Abstract: An isochronous output data stream format which is time multiplexed and has a fixed time period where input isochronous data streams are multiplexed into the output isochronous data stream and the output data stream is the same data rate as the fastest input isochronous data stream. One or more of the input data streams contain a code which has been run length limited and/or has a zero running digital sum with banded disparity. In another embodiment, an isochronous output data stream format which is time multiplexed and has a fixed time period where input isochronous data streams are multiplexed into the output isochronous data stream and the output data stream is the sum of the maximum input isochronous data streams. One or more of the data streams contain a code which has been run length limited and/or has a zero running digital sum with banded disparity.

Abstract: A PC-type computer has a system bus (e.g., a PCI bus) configured with a main CPU board, a statistical multiplexing (stat-mux) board, and a plurality of video/audio encoder boards, each configured to receive and compress a corresponding video/audio stream. The stat-mux board performs statistical multiplexing on the different compressed bitstreams to transmit multiple bitstreams over individual shared communication channels. Although each of the boards is configured to the system bus, each encoder board has a digital signal processor (DSP) with a synchronized serial interface (SSI) output port that is directly connected to an SSI input port on a DSP on the stat-mux board (which, in one embodiment, has four such DSPs each with six such SSI input ports). As such, (up to 24) compressed video/audio bitstreams generated on the various encoder boards can be transmitted directly to the stat-mux board without having to go through the system bus.

Abstract: In DVD Stream Recording Stream Object Units (SOBU) are real-time recorded (STR), wherein such fixed-length Stream Object Units serve as a container for Application Packets (AP_PKT) that have a variable length and carry payload data and an Application Time Stamp (ATS), this timestamp enabling proper real-time playback. In case the temporal distance between two succeeding application packets is too big, stuffing data (STPCK) must be inserted into the corresponding Stream Object Units. The real-time stuffing control is performed such that overflow of the input buffer (TSBS) is avoided in case of a specific kind of input signals.

Abstract: A system and method for maximizing the efficiency of a video transport stream combines a number of lower rate transport streams into an aggregate higher rate transport stream while maintaining the accuracy of timing information in the aggregate transport stream. The system and method of the invention synchronize and compact each of the lower rate transport streams into the higher rate transport stream while preserving the accuracy of timing information in the aggregate transport stream.

Abstract: A format converting apparatus for a mutual data exchange between an IEEE 1394 serial bus and a VSB remodulator is disclosed. The present invention allows a conversion from a format of the IEEE 1394 to the VSB remodulator and also a conversion from a format of the VSB remodulator to the IEEE 1394. Therefore, digital equipment having both the IEEE 1394 and the VSB remodulator can be utilized without problem.

Abstract: The invention relates to a method and apparatus for multiplexing traffic from a plurality of fixed bit rate sources over an ATM network. The traffic from the fixed bit rate users is multiplexed to form a TDM trunk group which is assembled into AAL2 minicells prior to being converted to ATM cells for transmission on the ATM network. By combining the fixed rate traffic sources into a TDM trunk group and then mapping the trunk group into AAL2 minicells, it is possible to improve efficiency of fixed bit rate traffic transmission using the ATM protocol.

Abstract: A broadband communication system including an Internet Protocol Telephony Network and public switched telephone network. The system may include one or more conference servers for combining IP packet streams in a conference call into a combined IP packet stream, such that the combined IP packet stream utilizes no more bandwidth than each of the original IP packet streams. This allows the traffic volume coming from, and arriving at, each party to a conference call to remain essentially the same no matter how many parties are connected to the conference call. A plurality of the conference servers may be configured to interwork with each other so as to allow for a much larger conference call.

Abstract: A voice playout buffer for a dual PHY-based integrated access device platform has a plurality of voice signal buffer sections. A respective buffer section has a capacity in excess of the number of digitized voice signal bytes contained in a respective cell-based communication signal. A respective buffer section sequentially stores digitized voice signals of a single TDM channel into successive storage locations of a first portion thereof at a first data rate, and reads out digitized voice signals at a second, higher data rate for transport over an ATM cell bus. The storage capacity of a buffer section accommodates a communications control processor writing new outgoing digitized voice signal bytes into the first portion of the voice signal buffer section for transport over a TDM communication link, prior to digitized voice signals newly received from the TDM communication link being written into the first portion of the voice signal buffer section.

