A Prototype of beam position and phase measurement electronics for the LINAC in ADS

This article presents a prototype of beam position and phase measurement(BPPM)electronics designed for the LINAC in China Accelerator Driven Sub-critical system(ADS).The signals received from the Beam Position Monitor(BPM)detectors are narrow pulses with a repetition frequency of 162.5 MHz and a dynamic range more than40 dB.Based on the high-speed high-resolution Analog-to-Digital conversion technique,the input RF signals are directly converted to In-phase and Quadrature-phase(IQ)streams through under-sampling,which simplifies both the analog and digital processing circuits.All signal processing is integrated in one single FPGA,in which real-time beam position,phase and current can be obtained.A series of simulations and tests have been conducted to evaluate the performance.Initial test results indicate that this prototype achieves a phase resolution better than 0.1 degree and a position resolution better than 20μm over a 40 dB dynamic range with the bandwidth of 780 kHz,which is well beyond the application requirements.

Design and Application of Software for Generating Simulated Signal Data

Simulated signal, produced by digital to analog converter, is important and necessary in many fields, such as electronic experiment, equipment debugging and maintenance, especially, in medical area. In this paper, the design and application of an effective software which may be used to generate simulated signal data by special wave picture obtained by scanner or drawing software are presented. First, we introduce how to realize producing needed data that meet the given conditions including amplitude, samples and resolution by this software. Second, the method and steps of getting the stimulated signal data from wave figure file is given. Third, an example of application about this software to generate simulated physiological signal data is shown. Then, the data are put into use and by digital to analog converter, an idea stimulated signal is produced. Therefore, with full confidence, we could draw a conclusion that it is very convenient and effective to get needed data for digital to analog conversion to generate all kinds simulated signal with a novel method.

Hardware Implementation and System Control Strategy of Videoconference System Based on Rec. H. 261

The design and realization of a videoconference system based on international recommendation are introduced in this paper, and the hardware implementation of video codec based on ITU-T H. 261 is briefly discussed. Furthermore, the buffer control method and the adaptive control strategy for quantization are proposed, which are adaptive and robust. This system can be operated under the transmission rate ranging from 128kb/s to 2Mb/s. With these strategies for the videoconference system, the high quality image is obtained. The time delay of the system is about half a second.

A Novel Device for Real-Time Monitoring of High Frequency Phenomena in CENELEC PLC Band

This paper proposes the design and development of a novel, portable and low-cost intelligent electronic device (IED) for real-time monitoring of high frequency phenomena in CENELEC PLC band. A high speed floating-point digital signal processor (DSP) along with 4 MSPS analog-to-digital converter (ADC) is used to develop the intelligent electronic device. An optimized algorithm to process the analog signal in real-time and to extract the meaningful result using signal processing techniques has been implemented on the device. A laboratory environment has setup with all the necessary equipment including the development of the load model to evaluate the performance of the IED. Smart meter and concentrator is also connected to the low voltage (LV) network to monitor the PLC communication using the IED. The device has been tested in the laboratory and it has produced very promising results for time domain as well as frequency domain analysis. Those results imply that the IED is fully capable of monitoring high frequency disturbances in CENELEC PLC band.

6-DOF磁悬浮轴承同步数据采集系统设计

以6自由度磁悬浮定位平台控制系统为研究对象,结合被控对象的实际特点,在平面磁悬浮平台(PAMB)数学模型的基础上,介绍了一种用于磁悬浮轴承实时控制的数据采集与处理系统。采用DSP作为主控单元,对传感器信号高速采集。由于A/D集成在DSP内部,可以对两路信号精确同步采样。对数据进行运算后,实现D/A转换输出控制电压信号。控制软件采用JTAG接口下载到DSP的内部闪存。为了方便实时改写参数,还设计了DSP与计算机通讯接口。仿真结果表明,这种控制方案有较好的动态和静态特性。

低分辨率ADC下MIMO-OFDM系统中的广义Turbo信号检测

针对高分辨率模数转换器(analog-to-digital converter, ADC)接收机给大规模多输入多输出(multiple input multiple output, MIMO)系统带来的硬件成本昂贵和高功耗问题,研究了低分辨率ADC在毫米波MIMO正交频分复用(orthogonal frequency division multiplexing, OFDM)量化系统中的应用方案。通过将单输入单输出(single input single output, SISO)量化系统中的广义Turbo信号检测算法推广到MIMO-OFDM量化系统,实现了该算法的低复杂度实现方案。在4×32 MIMO-OFDM系统中,当误比特率为10^(-3)时,GTurbo算法与广义近似消息传递(generalized approximate message passing, GAMP)算法相比能得到约3 dB的性能增益。仿真表明,与GAMP算法相比,所提算法更适用于大规模天线阵列系统。

OFDM系统中高性能帧同步算法

提出了正交频分复用(OFDM)系统中一种新的帧同步算法.该算法采用一种具有中心对称结构的训练序列.借助于该训练序列,新算法在信噪比为10dB且误报概率为10-3的环境下具有10-3的训练序列漏检概率.在实现时间同步的同时,载波频偏也可以被纠正到0.5倍的子载波间隔范围内.

