公开(公告)号：DE69815104T2

公开(公告)日：2004-03-18

申请号：DE69815104

申请日：1998-06-10

Applicant: ST MICROELECTRONICS NV

Inventor： OLOFSSON SVEN-RUNE ,  JOHANSSON JOACHIM ,  ISAKSSON MIKAEL ,  OEHMAN HANS ,  BENGTSSON DANIEL ,  OLSSON LENNART ,  ISAKSSON ANDERS ,  OEKVIST GOERAN ,  LJUNGGREN LIS-MARI ,  LUNGBERG HANS ,  STEFANSSON TOMAS ,  BAHLENBERG GUNNAR ,  HAKANSSON SIWERT ,  JOHANSSON MAGNUS

IPC: H04J11/00 ,  H04L1/00 ,  H04L29/10 ,  H04M11/00 ,  H04M11/06

Abstract: A VDSL-modem which is divided into an analog part which is placed in an optical node and a digital part which is placed in a local station. The analog part of the VDSL-modem includes an A/D-converter and D/A-converter, a filter, an amplifier, a hybrid/balun, an adaptive noise attenuator, an optical interface, and possibly an echo canceller. The digital part of the modem includes an FFT/IFFT-processor, a synchronizer, an equalizer, an interleaving unit, an error correction unit, a protocol manager, and an optical interface. The VDSL-modem simplifies synchronization of the modem and reduces power consumption in the optical node. A multiplexor function in the optical node in addition is simpler because it need not manage a protocol.

公开(公告)号：DE69719333T2

公开(公告)日：2003-12-04

申请号：DE69719333

申请日：1997-09-01

Applicant: ST MICROELECTRONICS NV

Inventor： ISAKSSON MIKAEL ,  JOHANSSON MAGNUS ,  TONVALL HARRY ,  OLSSON LENNART ,  STEFANSSON TOMAS ,  OEHMAN HANS ,  BAHLENBERG GUNNAR ,  ISAKSSON ANDERS ,  OEKVIST GOERAN ,  LJUNGGREN LIS-MARIE ,  NORDSTROEM TOMAS ,  ISAKSSON LARS-AKE ,  BENGTSSON DANIEL ,  HAKANSSON SIWERT ,  WEN YE

IPC: H04L27/34 ,  H04J11/00 ,  H04L1/00 ,  H04L27/26 ,  H04M3/00 ,  H04M11/00 ,  H04L5/06

Abstract: A multi-carrier transmission system using orthogonal carriers with high order QAM constellations for the transmission of multiple bits per carrier and symbol. Such systems place high demands on the synchronization of the receiver with the transmitter. The maximum permitted deviation from exact synchronization is usually a small fraction of a sampling interval. A reserve carrier, the pilot carrier, which is given a fixed phase, is usually used as the reference to achieve this high accuracy. The receiver sampling clock oscillator is phase locked to the pilot carrier. It is therefore necessary to estimate the phase of the pilot carrier. Using a bandpass filter to recover the pilot carrier, regardless of the frame structure of the DMT signal, does not eliminate the influence of neighboring carriers on the pilot carrier.

公开(公告)号：AU2003229149A8

公开(公告)日：2003-12-02

申请号：AU2003229149

申请日：2003-05-19

Applicant: ST MICROELECTRONICS NV

Inventor： HUG ROLAND ,  BONAVENTURA MARCO ,  PISONI FABIO

IPC: H04B3/23 ,  H04L25/03 ,  H04L27/26

Abstract: There is disclosed a multi-carrier transceiver system for use in echo-cancellation. The transceiver system is arranged to generate from input data (1) a multi-carrier transmit signal (u) comprising a plurality of multi-carrier data blocks. The transceiver system also has a multi-carrier signal receiver responsive to an input multi-carrier receive signal (Yi) received from a remote signal transmitter. An echo canceller (2000) is arranged to generate from a pair of multi-carrier data blocks (u) a set of frequency-domain echo parameters (W) for use in generating an echo signal (Y ), to generate the echo signal using the frequency-domain echo parameters (W), and to input the echo signal (Y ) to the multi-carrier signal receiver for use in generating an echo-cancelled receive signal (Ei) from the input receive signal (Yi) and the echo signal (Y ).

