查询词典 pulse amplitude modulation

The modulation that function of modulation of in-house AM, FM, PM, FSK makes the instrument can go to the lavatory is undee, and need not sole modulation source.

内部AM、FM、PM、FSK调制性能使仪器能够便利的调制波形，而无需零丁的调制源。

The paper investigates both block-type pilot linear minimum mean square error algorithm and IEEE802.16 OFDM channel estimation analysis. Simulation results confirm the block-type pilot structure is more suitable for IEEE802.16 system. An optimal pilot setting algorithm, based on space frequency domain, is explored and the pilot chart is presented. The proposed algorithm finds its application in MIMO-OFDM. Simulation results show the algorithm presents a good approximation to the perfect channel state information curve, with about 2dB difference in SNR. The simulation results also demonstrate the algorithm achieves fairly high stability in the environment of fast fading, performance of the proposed algorithm is better that of pilot training channel estimation.3. Taking into account the characteristics of IEEE802.16 OFDM system, OFDM system simulation platform is constructed in Matlab, exploiting simulink as a tool. OFDM modulation and demodulation simulation system are configured on LabVIEW platform. All the system signal processing is simulated, including defining system parameters, designing modulation model, and verifying all the proposed algorithms under different environments, such as white Gaussian noise, multi-path fading, with or without guard interval etc. Bit error performance is evaluated. The research provides valid theoretical basis for practical OFDM system performance evaluation.4. Taking advantage of software radio, the paper designs a hardware platform with both 256-IFFT/FFT and 512-IFFT/FFT OFDM schemes co-existing in one platform. You can predetermine one from the two schemes to carry out almost the same model function with different system performance and parameter setting.5. Referring to IEEE802.16 standard, the paper proposes a design method for generating signals and frames suitable for laboratory investigations implemented in laboratory environment.6. Based on 6701evm digital evaluation card, combined with analogy front-end, the paper designs a DSP software model to deal with baseband signal processing. An overall OFDM scheme, with modulation and demodulation function, is accomplished.

讨论分析了MIMO-OFDM中一种基于空频域的最优导频设置算法，给出了导频图案，通过仿真实验表明，该算法与理想的信道状态信息曲线非常接近，信噪比差距约在2dB左右，并且在快衰落条件下具有较好的稳定性，其性能要优于基于前导训练的信道估计方法。3、根据IEEE802.16OFDM系统特点，论文分别在Matlab中应用Simulink工具构建OFDM系统仿真平台、在LabVIEW平台上实现了OFDM调制解调仿真系统，模拟了整个系统的信号流程，进行了OFDM仿真系统参数的选择和调制模块的仿真设计、论证各算法性能，并根据各种不同的条件：例如高斯噪声、多径衰落、有无保护间隔等，对系统的误码特性进行了评估，为正确评价实际OFDM系统的性能提供了有效的理论依据。4、论文以软件无线电思想作为指导，提出了以256点IFFT／FFT为核心和以512点IFFT／FFT为核心的两种OFDM算法模式并存于同一个硬件平台、且可预选的方案，它们在参数选取和性能指标上有所差异，均实现了相似的模块和功能。5、论文参考IEEE 802.16无线网络标准的参数设置，针对本设计系统的应用环境和系统硬件的性能速率，提出了一种应用于实验室环境的信号结构、帧格式等参数设计。6、论文基于TI公司的6701evm数字评估板卡，结合模拟前端搭建数字中频平台，设计了基带处理的DSP软件模块并进行系统调试，基本实现了一套完整的OFDM调制解调方案。

In the last new years , as the demands of wireless communication system grows rapidly , the bands of microwave frequency had been saturated with various communication applications . To achieve wider spectrum for high-speed and high-capacity transmission , bands of millimeter-wave frequency are the solution of this problem . The advantage of MMW wireless communication systems is wider bandwidth comparing with microwave communication systems . To utilize the spectrum efficiently , many methods of complexly digital modulation is proposed . The more complex modulation , the higher linearity is required , and more various phase of signals are required to accomplish process of modulation . Therefore high-linearity and quadrature-phase modulator and demodulator are the emphasis of this thesis . For high level of integration , high performance and low cost , this chip is fabricated by the complementary oxide semi-conductor 0.13um process . A compact size of direct down-conversion and direct up conversion circuits will be presented in this thesis .