Abstract: Circuitry combines a plurality of digital communication channels in a telecommunication system with reduced hardware requirements. The circuitry accumulates samples of the input communication channels in a register using an adder. The bit width of the connection lines between the register and the adder may be selected considering the bit width and number of input communication channels, such that minimal bit widths are provided.

Abstract: A multi-channel coding and multiplexer apparatus comprises a number of coders, buffers and a multiplexer. For each channel, a coder receives an input signal and provides coded data to a corresponding buffer. A surplus bandwidth is determined in accordance with the amount of coded data provided by the coders. The multiplexer distributes this surplus bandwidth to one, or more, channels by adjusting the rate at which the coded data is read from the corresponding buffer.

Abstract: A data transmitting device connected to a prescribed network includes a coding device for receiving plural kinds of coded data, and coupling these coded data in first data units to generate a first coded stream. A divider divides the first coded stream into second data units of a prescribed data size to generate divided pack data corresponding to divided packs as the second units. A packet generating device adds header information to respective divided pack data to generate packet data corresponding to packets as data transmission units; and a transmitter outputs the respective packet data toward the network as a second coded stream which has a data structure different from that of the first coded stream.

Abstract: A digital broadcasting system capable of quickly acquiring long term program information. An SI generating part SG2 generates a long term program information S_EIT which is multiplexed in a transport stream TS2 only. The SI generating part SG2 gives information on whether the long term program information S_EIT is present or not for each service to other SI generating parts SG1 and SG3. The SI generating parts SG1 and SG3 multiplex the given presence information in transport streams TS1 and TS3. In this way, the presence information is multiplexed in all the transport streams. Therefore, the presence information may be acquired whichever transport stream is being received. If the presence information is retained beforehand, the information may be quickly used as required.

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: In a CDMA based wireless digital communications system, a CDMA communications station. A CDMA communications station includes a signal encoder adapted to encode signaling information into a signaling packet. A voice encoder is also included to encode voice information at a variable data rate and process the voice information into a voice packet. A multiplexer is coupled to receive the voice packet from the voice encoder and coupled to receive the signaling packet from the signal encoder. The multiplexer combines the voice packet and the signaling packet into a traffic frame. A transmitter is coupled to the multiplexer for transmitting the traffic frame as received from the multiplexer. The multiplexer is further coupled to receive an early data rate indication from the voice encoder such that the multiplexer is able to preconfigure the traffic frame for the variable data rate voice packet to be delivered once the processing of the voice encoder is complete.

Abstract: In a CDMA based wireless digital communications system, a CDMA communications station. The CDMA communications station includes a signal encoder adapted to encode signaling information into a series of signaling packets, wherein the signal encoder process the signal information into variable size signaling packets in accordance with an amount of the signaling information. A voice encoder is included in the station and is adapted to encode voice information and process the voice information into a series of voice packets, wherein the voice encoder processes the voice information into variable size voice packets in accordance with an amount of the voice information. A multiplexer is included in the station wherein the multiplexer is coupled to receive the voice packets and coupled to receive the signaling packets and for combining the voice packets and the signaling packets into a traffic frame. A transmitter is coupled to the multiplexer for transmitting the traffic frame as received from the multiplexer.

Abstract: A broadband communication system and method utilizing an asynchronous transfer mode core switch is provided. A plurality of central offices are connected to the asynchronous transfer mode network. An asynchronous transfer mode core switch connects to the asynchronous transfer mode network. The core switch is connected to each central office to allow an information provider, such as a video or data provider, to communicate with the plurality of central offices through the core switch. That is, the core switch provides numerous advantages, including a defined point of entry into the asynchronous transfer mode network.

Abstract: An asymmetric digital subscriber line (ADSL) termination unit, which at the transmission end includes a descrambler and a compressor between its scrambler and interleaver. The present invention provides for the use of compression on the data in a channel to remove some of the inherent redundancy, in order to yield much better throughput, particularly in conjunction with certain powerful forward error correction (FEC) schemes. In this manner the compression may be performed on unscrambled data that has a higher redundancy than scrambled data, thereby improving compression. At the reception end, the ADSL termination unit includes a decompressor and a scrambler between its deinterleaver and descrambler.

