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    X-ray densitometer detector calibration by beam flattening and continuous dark scanning
    1.
    发明授权
    X-ray densitometer detector calibration by beam flattening and continuous dark scanning 失效
    X射线密度计检测器通过光束平整和连续暗扫描进行校准

    公开(公告)号：US5771272A

    公开(公告)日：1998-06-23

    申请号：US484568

    申请日：1995-06-07

    申请人： Noah Berger ,  Tom Richardson ,  Eric von Stetten ,  Howard P. Weiss

    发明人： Noah Berger ,  Tom Richardson ,  Eric von Stetten ,  Howard P. Weiss

    IPC分类号： A61B6/00 ,  A61B6/04 ,  A61B6/06 ,  A61B6/08 ,  G21K1/10 ,  G21K5/10 ,  G01D18/00

    CPC分类号： G21K1/10 ,  A61B6/0421 ,  A61B6/0457 ,  A61B6/06 ,  A61B6/08 ,  A61B6/482 ,  A61B6/488 ,  A61B6/505 ,  A61B6/405 ,  A61B6/548 ,  A61B6/583

    摘要： Variations in x-ray beam, filtration and detector gain characteristics are corrected by a multiple thickness flattening system. Preferably, an automatic multi-position attenuator mechanism inserts into the x-ray beam one or more flat reference attenuators of uniform composition. Thereafter, the response at each detector channel is measured. Unique factors are thus collected for each channel at multiple attenuation levels. An overall uniform response across the scan field is achieved by applying these correction factors to subsequent scan data. The current system compensates for detector gain by alternately turning X-rays on and off, so that dark level measurements can be interspersed with X-ray signal measurements. Detector offsets are eliminated in a linear data representation, while beam and detector flattening corrections are applied in a logarithmic data representation.

    摘要翻译： x射线束的变化，过滤和检测器增益特性通过多重厚度平坦化系统进行校正。 优选地，自动多位置衰减器机构将均匀组成的一个或多个扁平参考衰减器插入到x射线束中。 此后，测量每个检测器通道的响应。 因此，以多个衰减级别为每个通道收集唯一因子。 通过将这些校正因子应用于后续的扫描数据来实现扫描场的整体均匀响应。 当前系统通过交替地将X射线开启和关闭来补偿检测器增益，使得暗电平测量可以穿插X射线信号测量。 检测器偏移在线性数据表示中被消除，而波束和检测器平坦化校正被应用在对数数据表示中。

    LCPC decoding methods and apparatus
    6.
    发明授权
    LCPC decoding methods and apparatus 有权
    LCPC解码方法和装置

    公开(公告)号：US08595569B2

    公开(公告)日：2013-11-26

    申请号：US12128516

    申请日：2008-05-28

    申请人： Tom Richardson ,  Hui Jin ,  Vladimir Novichkov

    发明人： Tom Richardson ,  Hui Jin ,  Vladimir Novichkov

    IPC分类号： G06F11/00

    CPC分类号： H04L1/0057 ,  H03M13/1137 ,  H03M13/116 ,  H03M13/6513 ,  H03M13/6516 ,  H04L1/0045

    摘要： A flexible and relatively hardware efficient LDPC decoder is described. The decoder can be implemented with a level of parallelism which is less than the full parallelism of the code structure used to control the decoding process. Each command of a relatively simple control code used to describe the code structure can be stored and executed multiple times to complete the decoding of a codeword. Different codeword lengths are supported using the same set of control code instructions but with the code being implemented a different number of times depending on the codeword length. The decoder can switch between decoding codewords of different lengths, without the need to change the stored code description information, by simply changing a code lifting factor that is indicative of codeword length and is used to control the decoding process. When decoding codewords shorter than the maximum supported codeword length some block storage locations may go unused.

    摘要翻译： 描述了一种灵活且相对硬件有效的LDPC解码器。 该解码器可以用低于用于控制解码过程的代码结构的完全并行性的并行级别来实现。 用于描述代码结构的相对简单的控制代码的每个命令可以被多次存储和执行以完成码字的解码。 使用相同的一组控制码指令支持不同的码字长度，但是根据码字长度，代码被实现不同的次数。 解码器可以通过简单地改变表示码字长度的代码提升因子而不需要改变存储的代码描述信息来切换不同长度的解码码字，并用于控制解码过程。 当解码短于最大支持码字长度的码字时，一些块存储位置可能不被使用。

    LDPC encoding methods and apparatus
    8.
    发明授权
    LDPC encoding methods and apparatus 失效
    LDPC编码方法和装置

    公开(公告)号：US08533568B2

    公开(公告)日：2013-09-10

    申请号：US12050119

    申请日：2008-03-17

    申请人： Tom Richardson ,  Hui Jin

    发明人： Tom Richardson ,  Hui Jin

    IPC分类号： G11C29/00

    CPC分类号： H03M13/6508 ,  H03M13/116 ,  H03M13/118 ,  H03M13/611

    摘要： A flexible and relatively hardware efficient LDPC encoder is described. The encoder can be implemented with a level of parallelism which is less than the full parallelism of the code structure used to control the encoding process. Each command of a relatively simple microcode used to describe the code structure can be stored and executed multiple times to complete the encoding of a codeword. Different codeword lengths can be supported using the same set of microcode instructions but with the code being implemented a different number of times depending on the lifting factor selected to be used. The LDPC encoder can switch between encoding codewords of different lengths, without the need to change the stored code description information, by simply changing a code lifting factor used to control the encoding processes. When coding codewords shorter than the maximum supported codeword length some block storage locations and/or registers may go unused.

