登录

双语推荐：瞬态信号

进入期刊文章
针对高频地波雷达中出现的瞬态干扰问题，提出了基于S变换（Stockwell transforms）的瞬态干扰抑制方法．首先分析了两次FFT信号处理机制下瞬态干扰的时频特征；然后应用s变换对雷达信号进行时频分析，利用瞬态干扰在时频维扩展性不同的特点，实现瞬态干扰的检测；最后应用三层BP（Back Propagation）神经网络对海洋回波信号进行预测和恢复．该方法避免了海杂波抑制的步骤，具有计算量小、信号损失小的优点．现场实测数据分析表明，该方法能够有效抑制瞬态干扰，使回波多普勒谱信噪比提高达10dB，有效提高了雷达的抗干扰能力．
A new method based on S tansforms is proposed to suppress instantaneous interference for high frequency surface wave radar (HFSWR ) application .The characteristics of instantaneous interference in time and Doppler domain were discussed within the twice-FFT signal processing framework ;then S transforms was applied to outline the characteristics of instantaneous inter-ference in time-frequency domain for interference detection and excision ;finally ,BP neural network was used to recover the sea e-cho signals .Experiment results show that the anti-interference ability is enhanced by this method ,and the SNR of Doppler spectrum is improved for about 10dB .

[ 可能符合您检索需要的词汇 ]

进入期刊文章
利用开机瞬态特征对蓝牙传输设备进行射频指纹识别时,开机瞬态信号的捕获与提取存在一定的局限性。为此,提出将频率跳变瞬态特征用于蓝牙设备的唯一性鉴别,以克服开机瞬态特征的局限性。在射频指纹识别中的数据获取、瞬态信号检测、指纹提取和分类过程中对该特征进行验证,根据实验数据对鉴别性能进行评估。分析结果表明,利用频率跳变瞬态特征能够成功鉴别蓝牙设备。以对虫洞攻击的检测和防御为例,进一步分析射频指纹识别在蓝牙网络安全协议中的应用,并给出基于蓝牙指纹识别的安全链路管理协议。
It is limitary to classify the radio devices by utilizing the turn-on transients character, when the turn-on transient signals are captured and extracted. Aiming at this problem, this paper investigates Frequency Hopping(FH) transients character which can be used to classify the bluetooth devices alike the Turn-on Transients(TOT) character but get rid of the limitation which the RFF based TOT character has. The FHT-Character based on the Radio Frequency Fingerprinting(RFF) process is validated, which includes data acquisition, transient detection, radio frequency fingerprint extraction, and classification subsystems. A classification performance of the identification system is evaluated from experimental data. It is demonstrated that the FHT character can be used to classify the bluetooth devices successfully. It further analyzes the implications of device fingerprinting on the security of bluetooth networking protocols which is illustrated by the example of the detection and combat fo

[ 可能符合您检索需要的词汇 ]

进入期刊文章
针对高速旋转机械转子发生早期动静碰摩故障时主要为转子工频成份及转子与支撑间碰摩所致瞬态冲击信号成份,据可调品质因子小波变换对信号品质因子定义为转子工频成份为高品质因子信号、转子动静碰摩所致瞬态冲击信号为低品质因子信号,分别构建高、低品质因子小波变换基函数实现转子早期动静碰摩信号工频成份与瞬态冲击成份有效分离,对碰摩故障进行模式识别。通过仿真信号及转子碰摩实验信号验证可调品质因子小波变换在转子早期碰摩故障诊断中的有效性。
When an early rub-impact occurs in a rotor system,its vibration signal is mainly composed of a periodic component with rotor rotating frequency and transient impulse signal components caused by rub-impact between the rotor and bearings.The periodic component with rotor rotating frequency can be defined as a signal with a higher Q-Factor and the transient impulse signal components can be defined as the signals with a lower Q-Factor based on the theory of tunable Q-Factor wavelet transformation.Here,two tunable Q-Factor wavelet transformation basis functions were constructed with a higher Q-Factor value and a lower Q-Factor value,respectively.An early rub-impact vibration signal was separated into two main components successfully using the constructed tunable Q-Factor wavelet transformation basis functions.At last, the feasibility and effectiveness of the tunable Q-Factor method for fault diagnosis of rub-impact in a rotor system were verified with simulations and tests.

