External Links
      Quick retrieval of articles
      Volume , No. 1 | 2024
      Display Method:
      • YANG Jinsheng,JI Huanli,SUN Ran

        2024(1):1-5, DOI: 10.11805/TKYDA2023288

        Abstract:

        A four-channel electron beam planar focusing system is designed to meet the application requirements of the planar integrated traveling wave tube for one-dimensional electron beam array focusing. The calculated results of the axial and transverse components of the magnetic field along the axis are compared with the measured results, which confirms the accuracy of Opera software in calculating the magnetic field distribution. In order to compare with the magnetic field distribution in the electron beam channel of the axisymmetric Periodic Permanent Magnet(PPM) focusing system, a model of the PPM focusing system is established, and the tested results are in good agreement with the calculated results. By comparing the longitudinal and transverse distribution characteristics of the magnetic field in the electron beam channel of the planar focusing system and the axisymmetric PPM focusing system, it is shown that the two focusing systems share the same magnetic field distribution characteristics in the electron beam channel, the ratios of transverse magnetic field component to the axial component are both about 0.11 on the circumference at the same off-axis position, and it is expected that the planar focusing system can achieve good focusing of the one-dimensional array electron beam.

      • GAO Chang,ZHANG Xiaoqing,MU Hanshuo,PAN Pan,CAI Jun,FENG Jinjun

        2024(1):6-10, DOI: 10.11805/TKYDA2023191

        Abstract:

        Millimeter-wave Traveling Wave Tubes(TWTs) have the characteristics of high power, broad band and high gain, and are widely used in modern military electronic equipment, such as radar, high-speed communication and electronic countermeasures, etc. In order to improve the coupling impedance of the Folded Waveguide(FWG) and the engineering applicability, a novel type of ear-FWG is proposed, which increases the coupling impedance in the working frequency band by more than 30% and reduces the loss by 10% compared with the conventional rectangular waveguide. When the ear-FWG W-band TWT operates at 21.9 kV and 210 mA, and the duty cycle is 5%, the output power in the 10.8 GHz bandwidth is higher than 192 W, the peak power reaches 278 W, the electron efficiency and gain reach 6.3% and 44.6 dB, respectively, and the TWT works stably.

      • YANG Jitao,WANG Shaomeng,LEI Yulu,DU Chaohai

        2024(1):11-16, DOI: 10.11805/TKYDA2023290

        Abstract:

        With the rapid development of terahertz technology, people are increasingly interested in its various applications in communications, spectroscopy, and sensing. The basis for the development and application of terahertz technology is high-performance terahertz sources. Traditional terahertz sources are large in size and require high-power power supply to drive and are difficult to adapt to the development of integrated terahertz technology. Therefore, there is an urgent need to develop micro-terahertz sources with new mechanisms. This paper studies a new type of miniaturized free electron terahertz radiator, which realizes the excitation of terahertz waves based on the interaction of free electrons and the terahertz waves excited in the grating dielectric waveguide structure. This research provides new options for developing efficient on-chip terahertz radiation sources and expanding advanced terahertz applications.

      • ZHANG Min,ZHANG Ke,YANG Pengyun

        2024(1):17-21, DOI: 10.11805/TKYDA2023289

        Abstract:

        In order to meet the demand of THz vacuum devices for miniature electron beam with high current density, a kind of miniature cathode has been prepared by depositing Ta/Zr coating on impregnated scandate cathode surface via dual Ion-Beam-Assisted Deposition (Dual IBAD) and etching an emission zone with a diameter of 100 m via Focus Ion Beam(FIB). Based on the previous study, this paper focuses on the characteristics of anti-emission coating. It is shown in the experimental results that Ta/Zr coating prepared by dual Ion Beam Assisted Deposition(Dual IBAD) can suppress electron emission more effectively and has a longer life time than that prepared by magnetron sputtering. The reasons for the sound anti-emission performance are that composition with high work function is formed in the process of Barium diffusion into the Ta/Zr coating, and that Barium diffusion is effectively suppressed by the high dense Ta/Zr coating.