Abstract: An architecture for providing high-speed access over frequency-division multiplexed (FDM) channels allows transmission of ethernet frames and/or other data across a cable transmission network or other form of FDM transport. The architecture involves downstream and upstream FDM multiplexing techniques to allow contemporaneous, parallel communications across a plurality of frequency channels. Also, the modulation indices of various upstream frequency channels may be different, but a plurality of upstream channels may be used to carry a single data flow generally in parallel. The upstream data flow is fragmented into blocks and formed into superframes to allow transmission over at least one upstream frequency channel. When a plurality of upstream frequency channels are utilized, the superframes facilitate the possibility of having different modulation indices on the plurality of frequency channels.

Abstract: A SONET format signal transport system and method providing an increased transport capacity. The transport system includes multiple low speed transport systems wherein each low speed transport system can have a pair of low speed terminals connected by N working channels and one protection channel. A clear channel high speed SONET transport system is connected between the low speed transport systems. The clear channel high speed SONET transport system has N+1 working channels that each terminate at a high speed terminal. The low speed system protection channels are multiplexed into a protection channel of the clear channel high speed system, while each working channel of each individual low speed system is multiplexed into different high speed channels.

Abstract: A protocol independent multiplexer is described that allows for multiple different protocols that operate at different bit rates to be combined and output in a format that may have yet another bit rate. The multiplexer includes a series of inputting devices that are each coupled to a respective buffering device, a mapping device coupled to each of the buffering devices, and an outputting device coupled to the mapping device. Each of the inputting devices receive an input optical signal and forwards recovered data information to the corresponding buffering device. The buffering devices store the data information and output to the mapping device, the outputting being controlled by the mapping device to ensure that the buffering devices remain approximately half full. The mapping device formats the data information into individual data units and outputs the data units to the outputting device which subsequently multiplexes the data units.

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: Interface and method for trasparently transporting tributary frame payload flows, the flows being of different type and/or at different clocks, said interface comprising: a multiplexing side receiving said tributary payload flows and outputting an aggregate flow; and a demultiplexer side receiving said aggregate flow and outputting single tributary payload flows, wherein it further comprises means for independently handling the tributary payload flows in order to obtain homogeneous payload flows at the same clock to be multiplexed.

Abstract: A method for configuring a telecommunication system having at least one sending entity and one receiving entity connected by a link that ensures the transmission of several transport channels of different qualities of service in which the sending entity performs a rate matching between various qualities of service, after which the various qualities of service are multiplexed and where the matching rate specific to each quality of service is determined on the basis of a parameter (Eq) representative of the ratio Eb/I specific to the quality of service considered.

Abstract: A direct spread spectrum communication system in accordance with a delayed multiplex mode in which improvement in correlation and improvement in error rate can be perfectly realized in any data length. A data generating section appends addition bits so as to generate an integral multiple of information to be transmitted, from data received from an upper (MAC) layer. The symbol length of a data part is determined from information obtained from the upper layer, and the generating section knows the symbol length of a bit synchronization section, a frame synchronization section and a various information section in the system, which should be originally appended as a packet. Therefore, the number of additional bits are added so that the total number of symbols amounts to an integral multiple of the data to be multiplexed.

Abstract: The present invention provides data communication devices, personal handy-phone system base stations, and methods of communicating data. One embodiment of the present invention provides a data communication device including: a transceiver operable to receive wireless signals and recover a baseband signal containing a plurality of first slots from the received wireless signals; a multiple access processor coupled with the transceiver, the multiple access processor being operable to extract data from the first slots and communicate data at a first information transfer rate; a data formatter operable to combine data from plural first slots to form a second slot, the data formatter further being operable to output the second slot at a second information transfer rate; and an interface coupled with the data formatter, the interface being configured for connection with a network and operable to communicate the second slot.

Abstract: A method and system including a broadcast and a local information source, a headend, and a link are described for providing local information to a user device. A broadcast information stream generated at a first data rate is received at the headend. Local information packets are inserted at the headend into the broadcast information stream forming a combined information stream which is transmitted to the user device at a different data rate. Alternatively, local information packets are inserted in place of unusable packets in a broadcast information stream to form a combined information stream which is transmitted to the user device. The user device may be, a display, a, computer, a VCR, a DVR, a set-top box, or a TV.

