Method and apparatus for linear transmission by direct inverse modeling
    1.
    发明授权
    Method and apparatus for linear transmission by direct inverse modeling 失效
    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

    IPC分类号: H03F1/32 H04L25/49

    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。

    Dynamic Schema Creation
    7.
    发明申请
    Dynamic Schema Creation 有权
    动态模式创建

    公开(公告)号:US20100083092A1

    公开(公告)日:2010-04-01

    申请号:US12241720

    申请日:2008-09-30

    IPC分类号: G06F17/24 G06F17/30

    摘要: In a database application executing on a computer system, a database table view is represented by a structured object located on a storage device coupled to the computer system. Responsive to a user pasting content (e.g., spreadsheet data) onto the view of the table, the database application determines if the content to be pasted extends beyond the number of rows (records in a database) or columns (database fields) currently displayed in the table view. If the content extends beyond the number of rows or columns currently displayed, the database application automatically adds one or more records or fields to the structured object on the storage device, and updates the table view to display one or more rows or columns corresponding to the records or fields added to the structured object.

    摘要翻译: 在计算机系统上执行的数据库应用程序中,数据库表视图由位于耦合到计算机系统的存储设备上的结构化对象表示。 响应于将内容(例如,电子表格数据)粘贴到表的视图上的用户,数据库应用程序确定要粘贴的内容是否超出当前显示的行数(数据库中的记录)或列(数据库字段) 表视图。 如果内容超出当前显示的行数或列数,则数据库应用程序会自动将一个或多个记录或字段添加到存储设备上的结构化对象,并更新表视图以显示一个或多个对应于 添加到结构化对象的记录或字段。