Abstract: A method for mitigating traffic congestions in a communication network uses concatenated data packets to transmit information between terminals, e.g., edge proxies, of the network. Embodiments of the invention are directed to packet communications over military or commercial networks. In one application, the method is implemented in a network using High Assurance Internet Protocol Encryption (HAIPE).

Abstract: According to one aspect of the present invention, a method is provided in which indications of signal quality associated with each of the plurality of user stations are received. Multiple user stations (e.g., a first user station and a second user station) are selected to receive data from a base station based on the indications of signal quality associated with the plurality of the user stations. A first packet is constructed which contains signaling data for the first user station and application data for the second user station. A second packet which contains application data for the first user station is super-imposed upon the first packet. The first and second packets are transmitted simultaneously from the base station to the first and second user stations.

Abstract: A device and method for controlling data unit communications between a sender and a receiver, and flexibly responding to a potential data loss event. Data units are transmitted from the sender to the receiver, and the receiver returns an acknowledgment data unit for each data unit received. If the receiver fails to receive a data unit, the sender retransmits the data unit in accordance with a data unit loss response procedure. If the potentially lost data unit is subsequently received, the sender determines whether the correctly received data unit was the initial data unit or the retransmission. If the correctly received data unit was the retransmission, the sender continues to transmit subsequent data units in accordance with the data unit loss response procedure. However, if the correctly received data unit was the initial data unit, the sender transmits subsequent data units in accordance with an excessive delay response procedure.

Abstract: A field programmable gate array (FPGA) for multiplexing data and enable signals input from a plurality of input ports and outputting the multiplexed signal to one output port is disclosed. The FPGA includes a plurality of memories, which are connected to the input ports, for storing the input data and enable signals, respectively, and outputting one-shot signals at trailing edges of the enable signals; and a finite state machine (FSM) for sequentially reading the data signals stored in the memories in an order of the one-shot signals input from the memories.

Abstract: A digital broadcast system which, during the control of caching tables multiplexed into a transport stream, optimally updates the caching without wasting filter resources on changes such as updates to a higher version, addition, or disappearance of the tables. A digital broadcast apparatus broadcasts a transport stream into which an available table information table (ATT) is multiplexed. The ATT monitoring unit in the receiving apparatus regularly monitors an update in the ATT and generates an available table information list every time the ATT has been updated to a higher version. The cache controlling unit compares the available table information list with a cache information list, assigns a filter resource and updates the cache of the table when there is a table updated to a higher version or added, and clears the cache of the table when there is a table that has disappeared.

Abstract: An optical transmission system for performing frequency synchronization even with a client signal with low frequency accuracy, and for transmitting thereof by accommodating/multiplexing without causing a bit slip. A new overhead is added to the entire client signal, and the signal including the new overhead being stuffed is transmitted in conjunction with a plurality of stuffing bits as an optical signal wherein a data storing bit for a negative stuffing, a stuffing information notification bit, and a stuff bits inserting bit for a positive stuffing in the payload are defined in plurality as stuffing bits for adjusting clock frequencies of the client signal in this new overhead.

Abstract: A method and system for providing window shaping for multiline transmission in a communications system are described. A last portion of a prefix symbol is extracted. A prefix with a prefix window is shaped to create a shaped prefix. A DMT symbol is shaped with a DMT window to create a shaped DMT symbol. The shaped DMT symbol is combined with the shaped prefix.

Abstract: Multiple characteristics of a DC-DC converter, such as its mode of operation (e.g., either forced continuous conduction mode, or discontinuous conduction mode), and an operational parameter (such as the dead-time between switching times of the output switching devices (upper and lower MOSFETs) of the converter, whose associated driver integrated circuit has a pin usage that leaves only a single pin available for auxiliary purposes, are programmed by a single pin-based digital and analog information multiplexing circuit that couples both digital information and analog information within the same control signal to the driver IC by way of only the one available pin.

Abstract: A method of fragile watermarking is characterized by the step of generating at least a first ill-conditioned operator, said ill-conditioned operator being related to values extracted from an image or portion thereof A.

Abstract: The punctured pilot channel comprises information symbols of uncertain sign punctured into a sequence of pilot channel symbols of predetermined sign. The apparatus includes an information sign demodulation circuit for determining the sign of the information symbols in response to the pilot channel symbols. A continuous pilot generator generates a non-punctured pilot channel of predetermined sign from the information symbols and the pilot channel symbols. In a first embodiment, the information sign demodulator further comprises a dot product circuit for calculating a dot product of the pilot channel symbols and the punctured information symbols, and a threshold comparator for comparing the dot product to a predetermined threshold.

