摘要:
A digital transmission system comprising at least two transmitting-receiving (T/R) units and a single transmission line connected therebetween. One of the T/R units the first transmits a control signal to the other T/R units with which frame synchronization and timing recovery are carried out using the transmitted control signal. At the same time, the other T/R unit inhibits transmission of send signal therefrom to the first T/R unit. Further, the send signal from one T/R unit to the other T/R unit is transmitted in the form of a frame. Each frame includes, at its end portion, a non-signal duration portion.
摘要:
An initial gain of an automatic equalizer is fixed to a predetermined value. Then, the most appropriate gain of the automatic equalizer is determined when a training signal is received by the automatic equalizer. An echo replica signal produced by an echo canceler is multiplied by the value obtained by dividing the most appropriate gain by the initial gain. Thus, the echo replica signal is corrected to cancel the echo signal included in the output of the automatic equalizer. The sampling rate of the A/D converter used in the transmitter and receiver is shifted by a predetermined value from the transmission line rate at an initial training stage. Thereafter, the sampling rate of the A/D converter is determined to be near that of the transmission line.
摘要:
A digital subscriber line communicating system having a central office and a remote terminal connected through a telephone line, the transmitting side comprising a sliding window transmitting unit for transmitting DMT symbols according to the sliding window through the telephone line to the receiving side, and the receiving side comprising a sliding window receiving unit for receiving DMT symbols according to the sliding window from the transmitting side, the sliding window indicating the phase of cross-talk condition due to a TCM-ISDN transmission at the receiving side, whereby TCM cross-talk can be reduced without largely departing from the standard system.
摘要:
When training carried out prior to data communication is performed in digital subscriber line transmission (xDSL), the side which transmits training symbols adds some data that is contained in a training symbol sequence onto at least one of the beginning and end of this symbol sequence and then transmits the training symbol sequence. The receiving side removes the data that has been added onto the training symbol sequence and executes training processing. The length of the training symbol sequence and of a transmit symbol sequence at time of normal communication is set in such a manner that the symbol sequence will not fall within an interval in which effects of near-end crosstalk from a neighboring line are received. Further, at the time of training prior to data communication, timing information, which specifies an interval in which effects of crosstalk from a neighboring line are received, is inserted into a training symbol sequence and the training symbol sequence is transmitted from a device on the office side to a device on the subscriber side.
摘要:
An echo canceller is disclosed which generates an echo replica based on a transmit signal to cancel an echo. The echo canceller includes a linear echo canceller circuit for generating an echo replica of the transmit signal in the absence of distortion. The echo canceller further includes a waveform-distortion compensation circuit, coupled with the linear echo canceller circuit, for generating an echo replica for compensating waveform distortion occurred in an echo response when the transmit signal is distorted. In the echo canceller, the echo is canceled by use of the echo replica generated in the linear echo canceller circuit in the absence of distortion in the transmit signal, and is canceled by use of the echo replica generated in the waveform-distortion compensation circuit when the transmit signal is distorted.
摘要:
An input analog signal having a periodicity is converted into one-bit digital signals by an A/D converter (42), and the one-bit digital signals are converted into parallel signals by a serial-to-parallel converter (43). A correlation between the parallel signals and a reference signal string is detected by a correlation device (45). When the correlation is detected, a hold circuit (48) holds detection of the correlation and hence outputs a tone signal detection result. With the above simple, low power consumption circuit structure, the tone signal can be detected.
摘要:
A digital subscriber line transmission (xDSL), system includes a transmitting side which transmits training symbols by adding some data that is contained in a training symbol sequence onto at least one of the beginning and the end of this symbol sequence and then transmits the training symbol sequence. A receiving side removes the data that has been added onto the training symbol sequence and executes training processing. The length of the training symbol sequence and of a transmit symbol sequence at time of normal communication is set in such a manner that the symbol sequence will not fall within an interval in which effects of near-end crosstalk from a neighboring line are received. The data added to the training symbol sequence specifies an interval in which effects of the crosstalk are received.
摘要:
A workflow management apparatus that manages a plurality of processes constituting a workflow, comprises: an I/O information acquisition unit 13 that acquires I/O information defining, in each of the processes, output data obtained as a processing result and input data serving as the data related to processing; a process management unit 14 that allows each of the processes to perform processing based on input data of a currently acquired version number; a version number acquisition unit 15 that acquires information related to version numbers of the input and output data handled in each of the processes; and a state registration unit 11 that registers the state of each of the processes, wherein when the output data in any of the processes is updated, the state registration unit resisters the state of the process including the updated output data in the input data thereof as “Being executed” based on the information related to the acquired I/O information and version number.
摘要:
A digital subscriber line communicating system having a central office and a remote terminal connected through a telephone line, the transmitting side comprising a sliding window transmitting unit for transmitting DMT symbols according to the sliding window through the telephone line to the receiving side, and the receiving side comprising a sliding window receiving unit for receiving DMT symbols according to the sliding window from the transmitting side, the sliding window indicating the phase of cross-talk condition due to a TCM-ISDN transmission at the receiving side, whereby TCM cross-talk can be reduced without largely departing from the standard system.
摘要:
A digital subscriber line communicating system having a central office and a remote terminal connected through a telephone line, the transmitting side comprising a sliding window transmitting unit for transmitting DMT symbols according to the sliding window through the telephone line to the receiving side, and the receiving side comprising a sliding window receiving unit for receiving DMT symbols according to the sliding window from the transmitting side, the sliding window indicating the phase of cross-talk condition due to a TCM-ISDN transmission at the receiving side, whereby TCM cross-talk can be reduced without largely departing from the standard system.