公开(公告)号：US06748023B2

公开(公告)日：2004-06-08

申请号：US10427992

申请日：2003-05-02

申请人： Yutaka Murakami ,  Shinichiro Takabayashi ,  Masayuki Orihashi ,  Akihiko Matsuoka

发明人： Yutaka Murakami ,  Shinichiro Takabayashi ,  Masayuki Orihashi ,  Akihiko Matsuoka

IPC分类号： H04L2736

CPC分类号： H04L7/04 ,  H04L7/06 ,  H04L27/0008 ,  H04L27/206 ,  H04L27/34 ,  H04L27/3405 ,  H04L27/3455 ,  H04L2027/0024 ,  H04L2027/0087 ,  H04L2027/0093

摘要： In a multivalue modulation type with one pilot symbol inserted for every 3 or more symbols, signal points of each one symbol immediately before and after a pilot symbol are modulated using a modulation type different from that for pilot symbols. In this way, it is possible to suppress deterioration of the accuracy in estimating the reference phase and amount of frequency offset by pilot symbols and improve the bit error rate characteristic in the signal to noise ratio in quasi-coherent detection with symbols whose symbol synchronization is not completely established.

公开(公告)号：US06741645B2

公开(公告)日：2004-05-25

申请号：US10184384

申请日：2002-06-27

申请人： Loke Kun Tan ,  Tian-Min Liu ,  Hing “Ada”T. Hung

发明人： Loke Kun Tan ,  Tian-Min Liu ,  Hing “Ada”T. Hung

IPC分类号： H03H730

CPC分类号： H04N5/46 ,  H04B1/68 ,  H04L25/03057 ,  H04L27/02 ,  H04L27/066 ,  H04L27/2273 ,  H04L27/3427 ,  H04L27/3827 ,  H04L2025/03382 ,  H04L2025/0342 ,  H04L2025/0349 ,  H04L2025/03503 ,  H04L2027/0032 ,  H04L2027/0042 ,  H04L2027/0057 ,  H04L2027/0067 ,  H04L2027/0087 ,  H04N5/21 ,  H04N5/211 ,  H04N5/44 ,  H04N5/4401 ,  H04N11/002

摘要： A system for reducing the complexity of an adaptive decision feedback equalizer, for use in connection with a dual-mode QAM/VSB receiver system is disclosed. QAM and VSB symbols, which are expressed in two's compliment notation, include an extra bit required to compensate for a fixed offset term introduced by the two's compliment numbering system. A decision feedback equalizer includes a decision feedback filter section which operates on symbolic decisions represented by a wordlength which excludes the added bit representing the offset. The vestigal word is convolved with the decision feedback filter's coefficients, while a DC component, corresponding to the excluded bit, is convolved with the same coefficient values in a correction filter. The two values are summed to provide an ISI compensation signal at the input of a decision device such as a slicer. A DC component representing a pilot tone in VSB transmission systems also introduces a DC component, and additional bits, to a VSB wordlength. These additional bits are similarly excluded and the vestigal representation convolved with coefficient values in a decision feedback filter. The DC component, including the pilot tone representation, is convolved with the same coefficient values in a correction filter.

公开(公告)号：US06727936B2

公开(公告)日：2004-04-27

申请号：US10004515

申请日：2001-11-02

申请人： Tian-Min Liu ,  Loke Kun Tan ,  Steven T. Jaffe ,  Robert A. Hawley

发明人： Tian-Min Liu ,  Loke Kun Tan ,  Steven T. Jaffe ,  Robert A. Hawley

IPC分类号： H04N538

CPC分类号： H04B1/68 ,  H04L25/03057 ,  H04L27/02 ,  H04L27/066 ,  H04L27/2273 ,  H04L27/3427 ,  H04L27/3827 ,  H04L2025/03382 ,  H04L2025/0342 ,  H04L2025/0349 ,  H04L2025/03503 ,  H04L2027/0032 ,  H04L2027/0042 ,  H04L2027/0057 ,  H04L2027/0067 ,  H04L2027/0087 ,  H04N5/21 ,  H04N5/211 ,  H04N5/44 ,  H04N5/4401 ,  H04N5/46 ,  H04N11/002

