查询词典 Base Band

ZTE Base Band Unit and Remote Radio Unit Base Station adopts distributed structure and combines full frequency reuse of the W CDMA system to implement soft site moving and cutover conveniently.

中兴通讯股份有限公司的ZTE BBU+RRU 基站由于采用分布式结构，结合宽带码分多址同频组网特性，可以方便地实现软搬迁软割接。

ZTE Base Band Unit and Remote Radio Unit Base Station adopts distributed structure and combines full frequency reuse of the WCDMA system to implement soft site moving and cutover conveniently.

中兴通讯股份有限公司的ZTE BBU+RRU 基站由于采用分布式结构，结合宽带码分多址同频组网特性，可以方便地实现软搬迁软割接。

Research on the digital base-band transmission system is very meaningful.

对数字基带传输系统的研究是非常有意义的。

This paper Matlab language of the digital base-band transmission system simulation. Analysis and dissemination of multi-path ...

本文采用matlab语言编写了数字基带传输系统的模拟实现，并分析了多径传播和加网孔时的输出情况。

So it adapts to be applied to the software radio. In this system, the received IF signal is to be digital down converted, and then is to be processed through the base band filter.

本系统首先对收到的中频数字信号进行数字下变频，并进行基带滤波，得到两路正交信号I、Q。

Compared with traditional analog IF method and digital base-band method, this new method has some advantages such as simplicity, temperature insensitiveness and high reliability and can be used in spread-spectrum communication, pulse compression radar and IFF systems.

与传统采用的SAW中频模拟处理方法和数字基带处理方法相比，该方法具有结构简单、工作温度范围宽和可靠性高等优点，可用于扩频通信、脉冲压缩雷达和敌我识别等系统。

Source Module to provide digital modulation module base-band and bit synchronization signal BS (in experimental circuit board connected Link without manual wiring).

信源模块向调制模块提供数字基带信号和位同步信号BS（已在实验电路板上连通，不必手工接线）。

In chapter five, the base band signal process of CDMA base station simulator system is introduced, including channel coding and decoding, interleave and disinterleave, PN sequence generator, orthogonal spread spectrum and quadrature Spreading, scrambling code, power control, digital forming filter, the capture and track of PN code, dispreading and demodulation, etc. Some FPGA design graphic and waveform simulation of base band transmitter module is given and realization algorithm of base band receiver is discussed in detail.

第五章介绍了CDMA基站仿真系统的基带信号处理过程，包括信道编译码、交织与去交织、PN码发生器、正交扩频与四相扩频、扰码、功率控制、数字成形滤波器、PN码的捕获与跟踪、解扩与解调等，并给出了基带发射机模块的部分FPGA设计原理图和波形仿真，详细论述了基带接收机模块的实现算法。

With the support of a major research grant of Zhejiang Province (No. 001101027) and the Plan of Promoting Education of Excellence of Zhejiang University in the 21st Century, this dissertation is devoted to address the above problems and fabricate an L-band EDFA with low cost, high performance and technological innovation.First the mechanism of an erbium doped fiber amplifier is introduced. Various theoretical models based on classical rate propagation equations are summarized and compared for their applications. We use a modified numerical model based on the Giles model, which agrees with the experimental results well. This serves as the theoretical base for the whole thesis and will be used to optimize the characteristics of EDFAs. A novel method based on a map of noise figure and gain is proposed to analyze efficiently the dependence of the noise figure and gain for EDFAs on the EDF length and the pump power. The characteristics of various EDFAs are studied and compared.Secondly, some important parameters are introduced to describe the characteristics of EDFAs. The methods and the experimental setups for measuring the gain and noise figure of an EDFA are emphasized. We introduce how to measure the characteristics of each component of an EDFA, especially the gain and absorption coefficient of an erbium doped fiber.Thirdly, four types of simple and novel L-band EDFA structures with low noise, high gain and low gain ripple are proposed to satisfy the requirement of a DWDM system. They can be classified into two categories. In the first category, a single ASE pumping is served asa secondary pump. This category includes the following three types. Type: a new construction using a fiber Bragg grating in an unpumped EDF section at the input side. Type: a new structure of L-Band EDFA with two-stage pumps, which utilizes the forward ASE as a second pump.

本论文本着科技创新、服务于生产实践的精神，以设计价格低廉，性能优越、结构合理简单的L-band EDFA为目标，依托浙江省科技厅重大科学基金资助项目(001101027)和浙江大学振兴教育计划资助的全光网络的搭建—《光通信技术》课程实验建设项目，展开了如下工作：首先，介绍了掺铒光纤放大器的工作原理，归纳总结了基于速率方程基础的EDFA的各种理论模型，分析比较了各个模型的特点和适用场合，最终选择完善的Giles理论模型作为本论文分析设计EDFA的理论基础；针对实际实验条件提出了修正的EDFA模型的数值计算方法；创新地提出了增益—噪声系数全局分析法，直观有效地分析了EDFA的增益和噪声系数与掺铒光纤长度和泵浦功率的依赖关系，并对各种EDFA的性能作了全面的比较；第二，介绍了掺铒光纤放大器特性参数的定义与测量方法，重点介绍了噪声系数和增益系数的测量方法及实验装置；介绍了组成掺铒光纤放大器各组件的特性测量方法，重点介绍了测量掺铒光纤参数的方法和实验装置；第三，针对WDM系统对L-band EDFA谱平坦、低噪声、高增益的要求，我们创新地提出了四种不同的L-band EDFA结构，按设计思路可以分为两大类：一类是基于单抽运二级泵浦法，这一类包括在未泵浦掺铒光纤的输入端插入一根布拉格光纤光栅的两段L-band的EDFA的新结构；基于前向ASE光作为二级泵浦源推动下一级EDF工作的泵浦分配、两段级联L-band的EDFA的新结构；基于单根光纤光栅、泵浦分配、两段级联的EDFA；另一类则是基于同时应用前后向C-band ASE作二级泵浦源的双抽运法，如基于前后向ASE光作为二级泵浦源的三段级联L-band的EDFA的新结构。

Having studied the digital down-conversionprocess of IF signal before the base band process which follows A/D conversion in wireless communication,the paper puts forward a new idea of utilizing the FPGA to realize multi-channel digital signal DDC.Through analyzing the features and performances of CIC filters,HB filters and multiphase-filter,we combine them with decimators and decimate the A/D data,thus reducing the digital signal rate and the load of DSP when processing the base band signal.

软件无线电技术是在通用的开放式无线电智能平台上，通过安装不同的软件来完成各种通信功能，其结构的基本特征之一就是使A/D变换尽量靠近射频端，目前的方案是在中频对模拟信号进行数字化，对中频数字信号进行下变频处理，使数字信号量降低到高速DSP能够处理的程度[1]。

I didn't watch TV last night, because it .

昨晚我没有看电视，因为电视机坏了。

Since this year, in a lot of villages of Beijing, TV of elevator liquid crystal was removed.

今年以来，在北京的很多小区里，电梯液晶电视被撤了下来。