Position Sensorless Control for Permanent Magnet Synchronous Motor Using Sliding Mode Observer

An approach of position sensorless control for permanent magnet synchronous motor （ PMSM ） is put forward based on a sliding mode observer. The mathematical model of PMSM in a stationary αβ reference frame is adopted, and the system is controlled by the digital signal processor （ DSP; TMS320LF2407 according to the control achieve closed loop operation of the motor, the stator theory of sliding mode observer. In order to magnetic field should be vertical with the rotor magnetic field and be synchronous with rotor rotating, so the position and speed of PMSM is estimated in real time and the estimated position is modified continuously. The simulation results indicate that the proposed observer has high precision is more robust to the parametric variation and load in estimation of PMSM position and speed, and torque disturbance.

Development of readout electronics for bunch arrival-time monitor system at SXFEL

A bunch arrival-time monitor(BAM) system,based on electro-optical intensity modulation scheme, is under study at Shanghai Soft X-ray Free Electron Laser.The aim of the study is to achieve high-precision time measurement for minimizing bunch fluctuations. A readout electronics is developed to fulfill the requirements of the BAM system. The readout electronics is mainly composed of a signal conditioning circuit, field-programmable gate array(FPGA), mezzanine card(FMC150), and powerful FPGA carrier board. The signal conditioning circuit converts the laser pulses into electrical pulse signals using a photodiode. Thereafter, it performs splitting and low-noise amplification to achieve the best voltage sampling performance of the dual-channel analog-to-digital converter(ADC) in FMC150. The FMC150 ADC daughter card includes a 14-bit 250 Msps dual-channel high-speed ADC,a clock configuration, and a management module. The powerful FPGA carrier board is a commercial high-performance Xilinx Kintex-7 FPGA evaluation board. To achieve clock and data alignment for ADC data capture at a high sampling rate, we used ISERDES, IDELAY, and dedicated carry-in resources in the Kintex-7 FPGA. This paper presents a detailed development of the readout electronics in the BAM system and its performance.

基于霍尔效应的位置传感系统设计

磁敏位置传感系统广泛应用于汽车、高端装备和先进制造等领域中。文中设计了一种基于霍尔效应的位置传感系统,可以实现被测物旋转角度的检测。该系统通过由线性霍尔芯片和磁铁组成的传感模块获取旋转角度信息,经信号调理电路处理后由12 bit ADC采样转换为数字信号,FPGA读取数据并采用拟合、标准化等算法校准,再利用Cordic算法计算得到被测物旋转角度,最后通过串口屏将测量结果显示。测试结果表明该位置传感系统精度较高,测得的旋转角度误差小于2°。

基于FPGA的高精度振动采集传输系统

为了满足某飞行器飞行过程中不同部位振动监测的需求,完成多路振动信号实时采集,论文提出一种基于FPGA的高精度振动采集传输系统设计方案。首先设计调理电路,将传感器输出的电荷信号调理至采集范围内。其次,使用模拟开关对14路采集通道进行切换,使用16bit高精度ADC实现模数转换。最后,利用FPGA控制整个采集传输过程,将数字量编帧、打包、缓存,并通过以太网接口将采集数据发送至防护存储器进行数据存储。测试表明,数据可靠性高,在单路采样率为20kSPS、测量范围为±2000g时,振动信号的采集精度可达到±0.5%。

基于FPGA的X射线平板探测器信号采集系统设计

针对传统工业X射线平板探测器噪声高和像素低的问题,利用非晶硅薄膜晶体管(TFT)平板、亚德诺半导体(ADI)成熟的模数转换(ADC)芯片、奇景光电(Himax)公司的驱动模块和现场可编程门阵列(FPGA)设计了一种3072×3072像素的X射线平板探测器信号采集系统。本项目以ZYNQ7020为核心处理器进行电路设计,并实现FPGA的综合布局布线、仿真和调试,该系统在FPGA的控制信号作用下,实现了驱动模块控制TFT的开关、模拟前端(AFE)同时并行采集3072个通道的电荷信号,经过去噪、放大以及AD转换后数据在一个低压差分信号(LVDS)接口串行输出,最终成功得到采集信号,验证了系统的功能,可以为研究X射线探测器提供一种设计思路。

基于Simulink的匹配滤波器设计与实验

针对匹配滤波器教学内容中缺乏相关课程实验与实现的教学环节,基于Simulink仿真平台搭建了二进制确知数字信号的匹配滤波型最佳接收机架构,并采用了四种传输函数进行对比验证。这一实验教学活动的引入有助于增强教学内容的趣味性,激发学生的学习热情,使原本抽象且枯燥的知识点变得具体、生动形象,提升了学生对匹配滤波器原理的理解与应用能力。

