Increasing the number of atoms that interact with microwave fields represents a promising strategy for enhancing the sensitivity of Rydberg atom-based superheterodyne receivers.Nevertheless,the practical implementatio...Increasing the number of atoms that interact with microwave fields represents a promising strategy for enhancing the sensitivity of Rydberg atom-based superheterodyne receivers.Nevertheless,the practical implementation of this approach is impeded by adverse effects such as excitation saturation of Rydberg atoms and power broadening.Here,we demonstrate enhanced microwave field measurements based on two specific velocity groups of atoms,simultaneously addressed by dual-channel probe beams in a Sagnac loop interferometer.The application of resonance detuning in two-photon excitation enables selective addressing of atoms moving along the beam direction,thereby significantly mitigating atomic transit noise.At 7.97 GHz,our method yields a 3 dB improvement in signal-to-noise ratio(SNR),achieving a sensitivity of 10.7 nV·cm^(−1)·Hz^(−1/2).This approach offers a viable pathway to further improve the sensitivity of Rydberg atom-based microwave electrometers.展开更多
There are numerous applications, such as Radar, that leverage wideband technology. However, the presence of noise introduces certain limitations and challenges. It is crucial to harness wideband technology for applica...There are numerous applications, such as Radar, that leverage wideband technology. However, the presence of noise introduces certain limitations and challenges. It is crucial to harness wideband technology for applications demanding the rapid and precise transmission of diverse information from one point to another within a short timeframe. The ability to report a signal without tuning within the input bandwidth stands out as one of the advantages of employing a digital wideband receiver. As indicated, a digital wideband receiver plays a pivotal role in achieving high precision and accuracy. The primary distinction between Analog and Digital Instantaneous Frequency Measurement lies in the fact that analog Instantaneous Frequency Measurement (IFM) receivers have traditionally covered extensive input bandwidths, reporting one accurate frequency per short pulse. In the contemporary landscape, digital IFM systems utilize high-sampling-rate Analog-to-Digital Converters (ADC) along with Hilbert transforms to generate two output channels featuring a 90-degree phase shift. This paper explores the improvement of sensitivity in current digital IFM receivers. The optimization efforts target the Hilbert transform and autocorrelations architectures, aiming to refine the system’s ability to report fine frequencies within a noisy wide bandwidth environment, thereby elevating its overall sensitivity.展开更多
A cueing wideband digital Electronic Warfare （EW） receiver is presented. The proposed receiver, which is to measure the instantaneous frequency and bandwidth of the intercept short-duration pulse radar signals that ...A cueing wideband digital Electronic Warfare （EW） receiver is presented. The proposed receiver, which is to measure the instantaneous frequency and bandwidth of the intercept short-duration pulse radar signals that cue and match the corresponding ones, meets the requirements of good sensitivity and dynamic range for EW and can save hardware resources greatly as well. In addition, real-time signal processing, which is the main bottleneck for covering a wide instantaneous frequency band for EW receiver, is better solved in the proposed design structure. The highly efficient implementation and good parameter estimation algorithms are proposed as welL Theoretical analysis and experimental results show that this structure is feasible.展开更多
The paper mainly introduces concrete design of the hardware and program steps of Infrared Telecontrol Code Measuring Device based on AT89C51RC. In addition, it also gives out the design circuit of infrared transmitter...The paper mainly introduces concrete design of the hardware and program steps of Infrared Telecontrol Code Measuring Device based on AT89C51RC. In addition, it also gives out the design circuit of infrared transmitter and infrared receiver and the typical design circuit of the system, and the application method as well. Through particularly researching on sending and receiving technology of in- frared, a precise method decoding the signal send by infrared controller and its circuit is designed.展开更多