Abstract: One aspect of the present invention is a method for the wireless transmission of information from one or more antennas to one or more separate users. The method comprises processing information to produce transmission vectors that minimize simultaneous interference between separate user channels and adjusting the radiation patterns to minimize total system radiation power for users specified capacities. In another aspect, the present invention includes apparatus and methods for providing multiple users of a network with information in such a manner that only the user that the signals are intended for receives the information.

Abstract: Embodiments of a method and apparatus for aggregating Ethernet streams are generally described. According to but one example embodiment, implementations of a physical coding sublayer (PCS) modify one or more Ethernet streams to uniquely distinguish at least one of the Ethernet streams from the other Ethernet streams. Any two or more of the modified Ethernet streams may be interleaved to form an aggregate Ethernet stream. The aggregate Ethernet stream may by transmitted over a serial link.

Abstract: One or more atmospheric propagation effects are estimated by using a phase comparison between and upper sideband and a lower sideband of a modulated signal. In one embodiment, one or more propagation effects are estimated by using a phase comparison between an upper sideband and a lower sideband of a satellite navigation signal. In one embodiment, one or more ionospheric propagation effects are estimated by using a phase comparison between an upper sideband and a lower sideband of a GPS M-code signal.

Abstract: A method and apparatus are provided in which control data for a generator system is multiplexed onto a synchronization signal.

Abstract: Disclosed is an operation, administration, and maintenance method for very high bit rate digital subscriber line, which has a simplified frame structure, can be easily modified, and can provide various information. In very high bit rate digital subscriber line system which performs a link set between central office and customer premises equipment connected to each other by a very high bit rate digital subscriber line by transmitting/receiving very high bit rate digital subscriber line overhead control frame having operation code, unique operation codes are identically set at the central office and the customer premises equipment. Unique operation codes prescribe all kinds of messages to be transmitted between central office and customer premises equipment. Operation, administration, and maintenance for customer premises equipment is performed by exchanging messages by central office and customer premises equipment in very high bit rate digital subscriber line overhead control frames.

Abstract: In a data transmission method for information data containing additional information data therewith, comprising, at a transmitter side, following steps: adding error correction codes for correcting error to said additional information data; embedding said additional information data added with said error correction codes into the information data by plural times, repetitively; and transmitting the information data embedded with the repetitive additional information data therein, and comprising, at a receiver side, following steps: receiving the transmitted information data embedded with the repetitive additional information data therein; detecting the repetitive additional information data embedded from said transmitted information data received; determining said additional information data on a basis of a majority rule when receiving said information data; and correcting error with using the error correction codes received and determined when said additional information data contains error(s) therein.

Abstract: The invention concerns a procedure for estimating unknown amplification factors of a received CDMA signal, which encompasses a plurality of code channels, in which respectively an input signal from a symbol plane is split on a symbol plane through splitting with a split code (?ab(?)) in a chip plane. The procedure is executed in the following steps: formation of a cost function dependent upon estimated values of all unknown amplification factors, partial differentiation of the cost function according to estimated value of the unknown amplification factors, formation of a matrix-vector-equation on the basis that all partial differentials of the cost function are zero and thus a minimum of the cost function is present, and the computation of at least some of the matrix coefficients of the matrix-vector-equation with a correlation function on the symbol plane.

Abstract: A mobile station, and corresponding system and method, the mobile station including an IQ multiplexer configured to IQ multiplex transmission data for a data channel and control data for a control channel, and to generate a complex signal; and a transmitter configured to modulate the complex signal generated by the IQ multiplexer, and to transmit the modulated complex signal. When control data for a control channel are added, the IQ multiplexer is configured to assign the control data to be added to the Q axis when a set number for the data channel is an odd number, and to the I axis when an even number.

Abstract: A communication system for a mobile platform satellite service (MPSS) system includes a receiver subsystem (RS) and a transmitter subsystem (TS). A satellite transponder is in communication with the RS and the TS of the mobile platform. A satellite service ground station includes a transmitter subsystem (TS) and a receiver subsystem (RS). A communication link is established between the MPSS system and the ground station, via the satellite transponder. The communications link includes fixed satellite service (FSS) data superimposed on MPSS data in the same frequency band to thereby maximize both satellite transponder utilization and interference budget usage.

