Optimized interpolator filters for timing error correction in DMT systems for xDSL applications
Optimized interpolator filters for timing error correction in DMT systems for xDSL applications
复制标题
用于 xDSL 应用的 DMT 系统中定时误差校正的优化插值器滤波器
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
J. T. E. Munoz
中科院分区：
文献类型：
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作者：
E. Martos;Jesús López;L. D. Río;M. Aguayo;J. T. E. Munoz
离散多音 (DMT) 调制是一种多载波技术，允许在频带有限的信道上传输高速数据。由于涉及大量载波和高密度星座，这种类型的系统在数字用户环路应用 (xDSL) 中使用时对同步错误非常敏感。本文讨论了 xDSL 应用的 DMT 系统中的全数字定时纠错主题，其中定时纠错过程完全基于信号插值。对插值器滤波器性能进行了分析研究，得出了接收器输出端信号失真比 (SDR) 的表达式，作为指标。在此推导中，固定频域均衡器 (FEQ) 发挥着重要作用，因为它补偿了内插器引入的大部分失真。根据这项研究，提出了基于带有 Kaiser 窗的多速率方法的 SDR 最佳插值器滤波器的设计。获得了针对 ASIC 和基于 DSP 的实现的具体设计。性能结果非常出色，所有载波的 SDR 值均高于 50 dB，同时保持较低的计算成本。
Discrete multitone (DMT) modulation is a multicarrier technique that allows the transmission of high speed data over band limited channels. This type of system is very sensitive to synchronization errors when used in digital subscriber loop applications (xDSL), due to the high number of carriers and high density constellations involved. This paper addresses the topic of all-digital timing error correction in a DMT system for xDSL applications, where the timing error correction procedure is based entirely on signal interpolation. An analytical study of the interpolator filter performance is carried out, arriving at an expression for the signal-to-distortion ratio (SDR) at the output of the receiver, as a merit figure. In this derivation, the fixed frequency domain equalizer (FEQ) plays an important role since it compensates for a great part of the distortion introduced by the interpolator. From this study, the design of the optimal interpolator filter in terms of SDR, based on a multirate approach with Kaiser window, is presented. Specific designs for ASIC and for DSP-based implementations are obtained. Performance results are excellent, yielding SDR values above 50 dB for all carriers while keeping the computational cost low.