      • YANG Xiao,GUO Zugen,WANG Xinyang,GONG Huarong

        2024(1):22-27, DOI: 10.11805/TKYDA2023277

        Abstract:

        A design of the electro-optical system for D-band Travelling Wave Tubes (TWTs), including an electron gun and a Periodic Permanent Magnet(PPM) focusing system, is presented and verified. The electron gun utilizes the classical Pierce electron gun structure, the outer layer of the cathode emission surface is set with a cathode sleeve to suppress stray emission at the edge of the cathode, and a cylindrical control electrode is used instead of a conical control electrode, and a negative bias is added to the focusing electrode to adjust the compression state of the electron injection. The electron gun can provide a beam current 57 mA with the beam waist radius of 0.068 mm and the shooting distance of 14.9 mm at the beam voltage of 1.9 kV. A sleeve tube is attached on the cathode to block the electron emission from the edge of the cathode. A cylindrical focusing electrode is used in the electron gun for adjusting the beam focusing state. To stably focus and transmit the electron beam in the beam tunnel of 0.15 mm radius, a PPM focusing system is employed. The peak magnetic field is 2.9 times the Brillouin magnetic field to increase the rigidity of electron injection. The simulated result shows the fluctuation radius of the electron beam is less than 0.1 mm. In order to validate the effectiveness of the D-band TWT electro-optical system, the electron gun and the PPM focusing system have been machined and assembled. The experimental results show the beam current is 49.83 mA, and the collector current is 49.6 mA. The beam transmission rate of 99.5% are obtained by carefully adjusting the PPM system, which achieves the design goal.

      • ZHANG Yichi,GAO Dongshuo,ZENG Xu,LI Kun,HAO Wenteng,LI Boyang,FENG Jinjun

        2024(1):28-34, DOI: 10.11805/TKYDA2023280

        Abstract:

        To satisfy the application requirements of sapphire output window for the 170 GHz megawatt-class gyrotron short-pulsed experiment, by calculating the characteristic of reflection and absorbing of Gaussian beam transmitted through sapphire window, a sapphire window unit is designed with low reflection and low loss power. The low reflectance is verified by vector network analyzer that the Voltage Standing Wave Ratio(VSWR)<1.1. The maximum output average power threshold of the sapphire window has been calculated approximately to be 590 W by analyzing the damage mechanism. The 170 GHz gyrotron employing sapphire window is fabricated, and the power threshold calculated theoretically is verified, providing a reliable theoretical basis for the application of sapphire output window used in high power gyrotron.

      • LEI Yulu,YANG Jitao,DU Chaohai

        2024(1):35-38, DOI: 10.11805/TKYDA2023283

        Abstract:

        As an important vacuum electron device, the gyrotron has the capability to generate high peak and average powers in the millimeter-wave and terahertz frequency ranges, holding broad prospects of application in fields such as spectroscopy, radar, communication, and biomedical science. However, conventional gyrotrons inevitably face intense mode competition issues, and the introduction of quasi-optical cavity is expected to significantly alleviate the severity of mode competition. In this study, based on the theory of electron gyrotron oscillation, the innovative combination of quasi-optical cavity and sheet electron beam is proposed with the aim of achieving higher output power and efficiency. Simulation results indicate that under conditions of 40 kV electron voltage and an 8.4 T background magnetic field, the designed quasi-optical gyrotron can generate 6.1 kW of output power at a frequency of 220 GHz, with an electron efficiency of 6.1% and stable operation over a certain duration. The proposed structure in this study may provide a novel solution for gyrotron design operating in high-frequency and even higher harmonic regimes, thus furthering its applications in fields such as radar and controlled nuclear fusion.