Abstract: With this invention, upon scanning a print, since additional information recorded together with that print is reproduced while displaying the scanned image, a special effect that cannot normally be obtained from still images can be obtained. A print on which image information and additional information, different from the image information, are printed is scanned by a scanner (209). An additional information demultiplexer (210) demultiplexes that additional information, which is decoded by an error correction decoder (211). After that, the image and the decoded additional information (moving image or/and acoustic information) are simultaneously reproduced in combination.

Abstract: In a data transmission method for information data containing additional information data therewith, comprising, at a transmitter side, following steps: adding error correction codes for correcting error to said additional information data; embedding said additional information data added with said error correction codes into the information data by plural times, repetitively; and transmitting the information data embedded with the repetitive additional information data therein, and comprising, at a receiver side, following steps: receiving the transmitted information data embedded with the repetitive additional information data therein; detecting the repetitive additional information data embedded from said transmitted information data received; determining said additional information data on a basis of a majority rule when receiving said information data; and correcting error with using the error correction codes received and determined when said additional information data contains error(s) therein.

Abstract: A method transmitting a message over at least one of a plurality of radio frequency (RF) channels of an RF communications network is provided. The method comprises the steps of detecting a presence of jamming pulses in the at least one of the plurality of RF channels. The characteristics of the jamming pulses in the at least one of the plurality of RF channels is determined wherein the determined characteristics define at least interstices between the jamming pulses. The message is transmitted over the at least one of the plurality of RF channels wherein the message is transmitted within the interstices of the jamming pulse determined from the step of determining characteristics of the jamming pulses.

Abstract: A method for processing a composite digital audio broadcasting signal including an analog modulated portion in a central frequency band and digitally modulated portions in upper and lower sidebands with respect to the central frequency band, the method comprises the steps of wideband filtering the composite digital audio broadcasting signal to produce a first intermediate frequency signal, narrowband filtering the composite digital audio broadcasting signal to produce a second intermediate frequency signal, simultaneously processing the first intermediate frequency signal to retrieve a digitally modulated version of program material from the first intermediate frequency signal, and processing the second intermediate frequency signal to retrieve an analog modulated version of the program material from the second intermediate frequency signal, making a determination of the quality of the digitally modulated version of the program material, and using the quality determination to select the analog modulated versi

Abstract: A method of encoding at least two sets of data bits into a single encoded block is provided, wherein each set of data bits includes a primary set of bits to be encoded and a secondary set of bits to remain unencoded, wherein the encoding technique requires a set of code terminating bits to be added to the primary set of bits; the method comprising: combining the two sets of primary bits, whereby one set of code terminating bits is added to the combined two sets of primary bits. The two sets of data bits may each include a header portion and a payload portion, the payload portion comprising encoded speech. The encoding step may be a channel encoding step for encoding the at least two sets of data bits for transmission on a packet switched network. The data bits may be for transmission on an EDGE packet switched network, wherein the at least two sets of data bits are encoded into a single RLC/MAC block.

Abstract: The invention includes a protocol, systems and methods for operating, administering, and maintaining (OAM) physical links in a network that carries packet switched data. A network control point implementing the protocol assigns addresses to all ports of the network, discovers network topology and capabilities, and initializes remote parameters through OAM frames sent to the ports. The OAM protocol maintains all physical transmission links through the communication of OAM frames with information concerning link errors and the status of ports and boxes. The OAM frame has a preamble that is an inverse of a preamble of a data frame, allowing decoupling of the OAM and data services. The OAM frames are initiated and terminated at the physical layer of the network. Ports of the network may include ASIC integrated circuits that create, transmit, receive, and process the OAM frames at the physical layer of the ports.

Abstract: A device and method for controlling data unit communications between a sender and a receiver, and flexibly responding to a potential data loss event. Data to be sent are divided into data units and transmitted from the sender to the receiver. If the receiver fails to receive a data unit, the sender retransmits the data unit using a flow control procedure using adaptive parameters. The sender inserts a mark in each transmitted data unit indicating whether each data unit is an original transmission or a retransmission. For each data unit correctly received, the receiver inserts the corresponding mark in an acknowledgment data unit and sends the acknowledgment to the sender. The sender determines whether the correctly received data unit was an original transmission or a retransmission based on the mark or by comparing the round-trip time for the acknowledged data unit with a predetermined round-trip time for an original transmission.

