基于FPGA的AMC信号处理卡的设计与实现

国内外早期,探测器装置的数据传输系统普遍采用并行总线架构,如VME、PXI总线等。随着核物理实验的发展,数据的传输速度不断提高,并行总线难以提速的弊端逐渐显现,总线速度不够导致数据无法通过背板传输。本工作采用基于MicroTCA(Micro Telecom Computing Architecture)架构设计一种新型先进的数据传输AMC(Advanced Mezzanine Card)信号处理卡。该AMC信号处理卡的背板总线使用在速度提升方面有着巨大优势的高速PCIe串行总线。通过测试验证,整个传输链路传输功能正确,链路传输的光纤误码率低于7.62×10^-15,传输速度也接近理论的极值,达到了430 MB/s。最后,该AMC信号处理卡与前端电子学进行了联测,验证了系统的正确性。     

磁共振成像系统中的自动梯度预加重调节方法研究

提出了一种利用核磁共振信号测量梯度涡流,然后通过拟合、迭代程序快速找到最佳预加重参数的方法．该方法通过预先寻找信号区,确保了测得数据的可靠性,实现了梯度预加重参数的自动设置,可在大约10 min内得到较好的补偿效果．通过在OPM35I型低场磁共振系统中的具体实验,证明该方法简单、有效．     

一种自适应前向均衡与判决均衡组合结构及变步长改进算法

信号在超长线缆传输中, 线缆的线间串扰及温度梯度变化造成噪声干扰, 特别是线缆介电损耗和肌肤效应的影响, 导致接收端信号频率色散失真严重, 难以恢复原始信号, 限制了传输速度. 另外, 在页岩气、煤层气等资源勘探领域, 在用长缆传输数据时, 还要求传输高精度同步脉冲信号, 用于采集数据相位的标定. 线缆的传输效应及噪声干扰严重影响了接收端的信号同步, 造成采集数据相位失真. 本文针对信号在长缆传输中的非线性失真及衰减问题, 提出了一种新型均衡结构, 并针对新模型给出了最优系数组合. 在此基础上针对改进的结构提出了一种基于反正切函数的变步长算法, 该算法配合三误差因子, 形成收敛函数, 该函数具有收敛速度快, 稳态误差小的优点. 改进后的自适应组合均衡器计算复杂度低, 收敛快, 信道跟踪能力强, 加快了数据处理速度, 同时能较好地应对信道的时变性. 仿真结果表明, 基于新变步长算法的自适应组合均衡器, 性能上提高了50%, 并且消除了噪声干扰和码间干扰, 测试实验表明, 在无中继超长缆(7 km以上)传输中, 信号速度提高了一倍.     

USB3.0接口在数据存储系统中的应用

USB3.0的传输速率最快可达5Gbps,因此,为实现大量数据的快速稳定传输,介绍了一种以FPGA为控制核心,DDR2 SDRAM为高速大容量缓存,USB3.0为记录器与计算机进行数据通信接口的高速数据传输系统,通过模块硬件电路及软件协议实现了数据的高可靠性稳定传输,解决了大容量记录器的数据传输速度瓶颈。经长期试验证明：该接口传输速度可稳定到达150M/s,且数据可靠无误,满足任务设计要求。     

结构简单的D波段矢量毫米波信号产生的方法

提出一种新的基于单个强度调制器的D波段矢量毫米波产生方法.研究基于强度调制器,通过预编码技术,产生了八倍频D波段矢量毫米波信号,信号经过一定距离的无线传输之后输入接收端,最后对信号进行解调和误码分析.该方法具有一定的中心载波抑制功能,在无光学滤波器下成功传输了信号,降低了光载无线系统的链路成本.实验验证了152 GHz...     

大功率四极管调制器的嵌入式控制设计

提出了一种大功率四极管调制器的嵌入式反馈控制系统的设计方法。该系统以DSP为控制核心,采用闭环反馈控制,开发了大功率四极管的高压端控制器,并在系统反馈信号传输中采用一种新的改进型VF光纤隔离传输方案,提高了反馈信号的传输速度。实验结果表明,该嵌入式反馈控制系统简化了HL-2A装置原有的系统,极大地提高了系统响应速度,改善了四极管输出性能,且工作可靠稳定。     

�����ļ��ܵ�������Ƕ��ʽ�������

提出了一种大功率四极管调制器的嵌入式反馈控制系统的设计方法。该系统以DSP为控制核心,采用闭环反馈控制,开发了大功率四极管的高压端控制器,并在系统反馈信号传输中采用一种新的改进型VF光纤隔离传输方案,提高了反馈信号的传输速度。实验结果表明,该嵌入式反馈控制系统简化了HL-2A装置原有的系统,极大地提高了系统响应速度,改善了四极管输出性能,且工作可靠稳定。     

