Abstract:To improve FPGA resource utilization，this study introduced fundamental and classification about dynamically reconfigurable FPGA at first, then the Virtex-4 FPGA configuration theory and two kinds of reconfiguration method were discussed, the hardware design of configuring FPGA with Digital Signal Processor(DSP) was proposed to implement the reconfiguration system．DSP was used to configure and reconfigure this FPGA in a SelectMAP configuration mode. The system could be configured fast and reconfigured partially. Finally the program flow chart of the dynamically reconfigurable system was presented according to procedure and time sequence relation. The experiment results indicated that the system was stable and could reconfigure FPGA with 5 Mbyte/s.
Abstract:The coding technology in Galileo system is more and more important. In this study, the spreading-spectrum technology was applied to Galileo system; the channel characteristics were discussed and simulated with the excellent stochastic and orthogonal performances. Simulation results indicated that the attenuation of channel was less than -40 dB, which had reached the specification of CDMA2000，thereby, it had simplified the complexity of Pseudo-Noise(PN) code generation, and had unified the usage of chaos sequence in the source signal and channel coding. The way of PN sequence replaced by chaos spreading-spectrum technology applied in Galileo system is feasible and practical.
Abstract:To improve the compatibility of the receiver, reduce design complexity and costs, this study researched the tracking channel design of configurable multi-system receiver based on FPGA and GPS hardware platform. The frame construction and function module of the tracking channel were explained firstly. Then the key technologies to implement the configurable channel, such as configurable carrier NCO(Numerically Controlled Oscillator), code NCO and code generator were analyzed. By simulating under the environment of ModelSim software and measuring with the GPS/COMPASS signals, it was verified that the channel was flexible and configurable. Resource analysis also showed that the logic resource was reduced by about a half compared to the independent system.
Abstract:By analyzing the classical algorithm for the three-dimensional(3-D) tri-station Time Difference Of Arrival(TDOA) location, the reasons to produce ambiguity and non-solution were discussed. The correlation of the distribution of non-solution area with the placement of stations, stations site error and TDOA error was analyzed. Some methods to solve the problems of ambiguity and non-solution were presented. In the practical application, the priori information of targets should be used adequately. The methods to solve the problems of ambiguity must be used well to reduce complexity and enhance operation efficiency. Meanwhile, the distribution of stations should be optimized to make the target area to be out of the non-solution area.
Abstract:Joystick is widely applied in the virtual reality technology and simulative equipments，but the related research is mainly limited on the game joystick and flying joystick without being broadened further. When the functional requirement is complex, joystick becomes impractical and failed to meet the equipment's demand. In order to control the change of parameters for the radar simulator by joystick，the projects of hardware connection and software connection were presented, which were proved to meet the functional requirements well. Therefore, the control on the change of simulator parameters by joystick was realized. It can also provide a reference for the flexible controlling on flying objects in all directions by joystick under the virtual reality environment.
Abstract:A multiple media system，which was feature-rich and easy to be expanded，was designed and realized. According to the research status and development trend of multiple media system，a scheme，taking OMAP3530 processor as the core of the hardware，was designed based on embedded Linux. The system was composed of multiple media processing module，display module，network module，and Human Computer Interaction(HCI) module. On this basis，the hardware，relative drivers and application layers were designed. The hardware drivers，encoding and decoding algorithms，and software were designed in the environment of Linux 2.6.28 kernel. The experiment results showed that the multiple media system was multi-functional，high-tech-combined，system-integrated and network based. It is an integrated platform with strong scalability and could be functionally reorganized for different users and manufacture. The flexibility and convenience make it a good application prospect in multiple media and communication system.
Abstract:Millimeter-wave systems have been widely applied in military communications. As a key component, the output power of millimeter-wave transmitter has become an important parameter to evaluate these systems’ performance. This study designed a Ka-band solid-state power amplifier, and analyzed the problems of circuit stability about debugging. The measurement result indicated that the gain was more than 35 dB within f0±1.5 GHz, and P-1 was 33 dBm.
Abstract:A new technique called Substrate Integrated Waveguide(SIW) was proposed, and then its dominant mode(TE10) was briefly analyzed. In order to miniaturize the millimeter wave circuit system, this study improved the traditional chain SIW filter and brought forward a new type of compact configuration with chamfer angle. Based on these two structures, the bandpass filters were designed with the center frequency of 31.15 GHz, the Fractional Bandpass Width(FBW) of 7.7%, and the maximum insertion loss less than 1.9 dB. The simulation results showed that when compared with the traditional one，the compact SIW filter with chamfer angle tended to be more structurally compact, with the maximum length being shortened by half. Moreover, the performance of the filter was getting better than before.