Abstract: A mobile station, and corresponding system and method, the mobile station including an IQ multiplexer configured to IQ multiplex transmission data for a data channel and a control data for control channel, and to generate a complex signal; and a transmitter configured to modulate the complex signal generated by the IQ multiplexer, and to transmit the modulated complex signal. When control data for a channel are added, the IQ multiplexer is further configured to assign the control data to be added to the I axis or the Q axis according to whether a set number for the data channel is an odd number or an even number.

Abstract: A method of processing an AM radio signal comprises the step of receiving an AM radio signal including an upper sideband portion and a lower sideband portion, demodulating the upper sideband portion and the lower sideband portion to produce a demodulated upper sideband signal and a demodulated lower sideband signal, weighting the demodulated upper sideband signal and the demodulated lower sideband signal in response to noise power to produce a weighted demodulated upper sideband signal and a weighted demodulated lower sideband signal, and combining the weighted demodulated upper sideband signal and the weighted demodulated lower sideband signal to produce an output signal. Demodulators which process AM radio signals in accordance with the method, and receivers incorporating the demodulators, are also included.

Abstract: A mobile station, and corresponding system and method, the mobile station including an IQ multiplexer configured to IQ multiplex transmission data for data channels, control data for a control channel, and control data for an exclusive control channel for high speed downlink packet data, and to generate a complex signal; and a transmitter configured to modulate and transmit the complex signal generated by the IQ multiplexer. The IQ multiplexer assigns the transmission data for the data channel to the I axis and the Q axis, alternately, and assigns control data to the Q axis. When control data for high speed downlink packet data are added, the IQ multiplexer assigns the control data for high speed downlink packet data to the Q axis when a set number for the data channel is an odd number and to the I axis when the set number is an even number.

Abstract: In a bidirectional ring network, in which nodes are mutually connected by network segments, a method of fault protection includes constructing a general mask indicating which of the segments can be reached. For a given data flow to be conveyed through the network from a source node to a destination node, a specific mask is constructed indicating the segments on a desired path of the flow. The general and specific masks are superimposed in order to determine a disposition of the flow.

Abstract: A method and apparatus encode a source data stream via convolutional encoding. One or more encoded data streams are interleaved and transmitted on one or more transmission channels. Data groups generated via convolutional encoding are interleaved via time-interleaving functions to disperse selected bits within puncture groups of the data groups, bits in between data groups, and bits in selected sets of data groups to facilitate reconstruction of the source data stream from at least a portion of the interleaved data stream received on at least one transmission channel. The time-interleaving functions are selected to facilitate reconstruction of the source data stream from one transmission channel following continuous blockage. Subsets of bits of puncture groups are selected to allow reconstruction of the source data stream from the transmission channels using a minimum number of subsets.

Abstract: A multiplexing equipment included in an ATM network to transmit control line signals for interfacing data communication terminals. The transmission of the control line signals is realized by reserving a field in a payload in a cell format for the control line signal transmission between the data communication terminals, mapping RS/CD, CS, ER/DR, CI of the control line signals at intervals based on a terminal speed, multiplexing the mapped control line signals at the transmission side, and separating the multiplexed control line signals at reception side.

Abstract: A method and system are provided for the transmission and reception of an In-band On-channel (IBOC) FM-band digital audio broadcast (DAB) signal. The IBOC DAB signal is generated in the transmitter to substantially occupy the upper and lower sideband frequency regions in the RF emission mask for the conventional broadcast analog FM-band. Redundant source bit information is transmitted in both the upper and lower sidebands so that the loss of information in either one but not both sidebands due to large amounts of interference or distortion, caused by, for example, first-adjacent interference, does not deleteriously affect the IBOC DAB receiver performance. The system exhibits both frequency-diversity and time-diversity. The receiver determines which codeword bit estimate, corresponding to either upper or lower sideband signals, is less likely to be erroneous.

Abstract: An optical multiplex communication system includes a multiplexer and a demultiplexer. In the multiplexer, one of two modulated optical pulse train signals is attenuated by an optical attenuator so that amplitudes of the two signals differ from each other. Then, the two signals are time-division multiplexed to produce a multiplexed optical pulse train signal. In the demultiplexer, a VD detector indirectly derives the amplitude of the extracted optical pulse train signal and outputs it to a comparator. A VR detector derives the mean amplitude of the multiplexed optical pulse train signal and outputs it to the comparator. Based on the inputted amplitudes, the comparator identifies the extracted optical pulse train signal. A controller and a mixer control the signal extraction timing such that the extracted optical pulse train signal as identified by the comparator agrees with selection designated by an externally inputted select signal.

