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公开(公告)号：US4475211A
公开(公告)日：1984-10-02
申请号：US417753
申请日：1982-09-13
CPC分类号： H04L27/01
摘要： An adaptive equalizer performs equalization at IF, demodulates the input signal and then generates the equalization coefficients at baseband from the demodulated data. Coefficient updating can be done on a non-real time basis and coefficients for individual bursts stored in a coefficient memory for retrieval when the same burst occurs in the next frame, thus obtaining a pseudo-continuous equalization for each burst. The error signal is derived from demodulated equalized data and correlated with demodulated unequalized data to generate the correlation coefficients, and individual error signals from each channel can be combined into a single composite error signal for correlation purposes.
摘要翻译： 自适应均衡器在IF进行均衡，对输入信号进行解调，然后从解调数据生成基带的均衡系数。 可以在非实时基础上进行系数更新，并且当在下一帧中发生相同的突发时，存储在系数存储器中用于检索的各个突发的系数，从而获得每个突发的伪连续均衡。 误差信号是从解调的均衡数据导出的，并与解调的不相等的数据相关，以产生相关系数，并且每个信道的各个误差信号可以组合成单个复合误差信号进行相关。
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公开(公告)号：US4169286A
公开(公告)日：1979-09-25
申请号：US914108
申请日：1978-06-09
CPC分类号： H04B7/2125 , H04L7/042
摘要： A surface acoustic wave device is used as a unique word detector and coherent demodulator for a digital code differential phase-shift signal. The device improves code word detection by providing a coherent reference with a correlation gain of 10 log M dB. M is the additional number of fingers introduced into the surface acoustic wave device, which determine the phase of the unique word. To achieve this result with higher reliability and higher correlation coefficient, use is made also of a few bits of the clock recovery which precede the unique word in a preamble as used in Time Division Multiple Access (TDMA) systems. The device requires two interdigital output transducers, one of which provides a maximum output in response to surface acoustic waves representing the unique word, and the other of which provides a maximum output in response to surface acoustic waves corresponding to a preassigned pattern of the unique word, such as a sequence of all zeros combined with a partial sequence of the clock recovery bits. The outputs of the two interdigital output transducers are maximized at the same instant to detect the auto-correlation peak of the unique word with performance equivalent to coherent demodulation. Also, clock and data are recovered in the second set of interdigital transducers.
摘要翻译： {PG，1 A表面声波装置用作数字码差分相移信号的唯一字检测器和相干解调器。 该器件通过提供具有10log M dB的相关增益的相干参考来改进码字检测。 M是引入声表面波器件的额外数量的手指，这决定了独特字的相位。 为了以更高的可靠性和更高的相关系数实现该结果，还使用在时分多址（TDMA）系统中使用的前导码中的唯一字之前的时钟恢复的几比特。 该装置需要两个叉指式输出换能器，其中之一提供响应于表示独特字的表面声波的最大输出，另一个响应于对应于唯一字的预分配图案的表面声波提供最大输出 ，例如与时钟恢复位的部分序列组合的全零序列。 两个交叉指示输出变换器的输出在同一时刻被最大化，以检测具有与相干解调相等的性能的唯一字的自相关峰值。 而且，在第二组交叉指示器中恢复时钟和数据。
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