal is considerably simpler and less expensive than a full-spec MPEG decoder. A decoding method is also described.

Abstract: A statistical multiplexing apparatus and method for generating and combining a plurality of encoded video bit streams. A storage device contains pre-stored a priori statistics indicative of the encoding complexity of the video signals from which the encoded video bit streams will be generated. The pre-stored a priori statistics may include inter-pixel differences in the same picture or between multiple pictures or pre-encoding a priori statistics generated during a preliminary encoding of the video signals. Examples of pre-encoding a priori statistics include the number of bits per picture at a given quantization level, an average quantization level, picture types, scene change locations and repeat field for one or more of the video bit streams. The video signals are applied to encoders which compress the signals in accordance with bit allocation decisions generated by a statistics computer.

Abstract: A multiplexing system for converting a plurality of variable-length burst data streams supplied from a plurality of data suppliers into a multiplexed averaged-transfer-rate fixed-length packet stream. Within each output period, for each of the input buffers of a multiplexer, a virtual data quantity in the input buffer at the time t.sub.n is calculated by using the length of each output period and average supply rates at time t.sub.n-1 which are also supplied from the data suppliers. A predetermined amount of data is supplied to a header adder from one of the input buffers which stores data not less than the predetermined amount during the output period from time t.sub.n to time t.sub.n+1.

Abstract: Switch architecture is provided for interfacing a high speed broad bandwidth communication network to a communication fabric having a bandwidth which is a fraction of the high speed broad bandwidth with the network and the fabric having different data packet formats. A multiplex/inverse multiplex unit is provided for converting data packets at the first carrier rate and in the first format to data packets in the second format, and a switch converter then converts the data packet headers in the second format into switch format headers for transmission of the data packets through ports of the communication fabric. A splitter receives the data packets from the switch converter and routes the data packets to one of a plurality of the fabric ports in accordance with the connection identifier in the switch format header, the data packets to one of a plurality of fabric ports being at a second carrier rate.

Abstract: A multiplex device is provided for monitoring computer video signals and receives as input the video signals of a plurality of computers. The multiplex device selects the video signals of one of the plurality of computers to be inputted into a monitor for monitoring. The multiplex device for monitoring the computer video signals has three sets of switch circuits, a control signal generating circuit, three sets of voltage amplifying circuits, three sets of current amplifying circuits, a synchronous signal multiplex selecting circuit, and an interface circuit.

Abstract: A plurality of transmitters are multiplexed to a hub through clocked serial links. Timing problems that may arise when switching between links are eliminated with a system including a group serial receiver for each link for performing serial to parallel conversion of data sent over the serial link, outputing a group clock signal based on the serial clock signal, outputing parallel data clocked by the group clock signal, and determining a data enable signal from the serial link. A select signal for determining the serial link being read by the hub selects the corresponding group clock, parallel data, and data enable. A load control clocks the selected parallel data into a first-in, first-out buffer using the selected group clock when the selected data enable is asserted. When the selected data enable is not asserted, the load control is held in reset and, hence, is insensitive to irregularities in the selected clock signal due to switching between links. Data is clocked from the buffer by a local clock.

Abstract: In a digital data transmission system of the present invention, the total transmission rate which changes with the passage of time in a plurality of video/audio signals multiplexed with a plurality of digital data on a transmission path is monitored without allocation of individual transmission rates to the plurality of video/audio signals so that encoders are controlled only when the total transmission rate exceeds the maximum transmission rate. Further, the plurality of digital data are transmitted within a range of the residual transmission rate obtained by subtracting the total transmission rate of the plurality of video/audio signals from the maximum transmission rate in the transmission path, whereby real-time transmission of video/audio signals and transmission of digital data can be made consistent with each other on one transmission path without reduction in video/audio quality of the transmitted video/audio signals.

Abstract: An apparatus and a method for transferring an audio/video/data service from a transmission end to a reception end over a radio interface. The audio/video/data service includes one of audio information, video information and data. The radio interface includes a plurality of subchannels and a plurality of carriers for transmitting the audio/video/data service and at least one information channel. The audio/video/data service is divided into a set of files, wherein the set of files forms a service ensemble. A parameter group is associated with and describes each corresponding one of the files. Each of the files, along with a corresponding parameter group is placed onto one of the subchannels. A placement indicator and a corresponding parameter group is placed on the at least one information channel.

Abstract: In a telecommunication system that generates more than one type of communication data stream, in which each data stream exhibits a distinctive data transfer format, bandwidth utilization is improved by first reformatting the different data transfer formats so that all of the data is compatible with a common data transfer protocol, for example, the Asynchronous Transfer Mode (ATM) protocol. The communication data and the corresponding control data, required to maintain communication data alignment, are multiplexed into a single data stream which is then transmitted over a common telecommunication channel to a receiving station.