The analysis of existing method for calculation of total content of electrons (TEC) in ionosphere using GPS occultation method does show that due to different values of signal/noise ration in GPS signals ?and , the ne...The analysis of existing method for calculation of total content of electrons (TEC) in ionosphere using GPS occultation method does show that due to different values of signal/noise ration in GPS signals ?and , the new method of optimum measurements of relevant frequency components of TEC measured by phase and code methods should be developed. The optimum quantity of measurements of the above-mentioned frequency components is determined taking into account the limitation imposed on general number of necessary measurements.展开更多
Accounts receivables are amounts that customers owe on account, which resulting from sale goods and services. Compames generally expect to collect accounts receivable within 30 to 60 days. Sales and profits can be inc...Accounts receivables are amounts that customers owe on account, which resulting from sale goods and services. Compames generally expect to collect accounts receivable within 30 to 60 days. Sales and profits can be increased by granting customers the privileges of making payment a month or more after the date of sale. The accounts receivable play significant important role in company＇ s flow of funds, lots of companies was bankrupted and going bankrupt because capital turnover is so bad in reality, so that how to strength the management of the accounts receivable becomes the key in the process of making the industry survive and develop. Especially the construction industry, it will produce a large amount of the accounts receivable because of the it ＇ s own character of whole industry. This text will to come up with the corresponding countermeasure by analyzing accounts receivable management situation and the influence to companies and forming causes.展开更多
The Spatial Only Processing Power Inversion(SOP-PI) algorithm is frequently used in Global Navigation Satellite System(GNSS) adaptive array receivers for interference mitigation because of its simplicity of implementa...The Spatial Only Processing Power Inversion(SOP-PI) algorithm is frequently used in Global Navigation Satellite System(GNSS) adaptive array receivers for interference mitigation because of its simplicity of implementation. This study investigates the effects of SOP-PI on receiver measurements for high-precision applications. Mathematical deductions show that if an array with a centro-symmetrical geometry is used, ideally,SOP-PI is naturally bias-free; however, this no longer stands when non-ideal factors, including array perturbations and finite-sample effect, are added. Simulations are performed herein to investigate how exactly the array perturbations affect the carrier phase biases, while diagonal loading and forward-backward averaging are proposed to counter the finite-sample effect. In conclusion, whether SOP-PI with a centro-symmetrical array geometry will satisfy the high precision demands mainly depends on the array perturbation degree of the element amplitude and the phase center.展开更多
To enable simultaneous transmit and receive(STAR)on the same frequency in a densely deployed space with multi-interference sources,this work proposes a digitally-assisted analog selfinterference cancellation method,wh...To enable simultaneous transmit and receive(STAR)on the same frequency in a densely deployed space with multi-interference sources,this work proposes a digitally-assisted analog selfinterference cancellation method,which can acquire reference signals through flexible wired/wireless switching access.Based on this method,the Minimum Mean Square Error algorithm with known channel state information is derived in detail,determining the upper limit of the cancellation performance,and the Adaptive Dithered Linear Search algorithm for real-time engineering cancellation is given.The correctness of theoretical analysis is verified by the practical self-interference channel measured by a vector network analyzer.Furthermore,we have designed and implemented the corresponding multiinterference cancellation prototype with the digitallyassisted structure,capable of handling multiple interferences(up to three)and supporting a large receive bandwidth of 100 MHz as well as a wide frequency coverage from 30 MHz to 3000 MHz.Prototype test results demonstrate that in the presence of three interferences,when the single interference bandwidth is 0.2/2/20 MHz(corresponding to the receive bandwidth of 2/20/100 MHz),the cancellation performance can reach 46/32/22 dB or more.展开更多
在基于接收信号强度(received signal strength,RSS)的定位中,传感器量测的系统偏差及锚节点位置的不确定性会对定位结果造成严重影响。对此,提出一种面向不确定量测的鲁棒定位方法。首先,针对传感器量测有偏差及锚节点位置不确定的定...在基于接收信号强度(received signal strength,RSS)的定位中,传感器量测的系统偏差及锚节点位置的不确定性会对定位结果造成严重影响。对此,提出一种面向不确定量测的鲁棒定位方法。首先,针对传感器量测有偏差及锚节点位置不确定的定位问题,建立相应的量测模型;其次,基于经典的极大似然估计准则建立关于目标位置的估计问题;最后,对所建立的非凸位置估计问题,采用合理的近似、松弛数学手段,将其转化为凸的半正定规划问题,从而保证得到全局最优解。仿真实验表明,在不同定位场景和条件下,所提方法的定位精度相比文献中的几种定位方法均有明显的优势,最高可提升约50%,证明其能有效降低量测不确定性对定位结果的不利影响,具有良好的鲁棒性。展开更多
