A novel packet format with non-return-to-zero （NRZ） label and duobinary carrier-suppressed return-to-zero （DCS-RZ） payload is proposed for optical packet switching networks. NRZ label is followed by DCS-RZ payload...A novel packet format with non-return-to-zero （NRZ） label and duobinary carrier-suppressed return-to-zero （DCS-RZ） payload is proposed for optical packet switching networks. NRZ label is followed by DCS-RZ payload with a certain guard time. The spectra of the low-rate NRZ label locate around the optical carrier frequency where some parts of the corresponding spectra of the high-rate DCS-RZ payload have been suppressed due to DCS-RZ modulation. At the switching node, the label or payload extraction can be realized simply through an optical bandpass or notch filter respectively. The feasibility of the scheme is verified by the simulation on the famous photonic design platform designed by Virtual Photonics Inc. （VPI）. The effects of optical filter bandwidth on the received signal quality are discussed by analyzing bit error rate （BER） and contrast ratio performances.展开更多
文摘宽频惯性基准(H-IRU)能够提供一束稳定于惯性空间的参考光束,作为捕获、跟踪与瞄准(ATP)系统视轴的惯性参考.根据H-IRU的弹簧-质量模型推导了系统的传递函数,并对系统的频响特性进行了辨识实验.为了抑制H-IRU柔性支撑结构引入的低频谐振,提出了一种改进型陷波器.为了避免因陷波器参数设计不合理导致谐振抑制效果不理想或设计过程反复等情况的发生,提出了一种陷波器参数优化设计方法.以H-IRU系统模型幅频特性曲线最大幅值处的频率确定陷波中心频率,根据系统的直流增益与最大幅值之差确定陷波深度参数,以最小化加入陷波器后系统幅频曲线凸起为目标构造目标函数,对陷波器宽度参数进行快速寻优.将设计的陷波器串联入控制回路,结合不完全微分PID控制和噪声抑制扰动观测器设计了一种混合控制器作为H-IRU的位置环控制器.对串联陷波器后的H-IRU系统的开环及闭环频域特性进行了Matlab仿真,并利用扫频法和辨识法对其实验频域特性进行了测试.仿真和实验结果表明:采用参数优化方法设计的陷波器能够有效抑制系统27 Hz附近的低频机械谐振,结合闭环控制方法,可拓展系统闭环带宽至110 Hz.
基金the National Nature Science Foundation of China under Grant No.60572008
文摘A novel packet format with non-return-to-zero （NRZ） label and duobinary carrier-suppressed return-to-zero （DCS-RZ） payload is proposed for optical packet switching networks. NRZ label is followed by DCS-RZ payload with a certain guard time. The spectra of the low-rate NRZ label locate around the optical carrier frequency where some parts of the corresponding spectra of the high-rate DCS-RZ payload have been suppressed due to DCS-RZ modulation. At the switching node, the label or payload extraction can be realized simply through an optical bandpass or notch filter respectively. The feasibility of the scheme is verified by the simulation on the famous photonic design platform designed by Virtual Photonics Inc. （VPI）. The effects of optical filter bandwidth on the received signal quality are discussed by analyzing bit error rate （BER） and contrast ratio performances.
