公开(公告)号：US07003030B2

公开(公告)日：2006-02-21

申请号：US10635194

申请日：2003-08-06

申请人： Youssef Abdelilah ,  Gordon Taylor Davis ,  Jeffrey Haskell Derby ,  Ajay Dholakia ,  Evangelos Stavros Eleftheriou ,  Robert F. H. Fischer ,  Dongming Hwang ,  Fredy D. Neeser ,  Malcolm Scott Ware ,  Hua Ye

发明人： Youssef Abdelilah ,  Gordon Taylor Davis ,  Jeffrey Haskell Derby ,  Ajay Dholakia ,  Evangelos Stavros Eleftheriou ,  Robert F. H. Fischer ,  Dongming Hwang ,  Fredy D. Neeser ,  Malcolm Scott Ware ,  Hua Ye

IPC分类号： H03K5/159

CPC分类号： H04L7/0062 ,  H04L7/0029 ,  H04L2025/03363 ,  H04L2025/0342 ,  H04L2025/0349

摘要： Receivers, methods, and computer program products can be used to demodulate a data signal transmitted from a digital source, which has a network sampling rate that is synchronized with a network clock. In an illustrative embodiment, a receiver includes a two-stage interpolator that receives digital samples of the data signal as an input and produces an interpolated digital sample stream to be filtered by an adaptive fractionally spaced decision feedback equalizer. The digital samples received in the interpolator are synchronized with a local clock; however, the interpolated sample stream is synchronized with the network clock. A slicer generates symbols for the samples output from the decision feedback equalizer by comparing the samples with a reference signaling alphabet. The receiver can be used in a V.90 client modem to demodulate pulse code modulated (PCM) data transmitted as pulse amplitude modulated (PAM) signals from a digital network. In addition, the receiver is compatible with legacy analog modem front ends and transmitters. The two-stage interpolator allows the timing synchronization to be performed with extremely fine granularity, which can be useful in PCM modems that typically require relatively high signal to noise ratios.

摘要翻译： 接收器，方法和计算机程序产品可用于解调从具有与网络时钟同步的网络采样速率的数字源发送的数据信号。 在说明性实施例中，接收机包括二阶插值器，其接收作为输入的数据信号的数字样本，并产生经过自适应分数间隔的判决反馈均衡器滤波的内插数字样本流。 在内插器中接收的数字样本与本地时钟同步; 然而，插值的采样流与网络时钟同步。 切片器通过将样本与参考信号字母表进行比较来生成从判决反馈均衡器输出的样本的符号。 接收机可用于V.90客户端调制解调器中，以解调从数字网络传输的脉冲编码调制（PCM）数据作为脉冲幅度调制（PAM）信号。 此外，接收机与传统模拟调制解调器前端和发射机兼容。 两级内插器允许以非常精细的粒度执行定时同步，这在通常需要相对较高的信噪比的PCM调制解调器中是有用的。

公开(公告)号：US06389064B1

公开(公告)日：2002-05-14

申请号：US09264272

申请日：1999-03-08

申请人： Ajay Dholakia ,  Evangelos Stavros Eleftheriou ,  Robert F. H. Fischer ,  Fredy D. Neeser ,  Malcolm Scott Ware

发明人： Ajay Dholakia ,  Evangelos Stavros Eleftheriou ,  Robert F. H. Fischer ,  Fredy D. Neeser ,  Malcolm Scott Ware

IPC分类号： H04B138

CPC分类号： H04L25/4927 ,  H04L5/16 ,  H04L7/0029 ,  H04L7/0062 ,  H04L25/03057 ,  H04L25/061 ,  H04L2025/03363 ,  H04L2025/0349 ,  H04L2025/03694

摘要： Modems, methods, and computer program products identify a signaling alphabet that is in variance with an ideal alphabet due to digital impairments and is used to decode received data symbols. In particular, a set of alphabet thresholds are established that correspond to the data symbols. The data symbols are received in an equalizer, which generates output symbols in response thereto. A collection of data symbols corresponding to a particular alphabet threshold are accumulated and an average value is computed, which is then used to replace the current value for the particular alphabet threshold to which the average value corresponds. Equalizer performance is enhanced as the improved accuracy of the alphabet thresholds results in better error information being fed back for adapting the equalizer filter coefficients.

摘要翻译： 调制解调器，方法和计算机程序产品识别由于数字损伤而与理想字母表不同的信令字母表，并用于对接收到的数据符号进行解码。 特别地，建立一组对应于数据符号的字母表阈值。 在均衡器中接收数据符号，该均衡器响应于此产生输出符号。 累积对应于特定字母表阈值的数据符号的集合，并且计算平均值，然后将其用于替换平均值对应的特定字母表阈值的当前值。 增强了均衡器性能，因为字母表阈值的改进的精度导致反馈更好的误差信息以适应均衡器滤波器系数。