公开(公告)号：US07986931B2

公开(公告)日：2011-07-26

申请号：US11736008

申请日：2007-04-17

申请人： Chih-Hung Lin ,  Chin-Fu Li ,  Chia-Jen Yu ,  Jiunn-Tsair Chen

发明人： Chih-Hung Lin ,  Chin-Fu Li ,  Chia-Jen Yu ,  Jiunn-Tsair Chen

IPC分类号： H04B7/00

CPC分类号： G06K7/0008 ,  G06K7/10346

摘要： An echo cancellation circuit for an RFID reader and the method thereof are provided. The echo cancellation circuit includes a gain calculator, a gain adjustment circuit, and a subtraction circuit. The gain calculator provides a complex gain value according to a carrier signal and a received signal through an adaptive algorithm. The gain adjustment circuit is coupled to the gain calculator. The gain adjustment circuit multiplies the carrier signal by the complex gain value, and outputs the result of the multiplication. The subtraction circuit is coupled to the gain adjustment circuit. The subtraction circuit subtracts the output of the gain adjustment circuit from the received signal, and then provides the result of the subtraction as the output signal of the echo cancellation circuit.

摘要翻译： 提供了一种用于RFID读取器的回波消除电路及其方法。 回波消除电路包括增益计算器，增益调整电路和减法电路。 增益计算器通过自适应算法根据载波信号和接收信号提供复数增益值。 增益调整电路耦合到增益计算器。 增益调整电路将载波信号乘以复数增益值，并输出乘法结果。 减法电路耦合到增益调整电路。 减法电路从接收信号中减去增益调整电路的输出，然后将减法结果作为回波消除电路的输出信号。

公开(公告)号：US20080136645A1

公开(公告)日：2008-06-12

申请号：US11736008

申请日：2007-04-17

申请人： Chih-Hung Lin ,  Chin-Fu Li ,  Chia-Jen Yu ,  Jiunn-Tsair Chen

发明人： Chih-Hung Lin ,  Chin-Fu Li ,  Chia-Jen Yu ,  Jiunn-Tsair Chen

IPC分类号： G08B1/08

CPC分类号： G06K7/0008 ,  G06K7/10346

摘要： An echo cancellation circuit for an RFID reader and the method thereof are provided. The echo cancellation circuit includes a gain calculator, a gain adjustment circuit, and a subtraction circuit. The gain calculator provides a complex gain value according to a carrier signal and a received signal through an adaptive algorithm. The gain adjustment circuit is coupled to the gain calculator. The gain adjustment circuit multiplies the carrier signal by the complex gain value, and outputs the result of the multiplication. The subtraction circuit is coupled to the gain adjustment circuit. The subtraction circuit subtracts the output of the gain adjustment circuit from the received signal, and then provides the result of the subtraction as the output signal of the echo cancellation circuit.

摘要翻译： 提供了一种用于RFID读取器的回波消除电路及其方法。 回波消除电路包括增益计算器，增益调整电路和减法电路。 增益计算器通过自适应算法根据载波信号和接收信号提供复数增益值。 增益调整电路耦合到增益计算器。 增益调整电路将载波信号乘以复数增益值，并输出乘法结果。 减法电路耦合到增益调整电路。 减法电路从接收信号中减去增益调整电路的输出，然后将减法结果作为回波消除电路的输出信号。

公开(公告)号：US20080129505A1

公开(公告)日：2008-06-05

申请号：US11752309

申请日：2007-05-23

申请人： Chih-Hung Lin ,  Chia-Jen Yu ,  Jiunn-Tsair Chen

发明人： Chih-Hung Lin ,  Chia-Jen Yu ,  Jiunn-Tsair Chen

IPC分类号： G08B13/14

CPC分类号： G06K7/0008 ,  H04L7/042

摘要： A method and a system for reading radio frequency identification (RFID) tags are provided. The method includes the following steps. First, receive a tag signal from the RFID tag. Recover a data clock rate from the tag signal according to statistics of pulse lengths of the tag signal. Next, determine a frame synchronization point of a data frame following a preamble in the tag signal by a signal correlation between the preamble and a predetermined signal pattern according to the data clock rate. Finally, decode the data frame by using an adaptive Viterbi algorithm on an extended trellis diagram. The extended trellis diagram includes a plurality of nodes and a plurality of branches connecting the nodes. The nodes and the branches are arranged according to the modulation scheme of the data frame and possible variations of the data clock rate.

摘要翻译： 提供了一种用于读取射频识别（RFID）标签的方法和系统。 该方法包括以下步骤。 首先，从RFID标签接收标签信号。 根据标签信号的脉冲长度的统计，从标签信号中恢复数据时钟速率。 接下来，根据数据时钟速率，通过前导码和预定信号模式之间的信号相关来确定标签信号中的前导码之后的数据帧的帧同步点。 最后，通过在扩展网格图上使用自适应维特比算法对数据帧进行解码。 扩展网格图包括多个节点和连接节点的多个分支。 节点和分支根据数据帧的调制方案和数据时钟速率的可能变化进行排列。

公开(公告)号：US07742547B2

公开(公告)日：2010-06-22

申请号：US11752309

申请日：2007-05-23

申请人： Chih-Hung Lin ,  Chia-Jen Yu ,  Jiunn-Tsair Chen

发明人： Chih-Hung Lin ,  Chia-Jen Yu ,  Jiunn-Tsair Chen

IPC分类号： H04L27/06

CPC分类号： G06K7/0008 ,  H04L7/042

摘要： A method and a system for reading radio frequency identification (RFID) tags are provided. The method includes the following steps. First, receive a tag signal from the RFID tag. Recover a data clock rate from the tag signal according to statistics of pulse lengths of the tag signal. Next, determine a frame synchronization point of a data frame following a preamble in the tag signal by a signal correlation between the preamble and a predetermined signal pattern according to the data clock rate. Finally, decode the data frame by using an adaptive Viterbi algorithm on an extended trellis diagram. The extended trellis diagram includes a plurality of nodes and a plurality of branches connecting the nodes. The nodes and the branches are arranged according to the modulation scheme of the data frame and possible variations of the data clock rate.

摘要翻译： 提供了一种用于读取射频识别（RFID）标签的方法和系统。 该方法包括以下步骤。 首先，从RFID标签接收标签信号。 根据标签信号的脉冲长度的统计，从标签信号中恢复数据时钟速率。 接下来，根据数据时钟速率，通过前导码和预定信号模式之间的信号相关来确定标签信号中的前导码之后的数据帧的帧同步点。 最后，通过在扩展网格图上使用自适应维特比算法对数据帧进行解码。 扩展网格图包括多个节点和连接节点的多个分支。 节点和分支根据数据帧的调制方案和数据时钟速率的可能变化进行排列。