Timing recovery system
    21.
    发明授权
    Timing recovery system 有权
    定时恢复系统

    公开(公告)号:US06275548B1

    公开(公告)日:2001-08-14

    申请号:US09243763

    申请日:1999-02-03

    IPC分类号: H04L700

    CPC分类号: H04L27/38 H04L7/0278

    摘要: The preferred embodiments generalize the Band Edge Component Maximization (BECM) timing recovery method and provide blind timing recovery in Quadrature Amplitude Modulation (QAM) using all the available information rather than sampling the BECM output at the symbol rate.

    摘要翻译: 优选实施例概括了带边缘组件最大化(BECM)定时恢复方法,并且使用所有可用信息提供正交幅度调制(QAM)中的盲定时恢复,而不是以符号速率采样BECM输出。

    Efficient look-up table methods for Reed-Solomon decoding
    22.
    发明授权
    Efficient look-up table methods for Reed-Solomon decoding 有权
    Reed-Solomon解码的高效查询表方法

    公开(公告)号:US06263470B1

    公开(公告)日:2001-07-17

    申请号:US09200348

    申请日:1998-11-25

    IPC分类号: H03M1300

    CPC分类号: H03M13/1515

    摘要: A programmable logic device (130) as may be used in a communication system device such as a digital subscriber line modem (408) to perform Reed-Solomon decoding upon a received frame of digital values is disclosed. The programmable logic device (130) may be implemented as a DSP (130) or a general purpose microprocessor, for example. According to one disclosed embodiment of the invention, a group of look-up tables (60) are arranged, each look-up table (60) associated with one of the possible power values of a finite field, number up to twice the number of correctable errors. The contents of each entry (SYN) of the look-up tables (60) correspond to the finite field (e.g., Galois field) multiplication of a primitive element raised to an index power with a character of the finite field alphabet. Galois field multiplications (62) in syndrome accumulation may now be performed with a single table look-up operation. According to other disclosed embodiments of the invention, look-up tables (60, 160) are similarly arranged to contain the contents of finite field (e.g., Galois field) multiplication products for use in a Chien search procedure. In a single-thread version of the disclosed Chien search procedure, a subset of the same look-up tables (60) as used in syndrome accumulation may be utilized.

    摘要翻译: 公开了可以在诸如数字用户线路调制解调器(408)的通信系统设备中使用的可编程逻辑设备(130),以在接收的数字值帧上执行里德 - 所罗门解码。 例如,可编程逻辑器件(130)可以被实现为DSP(130)或通用微处理器。 根据本发明的一个公开的实施例,布置了一组查找表(60),每个查找表(60)与有限域的可能功率值之一相关联,数量高达两倍 可纠正的错误。 查找表(60)的每个条目(SYN)的内容对应于提高到索引权力的原始元素与有限字段字母的字符的有限域(例如Galois域)相乘。 综合征累积中的伽罗瓦域乘法(62)现在可以通过单个表查找操作执行。 根据本发明的其它公开的实施例,查找表(60,160)被类似地布置成包含用于Chien搜索过程的有限域(例如Galois域)乘法乘积的内容。 在所公开的Chien搜索过程的单线程版本中,可以利用在综合征积累中使用的相同查找表(60)的子集。