Abstract: The transmission quality of a first data stream, in particular a real time data stream, which competes with at least one further data stream for a restricted transmission capacity at a network node in a data packet oriented communication network, is improved by increasing the data rate of the first data stream by adding redundant data at the transmitter end. During an overload situation, the increase in the data rate of the first data stream in comparison to that of the at least one further data stream overrides the latter to the extent that a greater proportion of the jointly available transmission capacity at the network node is now taken up by the first data stream.

Abstract: The invention concerns a method of processing a set of coefficients representing a digital image (300) with a view to an insertion of at least one item of watermarking information in said image, this image being liable to undergo a set of geometric transformations and said coefficients being grouped together in regions, said method being characterized in that it includes a step (E220) of determining, amongst at least some of said regions, a set of so-called acceptable regions, adapted to receive said at least one item of watermarking information; and a step (E230) of sequencing, according to at least one predetermined criterion, at least one part of said set of acceptable regions, in an order which is invariant with respect to at least one of said geometric transformations.

Abstract: Multiple sub-streams are aharmonicaly interleaved into a high speed data signal by interleaving successive blocks of data from each sub-stream into the high-speed data signal using a predetermined interleaving pattern that is different for two consecutive sequences of N (an integer >2) blocks of data within the high-speed data signal. The resulting irregular distribution of bits of each sub-stream within the high speed data signal reduces the probability that error bursts due to low frequency noise will be localized in one or more of the recovered sub-stream extracted from the high speed data signal. This improved distribution of bit errors across the sub-streams reduces bit error rates in the most highly errored sub-streams, and thereby enables an increase in signal reach.

Abstract: In a radio access network (RAN) where information may be sent to a mobile radio unit using a shared radio channel shared by other mobile radio units, a first transport bearer is established between a first RAN node, e.g., a drift RNC, and a second RAN node, e.g., a base station, to transport data to be transmitted on the shared radio channel. A second transport bearer is established between the first and second RAN nodes to transport control information originated in the first RAN node that relates to the first transport bearer data. The first RAN node then transmits the control information over the second transport bearer to the second RAN node. The control information might include, for example, scheduling information known to the first RAN node because the first RAN node supervises scheduling of data to be transmitted on the shared radio channel. The control information may provide to the mobile radio unit information needed to decode the data transmitted on the shared radio channel.

Abstract: The system for recovering symbol timing offset and carrier frequency error from an orthogonal frequency division multiplexed (OFDM) signal includes a receiver circuit for receiving an OFDM modulated signal representing a series of OFDM symbols, and providing a received signal to an output thereof. A peak development circuit is included for developing a signal having a plurality of signal peaks representing symbol boundary positions for each received OFDM symbol, where each of the signal peaks is developed responsive to an amplitude and phase correspondence produced between the leading and trailing portions of each of the received OFDM symbols. The system includes a circuit for enhancing the signal peak detectability, which includes a circuit for additively superimposing and then filtering the signal peaks, to produce an enhanced signal peak having an improved signal-to-noise ratio.

Abstract: A method increases the wireless information carrying capability of a single bit-limited message by providing a plurality of different training sequences TS, such as a conventional 41 bit TS and two new 41-bit TSs, each with low cross-correlation and high auto-correlation. One of the TSs is selected, appended to an 11-bit Packet Channel Request message, and transmitted. The message with TS is detected and the message is interpreted in light of the TS. In EGPRS, selection of TS1 indicates one of a one-phase access request (OPAR), a short access request (SAR), or a two-phase access request (TPAR) with 8-PSK modulation capability on the uplink. Selection of TS2 indicates one of OPAR, SAR, or TPAR with GMSK modulation capability only on the uplink. Selection of TS_GSM indicates one of GPRS, OPAR, SAR or TPAR, or one of a page response, cell update, mobility management procedure, or a single block without a TBF establishment message.

Abstract: A system and method for implementing a control channel in a packet switched communications network. In a computer network, such as a local area network (LAN) it is known to utilize the Ethernet for distributing communications between stations. The Ethernet employs a standard frame format that includes header frames and, in particular a preamble frame which may be used to provide synchronization information between switching devices or nodes. The preamble frame is not required in a Gigabit Ethernet implementation and the present invention employs a portion of the preamble frame to implement a control channel between switching devices.