Abstract:The digital phase shifter is widely used in phased-array radar. The phase shifter was fabricated using tandem stub for 11.25°,22.5°and 45°, and using 3 dB branch-line coupler type for 90°and 180°. A 5-bit digital phase shifter circuit in Ka-band was presented. The measurement results indicated that the maximum of the phase error was 6.5°，the minimum of the phase error was 0.2°, the maximum of insertion loss was 11.8 dB, the minimum of insertion loss was 8.6 dB, and the VSWR was better than 2 in the frequency band of 30 GHz-31 GHz. The whole volume of the phase shifter was 110 mm× 55 mm×25 mm.
Abstract:This study researched and analyzed the analog phase-locked Ceramic Resonator Oscillators(CRO) technology based on low-phase noise，high-clutter suppression techniques. The analog phase-locked frequency source and the phase-locked frequency source implemented by traditional methods，were compared and analyzed. Based on the analysis of the working principle of sampling phase detector，an implementation scheme for the analog phase-locked CRO was proposed. Highlighting the operating principle and parameters setting of loop filter circuit and the auto-capture circuit，a method was given to improve the output signal spurious suppression. The phase noise indicators of the designed analog phase-locked CRO，were difficult to be obtained using general phase-locked methods. The practical test result of the proposed scheme indicated that the phase noise of analog phase-locked CRO was very low(with output frequency of 3 GHz，the phase noise could be less than or equal to -115 dBc/Hz@10 kHz)，and the spurious suppression index also showed certain advantages(could be better than -70 dBc).
Abstract:When percentage of changed area in whole scene is relatively too small or too large, general change detection methods can not detect the change information accurately. In order to solve this problem, this paper proposes a split window-based method for unsupervised change detection in multichannel remotely sensed images. This method splits difference image into a set of subimages, and determines segmentation threshold of the whole scene by combining the thresholds of subimages. Experimental results demonstrate that the proposed method can detect change information accurately even if percentage of changed area in whole scene is relatively too small or too large, and improve detection accuracy obviously comparing to general change detection methods.
Abstract:In order to improve the embedding efficiency and reduce the operating time，a novel steganographic method，based on JPEG and Bee Evolutionary Genetic Algorithm(BEGA)，was proposed. The proposed method first derived an optimal substitution matrix by BEGA for transforming the secret messages. By means of the substitution strategy，the quality of stego-images was improved. Next，it modified the standard JPEG quantization table for the purpose of accommodating more secret messages. The transformed messages were then hidden in the cover-image with its DC-to-middle frequency components of the quantized DCT coefficients modified. Finally，a JPEG file was generated through JPEG entropy coding. The experimental results showed that the proposed method had achieved a better image quality and security than steganographic method without optimal substitution，and it had costed less computation time than the genetic algorithm-based information hiding method.
Abstract:This study proposed a Beamlet-based method of extraction from core fissures images. Firstly, the collected core fissures images were transferred to the binary images using Otsu's thresholding segmentation algorithm, then the Beamlet transform was exploited to extract the linear features of fissures from the binary images with different scales and thresholds, and the relevant analytical data of fissures were added up according to pixel values. The results showed that the proposed method could extract clear images of core fissures in the cases of complex core backgrounds and noises, achieving satisfactory performance.
Abstract:The fingerprint image pre-processing is a very important part of Automatic Fingerprint Identification System(AFIS). It includes such processes like normalization，orientation filtering，binarization，thinning，etc. The fingerprint image pre-processing algorithm is complex with plenty of computation. This study designed a new fingerprint image pre-processing method by using System On Programmable Chip(SOPC) technology，realized the most of time-consuming processes by using Field Programmable Gate Array(FPGA)，and implemented the part of less time-consuming but handling complexly with the software. The soft-core Nios II processor which had been downloaded to FPGA was responsible for running the software and coordinating the software with hardware．Experimental results showed that this method could improve the quality of images and processing speed greatly，thus it ensured the real-time of AFIS and provided a new design thought for the study of AFIS.
Abstract:The hybrid waveform combined Linear Frequency Modulated and Pseudo-Random Binary phase Code(LFM-PRBC) is a new type of low probability intercept signal, which is widely adopted in radars and small detectors. It is significant to estimate the parameters of the hybrid waveform. This paper develops the Modified Cramer-Rao Lower Bound(MCRLB) for the modulation parameters of this signal with Gaussian noise. The modulation parameters considered are signal amplitude，carrier frequency, modulation slope and code width, and the nuisance parameters are codes and initial phase. Conclusions indicate that MCRLB is independent with nuisance parameters，and MCRLB in logarithmic form is linear with the Signal to Noise Ratio(SNR) when the vectors of estimated parameters are determined.