      • SONG Xiaoyan,LIU Youjiang,XU Huiyuan,HUO Feixiang

        2024(1):39-45, DOI: 10.11805/TKYDA2021410

        Abstract:

        For the physical layer security communication system based on artificial noise, traditional artificial noise is usually generated by using closed-form expressions derived from derivation or numerical optimization methods which both require accurate channel state information matrix to guarantee the secrecy of the communication system. However, the channel estimation error in the real scenarios causes the artificial noise precoding error to reduce the security capacity of the communication system. For this reason, this paper proposes an artificial noise precoding generation method based on deep learning. By taking the channel estimation information with estimation error as input and fitting it with the precoding matrix obtained by traditional numerical solution generated by perfect channel estimation, a well-trained deep neural network that can adapt to the channel estimation error is obtained. Simulation shows that the security performance and robustness of this method when there are errors in channel estimation are better than traditional artificial noise generation systems. Compared with other deep learning methods for physical layer security, the method proposed in this paper has faster convergence speed.

      • CHEN Qingxin,LIU Yabo,WANG Luhao,YU Zhongjun

        2024(1):46-53, DOI: 10.11805/TKYDA2022118

        Abstract:

        Synthetic Aperture Radar(SAR) works all day and all weather, and has a wide application in the field of earth remote sensing. Video SAR expands the spatial dimension information obtained by SAR imaging to the space-time dimension to obtain richer remote sensing information. The low frequency band of traditional SAR leads to long synthetic aperture time, large amount of data calculation, and great difficulty in high frame rate output. However, the low frequency terahertz wave has strong perception on target details and short synthetic aperture, which is especially suitable for video perception of weak targets. A video SAR system working in the W-band is designed, which adopts the solid-state front end system of bistatic continuous wave, with peak output power of 1 W and maximum transmission bandwidth of 1 GHz. The Polar Format Algorithm(PFA) along with Graphics Processing Unit(GPU) processing architecture is employed to realize high frame rate and low delay imaging. The simulation results show that the imaging resolution of the system can reach 0.15 m and the imaging frame rate is 5 Hz.

      • YUN Chao,TAN Zhiqiang,LU Hang,JIANG Panpan,HUANG Ligang

        2024(1):54-61, DOI: 10.11805/TKYDA2022093

        Abstract:

        Joint Tactical Radio System(JTRS) is an important communication equipment for all levels of cyberspace capabilities development and construction for US army, which is the major initiative for realizing the advantages of tactical cyberspace. The overview of JTRS is expounded, including the radio evolution and specification of Software Communication Architecture(SCA) standard. Then the radio station of JTRS architecture and typical networking construction are studied in detail. The primary waveforms and related radio stations of JTRS are analyzed and the latest developments are expected. This work can provide reference for the development of new tactical Internet and software defined radio.

      • WANG Yi,ZHANG Cuicui,YU Mingmei,WANG Jianzhong

        2024(1):62-67, DOI: 10.11805/TKYDA2021395

        Abstract:

        The test method of split cylindrical resonator is studied in order to realize the nondestructive test of dielectric constant of flat dielectric materials in microwave band. The electromagnetic field analysis theory of split cylindrical resonator is introduced, and the accurate solution of electromagnetic field distribution in the cavity under dielectric loading is realized by using mode matching technology. The exact relationship between the resonant frequency of the cavity and the dielectric constant of the material is obtained. On the basis of theoretical analysis, a split resonator with cavity resonant frequency of 10 GHz is fabricated and compared with the previously developed closed resonator. The relative error of the measurement results of the real part of dielectric constant is less than 1%. Compared with similar foreign products, the real results of dielectric constant are basically consistent, and the measurement result of loss tangent of this device is closer to the reference value. Therefore, the microwave split cavity method can realize the nondestructive measurement of flat dielectric plates, with outstanding advantages such as high accuracy and convenient use. It can accurately test the dielectric constants of various flat dielectric materials with dielectric constant range of 1~20, tangent of loss angle 1×10-3~1×10-5 and plate thickness of 0.1~2.0 mm in the microwave frequency band.

