针对截面变化的圆柱型编织物的参数控制,将EtherCAT(ethernet for control automation technology)通信技术引入编织机控制系统,设计了基于EtherCAT多轴伺服系统的编织机控制系统,并阐述了其组成及原理,构建了以触摸屏为主站以及倍福功...针对截面变化的圆柱型编织物的参数控制,将EtherCAT(ethernet for control automation technology)通信技术引入编织机控制系统,设计了基于EtherCAT多轴伺服系统的编织机控制系统,并阐述了其组成及原理,构建了以触摸屏为主站以及倍福功能模块为从站的网络结构。设计了控制算法以控制多电机协同,从而控制编织参数。采用两个芯模进行编织试验并采集编织参数进行分析,结果表明编织参数控制准确有效。展开更多
Mobile WiMAX(worldwide interoperability for microwave access) air interface adopts orthogonal frequency division multiple access(OFDMA) as multiple access technique for its uplink(UL) and downlink(DL) to improve the m...Mobile WiMAX(worldwide interoperability for microwave access) air interface adopts orthogonal frequency division multiple access(OFDMA) as multiple access technique for its uplink(UL) and downlink(DL) to improve the multipath performance.All OFDMA based networks,like mobile WiMAX,experience the problem of high peak-to-average power ratio(PAPR).The high PAPR increases the complexity of analog-to-digital(A/D) and digital-to-analog(D/A) convertors,and also reduces the efficiency of RF high-power-amplifier(HPA).In this work,a new zadoff-chu matrix transform(ZCMT) precoding based random interleaved orthogonal frequency division multiple access(OFDMA) system was proposed for PAPR reduction in mobile WiMAX system.The system is based on precoding the constellation symbols with the ZCMT precoder before subcarrier mapping.The PAPR of proposed system is analyzed with the root-raised-cosine(RRC) pulse shaping to keep out of band radiation low and meet the transmission spectrum mask requirement.Simulation results show that the proposed system has better PAPR gain than the hadamard transform(WHT) precoded random interleaved OFDMA systems and the conventional random interleaved OFDMA systems.Symbol-error-rate(SER) performance of the system is also better than the conventional random interleaved OFDMA systems and the random interleaved OFDMA systems with WHT.The good improvement in PAPR significantly reduces the cost and the complexity of the transmitter.展开更多
文摘针对截面变化的圆柱型编织物的参数控制,将EtherCAT(ethernet for control automation technology)通信技术引入编织机控制系统,设计了基于EtherCAT多轴伺服系统的编织机控制系统,并阐述了其组成及原理,构建了以触摸屏为主站以及倍福功能模块为从站的网络结构。设计了控制算法以控制多电机协同,从而控制编织参数。采用两个芯模进行编织试验并采集编织参数进行分析,结果表明编织参数控制准确有效。
文摘Mobile WiMAX(worldwide interoperability for microwave access) air interface adopts orthogonal frequency division multiple access(OFDMA) as multiple access technique for its uplink(UL) and downlink(DL) to improve the multipath performance.All OFDMA based networks,like mobile WiMAX,experience the problem of high peak-to-average power ratio(PAPR).The high PAPR increases the complexity of analog-to-digital(A/D) and digital-to-analog(D/A) convertors,and also reduces the efficiency of RF high-power-amplifier(HPA).In this work,a new zadoff-chu matrix transform(ZCMT) precoding based random interleaved orthogonal frequency division multiple access(OFDMA) system was proposed for PAPR reduction in mobile WiMAX system.The system is based on precoding the constellation symbols with the ZCMT precoder before subcarrier mapping.The PAPR of proposed system is analyzed with the root-raised-cosine(RRC) pulse shaping to keep out of band radiation low and meet the transmission spectrum mask requirement.Simulation results show that the proposed system has better PAPR gain than the hadamard transform(WHT) precoded random interleaved OFDMA systems and the conventional random interleaved OFDMA systems.Symbol-error-rate(SER) performance of the system is also better than the conventional random interleaved OFDMA systems and the random interleaved OFDMA systems with WHT.The good improvement in PAPR significantly reduces the cost and the complexity of the transmitter.
