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公开(公告)号：US5751768A
公开(公告)日：1998-05-12
申请号：US588348
申请日：1996-01-18
CPC分类号： H04L25/03044 , H04L2025/03509 , H04L2025/03617
摘要： The present invention relates to a method of fractionally spaced adaptive equalization which allows the achievement of the performances of the optimal linear receiver with a high degree of stability of the control algorithms. The technique is applicable to a generic communication system. The present method provides a fractionally spaced equalizer which is perfectly stable and has a good convergence rate without introducing any deterioration of the performances with respect to the optimal receiver and with an extremely low increase in the complexity of realization as compared to the prior art techniques. The invention is based upon the introduction of a whitening filter of the input signal to a fractionally spaced equalizer stabilized with the tap-leakage technique, where the whitening filter is a device able to make the power spectrum density of the signal--repeated with a period equal to the reciprocal of the signalling interval--constant.
摘要翻译： 本发明涉及一种分数间隔自适应均衡的方法，其允许以控制算法的高度稳定性实现最佳线性接收机的性能。 该技术适用于通用通信系统。 本方法提供了一种分数间隔的均衡器，其是完全稳定的并且具有良好的收敛速度，而不会相对于最佳接收机引入性能的任何劣化，并且与现有技术相比，实现的复杂度的极小增加。 本发明基于将输入信号的白化滤波器引入到利用抽头泄漏技术稳定的分数间隔的均衡器，其中白化滤波器是能够使信号重复的功率谱密度具有周期的装置 等于信令间隔常数的倒数。
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2.发明授权Method and circuits for combining baseband signals and recovery of clock timing 失效用于组合基带信号和恢复时钟时序的方法和电路
公开(公告)号：US5592516A
公开(公告)日：1997-01-07
申请号：US270140
申请日：1994-07-01
CPC分类号： H04B7/0854
摘要： The invention relates to a baseband signal combiner and to a sampler typically used in radio relay systems and also in generic communication systems. In order to avoid temporary failures in the free space links, space and/or frequency diversity techniques are used, which consist in the use of two suitably spaced receive antennas or of two transmission frequencies. By suitably combining the signals thus received, the failures in radio links can be redued. The invention provides the use of a particular algorithm of the type CMA (Constant Modulus Algorithm) which, being independent of the combined signal phase, does not interact with the carrier recovery circuits. Moreover, by also applying the same algorithm to the sampler, the cooperation of the two circuits for the optimization of the output signal is obtained.
摘要翻译： 本发明涉及基带信号组合器和通常用于无线电中继系统以及通用通信系统中的采样器。 为了避免自由空间链路中的暂时故障，使用空间和/或频率分集技术，其包括使用两个适当间隔的接收天线或两个传输频率。 通过适当地组合如此接收的信号，可以减少无线电链路中的故障。 本发明提供使用类型CMA（恒模算法）的特定算法，其独立于组合信号相位不与载波恢复电路相互作用。 此外，通过对采样器应用相同的算法，可以获得两个电路的协调来优化输出信号。
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3.发明授权Method and circuits for the transmission and reception of numeric signals, in which the peak power of the filtered signal transmitted is reduced, compatible with conventional coding techniques 失效用于发送和接收数字信号的方法和电路，其中传输的滤波信号的峰值功率减小，与常规编码技术兼容
公开(公告)号：US5608760A
公开(公告)日：1997-03-04
申请号：US506929
申请日：1995-07-26
CPC分类号： H04L27/3411
摘要： Efficiency of a digital link, e.g., a microwave link, is improved by coding numeric signals for transmission so as to transmit selected sequences, in terms of peak power of a filtered signal, for transmission through the link. The most favorable numeric sequences may be encoded by baseband numeric coding.