瞬时测频(Instantaneous Frequency Measuring, IFM)接收机因其良好的测频性能已成为国内外雷达侦察系统广泛应用的测频接收机。现有的IFM接收机理论是建立在窄带单频信号通过IFM接收机的基础上,当前关于IFM接收机在多路宽带复杂信号环...瞬时测频(Instantaneous Frequency Measuring, IFM)接收机因其良好的测频性能已成为国内外雷达侦察系统广泛应用的测频接收机。现有的IFM接收机理论是建立在窄带单频信号通过IFM接收机的基础上,当前关于IFM接收机在多路宽带复杂信号环境下独立的测频性能方面缺少研究。首先,从理论上推导了多路宽带复杂信号环境下的IFM接收机的输出,指出IFM接收机对单路宽带信号的测频精度较高,而在多路宽带复杂信号环境下IFM接收机测频结果会受到较大影响,因此,IFM接收机无法适应多路宽带复杂信号环境。展开更多
基金supported by the National Key R&D Program of China(Grant No.2022YFA1404003)the National Natural Science Foundation of China(Grant Nos.T2495252,12104279,and 123B2062)+2 种基金the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302100)the Fund for Shanxi“1331 Project”Key Subjects Constructionthe Bairen Project of Shanxi Province。
文摘Increasing the number of atoms that interact with microwave fields represents a promising strategy for enhancing the sensitivity of Rydberg atom-based superheterodyne receivers.Nevertheless,the practical implementation of this approach is impeded by adverse effects such as excitation saturation of Rydberg atoms and power broadening.Here,we demonstrate enhanced microwave field measurements based on two specific velocity groups of atoms,simultaneously addressed by dual-channel probe beams in a Sagnac loop interferometer.The application of resonance detuning in two-photon excitation enables selective addressing of atoms moving along the beam direction,thereby significantly mitigating atomic transit noise.At 7.97 GHz,our method yields a 3 dB improvement in signal-to-noise ratio(SNR),achieving a sensitivity of 10.7 nV·cm^(−1)·Hz^(−1/2).This approach offers a viable pathway to further improve the sensitivity of Rydberg atom-based microwave electrometers.
文摘There are numerous applications, such as Radar, that leverage wideband technology. However, the presence of noise introduces certain limitations and challenges. It is crucial to harness wideband technology for applications demanding the rapid and precise transmission of diverse information from one point to another within a short timeframe. The ability to report a signal without tuning within the input bandwidth stands out as one of the advantages of employing a digital wideband receiver. As indicated, a digital wideband receiver plays a pivotal role in achieving high precision and accuracy. The primary distinction between Analog and Digital Instantaneous Frequency Measurement lies in the fact that analog Instantaneous Frequency Measurement (IFM) receivers have traditionally covered extensive input bandwidths, reporting one accurate frequency per short pulse. In the contemporary landscape, digital IFM systems utilize high-sampling-rate Analog-to-Digital Converters (ADC) along with Hilbert transforms to generate two output channels featuring a 90-degree phase shift. This paper explores the improvement of sensitivity in current digital IFM receivers. The optimization efforts target the Hilbert transform and autocorrelations architectures, aiming to refine the system’s ability to report fine frequencies within a noisy wide bandwidth environment, thereby elevating its overall sensitivity.
基金Supported by the National Defense Pre-research Fund of China
文摘A cueing wideband digital Electronic Warfare （EW） receiver is presented. The proposed receiver, which is to measure the instantaneous frequency and bandwidth of the intercept short-duration pulse radar signals that cue and match the corresponding ones, meets the requirements of good sensitivity and dynamic range for EW and can save hardware resources greatly as well. In addition, real-time signal processing, which is the main bottleneck for covering a wide instantaneous frequency band for EW receiver, is better solved in the proposed design structure. The highly efficient implementation and good parameter estimation algorithms are proposed as welL Theoretical analysis and experimental results show that this structure is feasible.
文摘The paper mainly introduces concrete design of the hardware and program steps of Infrared Telecontrol Code Measuring Device based on AT89C51RC. In addition, it also gives out the design circuit of infrared transmitter and infrared receiver and the typical design circuit of the system, and the application method as well. Through particularly researching on sending and receiving technology of in- frared, a precise method decoding the signal send by infrared controller and its circuit is designed.
文摘The analysis of existing method for calculation of total content of electrons (TEC) in ionosphere using GPS occultation method does show that due to different values of signal/noise ration in GPS signals ?and , the new method of optimum measurements of relevant frequency components of TEC measured by phase and code methods should be developed. The optimum quantity of measurements of the above-mentioned frequency components is determined taking into account the limitation imposed on general number of necessary measurements.
