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15 March 2020 Volume 33 Issue 3
  
    Design and Implementation of a Passive High Linear Mixing Component
    YAN Yang,SHI Yu
    Electronic Science and Technology. 2020, 33(3):  1-5.  doi:10.16180/j.cnki.issn1007-7820.2020.03.001
    Abstract ( 311 )   HTML ( 14 )   PDF (1002KB) ( 76 )  
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    In the RF communication system, the mixer acts as the core device of the receiver, and its linearity directly affects the performance of the entire receiving system. A passive high linear mixing component circuit with the method of the “balanced mixer + absorption filter” to achieve high linearity requirements was designed and implemented in this paper. The balanced mixer was interconnected by a pair of double balanced mixers and the linearity was optimized with the phase cancellation. The nonlinear harmonics generated by the mixers were absorbed by the filter, which blocked the reflection in the space. The two parts worked together to optimize the linearity of the entire component. After actual testing, the IIP2 of the mixing component could reach 94 dBm and the IIP3 could reach 29 dBm with the RF frequency of 30~1 350 MHz, the local oscillator frequency of 3 030~4 350 MHz, and the intermediate frequency of 3 000 MHz. Compared to a single mixer, its linear performance was greatly optimized and was more suitable for high performance receivers.

    Adaptive Genetic Algorithm Based on Individual Ordering
    DING Jiahui,ZHANG Zhaojun
    Electronic Science and Technology. 2020, 33(3):  6-11.  doi:10.16180/j.cnki.issn1007-7820.2020.03.002
    Abstract ( 356 )   HTML ( 3 )   PDF (949KB) ( 50 )  
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    Aiming at the shortcomings of genetic algorithm which is easy to fall into local optimum, an adaptive genetic algorithm based on individual ordering was proposed in this study. In the traditional adaptive genetic algorithm, the adaptive update of the crossover probability and the mutation probability was based on the individual fitness value. But in the later stage of the algorithm, as the population falled into the local extreme value, the difference of the value became smaller, and it was difficult to reflect individual differences when updating. Referring to the idea of order optimization, in the proposed improved algorithm, the individual fitness values were sorted, and the ordering number was used instead of the fitness value. This method of replacing the value difference by using the order difference could increase the value of the crossover probability and the mutation rate in the middle and the late stage of the population, which was beneficial to avoid the premature convergence of the algorithm. Several standard functions were tested, which showed that the improved algorithm was superior to the other two adaptive improved algorithms in terms of convergence speed and convergence precision.

    Multi-label Image Annotation Algorithm Based on Transfer Learning and Weighted Ranking Support Vector Machine
    CHEN Lei,LI Feifei,CHEN Qiu
    Electronic Science and Technology. 2020, 33(3):  12-16.  doi:10.16180/j.cnki.issn1007-7820.2020.03.003
    Abstract ( 229 )   HTML ( 4 )   PDF (708KB) ( 33 )  
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    In order to resolve the class imbalance problem in multi-label image annotation, an improved annotation method based on transfer learning and WRSVM was proposed in this paper. As it was difficult to train a CNN from scratch by using small datasets, transfer learning was adopted to transfer the parameters of Alexnet trained by Imagenet dataset to the convolutional neural network model utilized in the study. Besides, the last fully connected layer was fine-tuned and the multi-label multi-hinge loss function was applied to constitute multi-class support vector machine. Finally, the weighted ranking was used to label the low-frequency labels to obtain the multi-label image annotation results. The experiments were performed on three datasets including Corel-5k, Esp-Game and IAPR-TC12. The experimental results showed that the average recall of the proposed method increased 10%, 9%, and 6%, respectively, and the average of precision increased 12% for the low-frequency labels, indicating the proposed CNN-WRSVM method could improve the average of recall and the average of precision for low-frequency labels.

    Design Method of the Ridge Waveguide Filter with Evanescent Mode Coupling
    LI Gang
    Electronic Science and Technology. 2020, 33(3):  17-20.  doi:10.16180/j.cnki.issn1007-7820.2020.03.004
    Abstract ( 381 )   HTML ( 21 )   PDF (631KB) ( 120 )  
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    In the design of traditional ridged waveguide filter, the design precision is not high because of the lack of the frequency characteristics of the coupling structure. This paper presented a design method for the ridge waveguide filter with evanescent mode coupling. The rectangular waveguide working in the evanescent mode was equivalent to a frequency dependent impedance inverter model. By establishing an equivalent circuit model, the frequency variation of the coupling structure was converted to influence the reactance slope parameters of the resonator. The filter structure size was determined by the step by step simulation strategy to avoid the time-consuming full wave simulation optimization. Finally, a ridge waveguide filter with four orders Chebyshev response was designed. Full wave simulation results showed the same bandpass equiripple property as the theoretical design and verifyied the validity of the method.

