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53 条记录 (耗时 0.061 秒)

    Data compression by discarding portions of data
    45.
    发明授权
    Data compression by discarding portions of data 失效
    通过丢弃部分数据进行数据压缩

    公开(公告)号：US5040233A

    公开(公告)日：1991-08-13

    申请号：US462206

    申请日：1990-01-09

    申请人： Rex W. Davy ,  David J. Harris

    发明人： Rex W. Davy ,  David J. Harris

    IPC分类号： B41J5/30 ,  G06F3/12 ,  G06F5/00 ,  G06T9/00 ,  H04N1/41 ,  H04N1/411

    CPC分类号： H04N1/411 ,  G06T9/00 ,  H04N1/41

    摘要： A method of modifying a digital representation of an image in which digital data defines the content of pixels of the image. The method comprisesa) determining whether a predetermined degree of compression can be achieved if data defining a block of pixels is compressed by applying a predetermined compression algorithm; and, if not,b) discarding a portion of the data in the block, andrepeating steps a and b on the most recently modified block until the predetermined degree of compression is achieved, and generating a compressed version of the image.

    Logic network for D/A conversion
    46.
    发明授权
    Logic network for D/A conversion 失效
    用于D / A转换的逻辑网络

    公开(公告)号：US4701641A

    公开(公告)日：1987-10-20

    申请号：US665871

    申请日：1984-10-29

    申请人： David J. Harris ,  Charles L. Vinn

    发明人： David J. Harris ,  Charles L. Vinn

    IPC分类号： H03M1/00 ,  H03K19/20 ,  G05B1/00 ,  G06F7/38 ,  H03K19/086

    CPC分类号： H03M1/745

    摘要： A digital-to-analog conversion circuitry is provided wherein a switching network is adapted to couple, or decouple, a selected one, or ones, of a plurality of identical current sources to, or from, an output bus selectively in accordance with the digital word being converted to produce an output current through an output bus having a level related to such digital word. The switching network includes: a logic network for selectively combining the plurality of bits of the digital word to produce a plurality of control signals, at least one thereof being related to a plurality of the bits of the digital word; and, a plurality of switching transistors, each one thereof having: a control (or base) electrode coupled to a corresponding one of the plurality of control signals; a first (or emitter) electrode coupled to a corresponding one of the plurality of identical current sources; and a second (or collector) electrode coupled to the output bus, such current source being coupled to, or decoupled from, such output bus selectively in accordance with the control signal fed to the control electrode of the transistor coupled to such current source, the logic network produces the plurality of control signals with substantially equal switching level variations. With such arrangement, the level of current produced by each current source and its contribution to the total output current are independent of the digital word being coverted and the level of current contributing to the total current flow through the output bus is also independent of the digital word being converted. Further, the switching time of the switching transistors is also independent of the digital word being converted.

    摘要翻译： 提供了一种数模转换电路，其中交换网络适于将多个相同电流源中的一个或多个选择的一个或多个耦合或去耦合到输出总线或从输出总线选择性地根据数字 字被转换以通过具有与这种数字字相关的电平的输出总线产生输出电流。 交换网络包括：逻辑网络，用于选择性地组合数字字的多个位以产生多个控制信号，其至少一个与数字字的多个位相关; 以及多个开关晶体管，其中的每一个具有：耦合到所述多个控制信号中的相应一个控制信号的控制（或基极）电极; 耦合到所述多个相同电流源中的相应一个的第一（或发射极）电极; 以及耦合到输出总线的第二（或集电极）电极，这样的电流源根据馈送到耦合到这种电流源的晶体管的控制电极的控制信号选择性地耦合到这种输出总线或从该输出总线去耦， 逻辑网络产生具有基本相等的开关电平变化的多个控制信号。 通过这样的布置，每个电流源产生的电流水平及其对总输出电流的贡献与被覆盖的数字字无关，并且对通过输出总线的总电流有贡献的电流水平也与数字 正在转换字。 此外，开关晶体管的切换时间也与被转换的数字字无关。

    Composite turbomachinery rotor
    47.
    发明授权
    Composite turbomachinery rotor 失效
    复合涡轮机转子

    公开(公告)号：US4037990A

    公开(公告)日：1977-07-26

    申请号：US691390

    申请日：1976-06-01

    申请人： David J. Harris

    发明人： David J. Harris

    IPC分类号： F01D5/30 ,  F01D5/32

    CPC分类号： F01D5/3053

    摘要： A turbomachinery rotor comprising a rotatable hub and a composite blade attached to the periphery thereof. The blade comprises a plurality of bonded filament laminates extending between, and wrapped around, a pair of hollow, semicylindrical inserts at the blade root. The laminates are bonded to the inserts so as to form a cylindrical blade root profile for insertion into a complementary cylindrical groove in the periphery of the hub. A slotted pin is positioned within the inserts to prevent the root from collapsing under loadings and to retain the blade in the hub.