Abstract:The design proposal and result of a FPGA-based Turbo decoder is introduced. Using the Max-Log-MAP decoding algorithm and the Verilog language for programming, the positive sequence operation and the reverse order operation can be simultaneously carried, and the intermediate results can be stored in array-based memory，which has enabled the decoding speed to be improved. The Turbo decoding theory, the Max-Log-MAP algorithmic analysis, the block diagram based on FPGA design and implementation, algorithm timing diagram and velocity analysis, are also presented. Results indicates that the program is correct and feasible, decoding/error correction is unmistakable, and the decoding speed is quick.
Abstract:In relative gradient algorithms of Independent Component Analysis(ICA), careful selection of step size is important to obtain good performance. In this study, an adjustable rate of relative gradient algorithm was proposed. With the changes of iteration number, the learning rate of relative gradient algorithm changed correspondingly，which solved the problem about the contradiction between the convergence rate and stability well. On this basis，this method was adopted in Blind Signal Separation(BSS) problems，and its effectiveness was validated by simulation. Adjustable rate algorithm with relative gradient has good prospects in independent component analysis.
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.
Abstract:High-voltage switch is a key component to discharge circuit. Nevertheless，the voltage on the high-voltage switch in discharge circuit appears transient sometimes，which will cause the spurious triggering or breakage of the high-voltage switch. Furthermore，the abnormity of the high-voltage switch will cause the failure of the discharge circuit. The reason of this kind of failure was explored in this study. The circuit was simulated and analysed. A protection method was proposed to solve this problem according to simulation results. Practical tests were employed on the real circuit，which validated the simulation results and the effectiveness of the protection method.
Abstract:This paper describes a control system of Free Electron Laser(FEL)-THz，which is a distributed control system based on Experiment Physics and Industrial Control System(EPICS). It gives detailed description of the injector control system，magnetic bunch compressor system and transport control system，including the hardware structure and software design. It also describes the process of creating device support module for the GPIB device and RS232 serial device. The implementation provides preparations for the upgrade of the FEL-THz control system.
Abstract:A design scheme about electric power quality monitor device based on OMAP-L137 was proposed. According to this, the framework and arithmetic of the device were introduced. Because of the existence of the harmonic disturbance, a scheme of adding windows combined with interpolation arithmetic was used to improve the accuracy of the measure scheme. Meanwhile, a good interface was designed with the programming tool of Delphi. The reliability and practicability were validated through experiments.
Abstract:This study discussed a low cost, portable, remote multi-channel data acquisition system design, and introduced the system structure, software and hardware design and Nios II system module structure, etc. The data acquisition system contained signal acquisition module, data processing module and data transmission module. The signal acquisition module contained a data acquisition module that measured six meteorological parameters—temperature, humidity, air pressure, rainfall, wind direction and wind velocity, a Global Position System(GPS) module and a Charge Coupled Device(CCD) module. FPGA(Field Programmable Gate Array) chip EP3C25F324 of ALTERA was adopted in the data processing module, characterized by high integration and flexibility of the System On Programmable Chip(SOPC). The data transmission module transmitted data by using two ways of General Packet Radio Service(GPRS) wireless and RS232 cable. Verifying simulation results completely met expected design requirements.
Abstract:PROFINET is the open standard for industrial Ethernet. PROFINET Component Based Automation(CBA) technology makes the communication between distributed automation systems easier and more efficient by providing standardized automation components. This study introduced the theory and model of PROFINET CBA. PROFINET CBA components based on PROFINET Runtime Source were developed and a real-time communication system was implemented. PROFINET CBA technology can be applied in constructing a distributed automation communication system.
Abstract:In order to meet the stability requirement of the waveform display of high-performance digital storage oscilloscope, this paper describes a display control circuit scheme of the Digital Storage Oscilloscope(DSO) which is built by the dual-port RAM IDT-70T3539M and EP1C4F324C8 as the main components, and discusses in detail the all functional modules within the FPGA and the preparation of the LCD-related driver. Comparing with the former display plan，this plan can meet better the performance requirements of the waveform display of the oscilloscope. The plan can achieve the update rate of waveform for the 2 000 waveforms/s，supporting a resolution of 640×480 and 18 bit color TFTLCD，and can achieve a variety of display.
Abstract:It is critical for the competence of robotic soccer that the wireless communication system transmitts and receives the command-data precisely and rapidly. How to construct a wireless communication system based on Conrad-433/868 wireless communication module in addition to the circuit of the transmitter and the reciever is presented in detail. This system is of advantages such as tiny volume, high integration, high communicating-rate and robustness, easy construction，low cost and without regulating- device，The performance of this system has been verified by the experiments and the competences.