The embedded design verification test of microwave circuit modules based on specific chips

In the Paper,the author introduces an embedded design verification test based on specific chips to solve the technical problems of microwave circuit test and fault diagnosis.The author explains embedded design of microwave circuit modules and approach of hardware design and software design,and finally verifies the embedded design of microwave circuit modules based on specific chips.

10Gb/s EML Module Based on Identical Epitaxial Layer Scheme

A 10Gb/s transmitter module containing an electroabsorption modulator monolithically integrated with a distributed feedback (DFB) semiconductor laser is fabricated using the identical epitaxial layer scheme.Gain-coupling mechanism is employed to improve the single mode yield of the DFB laser,while inductively coupled plasma dry etching technique is utilized to reduce the modulator capacitance.The integrated device exhibits a threshold current as low as 12mA and an extinction ratio over 15dB at -2V bias.The small signal modulation bandwidth is measured to be over 10GHz.The transmission experiment at 10Gb/s indicates a power penalty less than 1dB at a bit-error-rate of 10 -12 after transmission through 35km single mode fiber.

Small Signal Equivalent Circuit Model and Modulation Properties of Vertical Cavity-Surface Emitting Lasers

Small signal equivalent circuit model and modulation properties of vertical cavity surface emitting lasers(VCSEL's) are presented.The modulation properties both in analytic equation calculation and in circuit model simulation are studied.The analytic equation calculation of the modulation properties is calculated by using Mathcad program and the circuit model simulation is simulated by using Pspice program respectively.The results of calculation and the simulation are in good agreement with each other.Experiment is performed to testify the circuit model.

Digital Demodulation Algorithm for Multi-Tone FM Signal in New Type Track Circuit

The multi-tone frequency modulation （FM） signal transferred through track circuit in automatic train control （ATC） system is analyzed. A digital filter with ideal sloping shape in frequency domain is designed for frequency discrimination. With this filter, the FM signal is converted into AM-FM signal by frequency-to-amplitude conversion. The modulating signal is finally extracted from the envelope of the AM-FM signal. Simulations show that the digital demodulation method could accurately recover the modulating signal in low signal noise ratio （SNR） circumstance, and has good performance in suppressing interference of harmonies of traction current frequency. The feasibility of the proposed method is proved in a hardware system based on SHARC DSP.

Modulation of energy spectrum and control of coherent microwave transmission at single-photon level by longitudinal field in a superconducting quantum circuit

We study the effect of longitudinally applied field modulation on a two-level system using superconducting quantum circuits. The presence of the modulation results in additional transitions and changes the magnitude of the resonance peak in the energy spectrum of the qubit. In particular, when the amplitude ,λz and the frequency COl of the modulation field meet certain conditions, the resonance peak of the qubit disappears. Using this effect, we further demonstrate that the longitudinal field modulation of the Xmon qubit coupled to a one-dimensional transmission line could be used to dynamically control the transmission of single-photon level coherent resonance microwave.

A High-Performance Silicon Electro-Optic Phase Modulator with a Triple MOS Capacitor

We propose and analyze a novel Si-based electro-optic modulator with an improved metal-oxide-semiconductor （MOS） capacitor configuration integrated into silicon-on-insulator （SOl）. Three gate-oxide layers embedded in the silicon waveguide constitute a triple MOS capacitor structure, which boosts the modulation efficiency compared with a single MOS capacitor. The simulation results demonstrate that the Vπ Lπ product is 2. 4V · cm. The rise time and fall time of the proposed device are calculated to be 80 and 40ps from the transient response curve, respectively,indicating a bandwidth of 8GHz. The phase shift efficiency and bandwidth can be enhanced by rib width scaling.

DySnake-YOLO:改进的YOLOv9c电路板表面缺陷检测方法

针对印刷电路板生产时出现缺孔、开路、短路、毛刺和假铜等缺陷,由于缺陷尺寸微小和背景的相似性等问题造成的检测精度低,提出一种改进YOLOv9的电路板表面缺陷检测算法DySnake-YOLO。在特征提取部分,添加了一种动态的、查询感知的稀疏注意力机制BRA,来对印刷电路板的特征进行细粒度的提取。在特征融合部分设计了一种根据管状目标以适应电路板特性,以及关注区域连通性特征适合管状场景的RE4DConv卷积模块,提升了模型融合印刷电路板中的管状尺度特征的能力。通过在北京大学公开的PCB缺陷数据集上进行实验表明,改进后的算法相较于原型,mAP50提高了0.023,与YOLOv8n等主流目标检测算法相比,改进方法在mAP50、mAP50-95方面分别提升了0.071、0.085,在印刷电路板缺陷检测任务上的有着较高的应用价值。

Analysis and design of sigma-delta interface circuit for quartz flexural pendulum accelerometer

For the high resolution required in a digital interface circuit of an accelerometer used in feeble gravity measurement, a switched-capacitor （SC） sigma-delta modulator （SDM） is proposed. Based on the principle and the topology structure of the SDMs, the influence of oversampling ratio, bits of an internal quantizer and the cascaded structure on weak signal detecting precision is analyzed, and an ideal low-distortion SDM with a second-order 1-bit structure satisfying the high- resolution interface circuit of an accelerometer is designed. With the research on non-idealities of each SDM block in the SC circuit implementation and their impacts on power consumption, the realized parameters of low-power SDMs based on different bandwidths are devised and the power consumption of each SDM is estimated. Time-domain behavioral simulation is explored based on Simulink. The results demonstrate that a 21- bit resolution of the designed SDMs can be achieved on the premise of low power, and the parameters for the circuit implementation can be directed to the transistor-level circuit design.

