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公开(公告)号：US5007067A
公开(公告)日：1991-04-09
申请号：US414874
申请日：1989-09-29
申请人： Ender Ayanoglu , Richard D. Gitlin , Chih-Lin I , James E. Mazo
发明人： Ender Ayanoglu , Richard D. Gitlin , Chih-Lin I , James E. Mazo
CPC分类号： H04L1/02 , H04L25/4908
摘要： This invention is a technique for the substantially instantaneous self-healing of digital communications networks. Digital data streams from each of N nearby sources are combined and encoded to produce N+M coded data streams using a coding algorithm. The N+M coded data streams are then each transmitted over a separate long haul communications link to a decoder where any N of the N+M coded data streams can be decoded uniquely to produce the original N data streams. The orginal N data streams are then distributed to their respective separate end destinations. If any M or less of the N+M long haul communications links fails, i.e. as in a telephone line that gets cut or a long distance switch that fails, no rerouting of traffic need be done. Rather, the receiver detects loss of carrier on the failed link(s), and immediately supplies the missing data by decoding the data from the at least N remaining links. The technique overcomes a long felt problem of trying to reroute traffic by using sophisticated resource allocation techniques when a communications link fails.
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公开(公告)号：US5394437A
公开(公告)日：1995-02-28
申请号：US963539
申请日：1992-10-20
CPC分类号： H04L7/0054 , H04B14/046 , H04L25/4927 , H04L7/0334
摘要： A modem that operates reliably at a symbol rate that corresponds to twice its bandwidth even when it is coupled to a receiving A/D converter that operates under control of a clock is realized by synchronizing the modem's operation to the A/D's clock. The superior operation of this modem advantageously extends to A/D clock frequencies beyond the frequency of twice the modem's bandwidth. To minimize quantization noise, the modem's output is conditioned to minimize intersymbol interference by adjusting the modem's output to the A/D converter's sampling times and slicing levels. When the A/D's clock is higher than twice the bandwidth of the modem's output signal, some intersymbol interference cannot be avoided. In accordance with this invention, the position and value of this interference is computed at the receiver and subtracted from the received signal.
摘要翻译： 通过将调制解调器的操作与A / D的时钟同步，可以实现以对应于其带宽的两倍的符号速率可靠地操作的调制解调器，即使当其耦合到在时钟的控制下操作的接收A / D转换器时。 该调制解调器的优越操作有利地扩展到超过调制解调器带宽两倍的A / D时钟频率。 为了最小化量化噪声，调制解调器的输出通过将调制解调器的输出调整为A / D转换器的采样时间和切片电平来调节最小化符号间干扰。 当A / D的时钟高于调制解调器输出信号带宽的两倍时，无法避免某些符号间干扰。 根据本发明，在接收机处计算该干扰的位置和值，并将其从接收信号中减去。
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3.发明授权
公开(公告)号：US5528625A
公开(公告)日：1996-06-18
申请号：US176742
申请日：1994-01-03
CPC分类号： H04L25/4927
摘要： The present invention is a quantization-level-sampling (QLS) modem which includes means for separately equalizing each loop of an end-to-end digital telephone system network connection by employing a plurality of transmitter filters and a plurality of receiver filters in such a way that, in the direction of transmission from modem to central office, the voltage samples seen by the coder/decoder stations are equivalent to the network quantization levels transmitted by the modem, and in the direction of transmission from central office to modem, the voltage samples seen by the modem are equivalent to the network quantization levels encoded by the coder/decoder stations. The invention also includes a QLS modem communications system which includes the aforesaid digital telephone system network and a plurality of QLS modems. In preferred embodiments, an adaptation service unit within the telephone system network assists in the determination of the settings of the transmitter and receiver filters.
