To generate high-frequency radio frequency(RF) vector signals, a vector signal generation method by optical frequency sextupling using a dual-parallel modulator is proposed. The method modulates vector signal on +3 rd...To generate high-frequency radio frequency(RF) vector signals, a vector signal generation method by optical frequency sextupling using a dual-parallel modulator is proposed. The method modulates vector signal on +3 rd order optical sideband and local oscillator(LO) signal on-3 rd order sideband using the intermodulation process in the DPMZM. After suppressing of the optical carrier and other sidebands through proper adjustment for modulator biases and modulation index, a frequency sextupled millimeter-wave vector signal can be generated after photodetection. The frequency sextupling will lower the bandwidth of the modulator, the local oscillator and the driving circuits. In addition, the phase of generated signal is not distorted after detection, and the power fading after fiber transmission can be avoided. In the simulation, a 500-MSym/s QPSK signal at 60 GHz is generated by 10-GHz drive signal. After travelling over fiber with length of 20/30/40-km, receiver power penalty keeps below 2.5 dB.展开更多
Radio frequency fingerprinting(RFF)is a technology that identifies the specific emitter of a received electromagnetic signal by external measurement of the minuscule hardware-level,device-specific imperfections.The RF...Radio frequency fingerprinting(RFF)is a technology that identifies the specific emitter of a received electromagnetic signal by external measurement of the minuscule hardware-level,device-specific imperfections.The RFF-related information is mainly in the form of unintentional modulation(UIM),which is subtle enough to be effectively imperceptible and is submerged in the intentional modulation(IM).It is necessary to minimize the influence of the IM and expand the slight differences between emitters for successful RFF.This paper proposes a UIM microstructure enlargement(UMME)method based on feature-level adaptive signal decomposition(ASD),accompanied by autocorrelation and cross-correlation analysis.The common IM part is evaluated by analyzing a newly-defined benchmark feature.Three different indexes are used to quantify the similarity,distance,and dependency of the RFF features from different devices.Experiments are conducted based on the real-world signals transmitted from 20 of the same type of radar in the same working mode.The visual image qualitatively shows the magnification of feature differences;different indicators quantitatively describe the changes in features.Compared with the original RFF feature,recognition results based on the Gaussian mixture model(GMM)classifier further validate the effectiveness of the proposed algorithm.展开更多
Broadband optical frequency comb(OFC)generation based on a single electro-absorption modulator(EAM)is proposed.The EAM is driven by a radio frequency(RF)multi-frequency signal generated by a multiplication coupler com...Broadband optical frequency comb(OFC)generation based on a single electro-absorption modulator(EAM)is proposed.The EAM is driven by a radio frequency(RF)multi-frequency signal generated by a multiplication coupler composed of an electrical power splitter and an arithmetic circuit.Thus the number of comb-lines of the generated OFC can be increased.A complete theoretical model of OFC generation by an EAM driven by nth power of the RF source is established,and the performance of the OFC is analyzed by using OptiSystem software.The results show that,the number of comb-lines of the OFC is positively correlated with the number of multiplication of the RF source signal.The frequency spacing of the comb-lines is twice the frequency of the RF source signal and is tunable by adjusting the frequency of the RF source signal.Increasing chirp factor and modulation index of EAM could increase the number of comb-lines of the generated OFC.The amplitude of the RF source signal had little impact on the fatness of the OFC and the average OFC power.The scheme developed is not only simple and low-cost,but also can produce a large number of comb-lines.展开更多
针对室内定位系统中现有的行人航位推算(pedestrian dead reckoning,PDR)方法存在加速度计适用性较差,以及基于惯性和磁传感器的航向估计易受器件误差和磁场环境的影响,导致精度较低的问题,在不增加基础设施成本和现场勘察工作的前提下...针对室内定位系统中现有的行人航位推算(pedestrian dead reckoning,PDR)方法存在加速度计适用性较差,以及基于惯性和磁传感器的航向估计易受器件误差和磁场环境的影响,导致精度较低的问题,在不增加基础设施成本和现场勘察工作的前提下,提出一种调频(frequencymodulation,FM)广播信号辅助PDR的室内行人定位技术:在传播模型理论基础上探究FM信号接收信号强度指数(RSSI)与步长的关系,将其与加速度组合以提升步长估计的适用性;然后通过分析FM信号在直线/转弯运动模式下的变化,将其与角速度组合以提升模式识别准确率,并使用模式识别结果约束航向漂移误差;最后,综合步长与航向估计结果实现定位。实验结果表明,引入FM信号后定位误差均值可分别减小36.1%、78.9%。展开更多
基金Sponsored by the Programme of Introducing Talents of Discipline to Universities(Grant No.B08038)
文摘To generate high-frequency radio frequency(RF) vector signals, a vector signal generation method by optical frequency sextupling using a dual-parallel modulator is proposed. The method modulates vector signal on +3 rd order optical sideband and local oscillator(LO) signal on-3 rd order sideband using the intermodulation process in the DPMZM. After suppressing of the optical carrier and other sidebands through proper adjustment for modulator biases and modulation index, a frequency sextupled millimeter-wave vector signal can be generated after photodetection. The frequency sextupling will lower the bandwidth of the modulator, the local oscillator and the driving circuits. In addition, the phase of generated signal is not distorted after detection, and the power fading after fiber transmission can be avoided. In the simulation, a 500-MSym/s QPSK signal at 60 GHz is generated by 10-GHz drive signal. After travelling over fiber with length of 20/30/40-km, receiver power penalty keeps below 2.5 dB.