      • LIU Yang,SHU Feng,SONG Laipeng

        2024(1):68-74, DOI: 10.11805/TKYDA2021394

        Abstract:

        A Substrate Integrated Waveguide(SIW) is proposed, which bears the advantages of small size, easy processing, high Q value, and low cost, compared with the traditional slot antenna. The radiation characteristics of the proposed antenna can be optimized by adjusting the slot length, slot width, and cavity size. Calculating the model through electromagnetic simulation software HFSS, then the optimal structure of the antenna can be confirmed finally. The simulation results show that the relative bandwidth of this antenna is about 4.5%, the directivity is excellent, the resonance depth at the center frequency point is <-31 dB, and the maximum antenna gain is 5 dBi, which meets the design requirements and verifies the correctness of the design. The proposed SIW waveguide cavity-backed slot antenna broadens the available frequency spectrum of digital communication, which can provide new ideas for future research.

      • GE Chengliang

        2024(1):75-79, DOI: 10.11805/TKYDA2021416

        Abstract:

        For a complex opto-mechanical system related with optics, mechanics, electronics, control, thermodynamics, gas, liquid, etc, it is an unsolved key problem that how to assess the performance of complicated opto-mechanical system. Herein, combined with Analytic Hierarchy Process(AHP) method, grey method, fuzzy method, etc., one intuitionistic G-factor is presented to evaluate the performance of the system. The G-factor has only one value and can be a direct token of the whole system. Through the statistic progress, it can compare single parameter with that of other system.

      • LI Feixiang,LI Ning,LIU Mingzhe,HE Siyuan,SUN Tian

        2024(1):80-86, DOI: 10.11805/TKYDA2021402

        Abstract:

        Intelligent unmanned system is one of the important means to seize the information advantage, implement the precision attack and complete special combat tasks in information war. It is also a multiplier of future military forces. How to apply emerging technologies to improve the effectiveness of intelligent unmanned systems in future combat scenarios is one of the important research directions. The relevant background of intelligent unmanned system is introduced. The edge computing technology and its advantages in intelligent unmanned system are analyzed, and then the problems during the application of edge computing technology into intelligent unmanned system are modeled and solved. The effectiveness of the algorithm is verified by simulation experiments.

      • LIU Ying,JIANG Tao,YANG Qi,WANG Xuemin,ZHAN Zhiqiang,ZOU Ruijiao,LUO Jiawen,FAN Long,CHEN Fengwei,WU Weidong

        2024(1):87-95, DOI: 10.11805/TKYDA2021386

        Abstract:

        Quantum Cascade Lasers(QCL) are the important laser sources in mid-infrared bands. The tunable mid-infrared quantum cascade laser has been a research focus because of tunable frequency and single longitudinal mode. At present, the tunable frequency of mid-infrared quantum cascade lasers can be realized by the Distributed Feed Back(DFB) grating, the Distributed Bragg Reflect(DBR) grating, the external cavity diffraction grating, etc. The principle and applications of mid-infrared quantum cascade laser are introduced. The progresses of the DFB and DBR tunable quantum cascade lasers, of the external cavity tunable quantum cascade lasers nearly 10 years are summarized. The advantages and disadvantages of various tunable methods are discussed. Finally, the development trends of tunable quantum cascade lasers are prospected.

      • NIU Yiren,GUAN Zhijin,MA Tianhong,JIN Shengxiang

        2024(1):96-104, DOI: 10.11805/TKYDA2021406

        Abstract:

        The error of the double-qubit gate operation caused by the noise is an important reason for the reduction of the fidelity of the execution result in the reversible quantum circuit. A strategy for mapping quantum circuits to noisy quantum computing devices is proposed, so as to improve the success rate of quantum circuits on quantum computing devices. This strategy first provides a method for finding the neighbor path of two qubits on a quantum computing device in which the qubits are not fully connected; since the noise of any two neighbor qubits on the neighbor path is generally different, a heuristic function is constructed based on the execution success rate of the double-qubit gate on the nearest neighbor path to estimate the fidelity of the line in the look-ahead window, and the nearest neighbor method with the highest fidelity is selected according to the cost function. After testing multiple Benchmarks, the experimental results show that the proposed strategy improves the fidelity of the quantum circuit by an average of 65.67% and 71.60% respectively compared with the SabreSwap and BasicSwap methods in Qiskit. The proposed method can improve the fidelity of quantum circuits

      Quick retrieval of articles

      The "In Press" section displays the articles officially accepted after peer review. These articles are currently under copyediting process without volume/issue information, but are citable according to their Digital Object Identifiers(DOI).