Abstract: A method encodes an input data block with a block encoder. The block encoder is capable of processing consecutive coding blocks whose size has an upper limit which is smaller than the size of the input data block. The method comprises: determining the length of the input data block before encoding any of its data with the block encoder; dividing the input data block to a plurality of segments wherein all segments are of substantially equal size and no segment is larger than the upper limit; and processing each segment with the block encoder. If the last segment is shorter than the remaining segments, fill bits can be added to the last segment such that its length equals that of the remaining segments.

Abstract: The information coding device has: a first labeling means adapted to associate, with the information to be coded, K “initial” first degree polynomials, a coding means which performs a polynomial calculation: to form K “coded” sequences of P, greater than or equal to K, “coded” polynomials, the first being equal to one of the K initial polynomials and the others to the product of the preceding polynomial and a predetermined polynomial, and to form a “resultant” sequence of P “resultant” polynomials respectively equal to the sums of the coded polynomials of same rank of the K coded sequences, a second one-to-one labeling means adapted to label the points of a quadrature amplitude modulation signal constellation with the Q2 resultant polynomials, for two adjacent points of the constellation, the polynomials labeling them have one identical coefficient and the other coefficient differing only by 1 modulo Q, and a modulator for quadrature amplitude

Abstract: An elementary two-stream transport multiplexer provides for the addition of services contained in a transport stream to a pre-existing transport stream. The elementary multiplexer includes a pair of transport demultiplexers, a processor and a transport remultiplexer. The demultiplexers demultiplex a pair of input transport streams to their constituent service components and service control information tables. The service control information tables are routed to the processor which combines and reconfigures the information within the tables to provide a single set of output service control information tables. The demultiplexers filter the service components based on the output service control tables. The transport remultiplexer multiplexes the output tables with the filtered streams to provide an output transport stream.

Abstract: Data arriving from a plurality of channels asynchronously to each other are respectively stored in separate FIFOs (10). A controller (12) monitors the status of the FIFOs (10), retrieves the stored data in a predetermined order, and multiplexes the data, together with timing data indicating the presence or absence of the data, into a serial signal having a frame structure in which time slots are fixedly assigned to the respective channels. On the serial data, the same value appears successively as data, and when the data is valid, the corresponding timing data changes from a 0 to a 1. When the data is invalid, the value of the corresponding timing data does not change.

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: A multimedia communication arrangement processes and multiplexes different types of data, including data from an adaptive data rate data source and a nonadaptive data rate data source, to substantially increase data throughput over a communication channel. The rate at which data is collected from the adaptive data rate data source varies based on the available channel bandwidth of the modem. The transmission rate is optionally adjusted in response to a detected error rate. Furthermore, the amount of filtering performed by a video camera on an image before the image is encoded by a codec can be adjusted. In addition, a data recovery terminal optionally selectively adjusts intervals at which received audio data is sampled to potentially reduce latency periods.

Abstract: A process for ring bundling reduces the number of add/drop multiplexers required for a ring deployed in a telecommunications network. The input into the process is a list of all the time slots for a ring and the offices of the ring where each of the time slots adds or drops traffic. The process groups together time slots having many add/drops in common to maximize the number of offices where all the time slots pass through without adding or dropping traffic. OC-3 time slots are initially grouped in pairs, then in fours, then in eights, and finally in groups of sixteen to form one or more OC-48 optical signals transported in the ring.

Abstract: An architecture for a self-selective multi-rate transmitter that processes variable input rate data using a plurality of single input, multiple output interleavers. The transmitter, using a multitude of modulation formats, transmits the data at a constant symbol rate without a priori knowledge of the input rate. The transmitter employs a modulator that automatically selects between a multitude of signal constellations, depending on the rate of the source data to be transmitted. The modulator transmits data from various sources, each with an independent data rate. The modulator performs data formatting, forward error correction encoding, modulation onto an intermediate frequency, frequency conversion to a transmit radio frequency, and amplification with automatic gain control.