摘要： An electronic, programmable filter is disclosed which selectively removes interference, noise or distortion components from a frequency band without perturbing any of the other signals of the band. An input frequency band such as a television channel spectrum is initially demodulated to baseband and applied to the input of the filter. The baseband spectrum is combined in a complex mixer with a synthesized frequency signal that shifts the spectrum a characteristic amount, in the frequency domain, so as to position an interference component in the region about DC. Once shifted, the frequency components about DC are removed by DC canceler circuit and the resulting spectrum is mixed with a subsequent synthesized frequency signal which shifts the spectrum back to its original representation and baseband. The frequency signals are developed by a programmable frequency synthesizer which a user may program with an intelligence signal that defines the frequency location of an interference signal within the spectrum. Filter blocks may be added or subtracted in order to optimize the filter response for any number of interference components for which rejection is desired.

摘要翻译： 公开了一种电子可编程滤波器，其选择性地从频带中去除干扰，噪声或失真分量，而不扰乱频带的任何其它信号。 诸如电视频道频谱的输入频带最初被解调为基带并且被应用于滤波器的输入。 基带频谱在复合混频器中与合成频率信号组合，该频率信号在频域中使频谱偏移特征量，以便在DC周围的区域中定位干扰分量。 一旦移位，DC直流的频率分量被直流消除器电路去除，所得到的频谱与随后的合成频率信号混合，后者将频谱转移回原来的表示和基带。 频率信号由可编程频率合成器开发，用户可以使用定义频谱内的干扰信号的频率位置的智能信号进行编程。 可以添加或减少滤波器块以优化对于期望的抑制的任何数量的干扰分量的滤波器响应。

公开(公告)号：US20040017841A1

公开(公告)日：2004-01-29

申请号：US10436646

申请日：2003-05-13

发明人： Kazimierz Siwiak

IPC分类号： H04B001/69

CPC分类号： H04B1/7163 ,  H04B1/692 ,  H04B1/707 ,  H04B1/7174 ,  H04B1/7176 ,  H04B1/719 ,  H04J13/0022 ,  H04J13/10 ,  H04L25/03828 ,  H04L27/0014 ,  H04L2027/002 ,  H04L2027/0055 ,  H04L2027/0087

摘要： An RF transmitter includes a reference signal generator, a signal generator, and a mixer. The reference signal generator provides a reference signal that has a prescribed or desired frequency. The signal generator provides an operating signal in response to a selection signal. The operating signal has a frequency that equals the frequency of the reference signal multiplied by a number. The mixer mixes the operating signal with another signal to generate a transmission signal. An RF receiver includes a first mixer, a second mixer, an integrator/sampler, and a signal generator. The first mixer receives as its inputs an input RF signal and a second input signal, and mixes its input signals to generate a mixed signal. The integrator/sampler receives the mixed signal and processes it to provide an output signal. The signal generator provides an operating signal in response to a selection signal. The operating signal has a frequency equal to the frequency of a reference signal, multiplied by a number. The second mixer mixes the operating signal with a template signal to generate the second input signal of the first mixer.

摘要翻译： RF发射机包括参考信号发生器，信号发生器和混频器。 参考信号发生器提供具有规定或期望频率的参考信号。 信号发生器响应于选择信号提供操作信号。 操作信号的频率等于参考信号的频率乘以一个数字。 混合器将操作信号与另一个信号混合以产生传输信号。 RF接收机包括第一混频器，第二混频器，积分器/采样器和信号发生器。 第一混频器作为其输入接收输入RF信号和第二输入信号，并且混合其输入信号以产生混合信号。 积分器/采样器接收混合信号并处理它以提供输出信号。 信号发生器响应于选择信号提供操作信号。 操作信号的频率等于参考信号的频率乘以一个数字。 第二混合器将操作信号与模板信号混合以产生第一混频器的第二输入信号。