[ 可能符合您检索需要的词汇 ]

进入期刊文章
瞬态温度测试技术，涉及传感器选取、远传模块设计、信号抗干扰远距离传输、测点布局和防护等诸多技术问题。介绍了瞬态温度测试技术的发展过程，密封容器内爆炸实验瞬态温度测试系统的配置，硬软件设计思路、实现过程和关键技术解决办法，实验的测点布局和防护装置设计，并应用测试系统首次取得了某项实验瞬态温度数据。
Transient temperature testing technology research of explosion experiment in airtight container includes the sensor selection, remote transmission module design,anti-interference signal long-distance transmission,measuring point layout and protection, and many other technical problems. The development of the transient temperature measurement technology, the configuration of transient temperature test system of explosion experiments in sealed containers,the hardware and software design concepts,implementation process and key technology solutions, the layout of measuring points and protection design are introduced. The testing system is applied to obtain an experimental transient temperature data successfully for the first time.

[ 可能符合您检索需要的词汇 ]

进入期刊文章
为实现低信噪比条件下的水声瞬态信号检测，该文提出子波检测和局部瞬时能量密度级双重降噪方法。该双重降噪方法通过自适应选取含有用信号的某阶固有模态函数(IMF)，计算Hilbert能量谱并进行局部积分，滤除子波检测残留下来的带外噪声。此外，结合宽度-包络联合检测机制，构造了水声瞬态信号局部瞬时能量密度检测器。湖试数据处理结果表明，局部瞬时能量密度检测器可有效降噪并在低信噪比条件下提取瞬态信号，较传统能量检测器具有更好的检测性能。
In order to detect acoustic transient signal at low SNR, a double noise reduction method of sub-wave detection and partial instantaneous energy density level is proposed. A certain order of Intrinsic Mode Function (IMF) containing useful signal is selected adaptively. Then Hilbert energy spectrum is calculated and integrated partially to filter out the residual out-off-band noise. In addition, an acoustic transient signal partial instantaneous energy density detector is established combined with width-envelope detection tactics. Lake trial data processing results show that the partial instantaneous energy density detector can reduce noise effectively and extract transient signal at low SNR. It has better performance than the traditional energy detector.

[ 可能符合您检索需要的词汇 ]

进入期刊文章
针对单次爆炸加速度随机瞬态信号的高速采样存在信号完整记录与大量冗余数据相矛盾的问题,提出了一种采用负延迟和变频采样为手段的瞬态信号低冗余存储方法。该方法采用负延迟分区域存储减少随机瞬态信号高速采样中出现的大量冗余数据,利用变频采样实现测试仪的低功耗。仿真实验表明:负延迟分区域存储方法有效地减少了随机触发前的冗余数据,变频采样的策略降低了系统功耗,在保证有效数据完整记录的同时实现了数据的低冗余存储,为存储测试仪器的微型化提供了一种有效途径。
The single explosive acceleration stochastic transient signal being with the problem that a large num-ber of redundant data was recorded except besides full records of high-speed sampling signal.a kind of negative delay and low frequency sampling by means of the transient signal redundant storage method was put forward in this paper.The method adopted the negative storage areas to reduce the random delay transient signal in high-speed sampling of a large number of redundant data,and used variable frequency sampling tester to reduce power consumption.Simulation results showed that the negative delay storage areas method could effectively reduce the redundant data before random trigger.The power consumption of the system was reduced by the frequency sam-pling strategy.

[ 可能符合您检索需要的词汇 ]

进入期刊文章
为解决当前瞬态高温测试中存在的测试系统对瞬态高温参数信号响应速度慢、动态特性不足、设备布设及装置回收不便等问题，综合运用无线通信技术、数据采集与缓冲技术和存储测试技术，设计了一种通用一体化瞬态高温智能存储测试系统。该系统可用于特殊测试环境下瞬态高温参数的测试，并实时记录存储测试数据和处理结果。设计了基于蓝宝石黑体平面的瞬态高温敏感体、数据处理存储模块和无线模块，并将瞬态高温敏感体、数据处理存储模块和无线模块进行一体化设计。通过ZigBee模块对系统进行参数设置（上、下电、触发电平、测量范围等），使用AVR单片机和FPGA为主控芯片，解决了特殊测试环境下瞬态高温参数的测试采集问题。实际测试结果表明，该瞬态高温智能存储测试系统可准确获得被测温度场瞬态高温参数，具有无线遥控、微功耗、高精度、抗高冲击、抗干扰、微型化、工作稳定和可靠性高等特点，适于恶劣测试环境下瞬态高温参数的测试和记录。
Aimed at the problems of the slow response speed of the transient high temperature parameter signal, the inadequacy of the dynamic characteristics of the test system, the inconwenience of the equipment layout of the test system and the recycle of the test device in the current transient high temperature testing,the incorporate intelligent test system for transient high temperature,which is universal and multi-channel,was designed based on the wireless communication technology,the data acquisition and buffer technology and the storage test technology. The system can be used for transient temperature parameter test in special testing environment,and the real-time record storage of the test data and the processing results. The transient high temperature sensitive body was designed based on the sapphire plane blackbody,the data storage and processing modules and the wireless communication modules were also designed. What is more, an integrated design was made. Adopting the ZigBee