Abstract: An asynchronous transfer mode (ATM) switch includes a switch memory having a plurality of discrete queues. A queue is dedicated to a connection in which a traffic stream is transmitted in cells and an inverse multiplex ATM (IMA) format. A switch controller is operable to receive a plurality of cells, to identify cells for the connection, to queue cells for the connection in the queue based on order information received with the cells, to reconstitute from the queue the traffic stream, and to switch the traffic stream and the ATM cells.

Abstract: Transcoder apparatus is designed to transcode a receive signal (UR) into a transmit signal (UE). For this purpose, it includes a signaling transmitting member (14) for producing a signaling message and for introducing it into the transmit signal by stealing bits from said signal. According to the invention, the signaling transmitter member (14) also comprises a tone generator (15) to add a tone signal (UTS) to the transmit signal (UE) prior to applying the signaling message to said transmit signal.

Abstract: An apparatus comprising a parallel arrangement of circuits is described. Each circuit has a data net input. Each circuit has an indication signal net input configured to transport an indication signal having shapes and/or temporal locations different than a data signal on the data net input.

Abstract: A method and associated apparatus for embedding control information in a data signal to be transmitted over a data link by a network node includes the generation of control information to be transmitted over a data link by a network node. Additionally, a transmission signal is generated by combining the control information with data to be transmitted. In an embodiment of the present invention, the data is transmitted within a prescribed frequency bandwidth such that a frequency gap is defined within the frequency bandwidth. Control information is, as such, transmitted within the defined frequency gap.

Abstract: An FM broadcast transmitter transmits a broadcast signal having a carrier at a broadcast frequency and sidebands, able to be transmitted at full power, within a transmission band-width around the carrier. It includes a source of a modulated FM stereo signal having a carrier at the broadcast frequency and having sidebands with a bandwidth less than the transmission bandwidth representing a stereo signal. It also includes a source of a modulated IBOC signal, having carrier pulses spaced relative to each other to represent the IBOC digital data signal encoded as a variable pulse width encoded signal, and a bandwidth within the transmission bandwidth not overlapping the FM stereo signal sidebands. A signal combiner combines the modulated FM stereo signal and the modulated IBOC signal to form the broadcast signal.

Abstract: Clock information related to a reference clock is distributed from a master network node to a slave network node in an asynchronous packet-based network by embedding the clock information into an additional bit stream and multiplexing the additional bit stream with a primary data stream using an out-of-band channel. Multiplexing the additional bit stream with the primary bit stream using an out-of-band channel may involve selecting yB codes of an xB/yB encoded bit stream to represent bits of the additional bit stream or to balance the running disparity of the xB/yB encoded bit stream. The clock information that is embedded into the additional bit stream is used to generate a clock that is synchronized with a reference clock. In an embodiment, the clock information represents the time difference between a transmitted frame of the additional bit stream and a next edge of the reference clock.

Abstract: Program insertion in real time IP multicast enables the seamless insertion of a secondary program within an IP multicast session of a primary program. A primary content provider transmits its multimedia stream to a first proxy that transmits the data to a destination multicast session. A secondary content provider interested in inserting a program into that destination multicast session sends a request through a second proxy to the first proxy requesting a time slot to insert secondary program. The request includes the duration of the secondary program. The first proxy responds with a time slot or a denial of the request depending if a time slot is available. Assuming an available time slot, at the appropriate time the first proxy transfers control of the destination multicast session to the second proxy which transmits the secondary program. Upon completion of the secondary program the second proxy returns control of the session to the first proxy.

Abstract: An improved satellite communications system allows for greater spectral efficiency by requiring just two frequencies for wireless communications between a first ground-based station and a second ground-based station via a satellite. Both the first station and the second station use the first frequency to transmit signals to the satellite; the satellite transponds the signals it receives on the first frequency to the second frequency and transmits the signals to the first and second stations on the second frequency. Use of two frequencies in such a manner results in some own-signal interference. The first station preferably stores its outgoing signals in memory and then subtracts out these stored signals to eliminate the its own-signal interference. The second station may likewise store and subtract out its transmissions, but this is not required.

Abstract: To improve the quality of audio signals transmitted over a computer network, a source computer (12) and a destination computer (30) that participate in the call exchange information concerning the gain and the frequency characteristics response of the audio components of each participating computer. The parameters of the audio components of the source and/or destination computer are then adjusted to produce an audio signal having one or more desired characteristics.