近年来随著无线通讯产业的蓬勃发展，微波频带已经趋近於饱和，为了追求更宽的频谱来达到更快传输速率及高资料容量的传输，宽频的毫米波频段提供了解决此问题的途径，毫米波无线通讯系统提供了相对於微波通讯系统宽频的优点，且为了更有效的使用频谱，各种不同且复杂的数位调变方式及方法被发表出来，越复杂的调变方式其所需的线性度越高，且需要更多不同的相位讯号来完成调变的过程，因此高线性度及四相位的调变及解调器将是此篇论文的研究重点，为了达到高整合性，高效能，及低成本的电路设计，我门利用互补式金氧半导体制程来完成此电路设计，因此一小面积的直接降频(Direct down-conversion)及直接升频(direct up-conversion)电路将在文中介绍。

Amplitude modulation: The form of modulation.

调幅：调制的一种形式。

Frequency modulation minimizes noise and provides greater fidelity than amplitude modulation, which is the older method of broadcasting.

调频最大程度的减小噪音，并且比调幅的保真度高，调幅是一种较老的传播方法。

The results show that the change of modulation period and modulation depth affect the period of soliton interaction and the difference of relative amplitude barely affects period of soliton interaction. In particular the lattice soliton interaction is effectively avoided by opposite phase soliton.

结果表明：调制周期和调制深度的变化影响了格子孤子相互作用的周期大小，而相对振幅的差异对孤子相互作用的周期影响较小，特别是反相孤子能够有效控制格子孤子的相互作用。

Based on radar backscatter theory and scatter point model,aimed at the same frequency vibration scatter point of radar target,radar echo universal model is derived and the periodicity of amplitude modulation function and phase modulation function is researched at length.

基于雷达后向散射理论和散射点模型，针对雷达目标的同频振动散射点，详细推导并建立了雷达回波通用模型，对其幅度调制函数和相位调制函数的周期性进行了详细的讨论。

At last,simulation research is carried out on radar echo of two same frequency vibration scatter points.Theoretical annlysis and simulation result indicate that the model is effective and that the periodicity of amplitude modulation function and phase modulation function is invariable as the number of scatter points increased,but,their amplitudes are variational.

最后对两个同频振动散射点合成雷达回波进行了计算机仿真研究，理论分析和仿真结果表明，该模型是有效的，并且随着同频振动散射点数的增加，其幅度调制函数和相位调制函数的周期性不发生变化，只是它们的值会随着振动点数的增加而改变。

After studying the altering direction and amplitude modulation mechanism of this type of reversible vibratory plate compactor,this paper discusses the principle of altering direction ,modulating amplitude and adjusting speed.

研究了平板夯换向调幅机构的结构，在力学分析的基础上，阐述了这一机构调幅、调速和换向机理。

The validities of amplitude features and their extraction method suitable in high-frequency SAR image are analyzed when they are used in UWB SAR image. An extraction approach of amplitude feature based on target contour is presented, and the corresponding effective amplitude features are proposed. The old dihedral angle model is analyzed and improved. The approach of azimuthal feature extraction is proposed based on the conclusion of the improved dihedral angle model. The problems, which appear when the common change detection methods are used to extract the change feature based on ROI, are analyzed. And a robust and feasible extraction approach is presented.

分析了适于高频SAR图像的幅度特征及其提取方法用于UWB SAR图像时的有效性，提出了基于目标轮廓的幅度特征提取方法及相应的适用幅度特征；分析了已有二面角模型在建模过程中存在的问题并进行了改进建模，基于改进二面角模型结论提出了方位向特征提取方法；分析了常用变化检测方法用于提取ROI变化特征时存在的问题，提出了一种稳健可行的变化特征提取方法。

Vishnu entered a dark fourth dimensional dream that did not support his field or continued life.

毗瑟挐进入了一个第四密度的黑暗梦想，那里并不支持他的能量场或继续生命。

Leaders and decision-making persons use it to collect the data, including the information of unit work, handing in fee, oweing fee, prepaying fee,changing and afterpaying and account transfering of joining-insurance employee, and account paying of all kinds of insurances from hospitalization insurance institutions.The collected data is picked up, organized, switched and showed to user.

该子系统主要面向各级领导、决策分析人员；从各个医疗保险经办机构和定点医疗机构采集数据，包括在各个医疗保险经办机构处理的单位办公信息，单位缴费、欠费、预缴费信息，参保职工变更信息，参保职工增减变动信息，参保职工补缴信息，参保职工帐户划拨信息：包括各定点医疗机构处理的各险种帐户支出信息，各险种的统筹金支付信息等；将采集的数据提取，组织和转换，然后展示给用户。