公开(公告)号：DE69912148D1

公开(公告)日：2003-11-20

申请号：DE69912148

申请日：1999-11-18

Applicant: ST MICROELECTRONICS NV

Inventor： SJOEBERG FRANK ,  WILSON KATE ,  NILSSON RICKARD ,  BENGTSSON DANIEL ,  ISAKSSON MIKAEL ,  NORDSTROEM TOMAS ,  OEDLING PER ,  BAHLENBERG GUNNAR ,  JOHANSSON MAGNUS ,  OLSSON LENNART ,  OEKVIST SVEN-GOERAN

IPC: H04J11/00 ,  H04B3/04 ,  H04B3/32 ,  H04L29/10 ,  H04M20060101

公开(公告)号：DE69718799T2

公开(公告)日：2003-11-13

申请号：DE69718799

申请日：1997-09-01

Applicant: ST MICROELECTRONICS NV

Inventor： ISAKSSON MIKAEL ,  JOHANSSON MAGNUS ,  TONVALL HARRY ,  OLSSON LENNART ,  STEFANSSON TOMAS ,  OEHMAN HANS ,  BAHLENBERG GUNNAR ,  ISAKSSON ANDERS ,  OEKVIST GOERAN ,  LJUNGGREN LIS-MARIE ,  NORDSTROEM TOMAS ,  ISAKSSON LARS-AKE ,  BENGTSSON DANIEL ,  HAKANSSON SIWERT ,  WEN YE

IPC: H04J11/00 ,  H04L1/00 ,  H04L7/033 ,  H04L27/26 ,  H04M3/00 ,  H04M11/00 ,  H04L5/06

Abstract: A multi-carrier transmission system, such as a DMT system. A receiver must be able to recover a sampling clock that is very accurately synchronized to a transmitter sampling clock. Typically, synchronization is achieved by using a reserved carrier, the pilot carrier, which is transmitted with a fixed phase. The receiver sampling clock is then phase locked to the pilot carrier. Frame timing can be recovered by using a correlation technique. Thus an improved method of recovering a sample clock and phase locking the sampling clock to a pilot carrier is provided.

公开(公告)号：AU2003217890A8

公开(公告)日：2003-09-22

申请号：AU2003217890

申请日：2003-03-04

Applicant: ST MICROELECTRONICS NV

Inventor： NORDSWORTHY STEVEN R

IPC: H03M3/02 ,  G06F40/00 ,  H03M3/04 ,  H04B1/04 ,  G06F17/20

Abstract: An Nth-order shaping coder with multi-level quantization and dithered quantizer. The coder is inherently stable and produces a purely white quantization error spectrum. In one exemplary embodiment, the coder is first order, and an improved dither scheme is employed including applying a M-times (e.g., M=2) sample-and-hold to the dither sequence, effectively holding a constant dither for multiple clock cycles. This advantageously results in a reduction of instances where the quantizer jumps over two quantization intervals in one clock cycle without first passing through zero for one clock cycle. Methods for implementing the shaping coder are also disclosed.

公开(公告)号：DE69717285T2

公开(公告)日：2003-09-04

申请号：DE69717285

申请日：1997-09-01

Applicant: ST MICROELECTRONICS NV

Inventor： ISAKSSON MIKAEL ,  JOHANSSON MAGNUS ,  TONVALL HARRY ,  OLSSON LENNART ,  STEFANSSON TOMAS ,  OEHMAN HANS ,  BAHLENBERG GUNNAR ,  ISAKSSON ANDERS ,  OEKVIST GOERAN ,  LJUNGGREN LIS-MARIE ,  NORDSTROEM TOMAS ,  ISAKSSON LARS-AKE ,  BENGTSSON DANIEL ,  HAKANSSON SIWERT ,  WEN YE

