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1. 发明授权

US5923712A Method and apparatus for linear transmission by direct inverse modeling 失效
标题翻译：通过直接逆模拟线性传输的方法和装置
公开(公告)号：US5923712A
公开(公告)日：1999-07-13
申请号：US850940
申请日：1997-05-05
申请人： Robert Richard Leyendecker , Jay Jui-Chieh Chen , Armando Cova Garrido , Yan Guo , Vladimir Pavlovic , Claudio Gustavo Rey , Desmond Wai Ming Yan
发明人： Robert Richard Leyendecker , Jay Jui-Chieh Chen , Armando Cova Garrido , Yan Guo , Vladimir Pavlovic , Claudio Gustavo Rey , Desmond Wai Ming Yan
IPC分类号： H03F1/32 , H04L25/49
CPC分类号： H03F1/3247 , H03F2201/3224 , H03F2201/3233
摘要： A system for linearly transmitting an amplified output signal using predistortion whereby a straight inverse modeling scheme is used to more easily and accurately determine the inverse of the distortion caused by a power amplifier of a RF transmitter. The "inverse" of the power amplifier is directly modeled by considering the power amplifier as a signal processing block with the input and output ports reversed. As a result, the computationally intensive inversion required by conventional schemes is avoided. The predistorter system stores complex coefficients in a predistorter LUT, which are then used as the tap weights of a digital filter implementing the predistorter. The predistortion is done by a non-linear filter which incorporates both instantaneous and average envelope power or magnitude effects. The predistortion LUT is addressed as a function of the instantaneous envelope power or magnitude and past power or magnitude envelopes. This scheme takes into account the instantaneous envelope power or magnitude of the current sample and a profile of the envelope power or magnitude of previous samples to accurately compensate for modulation envelope memory effects of the power amplifier. The past powers or magnitudes provide an indication of the trajectory of the power or magnitude leading to the current power or magnitude, which enables the predistorter to more accurately compensate for the power amplifier distortion. The predistorter LUT is updated with values that are indexed as a function of the powers or magnitudes of past samples and the power or magnitude of the current sample.
摘要翻译：一种用于使用预失真线性地传输放大的输出信号的系统，由此使用直的逆建模方案来更容易且准确地确定由RF发射机的功率放大器引起的失真的倒数。通过考虑功率放大器作为输入和输出端口反转的信号处理块，直接建模功率放大器的“反向”。结果，避免了常规方案所需的计算密集型反转。预失真器系统将复数系数存储在预失真器LUT中，然后将其用作实现预失真器的数字滤波器的抽头权重。预失真由非线性滤波器完成，其包含瞬时和平均包络功率或幅度效应。预失真LUT作为瞬时包络功率或幅度以及过去功率或幅度包络的函数来寻址。该方案考虑了当前采样的瞬时包络功率或幅度以及前一采样的包络功率或幅度的曲线，以准确地补偿功率放大器的调制包络存储器效应。过去的功率或幅度提供了导致当前功率或幅度的功率或幅度的轨迹的指示，这使得预失真器能够更准确地补偿功率放大器失真。预失真器LUT被更新为按照过去采样的功率或幅度以及当前采样的功率或幅度进行索引的值。

2. 发明授权

US5959500A Model-based adaptive feedforward amplifier linearizer 失效
标题翻译：基于模型的自适应前馈放大器线性化
公开(公告)号：US5959500A
公开(公告)日：1999-09-28
申请号：US13572
申请日：1998-01-26
申请人： Armando Cova Garrido
发明人： Armando Cova Garrido
IPC分类号： H03F1/32 , H03F1/00 , H04K1/02
CPC分类号： H03F1/3223
摘要： A linear RF transmitter uses an adaptive forward model of the power amplifier in a feedforward linearization system. The forward model outputs a modeled power amplifier output signal, which is then used to calculate the error signal. The error signal represents the distortion caused by the power amplifier, which is then subtracted from the power amplifier output signal. The forward model can optionally model memory effects of the power amplifier transfer characteristic to more accurately generate the error signal. In addition, the forward model may be generated from the power amplifier output signals using orthogonal predictor variables to further improve performance. These orthogonal predictor values are then used to calculate parameter values used by a feedforward filter to model the power amplifier. A coordinate mapper then maps these calculated parameter values into a set of parameter values having the same coordinate system of the feedforward filter. Still further, in-band distortion may be filtered out of the power amplifier output signal before calculating the parameter values to more accurately model the distortion of the power amplifier.
摘要翻译：线性RF发射机在前馈线性化系统中使用功率放大器的自适应正向模型。正向模型输出模拟功率放大器输出信号，然后用于计算误差信号。误差信号表示由功率放大器引起的失真，然后从功率放大器输出信号中减去该失真。正向模型可以选择性地模拟功率放大器传输特性的存储效应，以更准确地产生误差信号。此外，可以使用正交预测变量从功率放大器输出信号产生正向模型，以进一步提高性能。然后将这些正交预测值用于计算前馈滤波器使用的参数值，以对功率放大器进行建模。坐标映射器然后将这些计算的参数值映射到具有前馈滤波器相同坐标系的一组参数值。此外，在计算参数值之前，可以从功率放大器输出信号中滤除带内失真，以更精确地建模功率放大器的失真。

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