一种多通道高速数据采集系统软件北大核心CSCD

多通道高速数据采集软件面临:被测信号多样化,通道设置及管理难度大;传输数据并发量大,传输稳定性和瞬时传输速度要求高;测量数据量大,后处理及速度快;实验数据重要性高,测试软件必须稳定可靠的挑战。软件采用模块化+图形化设计,使用SCPI命令对设备及通道进行设置;测试了75台示波器同时上传数据的传输速度;对比了LabVIEW波形显示和GDI+波形绘制的区别;完成了上位机故障情况下数据获取功能设计。结果表明:该数据采集软件可完成75台示波器的管理,实现300通道数据的上传、处理、显示、存储。100 kpts存储深度300通道数据上传时间为9.7 s,300通道波形刷新时间为0.91 s。     

基于USB3.0 主模式高速接口卡设计

针对现行USB2.0接口已不能满足现代大容量数据高速度传输需求,提出一种基于USB3.0和FPGA的高速传输的解决方案。该方案通过配置可编程接口把EZ-USB FX3设置成master主模式,优化DMA数据传输通道,实现了电脑与接口卡之间数据高速传输。文章详细地介绍如何提高传输速度的方法,经实际传输测试,该接口卡能在传输速率高达350Mbyte/s依然能保持正确无误的高速传输。     

辐射驱动实验中预热对冲击波速度诊断的影响

使用主动式任意反射面速度干涉仪进行了平面靶预热膨胀量的观测,并对间接驱动下不同能量和靶型的预热膨胀量进行了计算。实验发现,在5kJ单端驱动的激光能量作用下,平面样品后界面的膨胀量可达2.1μm左右。优化靶设计后,在冲击波速度测量实验中使用双端驱动方式,通过测量膨胀量修正台阶厚度,可以获得更加精确的动态台阶厚度值。结合精确获得的冲击波传输时间,在匀速传输的条件下可以获得高精度的冲击波传输速度值。该方法在辐射驱动超高压条件下具有很好的适用性,可以为状态方程实验提供高精度的冲击波速度数据。     

Multi-level quantization and blind equalization based direct transmission method of digital baseband signal

The direct transmission of digital baseband signals has practical significance in the field of Ethernet terminal connection, high-speed digital communication, data transmission of various types of information peripherals. The signal amplitude gradually decays while the transmission distance increases. Also the attenuation is proportional to the signal frequency, resulting in signal distortion and receiving error. It is a common method for digital baseband signal transmission to use pre-emphasis chip and equalizer chip to improve the transmission quality with a wide range of mature applications. This paper describes a new type of digital signal transmission method, as the receiver using analog-to-digital converter, instead of equalizer chip, to achieve the multi-level quantization of receiving time-domain data waveform. The waveform of the transmitted digital high and low level signal is sampled into multi-bit values. Then, the paper realizes adaptive frequency domain equalization based on soft threshold and makes use of multi-level quantization soft information for error correction. Error correcting code is mainly used to correct the error caused by the channel bandwidth limit, external noise or interference in the process of data transmission, so as to improve the stability and reliability of the transmission. The paper uses the two-stage error correcting codec system based on both Turbo and BCH coding, to achieve the high performance of Turbo code, and good characters of respond time and complexity. The transmitter outputs 12.5 MHz pseudo-random sequence through a 199.93 meter unshielded balanced twisted pair transmission medium. And the receiver circuit using a 62.5MSPS analog-to-digital converter over-samples the waveform to 8-level quantity. The output error of a 65536 bit pseudo-random sequence is less than 8 bits, and the error correction can be further improved by 8b-10b codec. Compared with the traditional pre-emphasis and balanced interface ICs connection, the method described in this article has the advantages of longer transmission distance, better flexibility and wider scope of use.     

中国散裂中子源反角白光中子源T0信号的精确扇出方法

反角白光中子源位于中国散裂中子源(CSNS),是以不同中子能量下的核数据测量为目标的大型物理实验装置,中子的能量是通过中子飞行时间(TOF)来获取的.实验中,将质子束流轰击钨靶的时刻作为TOF的起始时刻(T0),相应的电子学信号被用于触发整个电子学系统的运行.为了保证TOF测量的准确性和电子学系统各通道采集的同步性,需...     

一种光纤通信系统中非线性克尔效应抑制新方法

本文从非线性薛定鄂方程出发,提出了一种全光学的相位预加重来抑制非线性克尔效应的新方法,通过在发射端将输入光脉冲的初始相位上叠加一个平方相位值,改变光脉冲的初始相位值,从而提高光脉冲在光纤传输中抗非线性克尔效应能力.通过理论研究,仿真分析以及实验验证了该方法的可行性,实验验证在接收端可以提高误码率2个数量级以上.在长距离大容量光纤通信系统中有很好的应用前景.     