摘要翻译： 数字链路（例如微波链路）的效率通过对用于传输的数字信号进行编码来改进，以便根据滤波信号的峰值功率传输所选择的序列以便通过链路进行传输。 最有利的数字序列可以由基带数字编码编码。
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4.发明授权Method and device for estimating the carrier frequency of a modulated data signal 失效用于估计调制数据信号的载波频率的方法和装置
公开(公告)号：US5299231A
公开(公告)日：1994-03-29
申请号：US810217
申请日：1991-12-19
IPC分类号： H04L27/00 , G01R23/12 , H04L27/18 , H04L27/227 , H04L27/22
CPC分类号： H04L27/2273 , G01R23/12 , H04L2027/0067
摘要： A method of estimating the carrier frequency of a numeric signal, in which two estimates of the carrier phase are carried out in successive instants of time and the estimated carrier frequency is obtained from the comparison of the above two estimates. The invention also concerns a device for implementing the method, the device including a circuit for estimating the phase of the signal at successive instants in time, a circuit for storing the estimates, and a circuit for comparing the estimates. In a preferred embodiment, both the phase estimator and the comparison circuit are implemented by multipliers and adders.
摘要翻译： 一种估计数字信号的载波频率的方法，其中载波相位的两个估计在连续的时刻进行，并且从上述两个估计的比较中获得估计载波频率。 本发明还涉及一种用于实现该方法的装置，该装置包括用于估计在连续时刻的信号的相位的电路，用于存储估计的电路，以及用于比较估计的电路。 在优选实施例中，相位估计器和比较电路都由乘法器和加法器实现。
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5.发明授权System and circuit for estimating the carrier frequency of a PSK numeric signal 失效用于估计PSK数字信号的载波频率的系统和电路
公开(公告)号：US5541966A
公开(公告)日：1996-07-30
申请号：US131208
申请日：1993-10-01
IPC分类号： H04L27/22 , H04L27/00 , H04L27/233 , H04L27/06
CPC分类号： H04L27/2332 , H04L2027/0065
摘要： The present invention concerns a system for estimating the carrier frequency of a PSK numeric signal, in which symbols are transmitted at frequency fs. The invention is characterized by the use of an estimate, at each symbol interval, of the angular difference between two successive data. Such estimate, suitably processed, provides the control signal for a circuit that compensates the frequency error between the carrier of the received signal and the local oscillator. In a not limiting embodiment, the invention can be implemented through digital circuitry.
摘要翻译： 本发明涉及一种用于估计PSK数字信号的载波频率的系统，其中以频率fs发送符号。 本发明的特征在于使用在每个符号间隔处的两个连续数据之间的角度差的估计。 适当处理的这种估计为补偿接收信号的载波与本地振荡器之间的频率误差的电路提供控制信号。 在非限制性实施例中，本发明可以通过数字电路实现。
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6.发明授权
公开(公告)号：US5412693A
公开(公告)日：1995-05-02
申请号：US097885
申请日：1993-07-27
CPC分类号： H04L27/3872
摘要： The present invention relates to a QAM signal demodulation system able to recover phase and frequency of the carrier and convert the signal to baseband, and to perform these functions when frequency errors are remarkable with respect to the symbol frequency (low capacity links); to reconstruct the synchronism of symbol in order to correctly sampling the analog signal to be processed; to complete the shaping of the signal through a digital filter and to equalize the baseband converted signal (in order to compensate the selective fading effects due to propagation and the linear distortions due to imperfections in the realization of the apparatus). Therefore the system comprises several subsystems devoted to performing the various functions and, in particular, at least a carrier frequency and phase recovery subsystem, a subsystem for reconstructing the synchronism frequency capable of driving the signal sampling circuit, and a subsystem of filters. The present invention is directed to the choice of the particular subsystems used as well as their implementation and interconnections.
摘要翻译： 本发明涉及能够恢复载波的相位和频率并将信号转换为基带的QAM信号解调系统，并且当频率误差相对于符号频率（低容量链路）是显着的时，执行这些功能; 重构符号的同步，以正确采样待处理的模拟信号; 通过数字滤波器完成信号的整形，并平衡基带转换信号（为了补偿由于传播引起的选择性衰落效应以及由于设备实现中的缺陷引起的线性失真）。 因此，该系统包括用于执行各种功能的几个子系统，特别是至少一个载波频率和相位恢复子系统，用于重构能够驱动信号采样电路的同步频率的子系统和滤波器子系统。 本发明涉及对所使用的特定子系统的选择及其实现和互连。
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