    摘要翻译： 描述了一种灵活且相对硬件高效的LDPC编码器。 编码器可以以小于平行度的水平来实现，该并行度小于用于控制编码过程的代码结构的完全并行性。 用于描述代码结构的相对简单的微代码的每个命令可以被多次存储和执行以完成代码字的编码。 可以使用相同的微代码指令集来支持不同的码字长度，但是根据所选择的使用的提升因子，代码被实现不同的次数。 LDPC编码器可以通过简单地改变用于控制编码处理的代码提升因子来切换不同长度的编码码字，而不需要改变存储的代码描述信息。 当编码比最大支持的码字长度短的码字时，一些块存储位置和/或寄存器可能不被使用。

    Efficient automatic repeat request methods and apparatus
    9.
    发明授权
    Efficient automatic repeat request methods and apparatus 有权
    高效的自动重复请求方法和装置

    公开(公告)号：US07813322B2

    公开(公告)日：2010-10-12

    申请号：US10780539

    申请日：2004-02-17

    申请人： Rajiv Laroia ,  Tom Richardson ,  Junyi Li

    发明人： Rajiv Laroia ,  Tom Richardson ,  Junyi Li

    IPC分类号： H04L1/00

    CPC分类号： H04L1/0057 ,  H04L1/1671 ,  H04L1/1692 ,  H04L1/1819 ,  H04L2001/125

    摘要： Different NAK signals are used to indicate different relative levels of success in regard to an unsuccessful attempt to decode a received signal. An ACK signal is used in the case of successful decoding. The device which generated and transmitted the original encoded signal receives the NAK signal and selects a portion of redundant information, e.g., additional error correction bits, to be transmitted based on the value of the NAK signal. If the NAK signal indicates a low level of decoding success indicating a relatively large number of errors in the decoded signal, a large set of redundant information is selected and transmitted. If the NAK signal indicates a relatively successful decoding, e.g., relatively few errors, a small set of redundant information is selected and transmitted. Where a small set of redundant information is transmitted new information can be transmitted with the redundant information.

    摘要翻译： 不同的NAK信号用于指示不成功尝试对接收到的信号进行解码的成功的相对水平。 在成功解码的情况下使用ACK信号。 生成并发送原始编码信号的装置接收NAK信号，并根据NAK信号的值选择要发送的冗余信息的一部分，例如附加的纠错位。 如果NAK信号表示在解码信号中指示相对大量错误的解码成功的低电平，则选择并发送大量冗余信息。 如果NAK信号指示相对成功的解码，例如相对较少的错误，则选择并发送一小组冗余信息。 在发送一小组冗余信息的情况下，可以用冗余信息传输新信息。

    Methods and apparatus related to composite beacon and wideband synchronization signaling
    10.
    发明授权
    Methods and apparatus related to composite beacon and wideband synchronization signaling 有权
    与复合信标和宽带同步信令相关的方法和装置

    公开(公告)号：US07801227B2

    公开(公告)日：2010-09-21

    申请号：US11486881

    申请日：2006-07-14

    申请人： Vladimir Parizhisky ,  Rajiv Laroia ,  Alexander Leonidov ,  Tom Richardson ,  Junyi Li ,  Sathyadev Venkata Uppala

    发明人： Vladimir Parizhisky ,  Rajiv Laroia ,  Alexander Leonidov ,  Tom Richardson ,  Junyi Li ,  Sathyadev Venkata Uppala

    IPC分类号： H04K1/00

    CPC分类号： H04L27/2613 ,  H04L5/023 ,  H04L27/2614 ,  H04L27/2655

    摘要： A composite signal includes a high power beacon signal and low power corresponding wideband synchronization signal and is communicated over a time interval exceeding a single OFDM transmission time interval. A base station transmits one or more different such composite broadcast signals in a recurring timing structure. Each different potential beacon signal, e.g., a single tone signal, is paired with a unique wideband synchronization signal. A wideband synchronization signal includes at least some predetermined null tones and at least some predetermined non-null tones. For a given wideband synchronization signal, the predetermined null tones carry predetermined modulation symbol values, A wireless terminal receives a composite signal, identifies a beacon, determines a corresponding known wideband synchronization signal, compares received to known wideband synchronization signals, and determines at least one of a timing adjustment, frequency adjustment and channel estimation.

    摘要翻译： 复合信号包括高功率信标信号和低功率对应的宽带同步信号，并且在超过单个OFDM传输时间间隔的时间间隔上传送。 基站以循环定时结构发送一个或多个不同的这种复合广播信号。 每个不同的潜在信标信号，例如单个音调信号，与唯一的宽带同步信号配对。 宽带同步信号至少包括一些预定的无效音调和至少一些预定的非空音调。 对于给定的宽带同步信号，预定的空音携带预定的调制符号值，A无线终端接收复合信号，识别信标，确定对应的已知宽带同步信号，将已接收的已知宽带同步信号进行比较，并确定至少一个 定时调整，频率调整和信道估计。