公开(公告)号：US06671342B2

公开(公告)日：2003-12-30

申请号：US10288833

申请日：2002-11-06

申请人： Thuji S. Lin ,  Tian-Min Liu ,  Stephen E. Krafft

发明人： Thuji S. Lin ,  Tian-Min Liu ,  Stephen E. Krafft

IPC分类号： H03D322

CPC分类号： H04N5/21 ,  H04B1/68 ,  H04L25/03057 ,  H04L27/02 ,  H04L27/066 ,  H04L27/2273 ,  H04L27/3427 ,  H04L27/3827 ,  H04L2025/03382 ,  H04L2025/0342 ,  H04L2025/0349 ,  H04L2025/03503 ,  H04L2027/0032 ,  H04L2027/0042 ,  H04L2027/0057 ,  H04L2027/0067 ,  H04L2027/0087 ,  H04N5/211 ,  H04N5/44 ,  H04N5/4401 ,  H04N5/455 ,  H04N5/46 ,  H04N11/002

摘要： Improved carrier recovery, symbol timing, and carrier phase tracking systems and methods suitable for use in connection with a dual-mode QAM/VSB receiver system are disclosed. Carrier and phase recovery systems operate on complex signals representing symbols having the same time stamp for each phase error term. in-phase signals are sampled twice a symbol at the in-phase symbol sampling time and at the quadrature-phase symbol sampling time. The signals are de-multiplexed to generate I and XI data streams, where I represents the in-phase sampling time signals and XI represents mid-symbol point sample times. A similar procedure is carrier out on quadrature-phase signals. When the in-phase signal is de-multiplexed to generate a symbol I, the quadrature-phase signal is de-multiplexed to generate its mid-symbol point XQ. Both I and Q are decoded in a decision device to define a symbol error term, which is combined with the opposite mid-symbol signal to define a phase error term PI and PQ for each rail. In both cases, the symbol (I) decision (Î), and mid-symbol (XQ) in each phase error term (PI) computation will have the same prime index.

公开(公告)号：US06671334B1

公开(公告)日：2003-12-30

申请号：US09185419

申请日：1998-11-03

申请人： Thomas L. Kuntz ,  Xiaofen Chen ,  Nikhil M. Deshpande ,  Kyle L. Bernard

发明人： Thomas L. Kuntz ,  Xiaofen Chen ,  Nikhil M. Deshpande ,  Kyle L. Bernard

IPC分类号： H04L2706

CPC分类号： H04L7/0029 ,  H04L25/0305 ,  H04L27/066 ,  H04L2025/03382 ,  H04L2025/03732 ,  H04L2027/0038 ,  H04L2027/0046 ,  H04L2027/0067 ,  H04L2027/0087 ,  H04N17/004

摘要： A measurement receiver demodulator has a first processing channel for producing a filtered signal sample output where the signal samples are processed through a transmission system receiver filter and a second processing channel producing an unfiltered signal sample output where the signal samples are not processed through the transmission system receiver filter. The first processing channel down converts digitally modulated IF signal samples and filters the down converted signal samples using a combined transmission system receiver filter and front end hardware compensation filter. A synchronizer produces timing phase and rate offset parameters that are applied to a resampling filter to synchronize the filtered signal samples to symbol instances of the symbol modulation. The filtered, time-aligned signal samples are scaled using a derived scaling factor. A pilot offset level, if present, is estimated and removed. The resultant signal samples are processed through an equalizer to produce filtered, time-aligned, scaled equalized signal samples that are output as filtered signal samples. The second processing channel receives the down converted signal samples and uses compensation and equalization filter coefficients, timing parameters, and the scaling from the first processing channel in compensation, resampling and equalization filters and a scaler to produce compensated, time-aligned, scaled equalized signal samples that are output as unfiltered signal samples.