基于MCS-51的高精度信号发生器设计与仿真验证

本文设计的信号发生器以MCS-51单片机为核心,辅助以按键电路、显示电路、数模转换电路,能够发出三角波、正弦波、方波、锯齿波四种波形。通过引入DAC0823芯片,将数字量和模拟量进行转换,使得信号发生器发出的波形的误差和噪声干扰更小,并简化了滤波过程。仿真过程中通过软件程序控制硬件电路,利用Keil仿真平台的元器件仿真功能和程序编辑功能将程序搭建好,然后一同放入Proteus仿真平台中,通过后者的元器件选择和参数调节功能将信号发生器的主控电路搭建完成。最后,利用模拟示波器得到了满足设计要求的波形,验证了信号发生器的性能。

电子纺织品用纺织信号传输线的研究进展

归纳现有纺织信号传输线的研究现状,介绍不同信号用纺织传输线及其制备方法,概述现阶段有关传输线在不同环境条件中的性能研究,总结其未来发展趋势,以期为今后研发可穿戴设备用纺织信号传输线提供方向。

用于低相干干涉测量系统的多通道数字与模拟信号同步采集方法研究

在现代工程领域中,模拟信号和数字信号同步采集的重要性变得越来越显著。同步采集这两种类型的信号可以提高数据采集和处理的准确性、可靠性,并避免数据延迟、抖动等问题,尤其对于一些特定应用场景具有极高的必要性。为了适应低相干干涉测量系统中多类型多路信号的同步采集与处理需求,基于已有的数据采集仪,设计并制作了数字信号调理板,并通过实验验证了数字信号与模拟信号的同步采集情况。实验结果表明:所设计的系统不仅可以实现两种信号的高速同步采集,而且系统整体位移采集的精度很高:电动位移台在0~70 mm行程内,系统测量值与干涉仪测量值最大误差为2.52μm;压电位移台在0~320μm内,系统测量值与干涉仪测量值最大误差仅为0.54μm。

强噪环境下分频段数字音频信号精细化采集研究

在强噪环境下,为了获取高质量、低失真度的数字音频信号,提出一种强噪环境下分频段数字音频信号精细化采集方法。通过麦克风设备获取音频信号,利用LM4550芯片对其作采样、编码等处理后生成数字音频信号,基于AC-97单元接收数字音频信号,利用频段分割器对其作频带分解,获得互不重叠子频段数字音频信号。采用多窗谱谱减法对其去噪,利用数据通信接口将其传输给LM4550芯片,在完成模拟信号转换后,通过耳机输出,实现数字音频信号精细化采集。实验结果表明,该方法处理后的各子频段数字音频信号有用信息得以完整保留,并提高了信号波形的规整度和规律性,强噪声环境下数字音频信号的PESQ指标达到4.08以上,最大失真度为3.74%。

一种具有纹波消除技术的10 bit SAR ADC

逐次逼近寄存器模数转换器(SAR ADC)在逐次逼近的过程中,电容的切换会使参考电压上出现参考纹波噪声,该噪声会影响比较器的判定,进而输出错误的比较结果。针对该问题,基于CMOS 0.5μm工艺,设计了一种具有纹波消除技术的10 bit SAR ADC。通过增加纹波至比较器输入端的额外路径,将参考纹波满摆幅输入至比较器中;同时设计了消除数模转换器(DAC)模块,对参考纹波进行采样和输入,通过反转纹波噪声的极性,消除参考纹波对ADC输出的影响。该设计将信噪比(SNR)提高到56.75 dB,将有效位数(ENOB)提升到9.14 bit,将积分非线性(INL)从-1~5 LSB降低到-0.2~0.3 LSB,将微分非线性(DNL)从-3~4 LSB降低到-0.5~0.5 LSB。

数字广播电视信号多路复用技术研究

深入探讨多路复用技术在数字广播电视信号传输中的应用及其优势与挑战。概述多路复用技术的基本原理及其在数字广播电视信号传输中的具体应用,详细分析多路复用技术存在的问题和挑战,提出相应的技术建议,旨在为广播电视行业的技术进步和信号传输优化提供理论支持和实践指导。

数字信号处理中的模拟信号恢复技术研究

数字信号能采用理想的低通滤波器,将其重新恢复到模拟信号。从时域角度来看,整个恢复过程是从无限多离散点和单位平移的内插函数相乘求和的过程。基于此,文中通过阐述数字信号处理中模拟信号恢复技术的基本原理,分析了常见的信号恢复方法,并将模拟信号恢复技术应用到各行业,充分发挥了模拟信号恢复技术的作用,提高了其应用效果。