TCM100型轨道电路改造方案

[目的]TCM100型轨道电路在我国首次应用于深圳地铁4号线和广州地铁8号线。在设备维保初期发现,原TCM(轨道电路模块)组的供电方式存在一定弊端,更换单个TCM将影响多个轨道区段的功能与显示,且更换TCM时设备故障频发,有必要对TCM100型轨道电路进行改造。[方法]通过对TCM100型轨道电路中的TCM组研究,指出了西门子股份公司提供的《TCM维护手册》以及TCM供电方式设计中存在的问题,并提出了一种TCM100型轨道电路改造方案。依托某车辆段试车线,对改造后的TCM100型轨道电路进行了TCM更换试验。[结果及结论]TCM100型轨道电路的改造方案如下:将原正极线所接的单个万可接线端子替换为3个带空气开关的万可接线端子,分别控制3个TCM的正极供电,负极供电不做变更,从而实现单个模块的独立供电。TCM更换试验确定了最优的更换方式,证明了该型轨道电路改造方案的有效性。

单片机的16×16动态扫描LED点阵模块设计

为实现静态字符和滚动字符的显示,本文设计了一个16×16单色点阵显示模块。采用4片8×8单色点阵模块构成16×16点阵模块,并使用Altium Designer进行电路原理图和印刷电路板的整体设计。控制系统基于51单片机最小系统,显示程序在Keil C51环境中编写,芯片选用74HC595和74HC138。该模块设计整体工作量较小,设计过程有益于锻炼实际动手能力以及提高分析问题和解决问题的能力。

基于电子执行模块场联信号异常关闭问题的解决方案

场联信号是车站2个场间安全高效行车作业的重要保证。将场联继电电路升级为电子执行模块后,应确保两场间敌对照查、邻场信号状态、接近预告等联锁信息的可靠传输。在场联信号设备升级工程分阶段实施过程中,存在已替换的电子执行模块与其余既有场联继电电路结合不匹配问题,导致场间作业过程中,因某些照查继电器短时落下造成出场信号异常关闭。结合实际案例,对现场数据和场联电路设计图进行分析,找出问题的直接原因。通过深入分析电子执行模块的处理逻辑,对比继电电路和电子执行模块在正负电转换过程中无电状态持续时间的差异性,提出相应的解决方案,包括优化电子执行模块处理逻辑、改进场联继电电路。该方案在具体工程项目中得到实际应用,取得较好的实施效果。

FPGA-based high resolution DPWM control circuit

Two improved structures of high resolution digital pulse width modulator(DPWM) control circuit are proposed. Embedded digital clock manager(DCM) blocks and digital programmable delay circuits are employed as the basic resources to construct the field-programmable gate array(FPGA)-based DPWM implementations. Detailed schemes are illustrated and the circuits have been successfully implemented on the Artix-7 FPGA device developed by Xilinx. Experimental results show that when the basic clock operates at the frequency of 200 MHz, the resolutions of the two approaches can reach 625 ps and 500 ps, respectively. Besides,the presented schemes possess other merits including flexible resolution, strong versatility and relatively good stability.

Hybrid material integration in silicon photonic integrated circuits

Hybrid integration ofⅢ-Ⅴand ferroelectric materials is being broadly adopted to enhance functionalities in silicon photonic integrated circuits(PICs).Bonding and transfer printing have been the popular approaches for integration of III–V gain media with silicon PICs.Similar approaches are also being considered for ferroelectrics to enable larger RF modulation bandwidths,higher linearity,lower optical loss integrated optical modulators on chip.In this paper,we review existing integration strategies ofⅢ-Ⅴmaterials and present a route towards hybrid integration of bothⅢ-Ⅴand ferroelectrics on the same chip.We show that adiabatic transformation of the optical mode between hybrid ferroelectric and silicon sections enables efficient transfer of optical modal energies for maximum overlap of the optical mode with the ferroelectric media,similar to approaches adopted to maximize optical overlap with the gain section,thereby reducing lasing thresholds for hybridⅢ-Ⅴintegration with silicon PICs.Preliminary designs are presented to enable a foundry compatible hybrid integration route of diverse functionalities on silicon PICs.

Design of 150kV bouncer modulator

The 150 kV bouncer modulator is designed to drive the 10 MW multi-beam klystron for the DESYTESLA Test Facility. The modulator is different from the 10 kV modulators previously built at Fermilab. First, thenew 150 kV bouncer modulator has no transformer, so the modulator circuit is simplified and the output waveform isimproved well. Second, the bouncer circuit has been changed to fit the output need, which is the most significantchallenge. This paper gives the design of the 150 kV long pulse bouncer modulator.