摘要翻译： 测量接收机解调器具有用于产生滤波信号采样输出的第一处理通道，其中通过传输系统接收机滤波器处理信号样本，产生未经滤波的信号样本输出的第二处理信道，其中信号采样不通过传输系统处理 接收机滤波器 第一处理通道使用组合的传输系统接收机滤波器和前端硬件补偿滤波器对数字调制IF信号采样进行下变频并对下变频的信号采样进行滤波。 同步器产生施加到重采样滤波器的定时相位和速率偏移参数，以将经滤波的信号样本与符号调制的符号实例同步。 滤波后的时间对齐信号样本使用导出的比例因子进行缩放。 估计和删除导频偏移量（如果存在）。 所得到的信号样本通过均衡器进行处理，以产生作为滤波信号样本输出的滤波的，时间对齐的，均衡的均衡信号样本。 第二处理通道在补偿，重采样和均衡滤波器中使用补偿和均衡滤波器系数，定时参数和来自第一处理信道的缩放，以及缩放器，以产生经补偿的，时间对齐的，均衡的均衡信号 作为未过滤的信号样本输出的样本。

公开(公告)号：US06625237B2

公开(公告)日：2003-09-23

申请号：US09919553

申请日：2001-07-31

申请人： Sumit Anil Talwalkar ,  Charles Leroy Sobchak ,  Leng H. Ooi

发明人： Sumit Anil Talwalkar ,  Charles Leroy Sobchak ,  Leng H. Ooi

IPC分类号： H04L2706

CPC分类号： H04L27/0014 ,  H04L27/227 ,  H04L2027/003 ,  H04L2027/0087

摘要： A null-pilot symbol assisted fast automatic frequency control (AFC) system for coherent demodulation of carrier phase modulation (CPM) includes (209) a pilot clock driven phase differentiator (252,253,255) for operating once every pilot clock cycle to determine the difference between the phase at a current pilot symbol location and the phase at a previous pilot symbol location. A frequency offset selector (256) is then used for choosing the most likely frequency offset from amongst a set of all frequency offsets that give rise to the same phase difference.

摘要翻译： 用于载波相位调制（CPM）的相干解调的零导频符号辅助快速自动频率控制（AFC）系统包括（209）导频时钟驱动相位微分器（252,253,255），用于每个导频时钟周期一次操作，以确定 在当前导频符号位置处的相位和先前导频符号位置处的相位。 然后使用频率偏移选择器（256）来从产生相同相位差的所有频率偏移的集合中选择最可能的频率偏移。

公开(公告)号：US20030161414A1

公开(公告)日：2003-08-28

申请号：US10364354

申请日：2003-02-12

发明人： Jung Sig Jun

IPC分类号： H04L027/14 ,  H04L027/16 ,  H04L027/22

CPC分类号： H04L27/066 ,  H04L2027/0028 ,  H04L2027/0053 ,  H04L2027/0067 ,  H04L2027/0087

摘要： Device for recovering a carrier including a first mixer for multiplying passband I, and Q signals and a first complex carrier to produce baseband I, Q signals, a filter part for providing pilot components of the baseband I, and Q signals only, a first phase error detector for receiving the pilot component to produce first phase error information, a second mixer for multiplying the passband I, Q signals and a second complex carrier, a second phase error detector for multiplying a difference of samples from the second mixer at first and second time points and a sample at a middle time point of the two samples for producing second phase error information, a loop filter for receiving first and second phase error information and selectively forwarding one of the first and second phase error information, and first, and second oscillators for producing the first and second complex carriers in proportion to an output of the loop filter, and providing to the first and second mixers respectively, thereby minimizing PLL residual jitter characteristics after FPLL convergence.