Abstract: Techniques whereby a transmitter/receiver pair are cooperatively arranged to buffer incoming data to both the transmitter and the receiver. The transmitter and receiver of the pair are coupled, generically, by pre-existing channel which has a known, fixed capacity. The transmitter/receiver pair exploits whatever delay is permissible, as determined by end-users of the data, for the data stream or streams that are using the channel for the purpose of accommodating periods of excessive instantaneous aggregate data transfer demands. The matched transmitter/receiver pair thereby permits (i) the transmission of a variable rate stream over a channel with capacity less than the peak rate of the stream, or (ii) the multiplexing of variable and/or fixed rate data streams.

Abstract: A SONET bus has a set of SONET mappers that transmit and receive facility signals on facility lines. Each facility line operates at a predetermined speed. Each SONET mapper generates a SONET signal by mapping the facility signals received by the SONET mapper into a predefined format for transmission. The predefined format includes timeslots associated with each received facility signal. Each SONET mapper receives a SONET signal and maps the received SONET signal into the facility signals transmitted by the SONET mapper on the facility lines. Each SONET signal includes an associated set of the facility signals. At least one counter outputs a timeslot count signal for synchronizing the timeslots of the facility signals. A set of bidirectional drivers has a mapper side and a system side. Each bidirectional driver receives the timeslot count signal.

Abstract: Disclosed is an apparatus for transmitting a sequence of information bits and sequences of parity bits to a receiver in a transmitter of an HARQ transmission system. A turbo encoder receives a sequence of L information bits, and generates the sequence of information bits and M sequences of L parity bits for the information bits, wherein M is determined depending on a transmission code rate. A redundancy selector includes the sequence of information bits in an initial data block during initial transmission, and uniformly includes non-transmitted parity bits out of parity bits provided from each sequence of the parity bits in a retransmission data block upon every receipt of a retransmission request from the receiver.

Abstract: A service multiplexer (2) for connecting a plurality of signal sources to a public switched communication network transfers data in the form of a synchronously transferred data cells from a plurality of inputs (4) to an output (6) for connection to the network. The multiplexer (2) includes a bandwidth control unit which receives a bandwidth control signal from the network representative of available bandwidth for transmission of cells to the network and generates feedback control signals for transmission to the signal sources to cause them to alter their data transmission rates in accordance with the available bandwidth. An activity detector coupled to the bandwidth control unit monitors the bandwidth of data received at the inputs. The multiplexer allows ABR (available bit rate)—commandable signal sources to be linked to a single port of a public network operating on an ABR basis to provide an efficient and fair allocation of bandwidth for each source.

Abstract: A multiplexing and transmission apparatus including a transmitter and a receiver is provided. The transmitter includes a control pulses generating circuit generating control pulses having different phases; channel-frame generating circuits each outputting low-speed frame signal in synchronization with the control pulse; and a multiplexing circuit multiplexing the low-speed frame signals into the high-speed serial signal. The receiver includes a demultiplexer demultiplexing high-speed serial signal into low-speed frame signals; channel-frame synchronization circuits each generating a frame pulse corresponding to the low-speed frame signal; a switching circuit switching each of the low-speed frame signals to an appropriate port of the channel; and a switch controller circuit controlling the switching circuit.

Abstract: A data transmission system using at cellular phones, in which existing transmission lines having a designated transmission capacity can be used efficiently, and the quality of video and audio data to be transmitted can be improved, is provided. The data transmission system using at cellular phones provides a video data encoder that encodes inputted video data, an audio data encoder that encodes inputted audio data, video data storage that stores encoded video data outputted from the video data encoder, audio data storage that stores encoded audio data outputted from the audio data encoder, and a multiplexer that multiplexes smoothed video data outputted from the video data storage and smoothed audio data outputted from the audio data storage, and transmits multiplexed video and audio data.

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: The present invention is provided to process more than one level 2 protocols by implementing a signalling link of the level 2 at a message transfer part in a common channel signalling system. Internal devices within a central processing unit and a control function of a signalling link controller are initialized and data of the signalling link controller received at the central processing unit is processed for transmit/receive to/from the upper level. A state of a level 3 receiver buffer within the central processing unit is checked, a primitive of data which was received from a level 3 but not processed is analyzed, and the primitive is performed at the signalling link controller, wherein a plurality of level 2 protocols can be processed.

