METHOD FOR DETERMINING AUTOMATICALLY A FEXT/NEXT TRANSFER-FUNCTION

摘要

A method is suggested for determining FEXT/NEXT transfer function. In the method a pair of lines in the bundle of lines is selected with a first line A and a second line B. The first line A is provided with an input test signal SA at a first end or near end, while a received signal on line B is measured at a first end or near end and a second end or far end. On the basis of the input test signal and the received signals measured on line B at the near end and at the far end the FEXT/NEXT transfer function may be determined. According to the invention a test signal with a known power spectrum density (PSD or PA) covering the jfre- quency range of interest is transmitted on line A at least during measuring intervals. A first received signal or a noise related quantity is measured at a first or near end of line B and a first report of the first received signal or PSD is sent to a central control unit. Then a sec¬ ond received signal or a noise related quantity is measured at a second or far end of line B and a second report of the second received signal or PSD is sent to a central control unit in a first phase. In a second phase the transmission of the test signal on line A is stopped. In this phase a third received signal or noise related quantity is measured at a first or near end of line B and a third report of the third received signal or PSD is sent to a central control unit. Then a fourth received signal or noise related quantity is measured at a second or far end of line B and a fourth report of the fourth received signal or PSD is sent to a central control unit. In a last phase the FEXT/NEXT transfer function is determined on the basis of the reported data on the received signals at the central control unit wherein all steps are coordinated and controlled from a central location at the central office or customer side.