摘要翻译： 用于恢复载波的装置，包括用于乘以通带I的第一混频器，以及Q信号和第一复数载波以产生基带I，Q信号，仅用于提供基带I的导频分量的滤波器部分和仅用于Q信号的第一相 误差检测器，用于接收导频分量以产生第一相位误差信息;第二混频器，用于将通带I，Q信号和第二复数载波相乘;第二相位误差检测器，用于将来自第二混频器的样本的差在第一和第二 用于产生第二相位误差信息的两个样本的中间时间点的时间点和样本，用于接收第一和第二相位误差信息并选择性地转发第一和第二相位误差信息之一的环路滤波器，以及第一和第二相位误差信息 振荡器，用于与环路滤波器的输出成比例地产生第一和第二复数载波，并分别提供给第一和第二混频器 从而使FPLL收敛后的PLL残留抖动特性最小化。

公开(公告)号：US06549583B2

公开(公告)日：2003-04-15

申请号：US09790429

申请日：2001-02-21

申请人： James A. Crawford

发明人： James A. Crawford

IPC分类号： H04K110

CPC分类号： H04L27/2657 ,  H04L27/2675 ,  H04L27/2679 ,  H04L2027/0067 ,  H04L2027/0087

摘要： A method and apparatus of pilot phase error estimation in an orthogonal frequency division multiplexed (OFDM) receiver including the steps of: determining pilot reference points corresponding to a plurality of pilots of an OFDM preamble waveform; and estimating an aggregate phase error of a subsequent OFDM data symbol relative to the pilot reference points using complex signal measurements corresponding to each of the plurality of pilots of the subsequent OFOM data symbol and the pilot reference points. For example, a maximum likelihood based estimation is performed using the complex signal measurements and the pilot reference points. Thus, the poor phase performance in a radio portion of the OFDM receiver is compensated for by the pilot phase error estimation in the baseband portion of the OFDM receiver and improved OFDM signal tracking accomplished under poor SNR conditions.

摘要翻译： 一种正交频分复用（OFDM）接收机中的导频相位误差估计方法和装置，包括以下步骤：确定对应于OFDM前导波形的多个导频的导频参考点; 以及使用与随后的OFOM数据符号和导频参考点的多个导频中的每一个对应的复数信号测量来估计相对于导频参考点的后续OFDM数据符号的聚合相位误差。 例如，使用复信号测量和导频参考点来执行基于最大似然估计。 因此，通过OFDM接收机的基带部分中的导频相位误差估计来补偿OFDM接收机的无线电部分中的差的相位性能，并且在差的SNR条件下完成的改进的OFDM信号跟踪被补偿。

公开(公告)号：US20030054768A1

公开(公告)日：2003-03-20

申请号：US09972514

申请日：2001-10-05

发明人： Raghu Challa ,  Gilbert Christhoper Sih

IPC分类号： H04B015/00

CPC分类号： H04L27/0014 ,  H04L2027/0055 ,  H04L2027/0079 ,  H04L2027/0087

摘要： Techniques to acquire and track pilots in a CDMA system. In an aspect, frequency acquisition of a number of signal instances (i.e., multipaths) in a received signal may be achieved concurrently based on a frequency control loop (RAFC) maintained for each finger processor of a rake receiver. Upon successful acquisition, frequency tracking of acquired multipaths may be achieved based on a combination of a frequency control loop (VAFC) maintained for an oscillator used for downconverting the received signal and the RAFCs for the finger processors. In a tracking mode, the VAFC tracks the average frequency of the acquired multipaths by adjusting the frequency of the oscillator. The RAFC of each finger processor tracks the residual frequency error (e.g., due to Doppler frequency shift) of the individual acquired multipath by adjusting the frequency of a complex sinusoidal signal used in a rotator within the finger processor.

摘要翻译： 在CDMA系统中采集和跟踪飞行员的技术。 在一方面，可以基于为耙式接收机的每个手指处理器维护的频率控制环路（RAFC）同时实现接收信号中的多个信号实例（即，多路径）的频率采集。 在成功获取后，可以基于维持用于下变频接收信号的振荡器的频率控制回路（VAFC）和手指处理器的RAFC的组合来实现获取的多路径的频率跟踪。 在跟踪模式下，VAFC通过调整振荡器的频率跟踪获取的多路径的平均频率。 每个手指处理器的RAFC通过调整在手指处理器内的旋转器中使用的复数正弦信号的频率来跟踪个体获得的多路径的残余频率误差（例如，由于多普勒频移）。