Abstract: This device for transferring information between two digital signals includes means (26, 44; 62, 86) of selecting characteristics of a digital input signal, means (28, 46; 78, 94) of direct transmission to a digital output signal and means (28, 46; 80; 114) for the positioning within the latter, of elements of the input signal conveying first characteristics authorized, by the means of selection, to be transferred directly to the output signal, means (30, 32, 48, 50; 72, 74, 90, 92, 98) of measuring second characteristics of the input signal which are identified by the selection means, and means (78, 80, 102, 110) of modifying the output signal on the basis of the measurement values of the second characteristics so that the said second characteristics of the output signal and the input signal are identical.

Abstract: A system that allows multiple bundles of plesiochronous digital hierarchy (PDH) payload data streams to be synchronously trasmitted from one point to another is described. The system multiplexes multiple stages of the PDH using a single clock signal. This removes the need to perform stuffing and de-stuffing of the data streams at the various stages of the multiplexing.

Abstract: An improved method and apparatus are provided for queuing and triggering the flow of data across ATM networks. A connection is established between an insertion server and a client multiplexer. The insertion server prepares a timing response and establishes a transmit queue threshold for a pending trigger point for inserting data. The insertion server enqueues data. Responsive to receiving a timing request from the client multiplexer, the insertion server sends the timing response. Responsive to receiving a stream request from the client multiplexer, the insertion server transfers the enqueued data. The client multiplexer includes a timer for identifying an offset time between sending the timing request and receiving a timing response from the insertion server. The client multiplexer uses the offset time to set a count down timer for sending the stream request. The client multiplexer processes the data transferred by the insertion server and optionally sends a stop stream command to the insertion server.

Abstract: An MPEG multiplexed data transmission system accepts data from N program sources that are asynchronous and that have different data rates and multiplexes them into a common data stream. N buffers corresponding to the N program sources are provided along with a filler buffer that supplies a filler MPEG data packet when none of the N buffers includes a complete packet of data. An algorithm is described that modifies the fullness of the individual N buffers by a factor that comprises the program rate multiplied by an empirically determined constant K. The arrangement optimizes jitter introduced by multiplexing the programs.

Abstract: A local subscriber loop architecture embeds digitized POTS signals into the framing format of high bit rate digital subscriber loop signals being transported over a local loop for serving both subscriber digital terminal equipment and a POTS telephone. The remote transceiver unit is line-powered from the central office unit, facilitating installation of a reliable (office-powered) POTS interface (containing codec and subscriber line interface circuitry providing BORSHT functions) into the remote unit. The data rate of the added digital POTS signal is relatively small with respect to the data rate of the DSL channels, so that there is only slight increase in the overall data rate. As a consequence, adding the digital POTS signal has negligible impact on transport range.

Abstract: A method and apparatus for digital signal transmission, in which data of plural media is transmitted and received over a communication transmission channel. A digital signal format for the transmitted digital signal has an ancillary data section ANC within which there are a plurality of channels for audio signals, each channel including a leading line number area LN, a type area TP, a byte count area BC, an error correction code ECC and a data area DT. The digital signal format also has a payload section PAD within which there are a plurality of channels for video signals, or the like. Each channel includes a type area TP, a byte count area BC, an error correction code ECC and a data area DT.

Abstract: Video data is coded at either a minimum transfer rate or maximum transfer rate and stored in a storage unit as a video reply message. In a case where the video data has been coded at the minimum transfer rate and stored, the video reply message is transmitted upon being multiplexed with an audio reply message if the actual transfer rate agrees with the minimum transfer rate. If the two transfer rates are different, invalid bits conforming to the difference between the rates are generated and the invalid bits, the audio reply message and the video reply message are multiplexed and transmitted. In a case where the video data has been coded at the maximum transfer rate and stored, on the other hand, the video reply message is decoded when an incoming call arrives, the video data thus obtained is coded based upon the actual transfer rate, and the video reply message obtained by coding is multiplexed with the audio reply message and transmitted.

Abstract: A bursty traffic multiplexing arrangement (A) includes a multiplexing unit (MUX) to multiplex a plurality of bursty input flows (IF1, . . . , IFI, . . . , IFN) into an output flow (OF). Congestion due to insufficient throughput capacity of the multiplexing unit (MUX) is avoided by incorporating an input shaping device (ISDI) for each input (MII) of the multiplexing unit (MUX). Data elements constituting such an input flow (IFI) are stored in an input buffer (IBI) which forms part of the corresponding input shaping device (ISDI), and are applied to the multiplexing unit (MUX) at a rate (BI) which does not exceed a predetermined maximum input buffer reading rate (BIMAX) associated to this input buffer (IBI). Furthermore, via feedback input flow rate control information (IFRI), the input flow rates (A1, . . . , AI, . . . , AN) can be controlled to thereby avoid input buffer overload.