IPC: H04L27/34 ,  H04J11/00 ,  H04L1/00 ,  H04L27/26 ,  H04M3/00 ,  H04M11/00 ,  H04L5/06

Abstract: A multi-carrier transmission system such as a DMT based VDSL system. The system uses orthogonal carriers with high order QAM constellations for the transmission of multiple bits per carrier and symbol. This estimate includes digital receiver and transmitter units with the receiver unit including a symbol detection unit. This system is adapted to determine a parameter for each single carrier with the parameter being indicative of a deviation of a received signal from a corresponding constellation point. It compares the parameter with an upper lower limit and if the parameter is outside the limits, changes the constellation used to modulate the carrier to a neighboring constellation. The symbol detection unit may be used to determine a parameter such as the ratio d2/sigma2, where d is the shortest distance between neighboring constellations, sigma is a standard deviation and sigma2 is the variance of the deviations of the input and output signal values of the symbol detection unit.

公开(公告)号：DE69717128T2

公开(公告)日：2003-07-10

申请号：DE69717128

申请日：1997-09-01

Applicant: ST MICROELECTRONICS NV

Inventor： ISAKSSON MIKAEL ,  JOHANSSON MAGNUS ,  TONVALL HARRY ,  OLSSON LENNART ,  STEFANSSON TOMAS ,  OEHMAN HANS ,  BAHLENBERG GUNNAR ,  ISAKSSON ANDERS ,  OEKVIST GOERAN ,  LJUNGGREN LIS-MARIE ,  NORDSTROEM TOMAS ,  ISAKSSON LARS-AKE ,  BENGTSSON DANIEL ,  HAKANSSON SIWERT ,  WEN YE

IPC: H04L27/34 ,  H04J11/00 ,  H04L1/00 ,  H04L27/26 ,  H04M3/00 ,  H04M11/00 ,  H04L5/06

Abstract: A multi-carrier transmission system. A received multi-carrier signal is sampled and digitized before FFT processing. Multi-carrier signals consist of many narrow band carrier waves which convey data via a wide band channel. The amplitude distribution of the sum of all the individual carriers is Gaussian. This means that high amplitudes occur with low probability. At the present time, analog to digital converters have a limited dynamic range. It is therefore normal practice to provide a compromise between cutting and quantization noise. The adverse affects of a course quantization have to be balanced between signal distortions caused by the loss of the low probability high amplitude signals.

公开(公告)号：AT235765T

公开(公告)日：2003-04-15

申请号：AT97937934

申请日：1997-09-01

Applicant: ST MICROELECTRONICS NV

Inventor： ISAKSSON MIKAEL ,  JOHANSSON MAGNUS ,  TONVALL HARRY ,  OLSSON LENNART ,  STEFANSSON THOMAS ,  OEHMAN HANS ,  BAHLENBERG GUNNAR ,  ISAKSSON ANDERS ,  OEKVIST GOERAN ,  LJUNGGREN LIS-MARIE ,  NORDSTROEM TOMAS ,  ISAKSSON LARS-AKE ,  BENGTSSON DANIEL ,  HAKANSSON SIWERT ,  WEN YE

IPC: H04J11/00 ,  H04B3/10 ,  H04L1/00 ,  H04L7/00 ,  H04L27/26 ,  H04L5/06

Abstract: A multi-carrier transmission system using DMT. It is known to recover a receiver sample and clock from a reserved carrier, a pilot carrier having a fixed phase. A sampling clock oscillator in a receiver is then phase locked to the pilot carrier. Multi-carrier receivers, such as DMT receivers, are normally equipped with an FFT processor. A complex number representing the pilot carrier is then available from the FFT processor output. If an FFT processor is not available, a one frequency DFT processor can be provided to produce a complex estimate of the pilot carrier. In a DMT system, frame synchronization is handled separately from sampling clock synchronization, although the two processes are intimately related and frame synchronization must be acquired before sampling clock synchronization.

公开(公告)号：DE69810293D1

公开(公告)日：2003-01-30

申请号：DE69810293

申请日：1998-10-01

Applicant: ST MICROELECTRONICS NV ,  ST MICROELECTRONICS SA

Inventor： MESTDAGH DENIS J G ,  ISAKSSON MIKAEL R ,  OEKVIST GOERAN S

IPC: H04B3/23 ,  H04J11/00 ,  H04L27/26 ,  H04B3/20