Alcatel N.v.

Alcatel

Alcatel Alsthom Compagnie Generale D'electricite

Paul Marie Spruyt

Frank Octaaf Van Der Putten

Peter P Reusens

Karel Adriaensen

Jean-Francois Van Kerckhove

Johan Peeters

A modulator/demodulator (MODEM) is equipped with a rotation circuit (TROT) in its transmitting part (TP) and a rotation circuit (RROT) in its receiving part (RP). To compensate for clock speed differences between the clocks of two communicating modems, the receive rotation circuit (RROT) of one of them rotates the phase of received data carriers in proportion to their respective frequencies. Furthermore, to align transmit data symbols with received data symbols, the transmit rotation circuit (TROT) of one of the modems rotates the phase of the transmit data symbols. Thereto, the phase rotation applied to each carrier whereon the transmit data symbols are modulated, is proportional to the frequency of this carrier and to a phase difference measured between a received pilot carrier (PT) and an expected received pilot carrier (PT.sub.-- E). When the rotation to be applied to a transmit data symbol corresponds to a time shift of half the length of one sample, a sample is duplicated or deleted in a transmit data symbol by transmit skip/stuff circuit (TSS).

Transmitter with phase rotor, modulator/demodulator, communication

To transparently transport an incoming clock signal (CLK2) with a known frequency over a network segment wherein transmission between a transmitter (TX) and a receiver (RX) operates synchronous to a transmit clock signal (CLK1) and receiver clock signal (CLK1') which are synchronized, the transmitter measures the phase difference (P) between the incoming clock signal (CLK2) and a reference signal (R) obtained from the transmit clock signal (CLK1). The measured phase difference (P) is communicated to the receiver (RX) and used therein to generate a copy clock signal (CLK2).

Method to transparently transport an incoming clock signal over a

A method for interleaving data frames, a forward error correcting device and a modulator including such a device, wherein each data frame to be interleaved is divided into a plurality of words, each containing the same amount of data bytes. An overhead extension is added to the words and additionally, the resulting codewords are applied to an interleave buffer (IB) to be written in matrix-shaped structure of memory cells included in the interleave buffer (IB). This matrix-shaped structure is filled column by column in such a way that each codeword occupies another column. Data bytes are read out of the matrix-shaped structure row by row, as a result of which the data frames are interleaved.

Method for interleaving data frames, forward error correcting device and

A method to realize synchronization in a receiver (RX), of data (DAT) sent from a transmitter (TX) to the receiver (RX), with a signal (SIG) available in the receiver (RX). The method includes the following steps: in the receiver (RX) generating trigger signals (T) from the signal (SIG) available in the receiver

Method to synchronize data and a transmitter and a receiver realizing

To allocate a number of data elements to a set of carriers, the carriers are divided into N subsets of carriers according to a predetermined carrier criterion whilst the data elements are classified into N groups of data elements according to a predetermined data criterion, N being an integer greater than one. The predetermined data and carrier criterion have a relation on the basis of which the N subsets of carriers are associated one by one to the N groups of data elements. The data elements classified in such a group are then allowed to be modulated only on carriers which form part of the subset associated with this group. In addition, for each subset of carriers and related group of data elements, the distribution is obtained by means of information from subset dependent `required SNR (Signal to Noise Ratio) per data element`-tables and previously carried out SNR measurements for each carrier.

Method for allocating data elements to a set of carriers, mapping unit

A method is described for detecting erasures in a stream of sets of digital signal values received at a receiver side after transmission from a transmission side. Subsets of these sets are modulated on distinct carrier signals, each transmitted and received thus modulated carrier signal corresponding to one of a number of predetermined subset related points and to a receipt point on a carrier dependent modulation representing map respectively. The method includes the steps of:

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Heverlee, Belgium

Paul Marie Spruyt