查询词典 signal

Extract information based on the instantaneous features : In the center is one of the instantaneous rate of the power spectral density of the maximum, is a center to the absolute value of the instantaneous rate of the standard deviation, Non-zero weak signal instantaneous phase of the nonlinear component absolute standard deviation, Non-zero weak signal instantaneous phase of the nonlinear component standard deviation, In the center is one of the non-weak signal of the absolute value of the instantaneous frequency standard deviation, a signal to one of the instantaneous frequency of the power spectral density of the maximum, According to 16QAM and QPSK signals XI axis projection in the different performance parameters raised.

提取信号七个基于瞬时信息的特征：零中心归一化瞬时幅度功率谱密度的最大值，零中心归一化瞬时幅度绝对值的标准偏差，零中心非弱信号段瞬时相位非线性分量绝对值标准偏差，零中心非弱信号段瞬时相位非线性分量标准偏差，零中心归一化的非弱信号段瞬时频率绝对值的标准偏差，一个信号段的归一化瞬时频率功率谱密度的最大值，根据信号 QPSK 和16QAM在 XI 轴投影的不同表现，提出特征参数。

Then the digital audio signal is set into segments and DWT is performed. Finally the modulated signal is embedded in the coefficients with relatively large absolute value on middle frequency range detail signal adaptively. The original digital audio signal is necessary when detecting the watermark.

在应用扩频技术的算法中，首先将视觉上可辨的二值水印图像降维为一维序列，再将一维水印序列伪随机排序并与m序列作扩频调制，最后对数字音频信号进行分段离散小波变换，把经过调制的水印信息自适应地嵌入到原音频信号小波分解中等尺度绝对值较大的分量上。

But, in the natural and artificial signal, a lot of signal phases don\'tvary linearly with time, for example, we usually use chirp signal in the radar technology,frequency step signal, linear modulation component of the ground echo in the SARtechnology, linear modulation component of the moving target echo, linear modulationcomponent while the airborn radar detecting the moving target, etc.

在自然界和人工信号中，许多信号的相位变化并不是随时间一次方变化，如雷达技术中常用的线性调频信号，频率步进信号，另外，SAR 技术中，地面回波所含有的线性调频分量，ISAR技术中，运动目标的回波所含有的线性调频分量，机载雷达探测运动目标时的线性调频分量，等等；傅里叶变换对此类信号分析所得的结果是信号在不同频率点上的能量分布，即信号在基函数上的投影。

First it produces the pulse signal by the multivibratorwhich is consisted of 555 timer and send in the detecting coil to form the alternating magnetic field, then it asopts UGN3503 linear half-effect as prode to the magnetic field change into the voltage signal change,after enlargement electric circuit and peak value examination electric circuit,the signal be treated to send into ADC0809 modulus converter change moduluses, then the digital signal after the modulus converter is changed is sent into AT89C51one-chip computers afterwards, after the digital filter, AT89C51one-chip computers afterwards compares the data to the reference voltage and judges whether to have detected the metal and alarm.

这个系统是以AT89C51单片机为核心，首先由555定时器构成多谐振荡器产生脉冲信号送入探测线圈以形成交变磁场，然后经过线性霍尔器件UGN3503将磁场变化转换为电压信号的变化，经过放大电路和峰值检测电路，经数模转换之后输入到单片机中，由单片机对数据进行软件滤波之后，与基准值比较之后，判断是否存在金属和报警显示。

The holistic design of the system and resolved the designs of software and hardware based on VXI bus are put forward according to the demand of test system. The hardware and software is designed, including the formation and design of hardware system, visual instrument software architecture, program design for instrument driver, high speed real-time data collection. In the dynamic test program, the idea of"software is instrument"was applied to meet the diverse test demands. Last, it is proposed that the VXI test system be developed to more totalization and networked. The basic theory of system identification was introduced briefly at first. The principle of spectrum analysis system identification based on Wiener-Hopf equation was expatiated. and the questions in applying Peusdo Random signal as spectrum analysis methods stimulate signal was studied, The generation principle of the peusdo random signal is researched, the characteristic of peusdo random are analyzed from time domain and frequency domain, the inverse repeat peusdo random signal is brought forward to make up the shortage of ordinary peusdo random signal. And a new chaos genetic algorithmis presented to solve the unprecise problem of the traditional method. In the servo valve dynamic characteristic test system, the spectrum analysis methods was applied successfully, the servo valve dynamic characteristic could be acquired rapidly and exactly, the test results were analyzed and the ameliorate methods were brought forward at last.

