Abstract: Digital precoding filter for a transmission filter (6) for minimizing the chrest [sic] factor of the signal (y) output by the transmission filter (6), having a modulo adder (22) of the source data symbols which are received from a data symbol source (2) at a signal input (15) of the precoding filter (4), and added with fedback filtered transmission data symbols to transmission output data symbols (p) which are output to the downstream transmission filter (6) via a signal output (41) of the precoding filter (4); and a digital feedback filter (36) which filters the transmission output data symbols present at the signal output (41) and feeds them back to the modulo adder (22), and that [sic] a digital correction filter (39) is connected to the signal output (41), the filter coefficients of the digital correction filter (39) being set as a function of the normalized pulse response of the transmission filter (6) in the case of that sampling phase (?) for which the output signal of the transmission filter (6) has a

Abstract: A method and a device for reducing the crest factor of a signal is operable to generate a correction signal as a combination of a plurality of partial correction signals having respectively predetermined frequencies and a signal having a reduced crest factor being issued as a differential between the correction signal and the signal. The respectively predetermined frequencies are selected such that the correction signal, which has a period length that is shorter than a length of the signal, is periodic. Therefore, according to the invention, only one period of the correction signal is determined and the correction signal is then determined as a periodic continuation of the one period.

Abstract: The invention relates to a method and an apparatus for determination of parameters for a transmission path in a telecommunications system by a transmitting/receiving apparatus having a transmitter and a receiver. In order to determine transmission parameters, a transmission signal is transmitted via the transmission path at a predetermined transmission power level and at a predetermined baud rate (fT) and an echo signal is sampled. A correlation function is calculated from the echo signal and from a correlation signal in a correlation function stage, an envelope function for the correlation function is calculated in an envelope function stage, the envelope function is evaluated, and an output signal is produced as a function of the relative timing and amplitude of the line start echo and/or of the line end echo in an evaluation stage.

Abstract: A system and method for compensating for signal echoes during duplex data transmission with discrete multitone modulation includes determining, the error of a first reference channel. The error of the first reference channel is determined in the frequency domain and is used to correct the other channels. The first reference channel is then corrected with a second error from a second reference channel.

Abstract: In a method for reducing RFI interference in a DMT data transmission a compensation signal for the purpose of reducing an RFI interference signal superposed on a transmitted DMT reception signal is generated. Only carrier frequencies of the DMT reception signal in the vicinity of the interference frequency of the interference signal which are not utilized for the data transmission are used, at least one normalized complex spectral function for all the carriers of said interference signal is provided, an FFT for the purpose of obtaining spectral values of said DMT reception signal is carried out, and an observation window to a current DMT frame of the DMT reception signal is assigned. A complex evaluating coefficient for the current DMT frame is calculated and the complex evaluating coefficient resulting from the spectral values of said DMT reception signal within the observation window and the complex evaluating coefficient are identical for all frequencies within the current DMT frame.

Abstract: In a method for generating a compensation signal for the compensation of at least one RFI interference signal that, in a DMT transmission, is permanently superposed on a received DMT reception signal being divided into a multiplicity of channels at least one reference channel from the multiplicity of channels is provided. The multiplicity of channels comprise a first portion provided as data channels for the data transmission and a second portion which is an observation region unused for the data transmission. Channel-specific coefficients for at least one of the data channels to be compensated are provided. The channel-specific coefficients specify a correlation of the RFI interference signal being superposed on the respective data channel in respect of the reference channel. A compensation signal is generated by weighting and summing the received DMT reception signals with the channel-specific coefficients per DMT frame and for each data channel to be compensated.

Abstract: The invention relates to a method of canceling noise in a signal generated by discrete multi-tone modulation. The noise is caused primarily by the transient of a transmission channel via which the signal is transmitted. The signal comprises a plurality of symbols each of which is preceded by a cyclic prefix. According to the invention, a plurality of parameters is calculated from the digitized sample values of the signal and the approximate transient of the transmission channel is calculated from said plurality of parameters. To cancel the noise the approximately calculated transient is subtracted from the digitized sample values.

Abstract: A digital receiver for receiving DMT signals includes a time-domain equalizer that includes a digital filter having fixed coefficients.

Abstract: The invention concerns a method and a device for determining parameters of a transmission link (2) which is connected to a transmission/reception device (1A; 1B) on the basis of an echo signal of a transmission signal which is transmitted onto the transmission link (2) with at least one individual pulse. The echo signal is first captured. The echo components of the echo signal are shortened by applying a preferably adjustable shortening filter (19) to the captured echo signal. The invention also proposes applying an adjustable further filter (18) to the echo signal, and adjusting the adjustable further filter (18) and preferably also the shortening filter (19) to select an effective central frequency of the at least one individual pulse. The parameters of the transmission link (2) are determined by evaluating the filtered echo signal on the basis of the temporal position and/or amplitude of at least the echo component from the end of the transmission link (2).

Abstract: A method and apparatus for reducing the crest factor of a signal uses a plurality of partial correction signals having respective predetermined frequencies. For each of the partial correction signals, the following steps are performed: (a) determining a time position of a maximum absolute amplitude of the signal; (b) calculating an amplitude and a phase depending on said maximum absolute amplitude and said time position for the respective partial correction signal; and (c) subtracting the respective partial correction signal from said signal to obtain a partially corrected signal which is used as the signal in step (a) for the next of the plurality of partial correction signals, and going to step (a) for calculating the next partial correction signal. The last-obtained partially corrected signal is output as the reduced-crest factor signal.