基金This work was supported by the Program for Innovative Research Groups of the Hunan Provincial Natural Science Foundation of China(2019JJ10004).
文摘Radio frequency fingerprinting(RFF)is a technology that identifies the specific emitter of a received electromagnetic signal by external measurement of the minuscule hardware-level,device-specific imperfections.The RFF-related information is mainly in the form of unintentional modulation(UIM),which is subtle enough to be effectively imperceptible and is submerged in the intentional modulation(IM).It is necessary to minimize the influence of the IM and expand the slight differences between emitters for successful RFF.This paper proposes a UIM microstructure enlargement(UMME)method based on feature-level adaptive signal decomposition(ASD),accompanied by autocorrelation and cross-correlation analysis.The common IM part is evaluated by analyzing a newly-defined benchmark feature.Three different indexes are used to quantify the similarity,distance,and dependency of the RFF features from different devices.Experiments are conducted based on the real-world signals transmitted from 20 of the same type of radar in the same working mode.The visual image qualitatively shows the magnification of feature differences;different indicators quantitatively describe the changes in features.Compared with the original RFF feature,recognition results based on the Gaussian mixture model(GMM)classifier further validate the effectiveness of the proposed algorithm.
基金supported by the National Natural Science Foundation of China(Grant No.61571237).
文摘Broadband optical frequency comb(OFC)generation based on a single electro-absorption modulator(EAM)is proposed.The EAM is driven by a radio frequency(RF)multi-frequency signal generated by a multiplication coupler composed of an electrical power splitter and an arithmetic circuit.Thus the number of comb-lines of the generated OFC can be increased.A complete theoretical model of OFC generation by an EAM driven by nth power of the RF source is established,and the performance of the OFC is analyzed by using OptiSystem software.The results show that,the number of comb-lines of the OFC is positively correlated with the number of multiplication of the RF source signal.The frequency spacing of the comb-lines is twice the frequency of the RF source signal and is tunable by adjusting the frequency of the RF source signal.Increasing chirp factor and modulation index of EAM could increase the number of comb-lines of the generated OFC.The amplitude of the RF source signal had little impact on the fatness of the OFC and the average OFC power.The scheme developed is not only simple and low-cost,but also can produce a large number of comb-lines.
文摘针对室内定位系统中现有的行人航位推算(pedestrian dead reckoning,PDR)方法存在加速度计适用性较差,以及基于惯性和磁传感器的航向估计易受器件误差和磁场环境的影响,导致精度较低的问题,在不增加基础设施成本和现场勘察工作的前提下,提出一种调频(frequencymodulation,FM)广播信号辅助PDR的室内行人定位技术:在传播模型理论基础上探究FM信号接收信号强度指数(RSSI)与步长的关系,将其与加速度组合以提升步长估计的适用性;然后通过分析FM信号在直线/转弯运动模式下的变化,将其与角速度组合以提升模式识别准确率,并使用模式识别结果约束航向漂移误差;最后,综合步长与航向估计结果实现定位。实验结果表明,引入FM信号后定位误差均值可分别减小36.1%、78.9%。