        Quick retrieval of articles
        • LIN Jia-sen,LI Zhi,LI Qiao-feng,MA Yi-sen

          2012,10(1):22-26, Doi:

          Abstract:

          Effective choice of the solution is essential to achieve a real-time, bi-directional(full- duplex) communication of the smart grid. The Power Line Carrier(PLC) technology provides a low-cost solution, which suits China's own national conditions. In this paper, the advantages of OFDM PLC modulation technology are introduced. A PLC module of system model is established through the analysis of the input impedance under the low-voltage power line channel. The high-speed PLC module based on low-voltage Power Line is also designed according to the studies of power line channel. The results show that the design of the PLC module has featured high receiving sensitivity and anti-noise ability.

        • WANG Yi,LIAO Xiao-ju,PAN Ze-you

          2011,9(1):7-11, Doi:

          Abstract:

          With the development of Internet applications, users’ demand for bandwidth is soaring sharply. Meanwhile,along with the development of broadband access technology, the endpoint can also adopt multiple network accesses. But due to one-way communication of traditional Transmission Control Protocol(TCP),the waste of resources will exist. To this end,IETF has specifically proposed Multi-Path TCP(MPTCP) to implement TCP multiplexing,thereby enhancing the efficiency and robustness. This paper gives a review of the IETF’s research on MPTCP,including MPTCP architecture, routing and congestion control, aiming to provide a reference for deeply studying.

        • WANG Xiao-xia,CHEN Lian,LI Xin-yao

          2010,8(5):569-572, Doi:

          Abstract:

          Traditional methods and instruments are not able to measure the true Root Mean Square(RMS) of distortion sine wave or non-sine signal accurately. This article introduces a method to measure the true RMS of any high frequency signal by using the true RMS measurement IC,AD536A,designed by AD corporation. The paper analyses the difference between the RMS measured by the average measure method and the true RMS in theory. It explains the disadvantages of current RMS measure method,and presents the design of true RMS measure circuit. The experiment results prove that the proposed method and circuit can measure the true RMS of any high frequency signal accurately.

        • JIANG Xiao-guo,YANG Xing-lin,LI Hong,WEN Long,SHI Jin-shui,ZHANG Kai-zhi,LI Jing,WANG Yuan

          2010,8(5):573-576, Doi:

          Abstract:

          The requirements for micro stress measurement of strain gauge are high precision,high linearity,high stability and high gain. One kind of differential amplifier circuit with excellent performance was designed. Some skillful techniques were adopted to avoid common voltage in the circuit and to reduce the temperature drift. The gain linearity is about 0.01%,and its Common-Mode Rejection Ratio(CMRR) is about 129 dB under work conditions.

        • XIAO Yong-jian,XIAO Li,SUN Zhi-gang

          2013,11(4):583-587, Doi:

          Abstract:

          Aiming at the problems in existing underground personnel positioning systems, an assisted positioning method based on pedestrian dead reckoning is proposed. Low-cost Inertial Measurement Unit(IMU) and magnetometer are employed to constitute a stable Attitude Heading Reference System (AHRS). The theory of inertial navigation is utilized, an algorithm for step detection is described, and Zero velocity Update(ZUPT) is adopted for velocity and position estimation to compose a pedestrian dead reckoning system. An experiment is performed in the corridor of a laboratory building to emulate the underground mine road environment. The experimental results demonstrate that the dead reckoning performs well and this method is an effective complement to existing underground positioning by improving the positioning accuracy.