多路串行数据光纤传输系统

提出一种适合于点-点或小局域间的中、长距离光纤(缆)传输系统。系统采用光纤(缆)作为传输媒介，因而具有抗电磁和核辐射等干扰能力，可应用于某些特殊的人工不宜到达的地理位置环境中；系统同时采用了单片机作串行数据的发射和接收，具有结构简单、可靠性高、数据处理能力强和串行波特率设置灵活等特点，能适应不同串行传输速率的需求，满足军用和民用的中、长距离的遥控及监控传输需求，应用前景广阔。     

A signal optimization strategy for next generation navigation and communication integration applications

For 6G and future communication technologies, integration of navigation and communication has become a hot research topic, which can greatly improve the transmission data rate and can be applied to self-driving vehicles. In former research, a novel integrated navigation and communication signal has been designed by combining traditional global navigation satellite system (GNSS) and cyclic code shift keying (CCSK) signals. In this paper, we design an enhancement strategy for this signal, optimizing the number of cyclic shifts of the CCSK signal, which can make larger values of cross-correlation function align with the peak value of self-correlation function to overcome the cross-correlation interference and improve communication performance. Simulation results validate that the proposal not only can avoid interference between navigation and communication signals, but also can improve the signal detection probability and reduce the transmit error rate. Taking Beidou B1I signal as an example, when the signal to noise ratio (SNR) is set to -27 dB, the detection probabilities for the navigation and communication signals increase about 11.4% and 13.5%, respectively, while the symbol error rate (SER) for the navigation and communication signals decrease about 16.3% and 17.8%, respectively.     

在低场MRI系统中用数字接收机测量梯度波形的方法

提出了一种用数字接收机来测量低场系统中梯度波形的方法,详细介绍了该数字接收机接收音频信号的原理,并且对接收机的音频接收性能进行了测试. 最后利用该接收机测得的梯度波形,设置了系统的预加重参数,有效地减小了梯度线圈引起的涡流.     

基于FPGA的快速脉冲数据采集及处理系统设计

为了提高脉冲信号多参数提取的准确性,从而更精确地表征细胞多种物理和生化特性,设计了基于FPGA 的快速脉冲数据采集与处理系统。首先,采用对时间窗口和幅值同时设定阈值的方法,有效避免了噪声对有效脉冲识别的影响;其次,采用FPGA实现数据采集、快速数字滤波、以及脉冲峰值、面积和脉宽三个参数的提取,并利用FPGA作为外部主控制器实现对USB芯片CY7C68013A内部FIFO的控制,实现脉冲数据的高速处理、传输;最后,对系统的可行性及准确性进行了实验。实验结果表明,本系统能够对脉冲信号进行有效实时识别和高准确度的参数提取,同时USB的数据传输速度可达29.8MB/S,满足系统数据传输的实时性要求。     

Influence of coding strategies in electric-acoustic hearing: A simulation dedicated to EAS cochlear implant,in the presence of noise

This work deals with electric-acoustic stimulation (EAS), which keeps the low frequency acoustic information and electrically codes the high frequencies of the signal. One of the goals of the coding strategies is to limit the phenomenon of channel interaction, which can occur in CIs. The “N-of-M” strategy, where only a subset of electrode channels is stimulated, may be of advantage. Generally, this processing is associated with a pre-emphasis filter. Two important parameters for the N-of-M strategy are the number of active channels (N) and the updating rate; the latter corresponds to the stimulation rate. M is the number of electrical channels.The goal of this study was to investigate the influence of these parameters on speech intelligibility in EAS. The signal was presented, in simulation, to normal-hearing (NH) subjects in acoustic (A), electric (E) and electric-acoustic conditions. Recognition performance was measured in quiet and in the presence of background noise (cafeteria noise).Signal-to-noise ratios (SNRs) ranged from 0 to +12 dB. Fifteen listeners participated in the experiment. The N values ranged from 2 to 10 (out of 10); M was 10. The frame updating rate was 250 updates per second (ups) and 1000 ups.Results showed that increasing N from 2 to 10 improved speech intelligibility, especially in the presence of the background noise, under E and EAS conditions. In noisy situations, 2/10 coupled with a high-pass pre-emphasis filter led to results similar to the 10/10 condition. Changing the frame rate from 250 ups to 1000 ups did not modify the performance.Future investigations on patients using EAS are now needed to validate the performance seen with NH listeners. Above all, in the strategy 2 out of 10, the number of pulses per second can be divided by 20, and when the pre-emphasis is used only a slight decrease in performance is expected; this is of interest when interaction between the electrodes corrupts the performance.     

光纤数据链路模拟器设计

为分析光纤制导导弹飞行中光纤信道变化情况,满足导弹动静态仿真需求,设计了一种能够模拟光纤数据链路传输损耗特性的装置。研究内容包括建立系统传输损耗的动态、静态模型。利用光模拟器实现导弹飞行中可能遇到的信道干扰、数据延迟、动态损耗等情况。实验结果表明,光信号干扰的变化范围达到-50 dBm～-40 dBm,光信号的传输延迟范围为16.65 s～99.9 s,模拟器动态损耗调整范围为0 dBm～50 dBm,可用于验证导弹光纤传输系统的性能。