    Design of a Comb Generator Based on PLL
    LIU Hanzi,SHI Yu,ZHANG Wei
    Electronic Science and Technology. 2020, 33(3):  21-25.  doi:10.16180/j.cnki.issn1007-7820.2020.03.005
    Abstract ( 407 )   HTML ( 3 )   PDF (970KB) ( 59 )  
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    It is difficult for the traditional analog comb generator to achieve high flatness, small frequency spacing and flexible adjustment. This study proposed a new way to realize comb signal based on phase-locked loop mechanism. Specifically, the output of the N divider in the phase-locked loop feedback branch generated a pulse signal with a narrow pulse width by dividing high frequency signal of the voltage-controlled oscillator. The pulse passed through the filter to obtain a high-flatness comb signal that satisfies the target bandwidth. By flexible programming control of the divider, the comb signal with different frequency spacing was obtained without modifying the hardware circuit design. The experimental results showed that the spectral line generated by the comb spectrum generator based on PLL had the advantages of large signal bandwidth, high amplitude uniformity, adjustable frequency spacing, miniaturization and low power consumption.

    k9 Glass Squeaking Acoustic Emission Signal Scratch Profile and Roughness Prediction
    HU Jixiong,JIANG Chen,LANG Xiaohu
    Electronic Science and Technology. 2020, 33(3):  26-32.  doi:10.16180/j.cnki.issn1007-7820.2020.03.006
    Abstract ( 238 )   HTML ( 2 )   PDF (1564KB) ( 19 )  
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    The current k9 optical glass material removal lacks the problem described by acoustic emission signals. A method based on acoustic emission signals to establish a theoretical model of scratch morphology was proposed to describe the method of scratch morphology and roughness prediction. Specifically, a single random abrasive scraper was used to perform a deep-depth squeaking acoustic emission test on the k9 optical glass on a five-axis joint bed and a bandpass filter was designed to analyze and process the acoustic emission signal. The amplitude of the target time domain acoustic emission signal was about 0.01dB, and the signal energy of the fourier transform of the acoustic emission signal in the target frequency domain was concentrated in the low frequency range of 60~160 kHz. The scratch roughness was calculated by the surface scratch model of the transmitted signal, and was further compared with the roughness measured by the microscope. The results showed that the predicted value of the proposed method was closer to the true value.

    Simulation Design of Horizontally Polarized Continuous Wave Illuminator Element
    MAO Sijie,ZHOU Xiang
    Electronic Science and Technology. 2020, 33(3):  33-37.  doi:10.16180/j.cnki.issn1007-7820.2020.03.007
    Abstract ( 213 )   HTML ( 2 )   PDF (985KB) ( 18 )  
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    Nuclear electromagnetic pulse weapon is harmful to the electronic equipment in the battlefield. Radiation test is necessary for the aim of ensuring the capability of electronic equipment in complex electromagnetic environment. In this study, a design method of CW illuminator was presented to meet the requirement of system level electromagnetic pulse test. A design method of horizontally polarized CW illuminator element working frequency range from 100 kHz to 500 MHz was presented by means of the structure design and loading design as well as the combination of MATLAB. The design results indicated that in the frequency band of 100 kHz~10 MHz, the shape change of the illuminator element had little influence on the field distribution in the test area. Besides, when the oscillator vibrator was loaded several times, the spatial impedance of the test area was also increased by the same factor.

    Copy-move Detection Algorithm Combining Keypoints and Block Advantages
    YANG Shanshan,ZHANG Daxing,GUO Jiawei,WANG Shitiao
    Electronic Science and Technology. 2020, 33(3):  38-43.  doi:10.16180/j.cnki.issn1007-7820.2020.03.008
    Abstract ( 217 )   HTML ( 0 )   PDF (1139KB) ( 20 )  
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    Digital images are widely used, and the use of various software for editing images has led to the authenticity of the images to be verified. Most of the algorithms based on keypoint detection have a limited number of key points, resulting in incomplete or unclear final detection results.This paper proposed a detection algorithm based on segmentation combined with keypoint features. First, SIFT was used to extract keypoint features and then used. The g2NN algorithm matched the key points, used the designed clustering to remove the mismatch, and according to the improved adaptive segmentation algorithm, marked the matched image blocks, and then finded the surrounding neighbor blocks to compare and matched the output results. The algorithm could effectively detected and marked the copy tampering area of large pictures, and was robust to most post-processing, and marked the tampering area more completely.

    A Two Degreeof Freedom PID Control Algorithm for Aircraft Pitch Angle
    CUI Yue,ZHANG Wei
    Electronic Science and Technology. 2020, 33(3):  44-49.  doi:10.16180/j.cnki.issn1007-7820.2020.03.009
    Abstract ( 302 )   HTML ( 3 )   PDF (821KB) ( 38 )  
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    As the most basic control mode of the aircraft longitudinal motion, it is difficult to control the aircraft pitch angle. A two-degree-of-freedom PID control algorithm was proposed for the first-order integrating system with time delay, which was simplified by a fourth-order system. The fourth-order system was composed of the increment of pitching angle and the offset of rudder surface. The main idea of the algorithm was to design the set-point filter and controller separately based on the multiple dominant pole placement method and the direct synthesis method. The tuning rules were given in form of analytical equation. Simulation results showed that the proposed method could be well applied to the fourth-order system of aircraft pitch angle, and also had excellent disturbance rejection performance and better servo performance and robustness.