        • WANG Bo,ZHANG Yan

          2015,13(1):1-12, Doi: 10.11805/TKYDA201501.0001

          Abstract:

          Terahertz(THz) optoelectronics has promoted the development of the THz generation, transparent control, and detection methods,and hastened many devices in the past decades. Especially, THz metamaterials and metasurfaces will exhibit extraordinary electromagnetic response when the subwavelength scale metal structure is excited by the THz illumination. Therefore, they have been applied to the devices such as wave beam shaper, waveguide, and modulator etc. The THz metamaterials and metasurfaces also show the potential applications in the research fields such as sensors, communications, and radars. In this paper, the works about the spectrum and wavefront modulation with THz metadevices carried out in our group are summarized. The basic theory and corresponding experiment results for different devices are introduced. It is expected these works can pave the avenue of the application of the THz metadevices.

        • LI Mo,SUN Peng,SONG Yu,DAI Gang,ZHANG Jiana

          2015,13(1):160-168, Doi: 10.11805/TKYDA201501.0160

          Abstract:

          According to the requirements of safe, simple and nondestructive radiation effect investigation of semiconductor devices, the method of laser simulation was proposed and greatly promoted. Compared with large-scale facilities, laser simulation has various unique advantages. It helps understand the ionization radiation effect in depth and is an effective low-cost, table-top supplement for the hardness assurance. Its research shows great significance for radiation effect study in both theory and practice. In this paper, the basic principles of the interactions of γ and laser with semiconductor devices are firstly presented. Then the physical basics and characteristics of laser simulation are given, with the research progress review followed. The existing problems of current research are deeply discussed providing with feasible research approaches. In the end, necessary research contents in the future are proposed.

        • JIANG Xiao-ping,LI Zhong-jie,YU Xiao-feng

          2010,8(4):451-454, Doi:

          Abstract:

          Radio Frequency IDentification(RFID) series Radio Frequency(RF) card has been applied widely because of its stability,reliability and easy operation features. Aiming at multiple protocols,such as ISO14443 protocol,ISO15693 protocol and Tag-it protocol,this study proposed a new type of circuit design based on Advanced RISC Machine(ARM) for the RFID series RF card reader. The data stream encryption was implemented by using peripheral device in the operation. The system composition,working principle and work flow were introduced. Then,the detailed circuit design of the RF network and encryption hardware were presented,and the test and analysis for the design were performed. The results showed that the circuit could accurately read, write and encrypt various types of card within effective range.

        • ZHANG Lidong,DAI Zuoxing

          2015,13(1):31-34, Doi: 10.11805/TKYDA201501.0031

          Abstract:

          The background requirements of the fuze antenna in terahertz spectrum as well as its advantages and disadvantages are introduced. The working principles and application characteristics of dielectric lens antenna in terahertz frequency are analyzed in order to implement the terahertz fuze antenna. The longitudinal size of H plane horn antenna can be reduced effectively by using fuze antenna formed by an H plane horn with dielectric lens antenna. The terahertz fuze antenna with different beam angles is achieved by focal technology of lens. The feasibility of the technology solution is verified through simulation.

        • ZHOU Tian,YUE Yantao,XU Guanxiong,ZHANG Yangyang,JI Chunlin

          2015,13(1):76-79, Doi: 10.11805/TKYDA201501.0076

          Abstract:

          Ultra-wideband(UWB) communication shows its advantages of fast data transfer(100 Mb/s or above) in a relatively short distance(typically below 10 m) with relatively weak power consumption (energy spectrum below -41.3 dBm/MHz). Integrated with Multiple Input Multiple Output(MIMO) technology, channel capacity could be further enhanced. As a critical link in the ultrawideband communication,UWB antenna needs extra efforts in design optimization to boost the performance of the whole system. UWB antenna is defined as the antenna whose bandwidth exceeds 500 MHz or relative bandwidth greater than 20%. This paper takes the most representative Vivaldi antenna as a show case for multi-objective optimization design with statistical methods. The optimized miniaturized antenna(sized130 mm×100 mm) shows a -10 dB bandwidth of 2.4 GHz. The design method provides guidance in common wideband,multi-parameter antenna design.

