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Modified viterbi detector for jitter noise dominant channels
Modified viterbi detector for jitter noise dominant channels
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机译:改进的维特比检波器,用于抖动噪声占优势的通道
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摘要
A Viterbi detector includes circuitry for receiving an NRZ encoded received signal in an EEPR4 channel to decode the signal according to &lgr;k(i)=(zk−yk(i))2−&agr;(i), wherein &agr;(i) is m &agr;, &agr; is a positive constant, m is a number of transitions within the most current four symbol periods, &lgr;k(i) is a branch metric at time k for an ith Viterbi branch, k is a time period, zk is a received value at time k, &lgr;k(i) is a metric used to determine a next state of the Viterbi based upon a maximum likelihood evaluation for an ith branch, ak, ak−1, ak−2, ak−3 are received state values at respective time periods k, k−1, k−2, and k−3, and yk is an ideal sample associated with an ith branch. The detector is operated to decode a received data value by determining whether the received value is in a space containing first (90) and second (92) possible decode values. The space has a boundary (96) substantially equidistant from the first (90) and second (92) possible decode values and separating the first and second possible decode values. If the received value is within a first portion of the space closest to the first decode value, the received value is decoded as the first decode value. If the received value is within a second portion of the space closest to the second decode value, it is decoded as the second decode value. A value (&agr;) that estimates an amount of jitter noise in a channel (26) through which the received value has passed is produced. The boundary (96) is then moved an additive amount (1&agr;, 2&agr;, 3&agr;) determined by the value that estimates an amount of jitter noise, wherein the boundary is moved (97, 98, 99) to enlarge whichever of the first and second spaces that contains a larger amount of jitter noise.
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机译:维特比检测器包括用于在EEPR4通道中接收NRZ编码的接收信号的电路,以根据 k Sub> (i) Sup>&equals;(z k Sub>&minus; y k Sub> (i) Sup>) 2 Sup>&minus;&agr; (i) Sup>,其中&agr; (i) Sup>是m&agr ;,&agr;是一个正常数,m是最近四个符号周期内的转换次数,&lgr; k Sub> (i) Sup>是时间k在i <第 Sup>个维特比分支,k是一个时间段,z k Sub>是在时间k的接收值,&lgr; k Sub> (i)< / Sup>是用于基于第i个 Sup>分支,a k Sub>,a k&minus的最大似然估计来确定维特比下一状态的度量; 1 Sub>,a k&minus; 2 Sub>,a k&minus; 3 Sub>是在相应时间段k,k&minus; 1,k&minus; 2和k&minus;的状态值。 3,而y k Sub>是与第i Sup>分支相关的理想样本。通过确定接收值是否在包含第一( 90 B>)和第二( 92 B>)可能的解码值的空间中,操作检测器以解码接收的数据值。该空间的边界( 96 B>)与第一个( 90 B>)和第二个( 92 B>)可能的解码值基本相等,并将第一个和第二个分隔开第二个可能的解码值。如果接收值在最接近第一解码值的空间的第一部分内,则将接收值解码为第一解码值。如果接收到的值在最接近第二解码值的空间的第二部分内,则将其解码为第二解码值。生成一个值(&agr;),该值估计接收值通过的通道( 26 B>)中的抖动噪声量。然后,将边界( 96 B>)移动一个附加值(1&agr,2&agr,3&agr),该值由估算抖动噪声量的值确定,其中边界被移动( 97 ,98、99 B>)来放大包含较大抖动噪声的第一和第二空间中的任何一个。
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