Abstract: Systems and methods for time division multiplexing are described. A time division multiplexer-demultiplexer system includes I) a signal transmitting system for transmittal of a serialized signal including A) latency free continuous data and B) at least one member selected from the group consisting of bursty data and packetized data, the signal transmitting system including a multiplexer and a timing control block; and II) a signal receiving system for reception of the signal without disrupting the laminarity of the latency free continuous data, the signal receiving system including a demultiplexer and a sequence detector. The systems and methods provide advantages in that continuous data can be simultaneously transmitted with bursty data and/or packetized data on the same tie line without disrupting the laminarity of the continuous data.

Abstract: Provided is a method and system for a radio system including at least one base station and terminal equipment including a receiver and a transmitter. The transmitter is structured and arranged to independently adjust a symbol rate of at least two signals and combine the two signals after adjusting the symbol rate. The transmitter then transmits the combined signal along one physical path. By adjusting the signal rate before combining the two signals, the transmitter optimizes the signal qualities of each of the signals.

Abstract: A SDH signal generation portion generates and outputs an SDH signal by increasing/decreasing the AU point values contained in the SDH signal, using a sequence pattern made of a plurality of arbitrary combinations of basic patterns, a single basic pattern being made of changing the AU pointer values successively for a predetermined repetition number of times with the same increase/decrease type and repetition cycle. A memory stores in a different memory area for each basic pattern, taking the increase/decrease type, repetition cycle and repetition number of times as one set of basic pattern information, for basic patterns used in the SDH signal generation portion, and, stores an address designating a memory area storing the basic pattern information of the basic pattern following its own basic pattern for respective basic pattern.

Abstract: The present invention provides a data transmission system comprising first and second source devices 102 and 103 for transmitting video data (isochronous data) 205 and 206 output from first and second data output units 1011 and 1012, and a sink device 101 for receiving the video data transmitted from the source devices and outputting the data to a video composition device 1020, in which the video data supplied from the data output units to the source device are synchronized in frame units and transmitted from the source devices to one sink device. In this data transmission system, synchronous information (reference signal information) 207a in the video composition device 1020 is transmitted from the sink device 101 to the source devices 102 and 103, and timing reference signals 208b1 and 208b2 in the data output units 1011 and 1012 are generated by the source devices on the basis of the synchronous information.

Abstract: An ATM switching system comprises a switch unit including a plurality of input ports and a plurality of output ports having the same cell transmission rate, and a multiplexer for multiplexing cell trains outputted from at least two output ports into a single cell train and outputting the cell train to a high-speed output line (and/or a demultiplexer for demultiplexing a cell train from an output port into a plurality of cell trains and outputting the cell trains to a plurality of low-speed output lines). The switch unit includes a buffer memory for temporarily storing cells inputted from the input ports while forming a queue chain for each output line to which each cell is to be outputted, a demultiplexer for distributing the cells read from the buffer memory among the output ports in circulation, and a buffer memory control circuit for controlling the write and read operation of cells with the shared buffer memory.

Abstract: A data reading control unit select packets to be transmitted so that the number of packets that are transmitted per unit time does not exceed the number of packets that can be transmitted per unit time. The data reading control unit performs this packet selection according to the transmission amount per unit time calculated by a transmission amount calculation unit, the priority information in a priority storing unit, and the transmission queue information in a transmission queue information storing unit. The data reading control unit 109 reads pointers to the selected packets from a cycle transmission queue buffer, reads TS packets from a TS packet buffer according to the read pointers, and outputs the read TS packets to a transmission unit.

Abstract: A Conversion system merges and converts data in a plurality of different data formats from a plurality of different sources, to a selected output data format for transmission on a selected transmission channel. A method for digital data format conversion involves de-packetizing an input packetized datastream. A timing recovery parameter is formed in response to a desired output data format. The depacketized data is re-packetized in response to the desired output data format and the timing recovery parameter is incorporated in the re-packetized data. The re-packetized data is multiplexed in response to the selected format and provided to an output channel.

Abstract: A data transmission rate control method in which a transmission control scheme used for data transmission over each channel is switched depending on a subband to which a proper transmission rate of the channel belongs, the subband being prepared by dividing an entire band by one or more boundaries. This makes it possible to solve a problem in conventional systems of variations in accuracy due to the bandwidth, and an increase in the circuit scale, when the a cell rate to be controlled ranges over wide bandwidth.