查询词典 side band

This paper discussed the double sideband noise figures and single side band noise figures of the superheterodyne receivers in a ideal hypothesis and the practical case respectively.

分别讨论了在理想假设和实际情况下超外差接收机的双边带噪声系数和单边带噪声系数，给出了单边带接收机的某些设计方案。

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。

Utilizing an external modulator, we can up-converse vector signals without electrical mixer based on single side band with carrier suppression.

我们提出了一个新颖的全光升频直接侦测多级格式正交多频分工系统。

First, there was the cabaret country of her Little Willies side band, then there was her appearance on gonzo art rocker Mike Patton\'s Peeping Tom project, and finally there\'s this hushed record, her first containing nothing but original compositions.

首先，国家的歌舞表演她的小Willies边带，那么她出现在贡扎艺术摇滚麦克顿的偷窥汤姆项目，并最终有这个安静的记录，她第一次载只是原始成分。

Something called 'side band addressing' also provides AGP with a performance boost.

有些所谓的边带处理的规定也agp版本的性能提升。

Three of the other advancements: pipelining, side band addressing and graphics address remapping table are described below.

还有其他三个优点是：流水线操作，边寻址和图形位址映射表，这些将在下面做叙述。

Double side band and/or single side band amplitude modulated citizens band radio equipment.

双边带和\或单边带调幅民用无线电频带设备。

We believe that the improvement of the frequency response is due to a two-mode beat that includes the main mode of the slave laser and the master laser mode, which coincides with the side band of the slave laser.

激光器频率响应的改善可以用两个模式的拍频来解释，一个模式是从激光器的主模，另一个是主激光器的模式，该模式与从激光器的边带重合。

Outstanding Features of the 148 GTL: FeatureBenefit 40 AM and 80 SSB Channels40 AM, 40 Upper Side Band, 40 Lower Side Band.

GTL 的杰出特征： FeatureBenefit 早上 40 点和 80 SSB Channels40 是，40 上面的边乐团，40 比较低的边乐团。

In these lasers, a section of Erbium doped fiber without undergoing bump used as saturatable absorber. A self-written grating may be formed by stable standing wave in this absorber. Because selfwritten grating possesses a characteristic of very narrow rejection band and can suppress any other side-band effectively, so the multi-longitudinal mode and mode jumping in other normal fiber ring laser are removed in this one.

将未泵浦掺铒光纤作为饱和吸收体，利用驻波干涉在掺铒光纤中诱发的自写入光纤光栅，由于自写入光纤光栅具有窄带滤波特性及对边模有效的抑制作用，解决了一般光纤环形腔激光的多纵模和易跳模之问题，获得具有极窄线宽，不跳模时间大于3小时单频激光输出。

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。