频带

The study has focused on: 1 The research background and the current state of the power measurement were analyzed systematically, and then wavelet-based power measurement algorithm was certified feasible for astable signals; 2 We developed a new method of RMS and power measurement based on Dmeyer wavelet. After that three other wavelet measurement approaches were compared with Dmeyer wavelet-based measurement approach. Then the impact on measurement errors of amplitude frequency property and energy leakage of wavelet filter banks were deeply researched, and some measures were proposed to reduce it; 3 We developed a new strategy of power measurement algorithm based on lifting wavelet, which had calculation advantage compared with the first wavelet, so that it was more suitable for the realization of hardware; 4 The running system of wavelet-based power measurement algorithm based on DSP was proposed, and then it was realized on ICETEK-VC5416-A EVM board; 5 Existing problems and the further research direction of wavelet-based power sub-band measurement algorithm was discussed.

本文对基于小波变换的功率测量算法展开深入的分析研究，主要内容有：1）系统地分析了功率分解测量的研究背景、国内外的研究现状，并从能量守恒的角度验证了小波功率分频带测量算法在非平稳信号条件下的可行性；2）首次提出了Dmeyer小波变换有效值与功率的测量方法，进而通过对该方法与3种已经提出的小波测量方法的对比分析，深入研究了小波滤波器组的幅频特性和能量泄漏特性对测量误差的影响，并针对电网谐波的特点提出了减小影响的相关措施；3）首次提出了二代小波功率测量算法，对比一代小波功率分频带测量算法，它大大减少了算法实现的运算量及内存的需求量，从而更适合于硬件的实时实现；4）提出了小波功率分频带测量算法的DSP实现方案，并在ICETEK-VC5416-A EVM板上进行了实现；5）探讨了小波功率分频带测量算法目前仍存在的问题，并提出了进一步的研究方向。

The dual-band differential LNA use Inductive source degeneration structure, a matching network is used for the LNA to develop dual-band. The micro-mixer use a matching network shunt and parallel LC elements to develop wide-band matching. The biasing method reduces the"voltage headroom" difficulties inherent to the Gilbert cell, and the mixer linearity can be improved using this biasing method "Charge -Injection"by accurate adjustment of the input MOSFET operating point. The complementary VCO based on 2.5GHz, and tuning output buffer to approach 2GHz/5GHz dual-band for dual-band down-converter with MMIC technology.

其中双频差动低杂讯放大器，本电路用Inductive Source Degeneration 架构，在匹配网上设计，使低杂讯放大器工作在个频带上达成双频带的效果；CMOS 微混频器上采用LC串联、并联电路做匹配，达到宽频匹配的效果，并加入了"Charge-Injection"的方法来改善"voltage headroom"的问题，并同时提高线性度的表现；互补式压控振荡器以2.5GHz为基频的振荡器为出发点，透过电路的调整，以期达成2.5/5GHz的双频带需求，能够完整达成双频带接收机系统。

First, we divide the input signal into four non-uniform subbands via discrete wavelet transform. In addition, a nonlinear Teager energy operator is then utilized into each subband signals. We show that the TEO can decrease the influence of noise on subbands significantly. Besides, the other advantage is suitable for the result of subband auto-correlation function.

首先，离散小波转换将输入讯号分成四个不均匀大小的子频带，而在每个子频带上采用一种非线性的Teager能量运算(Teager Energy Operator， TEO)以有效抑制噪音在各子频带的影响，而另一优点就是有助於子频带自我相关函示(spectral auto-correlation function， SACF)之结果。

The impedance ratio and the meander could control the frequency of the second harmonic and the baseband ratio. According to that,we analyze several kinds of stepped impeedance resonator and use them to design the dual-band bandpass filters.In the thsis , The proposed bandpass filters and dual-band bandpass filters are designed for IEEE 802.11a/b wireless communicatuon system.

双频带带通滤波器是利用步阶阻抗谐振器之阻抗比与传输线之折线，可用来控制第二次谐波的频率与基频通带的比值，藉由改变阻抗比，来求得所要的第二次谐波，利用此特性，其中分析了几种不同形式的步阶阻抗谐振器，皆可用来设计双频带带通滤波器，带通滤波器与双频带带通滤波器是针对IEEE80211a与IEEE802.11b无线区域网路所设计。

The ultra -- high -- frequency and ultra -- wideband partial discharge detecting methods is newly put forward. It is important for development of partial discharge de...