    Improved Kernelized Correlation Filter Tracking
    ZENG Zhao,WU Wei,WANG Xin
    Electronic Science and Technology. 2020, 33(3):  50-55.  doi:10.16180/j.cnki.issn1007-7820.2020.03.010
    Abstract ( 239 )   HTML ( 0 )   PDF (1126KB) ( 15 )  
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    In order to solved the probelmof scale specificity and occlusion judgment failure of Kernel-correlation Filtering algorithm in target tracking, a position filter based on adaptive feature fusion was proposed to judge whether the target was occluded or not. When the Peak-to- Sidelobe Ratio anomaly was detected, the adaptive updating of the model was stopped and online re-detection was started, and the target size was determined by combining the scale filter in the scale pyramid, thus the accurate target location was obtained. The experiment evaluated the performance of the improved algorithm through 10 groups of motion video in complex background. Compared with the basic Kernel-correlation Filtering algorithm, the average center position error of the improved algorithm was reduced by 36.683 pixels; the average distance accuracy was increased by 44.632% when the threshold of the pixel was set to 20 pixels; and the overlap accuracy was increased by 46.453% when the boundary frame overlap threshold was set to 0.5.

    Research on Stability of Nonlinear Systems Based on Event Triggering and Quantization
    GUO Xin,GAO Yan,JIANG Lin,ZHANG Zhishu
    Electronic Science and Technology. 2020, 33(3):  56-61.  doi:10.16180/j.cnki.issn1007-7820.2020.03.011
    Abstract ( 185 )   HTML ( 0 )   PDF (791KB) ( 25 )  
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    In this paper, based on the data sampling stability problem of nonlinear systems, a neural network controller based on event triggering mechanism and data quantization mechanism was designed. The sampler monitored the nonlinear system at any time, and the sampled signal was detected by the event trigger mechanism. After the threshold was satisfied, the quantizer was used to quantize the incoming controller, and the designed controller output the feedback and the nonlinear system. In order to reduce the conservativeness of the system, a novel piecewise Lyapunov-Krasovskii functional was selected. For the transmission time delay contained in the system, the time delay analysis method was used to transform the solving problem of the synchronous controller into the stability problem of the corresponding time-delay system. Combined with Jensen's inequality, the stability conditions of nonlinear systems were given. Finally, the effectiveness of the proposed method was verified by numerical simulation.

    Fabrication and Properties of GaN Energy Conversion Devices
    ZHANG Darui,WANG Ding,WANG Xianying
    Electronic Science and Technology. 2020, 33(3):  62-65.  doi:10.16180/j.cnki.issn1007-7820.2020.03.012
    Abstract ( 195 )   HTML ( 0 )   PDF (789KB) ( 18 )  
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    In this paper, an energy conversion device was made of GaN nanowire arrays for solving the problem that nanogenerators were difficult to generate stable direct current at lower temperatures. In order to detect the open circuit voltage and short circuit current generated by the device, and to detect the relationship between the electrical signal generated by the device and the temperature, the GaN energy conversion device was placed at a temperature of 25 to 74 ° C, respectively. The results showed that the GaN prepared by the etching method can be used as an energy conversion device, and the generated electrical signal increase as the ambient temperature increases. The open circuit voltage of 78 mV and short circuit current of 0.24 nA could obtained at around 74 °C.

    Study on Application Performance of Low Melting Point Alloy in Electrical Connector
    ZHAO Jiali,YIN Zhihong,ZHANG Wenbin
    Electronic Science and Technology. 2020, 33(3):  66-70.  doi:10.16180/j.cnki.issn1007-7820.2020.03.013
    Abstract ( 186 )   HTML ( 1 )   PDF (928KB) ( 19 )  
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    Aiming at the problem that the transmission and distribution lines are electrically connected to the hair heat and cause energy loss, the application performance of low melting point alloys in electrical connectors was studied. Low-melting alloys Sn-3.5Ag, Sn-1.6Cu, and Sn-Zn-0.7Cu with good wettability at the copper interface were selected and a joining process in the electrical connection was designed and constructed. The reliability of the interface after connection was judged by using the ERESCO MF4 portable X-ray machine. The SLQ-2000A up-flow experimental system was established and the actual working conditions were simulated. Finally, the low-melting alloy and electric composite grease samples were tested for the heat generation of the test piece during the continuous flow time of 4 hours at a rated flow rate of 180 A. The experimental results showed that the calorific value of the low melting point alloy as the electrical connection joint material is lower than the calorific value of the electric composite grease joint sample.

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