Abstract: The present invention provides a transmission system having a signal source which has an internal resistance, having a signal transmission line (102), one end of which is connected to the signal source, and having a terminating resistance which is connected to another end of the signal transmission line (102), the internal resistance of the signal source and the terminating resistance being complex and being chosen such that frequency-dependent signal attenuation in the transmission system is reduced in a frequency range which contains the frequencies of signals which are produced by the signal source.

Abstract: Fractional Spaced Equalizer FSEQ having adjustable coefficients ci for equalizing a reception signal of a transceiver, wherein said transceiver comprises an echo compensator EC which generates an echo compensation signal for compensating an echo signal of said transceiver, wherein said echo compensation signal is subtracted from said reception signal equalized by said fractional spaced equalizer FSEQ by means of a subtractor and wherein the adjustable coefficients ci of said fractional spaced equalizer FSEQ are set after a half-duplex training phase of said transceiver during which said echo compensator EC is deactivated.

Abstract: The invention relates to a method and an apparatus for determination of parameters for a transmission path (2) in a telecommunications system by a transmitting/receiving apparatus (1) having a transmitter (3) and a receiver (7). In order to determine transmission parameters such as the signal propagation time, the line length and the line attenuation from the echo pulse response, a transmission signal is transmitted via the transmission path (2) at a predetermined transmission power level and at a predetermined baud rate (fT) and an echo signal is sampled, which has at least one echo component from a line start (2a) of the transmission path (2) and an echo component from a line end (2b) of the transmission path (2).

Abstract: The invention relates to a method for production of a transmission signal with reduced crest factor having the following method steps: (a) Provision of a transmission signal which is to be transmitted and has at least one peak value in one area; (b) sampling, in particular oversampling of the transmission signal in order to produce sample values; (c) buffer-storage and/or delay of the transmission signal s1(+) corresponding to the delay in the production of a correction function; (d) production of a weighted correction function by detection of whether the magnitude of the transmission signal or of its sample values has exceeded a first threshold in this area of the transmission signal; calculation of a correction factor; production of a weighted correction function from the correction factor and from a predetermined correction function; (e) additives superimposition of the weighted correction function and the delayed and/or buffer-stored transmission signal in order to produce the transmission signal with a

Abstract: A splitter circuit (19) serves to combine on the transmission side signals which are to be transmitted in different frequency bands (A-C), as well as to separate on the reception side these signals which are transmitted in different frequency bands. For this purpose, the splitter circuit (19) has a circuit section (13) designed as purely passive, for the rough signal and impedance separation, as well as the filters (3, 4; 9, 10) allocated to the individual transmission and reception sections, for the exact filtering out of the individual signal in each case. These separate filters (3, 4; 9, 10) are arranged in the transmission direction upstream of a corresponding four-wire/two-wire conversion, and in the reception direction downstream of a corresponding two-wire/four-wire conversion, so that the signal stream takes place via these filters in one direction only, and the filters can be designed as purely active filters or digital filters.

Abstract: For digital demodulation of a quadrature amplitude- or phase-modulated signal (xE(t)), this is sampled with a sampling frequency fs and A/D converted, which has the relationship f s = 4 · f 0 1 + 2 · λ with the carrier frequency f0, whereby &lgr; is a whole number greater than or equal to zero.

Abstract: The invention relates to a method and a switching arrangement for the identification of Pupin coils in a telecommunications line.

Abstract: In order to change and, in particular, reduce the crest factor in a signal which is used, in particular, for data transmission by the method of discrete multitone modulation, it is known to store the signal in the form of individual sampling values in a signal vector (y), as a function of which a correction vector (&Dgr;y) is calculated for superimposition of the signal vector (y). The correction vector (&Dgr;y) is calculated here as a function of a maximum element of the signal vector (y) and reduces this maximum value in a targeted manner. In order to be able to reduce new maximum values of the signal vector (y) occurring after the reduction of a first maximum value, according to the invention the correction vector is windowed, so it acts with differing strength on different sections of the signal vector (y) or in that with the windowed correction vector (&Dgr;y) individual maximum values in the signal vector (y) can be reduced in a targeted manner.

Abstract: In a signal which is used, in particular, for data transmission by the method of discrete multitone modulation, in order to change and in particular to reduce the crest factor, it is known to store the signal in the form of individual sampling values in a signal vector (y), as a function of which, a correction vector (&Dgr;y) is calculated to be superimposed on the signal vector (y). When the frequency components of the corrected signal vector are to be changed by filtering, the crest factor is in certain circumstances disadvantageously increased again. According to the invention, to change the crest factor, the correction vector (&Dgr;y) is therefore superimposed on the signal vector (y) after prior filtering. Advantageously, the sampling frequency is doubled in the prior filtering and the elements of the signal vector (y) which has been doubled with respect to the sampling frequency are alternately divided over two part signal vectors.

Abstract: In a transmission system with Tomlinson preceding, the data are transmitted with N amplitude levels. In order to be able to resume the data transmission quickly and with little outlay after a temporary interruption, test signals (15-18) with data symbols which have W amplitude levels out of the overall N amplitude levels are transmitted in a warm-start phase for synchronisation or adjustment of a receiver (C), W and N being integers and W being <N. Even though only W amplitude levels are transmitted, the test signals are Tomlinson-precoded using N levels on the transmitter side and decoded using N levels on the receiver side, so that the transient process of the Tomlinson filter (2) is not perturbed when switching over to the N-level data mode and it is not necessary to change the Tomlinson preceding and decoding which depend on the number of data levels. The invention can be used, in particular, for the SDSL standard, although it may be used in all systems with Tomlinson preceding.