查询词典 delay 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。

Integrating trellis-coded modulation with threaded algebraic space–time block code, trellis-coded modulation space-time block code is presented, which has the advantage of full-diversity and small detection delay. Based on TCM pre-processing, the minimum distance between different codeword matrixes of the TCMST block code is maximized, so the average bit error rate of the TCMST block code is lower than that of the TAST block code at the same signal noise ratio.

TCMST分组码具有满发送分集度和检测延迟小等优点；由于采用了TCM预处理，使得不同TCMST分组码码字矩阵间的最小距离达到了最大化，因此在相同信噪比情况下，TCMST分组码具有比TAST分组码更低的平均误比特率。

Simulation results show that our algorithm enforces the adaptability of differential space-frequency modulation to the time delay expansion.Finally, we give our work to reduce the complexity of multiple symbol differential sphere decoding in differential space-time modulation. Through the modification of the enumeration strategy of the search tree in sphere decoding, we significantly reduce the complexity of detection at the expense of little loss on performance.

理论分析和仿真结果都验证了这种检测算法对长信道时延的适应能力论文最后还对差分空时调制中的多符号检测算法进行了研究，提出了一种降低差分空时调制系统中多符号差分球形译码算法复杂度的方法，通过改进球形译码中搜索树的排序策略，使得系统在牺牲较少性能的基础上大大降低了算法实现的复杂度。

Differential modulation is also a widely used method to the case of no knowledge of the channels in the receiver. Here we propose noncoherent sequence detection for differential space-frequency modulation, which can be used to alleviate the error floor that occurs in a multipath channel with long time delay expansion.

在接收端不知道信道状态信息的情况下，差分调制也是一种被广泛采用的技术，论文提出了应用于差分空频调制的非相干序列检测方法，该方法通过积累多个符号上的信道信息来完成发送符号的检测，可以消除由于长的信道延迟扩展带来的误码平层。

In order to analyze the influence of signal clearance delay on the system stability, and to offer direction to control parameter modulation during experiment, the influence of delay of gas clearance on control parameters' stable region is analyzed.

为分析间隙信号延时对系统稳定性的影响，并为实验过程中控制参数的调整提供方向，计算了间隙信号延时对控制参数稳定区域的影响。

The reason the default produced is analyzed and a new latest available unscheduled channel with smallest void algorithm is presented. The performance of the two algorithms is simulated. The results show that in LAUC-SV algorithm the effective window of the packet loss versus unit delay time of fiber delay lines is expanded significantly and the packet loss ratio is decreased about 100.5. The algorithm complexity of the LAUC-SV is only increased arithmetically with LAUC. Both the algorithms can not support delay reservation protocol effectively.

分析了产生此缺陷的原因并提出了一种LAUC算法的改进算法LAUC-SV算法，采用仿真的方法分析比较了两种算法的性能，结果表明LAUC-SV算法比LAUC算法的丢包率下降100.5，且LAUC-SV算法下的丢包率关于光纤延时线单元延时时间的工作窗口与传统LAUC相比大大展宽，而前者的算法复杂度与后者相比仅呈算术增长，但两算法均不能有效支持延时预约协议。

Then the delay is used in circadian model. Using the delay as a argument, the distribution of the roots of the characteristic equation associated with the model under light is analyzed. Then the stable and Hopf bifurcation condition of the circadian model with delay is obtained.

然后，将时滞引入到昼夜节律系统模型后，以滞量为参数，讨论光照昼夜节律模型线性部分特征方程根的分布情况，得到该系统的稳定性和Hopf分支产生的条件。

If all the flows getting into the system were constrained by the leaky-bucket parameters, the maximum cell delay and the buffer content bound were got when the capacity of the crosspoint was enough, and the maximum cell delay and the buffer capacity bound which can guarantee the maximum cell delay were also got when the content of the crosspoint was not enough.

在各数据流都由令牌桶参数约束的条件下，得到了交叉点缓存容量足够大情况下的最大信元时延和缓存临界容量大小，还得到了交叉点缓存容量不足够大情况下的最大信元时延以及保证信元具有时延上界的缓存临界容量大小。

Objective:To explore the feasibility of laparoscopy in diagnosing and treating of abdominal diseases.

目的：探讨腹腔镜用以诊断腹部外科疾病及选择治疗方案的可行性。

The lifetime of nylon 1010 and nylon 1010/POSS composites decreased with increasing temperature.

热重-红外联用分析表明尼龙1010在氮气气氛下的降解产物主要为小分子的低聚物，POSS并不改变尼龙1010降解产物的组成。