[ 可能符合您检索需要的词汇 ]

进入期刊文章
利用外场瞬态振动时间历程数据获得能量谱包络,借鉴振动台控制理论中随机信号产生原理获得具有包络能量谱幅值特性以及典型外场试验数据相位信息的时域波形,并用振动台波形再现的方式进行产品瞬态振动环境试验;该方法为今后直接使用能量谱控制的瞬态振动振动台试验方法提供技术支撑.
This paper used outfield transient vibration time history to gain ESD envelope ;used random signal replication method in vibrator control theory to gain ESD amplitude time history and used vibrator time waveform replication method to take transient vibration test.This method provides technology support for vibrator ESD di-rect control test method.

[ 可能符合您检索需要的词汇 ]

进入期刊文章
为解决常用数字化计数测量信号瞬态噪声和短期稳定度精度不高的问题，采用创新的相位重合检测技术来测量频率源的瞬态稳定度。多个不同分辨率的重合检测线路的状态可以转换成为相位起伏的幅度信息。测量的分辨率取决于重合检测电路的不稳定性。实验中采用的标准信号是超高稳定度晶体振荡器，被测信号分别为高稳定度的晶体振荡器和指标明显差的恒温晶体振荡器，利用相位重合检测技术均能够正确反映出实际稳定度情况。频率源的瞬态稳定度的测量对于频率源实时短期不稳定度以及远端相位噪声的描述具有重要的作用。
In order to solve measurement of transient noise and short-term stability of signals by conventional digital counting methods is not only difficult but also low in accuracy.So we introduce a novel phase coincidence detection technology which is an important detection method,and our group has worked on it for decades to measure the frequency source transient stability.According to the results of multiple phase coincidence detection circuits which are combined as a coincidence detection array,the detailed phase variation can be obtained.The measurement resolution depends on the stability of the coincidence detection circuit.In our experiment,the standard signal is a super-high stability crystal oscillator,measured signals are from the high stability crystal oscillator and OCXO whose parameters are significantly worse.Using the phase coincidence detection technique is able to properly reflect the actual stability situation.The measurement of transient stability of the frequency source pla

[ 可能符合您检索需要的词汇 ]

进入期刊文章
基于瞬态微波光电导少子寿命测试仪和MATLAB编程研究了确定硅片的复合中心浓度和陷阱中心浓度的方法。利用瞬态微波光电导少子寿命测试仪，我们测量了硅片的少子寿命及微波光电导瞬态电压信号随时间的变化特性。根据已知的注入水平和相关复合参数，建立少子寿命与复合中心浓度的关系，我们得到硅片中的复合中心浓度。利用瞬态电压信号的时间变化特性与非平衡载流子浓度的时间衰减特性的关系，我们得到非平衡载流子浓度随时间的衰减曲线。结合非平衡载流子时间衰减特性曲线和陷阱模型表达式，利用MATLAB软件进行数值拟合得到了硅片的陷阱中心浓度。
By using transient microwave photo -conductance technique and MATLAB software , we investigated the method of determining density of recombination centers and trapping centers .We measured the lifetime of minority carriers in silicon and the changing of microwave photo -conductance transient voltage with time .Based on the injection level and related parameters of recom-bination centers, we established the relationship of minority carriers ’ lifetime and recombination centers ’ density, and then obtained the density of recombination centers .Based on the relation between the changing of transient voltage and the decaying of minority carriers’ density, we obtained the decay curves of minority carriers ’ density with time.Based on the decay curves of minority carri-ers’ density with time and trapping model , we obtained the density of trapping centers by the usage of numerical fitting via MATLAB software .

[ 可能符合您检索需要的词汇 ]