结合航天某集团液压测试中心测试系统的需求，提出了基于VXI总线的液压测试系统的整体设计方案，完成了测试系统的硬件设计与软件设计，包括硬件系统构成与设计、虚拟仪器软件结构、仪器驱动程序设计、高速同步实时数据采集等内容；以伺服阀动态特性测试为例设计了测试模块，该模块体现了VXI总线仪器软件开发所倡导的&虚拟仪器&的思想，以软件的灵活应用满足了不同的测试需求；结合自动测试系统的发展，研究了VXI测试系统与网络技术结合，实现各种软硬件资源共享，进一步提高设备及数据的利用率和系统的扩展性，使自动测试向综合化、网络化方向发展；研究了伪随机信号作为谱分析法辨识的激励信号时存在的问题，讨论了伪随机信号的产生机理，从频域和时域分析了伪随机信号的性质及其应用，提出了用逆重复伪随机信号弥补了普通伪随机信号的不足，并以混沌遗传算法对逆重复伪随机信号产生过程中的参数进行优化，可以更合理而不是凭经验产生需要的逆重复伪随机信号。

The experimental results show the validness of the mechanism analyses.2. According to the generation mechanism of the leak acoustic signal, the characteristics of the leak acoustic signal are investigated. The auto correlation technology is adopted to descript the leak signal characteristics due to the ability to analyze the coherence of time series. A new procedure to identify the leak acoustic signal from the disturbed noises is proposed based on the conjunction of correlation and approximate entropy algorithm.3. The principle and application in leak location of the correlation and the adaptive filter techniques are introduced. The problems of the traditional leak location methods are analyzed.4. In order to establish the leak detection signal model, the leak acoustic propagation characteristics are investigated experimentally.

从泄漏声产生机理出发，分析了管道泄漏处湍流拟序结构与空泡间相互作用的机理，认为在该机理作用下，泄漏声信号产生过程具有&不可重复&的特征；由于相关函数具有分析时间序列拟序结构的能力，且近似熵从统计的角度区别时间过程的复杂性，因此，提出将信号相关分析和近似熵理论相结合的方法，提取泄漏声信号&不可重复&的特征，辨识管道泄漏故障发生；在实际检测现场，由于各种管内和管外固定声源噪声(如阀门噪声、工地施工噪声等)常导致泄漏误判和漏点定位错误，重点分析了管内固定噪声源的产生机理和特征，为复杂干扰环境下的泄漏辨识提供理论支持。

The method includes following steps:(1) initial frequency selection;(2) based on modulation mode adopted, the sending end carries out symbol mapping, changes signal spectrum based on label information of sub channel, and sends signal in time domain;(3) based on label information of sub channel, the receiving end carries out equalization for received signal, demodulates signal and accomplishes judgment;(4) carrying out channel estimation or prediction, the receiving end obtains updated information of signal state, and determines whether label information of sub channel is needed to update based on self-adapting judgment rule.

本发明提供了一种移动宽带信道中的自适应选频分块传输方法，该方法包括以下步骤：(1)初始选频；(2)发端根据所采用的调制方式进行符号映射，根据子信道标记信息改变信号频谱，并发送时域信号；(3)收端根据子信道标记信息对接收信号进行均衡，解调信号并完成判决；(4)收端进行信道估计或预测得到更新的信道状态信息，根据自适应判断规则，判断是否需要更新子信道标记信息。

There was significant difference in signal intensity between the cell concentration group and unlabelled cell group during 2 weeks. And significant difference occurred in the 5×105 SPIO-labeled cells per milliliter medium group and unlabelled cell group during 3 weeks.3. In kidneys of ischemia-reperfusion injury,the labeled BMSCs were demonstrated as signal intensity loss in renal medulla on T2*WI sequence in days 1,3,and5.The signal intensity loss was visualized up to 8 days after transplantation,and the signal intensity in the third day was the lowest. Histological analyses showed that most Prussian blue staining-positive cells were well correlated with the area where a signal intensity loss was observed in MRI.

在此细胞浓度的基础上，标记后细胞信号在T2*WI序列的降低在2w后失去统计学意义；而在细胞浓度为5×105/ml时，标记3w后信号在T2*WI序列的降低才失去统计学意义。3缺血再灌注肾损伤家兔细胞移植后第1、3、5天肾脏髓质区信号强度明显下降，至移植后第8天信号改变不明显，其中第3天信号改变最为明显；组织学分析见绝大多数普鲁士蓝染阳性标记细胞分布于肾小管周围，与MRI信号强度下降区域基本一致。

Based advanced controlling strategy now, self-adapting fuzzy PID controller is designed. Simulated with MATLAB/Simulink, system responses tracking step signal, square wave signal, sine signal, triangle signal and saw tooth signal are reproduced.

2结合当前先进的控制策略，针对电液伺服控制径向柱塞变量泵，设计了自适应模糊PID控制器，并通过计算机仿真，再现了系统跟踪阶跃信号、方波信号、正弦波信号、三角波信号、锯齿波信号时的系统响应。

In addition, there are two strands of the head is also black, and are rust, rust can be seen because of lead wire resistance increases, resulting in the signal can not be smooth, telephone through the audio signal, the low band signal can also only phone, there is always the voice of flap, and the use of the ADSL band signal is relatively high, head through the rust on it is very difficult, leading to slow or stop signal transmission.

此外有两处绞合的线头处也发黑了，都是锈，可见正是因为导线生锈导致电阻增大，导致信号不能畅通，电话通过的音频信号，频带低，信号还能通过，只是电话里老是有啪啪的声音，而ADSL的信号使用的频带比较高，线头生锈了就很难通过，导致信号传输变慢或者断流。

Neither the killing of Mr Zarqawi nor any breakthrough on the political front will stop the insurgency and the fratricidal murders in their tracks.

在对危险的南部地区访问时，他斥责什叶派民兵领导人对中央集权的挑衅行为。

In fact,I've got him on the satellite mobile right now.

实际上 我们已接通卫星可视电话了