本文简明扼要地阐述了局部放电信号的物理本质和超宽频带检测原理，运用自行研制的超宽频带局部放电检测系统，研究了典型放电信号和干扰信号的本征特征，为进一步建立超宽频带局部放电检测指纹库、提高绝缘诊断的准确性奠定了基础。

This paper mainly introduces the baseband transmission and the waveband transmission of digital communication system.

介绍了数字通信系统中信号的基带传输和频带传输；分别论述了基带传输系统和频带传输系统模型，说明了基带信号无码间干扰传输条件及频带数字调制的工作原理。

These antennas can cover GSM900/DCS/PCS/UMTS operation. In the chapter 2, the antenna is designed based on the concept of monopole antenna. Furthermore, the antenna structure have two radiant paths and coupled each other at tail end to do impedance matching. In addition, to raise distance between radiation plane and ground will avoid capacitative effect effectually. In the chapter 3, the antenna is designed based on the concept of planar inverted-F antenna. Furthermore, that the antenna structure have two radiant paths and coupled each other at tail end to do impedance matching is similar to chapter 2. But there is a difference in them. We can choose the short position to change input impedance at this structure. In the chapter 4, the antenna is designed based on the concept of planar inverted-F antenna which takes coupled-fed. It will produce the first mode and high-order mode near the frequency, 900MHz. The feature of this type is to reduce the volume effectually. This antenna can not only cover GSM900/DCS/PCS/UMTS operation but maintain good radiation efficiency. Finally, we will compare three antennas, and develop procedure with industrial view, and propose the prospect of the GSM/GPRS antenna in PND, as a conclusion.

在第二章中，我们使用单极天线设计概念，使用双路径架构并於末端耦合来对天线阻抗做匹配，产生涵盖GSM900/DCS/PCS/UMTS四频操作频带，并提高与接地面的辐射高度，以避免电容效应，使天线具有良好的辐射特性；在第三章中，使用倒F形天线设计概念，使用双路径架构於末端耦合，并於辐射臂上采取适当接地点电感效应作输入阻抗匹配，达成涵盖GSM900/DCS/PCS/UMTS系统的四个操作频带；在第四章中，采用倒F形架构并使用耦合馈入方式，使得长辐射金属臂在低频900 MHz附近产生共振，产生低频基频模态及高阶模态，以达成宽频及频宽涵盖GSM900/DCS/PCS/UMTS频带操作，并有效缩减使用体积；最后，分别比较此三种架构的优缺点，再加以业界角度来思考，研发产品天线的流程及思考方向，以及天线应用於可携式导航装置中未来的展望作为本论文的总结。

In this thesis. Interband coding techniques are investigated for effective compression of multiband images such as color images and hyperspectral images. A multiband lossless compression system based on context matching prediction schemes is proposed. The observation is that the interband correlation in multiband images is usually greater than the intraband.

中文摘要此论文探讨有效率的压缩彩色影像及卫星影像类型的多频带影像利用频带间预测编码的技术，提出一种基於频带间内文比对预测方式的多频带影像无失真压缩系统，观察结果显示多频带影像邻近频带相互之间冗余特性大於频带内。

Unlike traditional double-sideband with optical carrier suppression modulation scheme, which can carry only the on-off keying data format, the proposed scheme encodes the electrical vector signal on either the upper sideband or the lower sideband only, and a pure optical subcarrier on the other sideband.

不像传统的双旁频带载波抑制调变只能载送开关键移讯号格式，提出的架构不只可以把电的向量讯号编码在高旁频带也可以在低旁频带，且有一个很纯的次载波在另一个边带。

Instead of allocating several frequency bands block by block to a radiocommunication system, at least one frequency band of another radiocommunication system is arranged between the frequencies of the first and second frequency band, whereby a minimum distance is created between the frequency bands used in a location.

在频率分配的意义上讲，不是成块地给一个无线通信系统分配多个频带，而是在所述第一和第二频带的频率之间设置了其它无线通信系统的至少一个频带。于是在一个位置处使用的频带之间具有一个最小间隔。

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。