        • HE Xiao-dong,DING Li

          2010,8(3):313-317, Doi:

          Abstract:

          High-speed data acquisition system is an important component in modern radar signal processing. A design of high-speed data acquisition system based on band-pass sampling was presented and applied to the signal processing of wideband receiver. The Virtex Series FPGA was used as the main platform to control the high-speed ADC08D1000 for completing data acquisition, transmission,storage and signal processing. High-speed First Input First Output(FIFOs) were selected as the storage devices to implement data rate conversion. The system realized the software and hardware design,and test results verified the feasibility of the solution.

        • XU Ping,QING Lin-bo,HE Xiao-hai,YANG Chao,XU Guang-hui

          2010,8(1):67-70, Doi:

          Abstract:

          The implementation of TCP/IP protocol stack on TM320DM642 platform could provide technological support for the application of multimedia embedded systems to networks. Both the function of TM320DM642 chip and the hierarchical structure of LWIP(Light Weight Internet Protocol) were analyzed. Network communications for TM320DM642 systems were implemented by the transplantation of LWIP, not by a solution scheme of NDK(Network Developer’s Kit). Testing examples verified the effectiveness of the LWIP transplanted method.

        • WANG Peng,YANG Chun,WEN Zhao-Jin

          2010,8(3):247-250, Doi:

          Abstract:

          This article introduces a new type of high speed,multi-modulated digital modulator with adjustable center frequency and bit rate features. It can realize the Quadrature Phase Shift Keying(QPSK) and 16QAM(Quadrature Amplitude Modulation) with 80 MHz center frequency and 7.936 5 MHz bandwidth. The general-purpose modulation arithmetic based on software radio,symbol mapping and the realization of pulse shaping filter are discussed. The measuring results demonstrate that the modulation scheme meets the requirements of practicability and general utilization.

        • MIAO Jiang-hong,MA Guo-ning,HE Yu-dong,YIN Liang

          2010,8(6):647-651, Doi:

          Abstract:

          The design of code tracking loop is a key sector of the realization of noncoherent spectrum spread receiver. In order to realize the code tracking in noncoherent spectrum spread receiver, an energy-normalization digital delay-locked loop was designed, the structure of the loop and the calculating procedure of loop parameters were introduced. The characteristic of noncoherent spectrum spread was analyzed first,and then the key point of the loop design was pointed out. Based on this, the design and realization methods of code loop discriminator, loop filter, early and lag code generator were expatiated. A set of specific loop parameters were introduced as well. Modelsim simulation results and FPGA actual measured data prove the precise code tracking ability of the design.

        • ZHOU Xiao-qing,LI He-sheng,TAO Rong-hui,CAI Ying-wu

          2010,8(2):211-214, Doi:

          Abstract:

          The application of CORDIC(COordinate Rotation DIgital Computing) arithmetic in solving transcendental function has become popular in modern engineering. A brief introduction of CORDIC arithmetic was given in this study. Taking the hyperbolic sine and cosine functions as examples, the method of realizing the arithmetic in FPGA was presented and simulated on ISE(Integrated Software Environment) platform. The result showed this arithmetic was of good precision and instantaneity because of using pipeline. This arithmetic has great practical value in some applications. In addition, a curve of the relationship between the iterative number and the error obtained by the Matlab simulation of the arithmetic can help designers planning the number of iterations for practical applications.