摘要翻译： 本发明是量化级采样（QLS）调制解调器，其包括通过采用多个发射机滤波器和多个接收机滤波器来分别均衡端到端数字电话系统网络连接的每个环路的装置 在从调制解调器到中心局的传输方向上，由编码器/解码器站所看到的电压样本等同于由调制解调器发送的网络量化级别，并且在从中心局到调制解调器的传输方向上，电压 由调制解调器看到的样本等同于由编码器/解码器站编码的网络量化级。 本发明还包括一个包括上述数字电话系统网络和多个QLS调制解调器的QLS调制解调器通信系统。 在优选实施例中，电话系统网络内的适配服务单元有助于确定发射机和接收机滤波器的设置。
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公开(公告)号：US4901331A
公开(公告)日：1990-02-13
申请号：US354573
申请日：1989-05-19
IPC分类号： H04L27/34
CPC分类号： H04L27/3427
摘要： In a data transmission system using a predetermined trellis code, the output signal points are selected from a predetermined alphabet representing (k+n)-bit input words by using the values of n bits of each input word, and bits from previous input words, to identify a particular one of 2.sup.m subsets of the signaling alphabet m>n. The other k bits of the input word identify an ensemble of four signal points of the identified subset. This ensemble is characterized by having a first signal point whose odd components and even components each sum to a value no less than zero, a second signal point whose odd components sum to a value no less than zero and even components a value no greater than zero, a third signal point whose odd components sum to a value no greater than zero and even components a value no less than zero, and a fourth signal point whose odd components and even components each sum to a value no greater than zero. Two running sums of odd and even cmponents of the signal points previously generated are separately maintained. At any point in time, the system always manages to select and output a signal point in the identified ensemble so as to drive the individual running sums of the respective odd components and even components toward zero simultaneously. This scheme provides a passband signal having a spectral null at a carrier frequency.
摘要翻译： 在使用预定网格码的数据传输系统中，通过使用每个输入字的n位的值和来自先前输入字的位，从表示（k + n）位输入字的预定字母表中选择输出信号点， 以识别信令字母m> n的2m个子集中的特定一个。 输入字的其他k位识别识别的子集的四个信号点的集合。 该集合的特征在于具有第一信号点，其奇数分量和偶数分量各自总和为不小于零的值，第二信号点的奇数分量与不小于零的值相加，并且偶数分量的值不大于零 其奇数分量与不大于零的值相加并且偶数分量不小于零的第三信号点，以及奇数分量和偶数分量各自与不大于零的值相加的第四信号点。 先前产生的信号点的奇数和偶数的两个运行总和被分别维护。 在任何时间点上，系统总是设法选择和输出所识别的集合中的信号点，以便同时驱动各个奇数分量和偶数分量的各个运行和。 该方案提供了在载波频率处具有频谱零点的通带信号。
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公开(公告)号：US4489418A
公开(公告)日：1984-12-18
申请号：US486080
申请日：1983-04-18
申请人： James E. Mazo
发明人： James E. Mazo
CPC分类号： H04L27/3433
摘要： A stream of data to be transmitted is arranged in n streams of 2-bit words. Successive pairs of bits in each of those streams are differentially encoded by generating for each different combination of their values a predetermined one of the differentially encoded bit pairs (i,q), (q,i), (i,q) and (q,i) associated with that combination, where (i,q) is the previously generated differentially encoded bit pair. Words each comprised of the first (second) bit of a respective bit pair in each of the resulting n differentially encoded streams are then provided as n-bit words in a first (second) input stream for a two-dimensional channel coder. In the receiver, the channel decoder provides first and second streams of n-bit words. The bits of the latter are then arranged such that each word in the first (second) stream of channel-decoded words becomes the first (second) bit of a differentially encoded bit pair in a respective one of n differentially encoded bit pair streams. The pairs of bits in each of the n differentially encoded streams are then differentially decoded to recover the original data.
摘要翻译： 要发送的数据流以2位字的n个流排列。 通过针对每个不同的组合对差分编码的位对（i，q），（＆upbar＆q，i），（＆upbar＆i，＆upbar＆q）中的一个进行差分编码， 和（q，＆upbar＆i）与该组合相关联，其中（i，q）是先前生成的差分编码比特对。 然后，在二维通道编码器的第一（第二）输入流中，将由每个所产生的n个差分编码流中的相应位对的第一（第二）位构成的字作为n位字提供。 在接收机中，信道解码器提供n位字的第一和第二流。 然后布置后者的位，使得第一（第二）信道解码字中的每个字成为n个差分编码位对流中的相应一个中的差分编码比特对的第一（第二）比特。 然后对n个差分编码流中的每一个中的位对进行差分解码以恢复原始数据。
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