相位调制

Taking the reflective phase hologram grating as an example, the spectral properties of the gratings were analyzed, for recording material with refractivity modulated in the convex curve and concave curve, by the coupled-wave theory.

以反射相位型全息光栅为例，用耦合波理论分析计算了记录介质折射率调制为上凸型和下凹型调制曲线的体全息图的衍射光谱特性。

To improve the bandwidth and power efficiency of conventional QPSK signal, the continuous phase QPSK is proposed.

针对导致传统QPSK信号带宽效率和功率效率低的相位跳变问题，提出了连续相位QPSK， CPQPSK调制。

The results show the temporal pulse shape modulation is affected by the broadening factor and the delay time, as spectrum modulation is only affected by the delay time, and the intensity factor changes similarly with the cosine function of the phase factor.

研究结果表明，时间调制与基元脉冲的展宽量及相邻脉冲之间的延迟时间有关，光谱调制只与相邻脉冲之间的延迟时间有关，而强度的演化则与相位因子的余弦函数演化具有一定的相似性。

In this paper,a design method of two dimensional Linear Phase Nearly Perfect Reconstruction filter banks based on a new class of cosine modulation systems is presented,which can be described as follow: firstly,the Parks-McClellan algorithm is adopted for designing the prototype filter,then by employing cosine modulation,a series of analysis and synthesis filters can be obtained,accordingly a one-dimensional LP-NPR filter banks can be constructed;Secondly,cascading two one-dimensional LP-NPR filter banks in the form of tree structure and using the unimodular transformation,a two dimensional nonseparable LP-NPR filter banks can be obtained.

提出了一种基于一类新余弦调制系统的二维线性相位-近似完全重构滤波器组的设计方法，设计过程分为两个步骤：首先采用Parks-McClellan算法来计原型滤波器，再经过余弦调制能到一系列的线性相位分析和综合滤波器，从而可以构造一维LP-NPR滤波器组；然后利用树状结构来结合两个一维LP-NPR滤波器组，并运用单位模变换，可以得到二维不可分离LP-NPR滤波器组。

It can get the three-dimensional profile of the object surface effectively. Because of the cragginess of the three-dimensional surface when sine grating is projected the image of the sine grating is modulated and the modulated image is taken by a CCD camera with an angel compared to projecting direction. After the phase shift measuring method, the phase is gotten. Because the phase is calculated by the phase shift measuring ranges from –π to +π it isn't continuous. The phase unwrapping is necessary to recover the continuous phase about the object shape.

这种方法采用结构光照明，将正弦光栅图像投影到被测物体表面，用与投影方向成一定角度的CCD摄像机获取受物体表面面形调制的变形光栅像，根据数字相移算法计算出相位分布，由于从相移计算的相位被截断在反三角函数的主值范围内，因而是不连续的，必须通过相位展开恢复出连续相位分布，由相位－高度关系最终求出物体轮廓的三维数据信息。

After compensation of continuous motion of the platform and time difference between upslope and downslope signals for imaging, the moving target can be detected through displaced phase center antenna technology.

提出了一种利用三角波调制调频连续波进行地面高速运动目标检测的新方法，根据三角波调制调频连续波正、负调频导致动目标成像结果在径向反向移动的特点，通过对正、负调频信号分别成像，在补偿了载机平台的连续运动以及正、负调频信号之间的时间差对图像的影响后，将两幅图像通过偏置相位中心天线处理，检测出高速动目标。

ABSTRACT Continuous phase coded modulation is an important research field of the modern digital modulation technique.

相位连续编码调制是现代数字调制技术中的一个重要研究领域。

Similar to DFT modulated filter banks, the filter banks have a simple polyphase structure.

类似于DFT调制滤波器组，2M通道交替DFT调制滤波器组具有简单的多相位结构。

Chapter 4 discusses the maximum likelihood sequence estimation for CPM on the multipath channels, advances the adaptive MLSE technique for CPM on unknown multipath channels, and establishes the mathematical model and the realization way of adaptive equalization on time－variant and time－unvariant multipath channels.

第四章分析推导了多径信道下相位连续调制信号的最大似然估计问题，结合作者近几年对自适应均衡技术的研究，提出了非确知多径信道下相位连续调制信号的自适应最大似然序列估计技术，建立了比较完整的恒参及时变信道下自适应均衡技术的数学模型和实现方法。

The liquid crystals molecular can be reorientated by means of two-beam coupling.

样品经过二波耦合实验之后液晶分子进行一定的取向，这时在水平和竖直偏振光的照射下可观察到明显的自相位调制现象。

We will see more and more activist government policies that distinguish economic activities according to the nationality of the actors.

我们将看到越来越多激进的政府政策，这些政策根据企业的国籍来区分经济活动。

If we can prove the independence of an axiomatic system, then we can guarantee the conciseness of this system, ie.

如果能够证明某个一阶谓词系统的独立性，那么就能够保证该系统的建立是精炼的，即没有任何一条公理或推理规则是多余的。