        • JIA Zhuo,LIU Hao,DENG Yifeng,DENG Hong

          2015,13(1):174-178, Doi: 10.11805/TKYDA201501.0174

          Abstract:

          The Spatial Light Modulation(SLM) technology has been widely applied to the fields of threshold switch, high speed optical interconnection and optical logic operations, which demands good performance on the real-time and fast optical signal addressing. Compared with Electro-Addressing SLM(EA-SLM), Optically-Addressing SLM(OA-SLM) shows great advantages of fast speed and high resolution by parallel addressing. Nevertheless, how to achieve fast and stable optically addressing is the key point in practice. Based on ZnO thin film as a photoconductive layer, Liquid Crystal OASLM(LC-OASLM) is designed and fabricated; the modulation of the readout light intensity and phase distribution in the two-dimensional space is achieved effectively.

        • ZOU Xiang,QIN Linbo,HE Xiaohai,ZHANG Yuqiang,XU Shunfei

          2015,13(1):111-117, Doi: 10.11805/TKYDA201501.0111

          Abstract:

          The corresponding solutions are proposed to tackle with the disadvantages of conventional oilfield Geographic Information System(GIS), including inconvenience of Client/Server(C/S) mode operation and maintenance, being unable to perform real-time online Point of Interest(POI) rendering, being incapable of segmentation and location according to regions, etc. An oilfield information query system of Browser/Serve(B/S) framework based on AJAX+JSON+HTML5 is designed and implemented. Experimental results show that the POI real-time rendering and regional segmentation improve on their interactivities, and the experiences of users are enriched, which meets the actual requirements of oilfield development. This work has paved the way for the development of diversified network services.

        • LUO Ya,LIAO Qingmin,WANG Desheng

          2015,13(1):35-39, Doi: 10.11805/TKYDA201501.0035

          Abstract:

          A double gate setting with priority of Doppler velocity and the Extended Kalman Filter(EKF) based Multiple Hypothesis Tracking(MHT) algorithm are proposed in order to realize Multiple Targets Tracking(MTT) in High Frequency(HF) ground-wave radar, and to effectively improve the performance of MTT by using the Doppler measurement. In the EKF based MHT, parameters obtained in the EKF are adopted directly to calculate the probability of each hypothesis. A simulation scene is built, and the EKF based MHT algorithm is compared with the one which assumes that the Doppler measurement is independent from the radius measurement. Simulation results show that the double gate setting helps induce number of clutter, and the EKF-based MHT algorithm is better than the other one under dense environments of HF ground-wave radar with stronger track-catching and false-alarm-filtering ability and higher efficiency.

        • XU Lei,TU Xuecou,WAN Chao,PEI Yufeng,KANG Lin,WU Peiheng

          2015,13(1):27-30, Doi: 10.11805/TKYDA201501.0027

          Abstract:

          A detector can achieve quick response when it is much smaller than the wavelength of the source signal in THz wave band at the expense of signal coupling capability.Therefore, an antenna is applied to collect signals in order to enhance the signal coupling capability of the detector.The properties of antenna determine the frequency response band,the sensitivity and other parameters of the detector directly. A planar-integrated antenna is adopted for signal acquisition in the Nb5N6 microbolometer detector, which is fabricated by lithography,lift-off and other processes of micro-fabrication. The Nb5N6 microbolometer is placed in the center of the planar antenna. Aiming for the center frequency of 0.32 THz, a special capacitive coupling design is proposed to improve the signal coupling capability.

        • ZHANG Hao,YANG Yuhong,XIN Gang,DU Sen

          2015,13(1):142-147, Doi: 10.11805/TKYDA201501.0142

          Abstract:

          The single-channel blind separation of GMSK(Gaussian Minimum Shift Keying) mixing signals is researched. The GMSK mixing signals can not be separated by the Per-Survivor Processing (PSP) algorithm directly, therefore, linear approximation processing of the GMSK signal is considered, which enables GMSK signal to be separated by the PSP algorithm. This algorithm separates the GMSK mixing signals by maximum likelihood estimation in the joint space of the symbol sequential and the channel parameters, reserves the best path and outputs the symbol pairs to get the separated signals. Simulation results show that the bit error rate performance produced by the PSP algorithm on separating the GMSK mixing signals is slightly better than that produced by the particle filtering algorithm; and the complexity of the proposed PSP algorithm is much smaller.