Abstract: The present disclosure relates to methods and devices for communication systems comprising an electrically conductive line. The disclosure proposes a method in a line estimation device for determining termination characteristics of an electrically conductive line in a communication system. The method comprises outputting a test signal to the line, wherein the test signal is a wideband test signal with a bandwidth arranged to provide an adequate measurement time-resolution. The method further comprises receiving reflections from impedance discontinuities of the line in response to the test signal. The method also comprises forming a trace of the reflections. The method additionally comprises identifying at least one anomaly in the trace of reflections. The method yet further comprises determining termination characteristics of the line based on characteristics of the trace before and after the identified at least one anomaly.

Abstract: The present disclosure relates to methods and devices for communication systems comprising an electrically conductive line. The disclosure proposes a method in a line estimation device for determining termination characteristics of an electrically conductive line in a communication system. The method comprises outputting a test signal to the line, wherein the test signal is a wideband test signal with a bandwidth arranged to provide an adequate measurement time-resolution. The method further comprises receiving reflections from impedance discontinuities of the line in response to the test signal. The method also comprises forming a trace of the reflections. The method additionally comprises identifying at least one anomaly in the trace of reflections. The method yet further comprises determining termination characteristics of the line based on characteristics of the trace before and after the identified at least one anomaly.

Abstract: The present disclosure relates to wireline communication systems, and in particular to aspects of a method and a line estimation device for estimating a characteristic impedance of a section of a transmission medium. The method comprises determining, by a test equipment having a test port with known impedance Zref, an S11 scattering parameter vector S11ref[f] of the transmission medium, indexed by frequency f. The method also comprises generating, based on Zref and S11ref[f], a model of reflection in the transmission medium corresponding to an observation of the transmission medium via a test port having a test impedance ZT, and also estimating the characteristic impedance of the section as a value of ZT which minimizes a difference between a reflection value of the model of reflection and a respective target reflection value of the section.

Abstract: The present disclosure relates to wireline communication systems, and in particular to aspects of a method and a line estimation device for estimating a characteristic impedance of a section of a transmission medium. The method comprises determining, by a test equipment having a test port with known impedance Zref, an S11 scattering parameter vector S11ref[f] of the transmission medium, indexed by frequency f. The method also comprises generating, based on Zref and S11ref[f], a model of reflection in the transmission medium corresponding to an observation of the transmission medium via a test port having a test impedance ZT, and also estimating the characteristic impedance of the section as a value of ZT which minimizes a difference between a reflection value of the model of reflection and a respective target reflection value of the section.

Abstract: The present disclosure relates to determining parameters in a model of a transmission line. For determining the parameters, reflection coefficient defining data and the total capacitance of the transmission line are obtained. Further, true reflection coefficients obtained through the reflection coefficient defining data are applied in an objective function for the line. The objective function for the line is a sum of error signals and each error signal is the difference between a model value of a reflection coefficient and a corresponding true reflection coefficient. Further, the objective function is minimized by utilizing gradients of the objective function with respect to the transmission line parameters to be determined.

Abstract: A method and a test device for determining communication characteristics of a metal cable suitable for use in a communication system are provided. The method comprises transmitting a wideband test signal on the metal cable; receiving a reflected signal as a result of the wideband test signal; and determining an interval of the reflected signal to be analyzed, the interval corresponding to a part of the cable length. The method further comprises approximating the reflected signal within the interval by a regression model; and determining characteristics of the metal cable based on the regression model.

Abstract: The invention relates to a multi-carrier method in a measurement device for improving reach of a measurement, said method comprising: transmitting a first signal in a sequence, measuring a response to said first signal, calculating a first transfer function for frequency of each modulated subcarrier in the first signal, transmitting a second signal of the sequence, wherein at least one subcarrier in the second signal has modulation different from that of the subcarriers in the first signal, measuring a response to said second signal, calculating a second transfer function for frequency of each modulated subcarrier in the second signal, said second transfer function comprising for each frequency a thereto associated second distortion component, calculating a mean value of all first and second transfer functions. The invention further relates to a measurement device for performing said method.

Abstract: A method and a test device for determining communication characteristics of a metal cable suitable for use in a communication system are provided. The method comprises transmitting a wideband test signal on the metal cable; receiving a reflected signal as a result of the wideband test signal; and determining an interval of the reflected signal to be analysed, the interval corresponding to a part of the cable length. The method further comprises approximating the reflected signal within the interval by a regression model; and determining characteristics of the metal cable based on the regression model.

Abstract: The invention relates to a multi-carrier method in a measurement device for improving reach of a measurement, said method comprising: transmitting a first signal in a sequence, measuring a response to said first signal, calculating a first transfer function for frequency of each modulated subcarrier in the first signal, transmitting a second signal of the sequence, wherein at least one subcarrier in the second signal has modulation different from that of the subcarriers in the first signal, measuring a response to said second signal, calculating a second transfer function for frequency of each modulated subcarrier in the second signal, said second transfer function comprising for each frequency a thereto associated second distortion component, calculating a mean value of all first and second transfer functions. The invention further relates to a measurement device for performing said method.

Abstract: Embodiments of the present invention relate to an arrangement for analyzing transmission line properties. Measurement data providing means provide data of a first frequency dependent line property, line property calculation arrangement with model handling means, a Hubert transform handler and line property determination means calculate said first property based on model parameters, line resistance at 0 frequency, roc, a cut-off frequency, v, a line capacitance C? and a line inductance L?H. The line model handling means calculates the line inductance L(f) via a Hubert transform of a function of Q(f/v), wherein the function Q(f/v) relates the line resistance R(f) to roc as R(f)=roc·Q(f/v). The Hilbert transform values are calculated using a parameterized closed form expression for the Hubert transform or they are tabulated.