Simulation calculation of 24kV long pulse TESLA modulator

A 24 kV long pulse modulator is designed for DESY’s TESLA Test Facility (TTF). This modulator, with a 120 kV, 1.7 ms width pulse output, is used to drive a Thomson TH1801 multibeam klystron. In order to make waveform flatness of the klystron voltage less than ±0.5%, it is necessary to use a bouncer circuit. This paper gives the Pspice simulation results of the 24 kV long pulse TESLA modulator.

Lightwave Modulation Techniques for Advanced Modulation Formats

Arbitrary waveform can be synthesized by two orthogonal components: in-phase and quadrature components. Thus, if we can manipulate the two components independently, various complicated modulation can be achieved. This technique is called vector modulation, which is commonly used in wireless radio communication systems where the carrier frequency is lower than 100GHz. On the other hand, in lightwave transmission systems, the carrier frequency is higher than 100THz, and the stability of the signal sources would be much poorer than in radio systems, so that the simplest modulation format (on-off-keying) was often used in commercial systems. However, recently, various modulation techniques such as quadrature amplitude modulation, etc., have been demonstrated by using precise and rapid lightwave control. In this report, we review recent progress in optical vector modulation technologies which can generate highspeed and complicated optical signals. Integrated optical modulators can synthesize multi-level signals in photonic circuits.

Model Reduction by Generalized Falk Method for Efficient Dedicated to Professor Karl Stark Pister for his 95th birthday Field-Circuit Simulations

The Generalized Falk Method(GFM)for coordinate transformation,together with two model-reduction strategies based on this method,are presented for efficient coupled field-circuit simulations.Each model-reduction strategy is based on a decision to retain specific linearly-independent vectors,called trial vectors,to construct a vector basis for coordinate transformation.The reduced-order models are guaranteed to be stable and passive since the GFM is a congruence transformation of originally symmetric positive definite systems.We also show that,unlike the Pade-via-Lanczos(PVL)method,the GFM does not generate unstable positive poles while reducing the order´of circuit problems.Further,the proposed GFM is also faster when compared to methods of the type Lanczos(or Krylov)that are already widely used in circuit simulations for electrothermal and electromagnetic problems.The concept of response participation factors is introduced for the selection of the trial vectors in the proposed model-reduction methods.Further,we present methods to develop simple equivalent circuit networks for the field component of the overall field-circuit system.The implementation of these equivalent circuit networks in circuit simulators is discussed.With the proposed model-reduction strategies,significant improvement on the efficiency of the generalized Falk method is illustrated for coupled field-circuit problems.

Efficient evanescent coupling design for GeSi electro-absorption modulator

Efficient coupling from the silicon waveguide to the GeSi layer is the key to success in the GeSi electro-absorption （EA） modulator based on evanescent coupling. A lateral taper in the upper GeSi layer has room for increasing the modulating efficiency and alleviating the sensitivity of the extinction ratio （ER） and insertion loss （IL） to the length of the active region. The light behavior and the effect of the taper are explored in detail using the beam propagation method （BPM）. After optimization, the light can nearly be totally confined in the GeSi layer without any oscillation. The modulator with the designed taper can achieve low IL and high ER.

Micro capacitance detection circuit for MEMS capacitive sensor

With the development of micro-electr o-mechanical system(MEMS) technolog y,the MEMS-based capacitive sensor has been widely applied in the field of ele ctron components.However,the capacitance of the micromachined sensor is so sma ll that the detection of the smaller value change of the capacitance is a great challenge.Based on the principle of charging and discharging of the capacitor,a kind of pulse width modulated differential circuit is introduced in this paper.For subsequent amplification,a modified amplifier is presented.The different ial circuit converts the weak capacitance change to the change of the pulse widt h of the output voltage,and the linear relationship can be obtained.And the mo dified amplifier implements the processes of amplification and filtering synchro nously,and a large DC output voltage can be obtained by the lo w-pass filter.T he designed circuits have advantages as simplified circuit,high voltage stabili ty,perfect linearity and resolution.Besides,it is feasible to be integrated w ith the sensor to largely reduce the transmission error and interference.

Measurement and Characterization of Microwave Interaction between Integrated Distributed Feedback Laser Diode and Electro-Absorption Modulator

Integrated electro-absorption-modulated distributed feedback laser diodes(EMLs)are attracting much interest in optical communications for the advantages of a compact structure,low power consumption,and high-speed modulation.In integrated EML,the microwave interaction between the distributed feedback laser diode(DFB-LD)and the electro-absorption modulator(EAM)has a nonnegligible influence on the modulation performance,especially at the high-frequency region.In this paper,integrated EML was investigated as a three-port network with two electrical inputs and a single optical output,where the scattering matrix of the integrated device was theoretically deduced and experimentally measured.Based on the theoretical model and the measured data,the microwave equivalent circuit model of the integrated device was established,from which the microwave interaction between DFB-LD and EAM was successfully extracted.The results reveal that the microwave interaction within integrated EML contains both the electrical isolation and optical coupling.The electrical isolation is bidirectional while the optical coupling is directional,which aggravates the microwave interaction in the direction from DFB-LD to EAM.