中心频率

SAR成像系统中多普勒中心频率fD和模糊数m的估计

Estimation of Doppler Center Frequency f_D and Blur Number m in SAR Imaging System

分数阶Fourier变换对多分量Chirp信号中心频率的分辨能力

Resolution Ability of Fractional Fourier Transform in Multi-component Chirp Signal Center Frequency

一种中心频率可调节的高Q值微机械带通滤波器初探

Central Frequency Adjustable High Q Value Micromechanical Band Pass Filter

星载SAR的多普勒中心频率估计的新探索

A new study for the Doppler centroid frequency estimate from the SAR echoes

分布式小卫星多中心频率SAR实现宽域二维高分辨率成像

Using Multi-central Frequency Distributed Small Satellite SAR to Achieve Wide Swath and Two Dimensional High Resolution

探讨了同步轨道SAR多普勒中心频率和调频率的特征。

The properties of Doppler centroid frequency and Doppler frequency rate of GEO SAR is discussed in detail .

基于上述公式，分析了地球同步轨道SAR多普勒中心频率与低轨SAR的联系；

Based on these formulas , the relation of Doppler centroid frequency between GEO SAR and LEO SAR is analyzed .

通过引脚编程，可任意改变f0及Q值，实现中心频率的连续调节和数字显示。

By pin programming f0 and Q can be changed , The center frequency can be also stage-less selected with digital display .

重点阐述了多普勒中心频率fD的3种估计方法，并通过编程予以实现。

Then three methods for estimation of Doppler central frequency f_D are presented .

利用半经典理论分析方法分析具有不同中心频率的三束激光脉冲与物质相互作用的CARS过程。

The CARS course , in which three beams of laser pulse with different frequencies are used , is analyzed by using half-classic theoretical analysis .

在合成孔径雷达（SAR）成像的斜视模式下，多普勒中心频率估计往往会出现重频（PRF）模糊。

In squint mode of SAR imaging , doppler centroid estimation always suffers from the PRF ambiguity .

通过在地板上的矩形槽的边缘开槽和在馈线旁加载C形谐振器，该天线实现在中心频率3。

By inserting a slot at the edge of the rectangular slot on the ground plane and loading a C-shaped resonator near the microstrip line , dual band-notched characteristic at the central frequency at3 .

在无参考点海洋SAR定位方法中，多普勒中心频率估计对定位精度有着重要的影响。

Estimation of Doppler central frequency has an important effect to accuracy of fixed position in the fixing approach with no reference points for ocean SAR .

就模式识别中特征提取和分类决策两个阶段进行了研究.在特征提取方面，提供了一种用于提取图像不同中心频率和方位特征的Gabor滤波器组的设计方法；

A method for designing Gabor filter banks with various frequencies and orientations was proposed to perform feature extraction .

由于SAW器件具有频率选择性及较高的插入损耗，使得它的输入必须为高脉冲且脉冲的频谱宽度能覆盖SAW抽头延迟线的中心频率。

Due to the frequency selectivity and high insertion loss of SAW device , the input must be high pulse whose spectrum width can cover the center frequency of SAW tap delay line .

关于多中心频率FSK信号解调的探讨

Demodulator of FSK Signal with Multi-Center-Frequency

本文首先从SAR系统需要解决的问题入手，简要概述了形成匹配滤波的参考函数的关键参数多普勒中心频率的估计方法，以及用于估计残余相差的相位梯度自聚焦算法（PGA）；

At first , the estimate methods of Doppler Centroid frequency and Phase gradient auto-focus algorithm ( PGA ) for SAR are discussed .

两组对照组豚鼠不经声预处理，分别直接暴露在中心频率0.5KHz和1KHz110dB的信频带噪声下，暴露1h。

Two control groups received 0.5 kHz and 1 kHz OBN respectively at 110 dB for 1 h without prior sound conditioning .

所提电路结构简单、中心频率ω0和品质因数Q独立可调、无源元件全部接地，滤波器特性参数对无源元件灵敏度低。

The proposed circuits are with simple structure , seperately adjustable centre frequency ω 0 and the quality factor Q , all grounded passive components and low passive sensitivities .

该电路包括了用DDS产生的中心频率发生器、5对低通滤波器、20个乘法器和一个加法器。

This circuit include DDS which generate central frequency , five pair of low pass filter , 20 multipliers , and an adder .

但是在一些实时谱分析中，往往只需要N点DFT中的某一中心频率附近的部分频谱，同时要求较少的计算量。

However , there are real-time applications that require spectrum analysis only over a subset of the N center frequencies of an N-point DFT , and require fewer computations .

窄带噪声也有音调，其高低决定于通带中心频率f，清晰程度则和带宽B有关。

A narrow band noise gives a definite pitch , the height of which depends on its central frequency ( f ) and the brightness or tonality on its band width ( B ) .

通过该方案，可以得到应用DS扩频技术进行卫星重叠通信时DS扩频信号中心频率位置选择、带宽设置和给定条件下的可实现的最大重叠容量。

Applying the project the center frequency position , bandwidth and maximum capacity under given conditions were got . Also the computer simulations were done .

△W是角频率与中心频率的偏离值。基因频率：指某一特殊类型的等位基因在群体中所有等位基因总数中所占的比率。

△ W is the radian frequency deviation from the center frequency . Gene frequency The proportion of an allele in a population in relation to other alleles of the same gene .

本文提出了一种基于时频分析的多普勒中心频率估计方法，并给出了处理仿真及ERS－1实测数据的结果。

A new method of Doppler centroid estimation based on time frequency distribution is presented in this paper .

对具有不同函数形式、中心频率和波峰数的信号激励，结构中传播的Lamb波模式进行试验研究，为激励信号的选择与优化提供依据。

The Lamb wave propagating modes are experimentally analyzed under the different excitation signal parameters that include the function forms , center frequencies and wave peak number .

因为SAW器件的中心频率决定着检测气体的灵敏度，SAW器件的插损数值的大小关系着器件能否起振；检测电路又关系到传感器的精度和稳定度。

Since the center frequency of SAW device determines the sensitivity of detecting gas , the insert loss of SAW device relates to whether the device can start-up ; detection circuit relates to the sensor accuracy and stability .

这种滤波器很重要的优点是，可以很方便地通过外加电压控制滤波器的中心频率（ωo）和带宽（BW）。

Especially , the center frequency (ω 0 ) and bandwidth ( BW ) can be conveniently tuned by the external voltages .

分析了成形滤波器对载波频率估计算法的影响，并针对基于循环谱法的载波频率估计算法只适用于大于接收机中心频率的载波频率这一缺陷，提出了基于复数FFT的循环谱载波频率估计算法。

As the estimation algorithm of carrier frequency based on cyclic spectrum is only suitable for nonzero frequency , the new method which is based on complex power spectrum is proposed .

介质厚度的变化对Y孔中心频率、带宽的影响要比Y环单元FSS的大得多。

The center frequency and bandwidth of Y-aperture are much more influenced by the substrate thickness change than those of Y-loop element FSS .