Abstract: Transmission properties of a telecommunications transmission line may be estimated with improved accuracy by numerical solution for ? of Zin·j?^C=?coth(?). At least one curve is adapted to ? solutions already obtained and a starting point for numerical solution is selected in dependence of the at least one curve and in dependence of an already obtained solution close in frequency. In a first frequency range, starting points for numerical solution may be calculated from a biquadratic equation. In a second frequency range, a line in the complex plane may be adapted to solutions already obtained and new starting points selected in dependence of the line and in dependence of the previous solution. In a third frequency range, two lines in the frequency plane may be adapted to solutions already obtained and new starting points selected in dependence of the lines.

Abstract: The present invention relates to a method for estimating properties of a transmission line by means of features of a noise spectrum generated by noise entering said transmission line at an intermediate location between the ends of the line. The invention provides possibility to estimate a number of properties, e.g. length of a portion of the transmission line, line attenuation of said line portion and even line termination.

Abstract: Method, arrangement and devices for calibration of a line driving device, such as a DSLAM, having a line port. The method comprises deriving of a first parameter vector, PVinf, for example Hinf. The parameter vector PVinf is derived by performing, at a first site, an echo measurement on the line driving device while the line port on said line driving device is open. The method further comprises calibrating the line driving device based on the first parameter vector PVinf and a second parameter vector PVref, which second parameter vector is based on information on echo measurements performed on at least one reference line driving device.

Abstract: The invention concerns a method for determining parameters in a model of a transmission line. The method comprises obtaining (36) measurements of the line comprising reflection coefficient defining data and the total line capacitance, applying (38) true reflection coefficients obtained through the reflection coefficient defining data in an objective function for the line, which function comprises a sum of error signals, each comprising the difference between a model value of a reflection coefficient and a corresponding true reflection coefficient, minimising (40) the objective function by utilizing gradients of the objective function with respect to the transmission line parameters to be determined and employing a capacitive length and determining (42) at least two further transmission line parameters as combinations of a basic resistive transmission line parameter, a basic capacitive transmission line parameter and a basic inductive transmission line parameter of the transmission line model.

Abstract: Method, arrangement and devices for calibration of a line driving device, such as a DSLAM, having a line port. The method comprises deriving of a first parameter vector, PVinf, for example Hinf. The parameter vector PVinf is derived by performing, at a first site, an echo measurement on the line driving device while the line port on said line driving device is open. The method further comprises calibrating the line driving device based on the first parameter vector PVinf and a second parameter vector PVref, which second parameter vector is based on information on echo measurements performed on at least one reference line driving device.

Abstract: Method, arrangement and network node/device for estimating a quantity related to impedance in a first frequency interval, D1, of a telecommunication transmission line where the transmission line has a length d. The method involves determining a quantity related to impedance of the telecommunication transmission line for at least two frequencies, f1D2 and f2D2, in a second frequency interval D2. The frequencies f1D2 and f2D2 should fulfil the condition that the line length d times the absolute value of the difference between a line propagation constant ?(f1)D2 and a line propagation constant, ?(f2)D2, is less than ?, i.e. abs(d*?(f1)D2?d*?(f2)D2)<?. The method further involves estimating a quantity related to impedance in the first frequency interval D1 based on the determined quantity related to impedance in the second frequency interval D2, where the estimating involves the fitting of a Puiseux series to the determined quantity related to impedance in frequency interval D2.

Abstract: The present invention concerns methods for estimating one or more transmission properties of a telecommunications transmission line. Estimates of the line input impedance, Zin at a frequency ƒ, and the line capacitance ? are made. An estimate is then made in dependence of ?, the frequency ƒ and a value ?, where ? satisfies the relationship ? coth (?)=Zin·j??, and ?=2?ƒ. Accuracy may be improved by least squares fitting a curve to a set of intermediate values and then generating an estimate from the coefficients of the curve.

Abstract: A method and device for estimating one or more transmission properties of a telecommunication transmission line. At least one signal is sent on the line, the at least one signal including at least two frequencies for which the absolute value of the line propagation constant times the line length is less than ?, and a resulting signal is received. An estimate of at least one transmission line property is then determined by examining the relationship between the sent and resulting signal or signals. The process may be repeated, if necessary. The estimate determination may also be repeated one or more times, with each successive estimate preferably using for the determination only those frequencies for which, as previously estimated, the absolute value of the line propagation constant times the line length is less than ?.

Abstract: Embodiments of the present invention relate to an arrangement for analyzing transmission line properties. Measurement data providing means provide data of a first frequency dependent line property, line property calculation arrangement with model handling means, a Hubert transform handler and line property determination means calculate said first property based on model parameters, line resistance at 0 frequency, roc r cut-off frequency, v, line capacitance C?r and line inductance ??. The line model handling means calculates the line inductance L(J) via a Hubert transform of Q(f/v)r relating line resistance R(J) to roc such as formula (I). The Hilbert transform values are calculated using a parameterized closed form expression for the Hubert transform or they are tabulated.

Abstract: Transmission properties of a telecommunications transmission line may be estimated with improved accuracy by numerical solution for ? of Zin·j??C=?coth(?). At least one curve is adapted to ? solutions already obtained and a starting point for numerical solution is selected in dependence of the at least one curve and in dependence of an already obtained solution close in frequency. In a first frequency range, starting points for numerical solution may be calculated from a biquadratic equation. In a second frequency range, a line in the complex plane may be adapted to solutions already obtained and new starting points selected in dependence of the line and in dependence of the previous solution. In a third frequency range, two lines in the frequency plane may be adapted to solutions already obtained and new starting points selected in dependence of the lines.