Abstract: An electronic apparatus capable of transmitting data at two or more different data rates contains transmitter circuitry, a cable connection mechanism, and an isolation transformer having a primary winding and a secondary winding. The transmitter circuitry low-pass filters digital data which the transmitter circuitry transmits to the primary winding at a first data rate. The transmitter circuitry also transmits digital data to the primary winding at a second data rate different from, typically greater than, the first data rate. The cable connection mechanism provides outgoing data from the secondary winding to the communication cable. Importantly, the transmitter circuitry is operable to generate current-sourced data signals at both data rates and then to convert the current-sourced signals into impedance-produced voltage signals that constitute the outgoing data. Current-source amplifier circuitry normally generates the current-sourced signals.

Abstract: System for establishing a TDM information protocol over a communications path includes a transmit section and a receive section. In general, the transmit element receives a succession of data elements from each of a plurality of independent channels and combines the data elements to form a single TDM sequence of data elements. The receive element receives a TDM sequence of data elements and separates the sequence into its constituent components to form a plurality of channels, each forming a succession of data elements. In one form of the invention, data elements transmitted via the TDM communications path are limited to a single time slot in the TDM protocol.

Abstract: A master station and at least one slave station are connected by radio channels. Each slave station transmits data to the master station by time division multiple access. A first circuit equally divides a prescribed area into at least two sub-areas. The prescribed are is defined in a burst signal for transmitting data from each slave station to the master station, the prescribed area being provided for an arrangement of message signals which are sent from at least one terminal connected to the slave station. The first circuit also arranges a message signal in each sub-area. A second circuit generates a burst signal in which at least a control signal and a channel quality monitoring signal are arranged. The control signal and the channel quality monitoring signal are generated in the area peripheral to each sub-area in which a message signal is arranged. The prescribed area in the burst signal may be an area corresponding to a data quantity of 64 kbps in transmission speed.

Abstract: This invention concerns real-time assembly of a compressed audio-visual system data stream (22) so the audio and video data may be subsequently presented in synchronism. Assembly of a system data stream (22) in accordance with present invention interleaves packets of data selected from a compressed audio bitstream (16) with packets of data selected from a compressed video bitstream (18). If frames of video data being assembled into the system data stream (22) advance too far ahead of the audio data being assembled into the system data stream (22), then all the data for a single frame of the video signal is omitted from the system data stream (22). Conversely, if frames of video data being assembled into the system data stream (22) lag too far behind the audio data being assembled into the system data stream (22), then a second copy of all the data for a single frame of the video signal is assembled into the system data stream (22).

Abstract: A multi-rate transmission system (10) includes a receive section (12) and a transmit section (14). The receive section includes a receiver (16), a clock recovery unit (18), and a serial to parallel converter (20) all operating at a first clock rate (M). The receiver (16) also has a frame recovery unit (22) that operates at any of a plurality of clock rates, including the first clock rate (M) and a second clock rate (M/n). When the frame recovery unit operates at the first clock rate (M), frame information received by the receiver section (12) has unique bits occupying each bit position associated with each clock pulse of the first clock rate (M). When the frame recovery unit (22) operates at the second clock rate (M/n), each unique bit of the frame information occupies a number of bit positions according to a ratio of the first clock rate (M) to the second clock rate (M/n). Similar operation occurs with respect to a frame formatter (30) in the transmit section (14) of the multi-rate transmission system (10).

Abstract: A method and system for maximization of the use of bandwidth capacity of an optical network when adding a data stream received from a switch to the optical network. In one embodiment, a data stream is added to the optical network. A data stream is received from a switch and grouped into a destination group. The destination group is then sent to the network. In another embodiment, a method for dropping a data stream received from an optical network to a switch is provided. A segment is received from the optical network. If the segment is a private segment, then it is demultiplexed into at least one data stream. The data stream from the private segment is then sent to the switch. In still another embodiment, a method for providing an interface between a switch and an optical network is provided. In this embodiment, a data stream is received from the switch. The data stream is grouped into a destination group and the destination group is sent to the optical network.

Abstract: A method and apparatus multiplexing several encoded program streams into a single multiplex suitable for transmission over a data channel, the streams typically including video and audio. According to one embodiment of the invention, high data channel utilization is achieved by determining the order of sending data packets of program streams into the data channel. According to this embodiment, whenever data is to be sent into the data channel, a determination is made of which packet to send or append to the multiplex, said determination by selecting a channel that has a decoder buffer that is not approaching a full state, and said next packet is appended to said multiplex. The method further includes selecting a channel that substantially balances the decoder buffers of the decoders with which the program streams are decodeable.