文摘Accounts receivables are amounts that customers owe on account, which resulting from sale goods and services. Compames generally expect to collect accounts receivable within 30 to 60 days. Sales and profits can be increased by granting customers the privileges of making payment a month or more after the date of sale. The accounts receivable play significant important role in company＇ s flow of funds, lots of companies was bankrupted and going bankrupt because capital turnover is so bad in reality, so that how to strength the management of the accounts receivable becomes the key in the process of making the industry survive and develop. Especially the construction industry, it will produce a large amount of the accounts receivable because of the it ＇ s own character of whole industry. This text will to come up with the corresponding countermeasure by analyzing accounts receivable management situation and the influence to companies and forming causes.
基金supported by the National Natural Science Foundation of China (No. U1333203)the Civil Aviation Administration of China (No. MHRD20140102)
文摘The Spatial Only Processing Power Inversion(SOP-PI) algorithm is frequently used in Global Navigation Satellite System(GNSS) adaptive array receivers for interference mitigation because of its simplicity of implementation. This study investigates the effects of SOP-PI on receiver measurements for high-precision applications. Mathematical deductions show that if an array with a centro-symmetrical geometry is used, ideally,SOP-PI is naturally bias-free; however, this no longer stands when non-ideal factors, including array perturbations and finite-sample effect, are added. Simulations are performed herein to investigate how exactly the array perturbations affect the carrier phase biases, while diagonal loading and forward-backward averaging are proposed to counter the finite-sample effect. In conclusion, whether SOP-PI with a centro-symmetrical array geometry will satisfy the high precision demands mainly depends on the array perturbation degree of the element amplitude and the phase center.
基金supported in part by the National Natural Science Foundation of China under Grant 62071094in part by the National Key Laboratory of Wireless Communications Foundation under Grant IFN202402in part by the Postdoctoral Fellowship Program(Grade C)of China Postdoctoral Science Foundation under Grant GZC20240217.
文摘To enable simultaneous transmit and receive(STAR)on the same frequency in a densely deployed space with multi-interference sources,this work proposes a digitally-assisted analog selfinterference cancellation method,which can acquire reference signals through flexible wired/wireless switching access.Based on this method,the Minimum Mean Square Error algorithm with known channel state information is derived in detail,determining the upper limit of the cancellation performance,and the Adaptive Dithered Linear Search algorithm for real-time engineering cancellation is given.The correctness of theoretical analysis is verified by the practical self-interference channel measured by a vector network analyzer.Furthermore,we have designed and implemented the corresponding multiinterference cancellation prototype with the digitallyassisted structure,capable of handling multiple interferences(up to three)and supporting a large receive bandwidth of 100 MHz as well as a wide frequency coverage from 30 MHz to 3000 MHz.Prototype test results demonstrate that in the presence of three interferences,when the single interference bandwidth is 0.2/2/20 MHz(corresponding to the receive bandwidth of 2/20/100 MHz),the cancellation performance can reach 46/32/22 dB or more.
文摘在基于接收信号强度(received signal strength,RSS)的定位中,传感器量测的系统偏差及锚节点位置的不确定性会对定位结果造成严重影响。对此,提出一种面向不确定量测的鲁棒定位方法。首先,针对传感器量测有偏差及锚节点位置不确定的定位问题,建立相应的量测模型;其次,基于经典的极大似然估计准则建立关于目标位置的估计问题;最后,对所建立的非凸位置估计问题,采用合理的近似、松弛数学手段,将其转化为凸的半正定规划问题,从而保证得到全局最优解。仿真实验表明,在不同定位场景和条件下,所提方法的定位精度相比文献中的几种定位方法均有明显的优势,最高可提升约50%,证明其能有效降低量测不确定性对定位结果的不利影响,具有良好的鲁棒性。
文摘瞬时测频(Instantaneous Frequency Measuring, IFM)接收机因其良好的测频性能已成为国内外雷达侦察系统广泛应用的测频接收机。现有的IFM接收机理论是建立在窄带单频信号通过IFM接收机的基础上,当前关于IFM接收机在多路宽带复杂信号环境下独立的测频性能方面缺少研究。首先,从理论上推导了多路宽带复杂信号环境下的IFM接收机的输出,指出IFM接收机对单路宽带信号的测频精度较高,而在多路宽带复杂信号环境下IFM接收机测频结果会受到较大影响,因此,IFM接收机无法适应多路宽带复杂信号环境。
