查询词典 spectral density

This thesis is composed of two sections in which we discuss generalized spectral density test of conditional autoregressive heteroscedasticity for threshold autoregressive model.

本文分两节对门限自回归模型中自回归条件异方差的广义谱密度检验进行了讨论。

The system has realized signal generator, signal"s sampling and averaging function, signal"s power spectral density and cross special density analysis, the design and application of digital filter, signal analysis in time, frequency and inverted frequency domain.

实现了波形发生器的设计、信号采集及平均处理、滤波器的设计及应用、信号的时域、频域以及倒频域分析。

By adopting relationship in frequency domain coherence analysis method is presented on the thesis for conventional fMRI and resting-state fMRI. Otherwise I use cross spectral density function in the coherence analysis method to discuss the phase delay and phase lead.

本篇论文采用同调性分析的方法探讨频率上相关性的方法研究一般功能性影像与平静状态功能性的影像并藉由同调性分析里交互频谱密度函数来研究信号之间相位差的问题。

The main job and contribution of this paper are as follows:Based on narrowband signal processing, we propose a new method for FH signal blind detection and blind parameter estimation. Firstly, compute the cross-correlation function of FH signals from multichannels, then we get the cross power spectral density matrixCSDM Secondly, select the hops of FH signals from the CSDM via processing and analyzing the CSDM, meanwhile reduce the influence coming from noise, fixed frequency signal and other interferences; Lastly, estimating the DOA of every hop and according to the DOA, we can separate the hops, get the number of FH signals and their parameters. Propose a new method for designing the threshold in FH signal detection. This method makes it easy to get the threshold by theoretic computing and it can extremely reduce the interference of non-FH signals.Based on broadband signal processing, we propose a new method for FH signal blind detection and blind parameter estimation. Firstly, get the DOA of the signals by wideband spatial spectrum estimation; secondly, separate the signals by spatial filtering using wideband beamformer; Lastly, we propose two methods for FH signal blind detection and blind parameter estimation, one is for several constant hop-rate FH signals whose dwell-time are different and another is for a single FH signal whose hop-rate is alterable.By employing spatial interpolation in broadband signal beamforming, it can reduce the number of antenna elements and corresponding RF modules, A/D converters, etc. It can also eliminate the mutual coupling between antenna elements while getting the narrower main beamwidth and lower sidelobe level.

本文的主要研究工作和贡献如下：●提出了一种基于窄带处理的FH信号盲检测和参数盲估计的实现方法，即首先求出多路信号之间的互相关，进而得到互功率谱密度矩阵，然后通过对CSDM进行对折处理来抑制噪声、定频信号及其他干扰的影响，并将所有属于FH信号的hop(每一跳的驻留时间在时频图上持续的线段)从CSDM中筛选出来，最后用阵列信号处理中的到达方向估计理论在频域中估计出各个hop的方向参数，利用方位信息完成FH信号分离并得到FH信号的数目及其各自的参数集；●提出了一种确定FH信号检测门限的策略，该策略不仅使得检测门限能够通过理论计算得到，而且还显著地抑制了非跳频信号的干扰，从而能有效地检测出FH信号；●提出了一种基于宽带处理的短波FH信号盲检测和参数盲估计的实现方法，即首先利用宽带空间谱测向技术得到接收信号的DOA，然后采用宽带波束形成技术对特定方向进行空间滤波，实现多个信号的分离，最后分别提出了两种FH信号的盲检测和参数盲估计方法，第一种方法适用于空间某个特定方向上存在着几个驻留时间不同的恒跳速FH信号和其他干扰信号的混合信号，第二种方法适用于空间某个特定方向上仅含一个可变跳速的FH信号和噪声的混合信号；●将空间插值的概念和宽带波束形成技术结合起来，提出了一种基于频域处理的宽带恒定束宽的波束形成方法。

Based on the spectral density function,an efficient and practical method of wind loading simulation is presented.

1引言随着现代材料、施工技术以及设计理论的发展，出现了越来越多柔性的、自重轻、阻尼小的建筑物。

One way is point operation of an image and another is power spectral density function.

经过这些处理，使雷达图像质量较处理前有了很大提高。

A whole reference spectral density matrix is established in multiple shaker random vibration test.

多振动台随机振动实验中必须设置完整的参考谱矩阵。

Then, the matrix product of them determined the pressure fluctuations＇power spectral density function matrix .

实验还证实了单个气栓内部瞬时压力的均匀性和料栓内部空隙率的不变性。

In the method, the probability density function of a stochastic process is described from the spectral density function of the stochastic process.

根据S。 O。 Rice对随机过程峰的一维概率分布的研究方法，扩展到对随机过程峰的联合概率密度的分析。

In the method,the probability density function of a stochastic process is described from the spectral density function of the stochastic process.S.O.

根据S.O.Rice对随机过程峰的一维概率分布的研究方法，扩展到对随机过程峰的联合概率密度的分析。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。