Abstract: A method and apparatus for the transmission of digital signals comprises the steps of forming at least two data channels carrying data packets, and eventually header data. The channels have different levels of error protection and include picture data, wherein the data packets within one of the channels have the same level of error protection, and wherein a super-ordinate channel has a higher error protection than a subordinate channel. Important information of a subordinate channel is then transmitted in a super-ordinate channel. The important information allows following erroneous reception of the digital signals an improved recovery of picture data decoding.

Abstract: A method for communicating information from a first integrated circuit (IC) to a second IC. A sync signal is transmitted between the two IC's to indicate the start of a transmission of a frame of information from the first IC to the second IC. In this case, a frame of information includes a tag slot and a plurality of data slots. The tag slot contains a series of tag bits wherein each tag bit is associated with a data slot. The value of each tag bit indicates whether its corresponding data slot contains valid or invalid data. The first IC sends the tag slot and data slots to the second IC.

Abstract: By constructing a plurality of packs from a first packet including first data having a high bit rate and a second packet including second data having a low bit rate, when the first data and the second data are multiplexed, it is first detected whether a data length of second data is smaller than a maximum data length of second packet or not. Subsequently, when it is detected that the data length of second data is smaller than the maximum data length of second packet, one pack is constructed by a redundancy data packet including redundancy data of a data length which is equal to a difference between the maximum data length of second packet and the data length of second data and the second packet.

Abstract: A system and method are provided for multiplexing/demultiplexing asynchros high-speed digital data and asynchronous low-speed digital data. A first digital signal processor (DSP) receives complete low-speed data messages and is programmed to assemble each complete message into data blocks in accordance with a block format. Each data block is identical in size and includes provisions for a header that identifies the data assembled therein. A second DSP has a plurality of I/O ports, each of which has a direct memory access (DMA) associated therewith. One of the I/O ports is coupled to the first DSP to receive each complete message assembled into data blocks. The other I/O ports are coupled to a second plurality of channels transmitting asynchronous high-speed digital data. The DMAs associated with the other I/O ports are configured to assemble the high-speed data into data blocks in accordance with the same block format used for the low-speed messages.

Abstract: A multiple rate waveshaping method and apparatus for converting transmission data into communications code synthesized waveforms having different protocol frequencies in the physical layer of the fast Ethernet utilizes two state machines which convert the transmission data into appropriate waveforms using predetermined wave shaping signals, the outputs of the state machines being multiplexed and transmitted over the Ethernet media using a common set of differential current sourced drivers.

Abstract: In the data encoding/decoding method according to the MPEG (Moving picture Expert Group) system, the audio/video bit stream interleaving method includes a first step of determining as to whether a PTS (Presentation Time Stamp) is present in audio/video packets so as to estimate the PTS from a preceding packet in the absence of the PTS, a second step of comparing the audio packet with the video paket in the PTS to output one of the packets which has smaller PTS value, and a third step of multiplexing the audio or video packet to form an audio/video bit stream, so that the decoder is prevented from the overflow or underflow pheonomena in consideration of the decoding time within the audio/video packet data decoding time.

Abstract: A data multiplexing system which includes a plurality of data multiplexing buses through which a plurality of low-speed digital signals are collected into, and distributed from, a multiplexer/demultiplxer. In a data multiplexing mode, the low-speed digital signals entered from a plurality of low-speed transmission lines have their signal format converted by respectively corresponding low-speed interface circuits, and the resulting signals are multiplexed in time slots designated within a multiplexed signal of primary level on the up bus line of the corresponding data multiplexing bus. The high-speed multiplexer multiplexes the collected signals up to a predetermined signal level and sends the resulting secondary multiplexed signal to a high-speed interface module having a high-speed transmission line interface. The high-speed interface module converts the received secondary multiplexed signal and sends the resulting signal to the high-speed transmission line.

Abstract: A communication terminal apparatus for multiplexing a plurality of different types of data and for performing communications using the multiplexed data includes a network control unit connected to a communication network for transmission and reception of the plurality of different types of data. A multiplexing unit generates transmission data by multiplexing the plurality of different types of data and outputs the transmission data to the line control unit. A synchronizing unit generates a transmission synchronizing signal of the multiplexing unit. A separating unit separates reception data received from the network control unit in units of data type synchronously with the transmission synchronizing signal generated by the synchronization unit. A loop back path can be used for looping back and inputting the separated reception data to the multiplexing unit, and an adding unit adds dummy data to the looped back reception data.

Abstract: A system for storing variable transfer rate data sets and for multiplexing and outputting requested data sets on demand, comprises a memory for storing transfer rate information for each of the variable transfer rate data sets. On receiving a request for one of the data sets, an output start timing for the requested data set is set for such an earliest frame that, if the output of the requested data set is started at the frame period, the total transfer rate does not exceed a predetermined transfer rate throughout the transmission period of the requested data set.