传输频带

The results of numerical modeling indicate that the thin film microstrip lines with finite ground width have good broad band characteristics and the characteristic impedance, attenuation constant and effective dielectric constant have small change with the finite ground width changing.

作者用该程序对有限接地面薄膜微带线进行了时域仿真，结果显示在保证传输模不受干扰的情况下，在较宽频带范围内有限接地面对微带特性有微弱影响。

So MIMO systems theoretically can achieve very high data transmission rate on band limited frequency spectrum.

采用该技术不仅能在有限的频带上实现高速率的信息传输，而且还能够改善无线通信系统的性能。

In modern digital communication systems, frequency transmission system of the most prominent.

在现代数字通信系统中，频带传输系统的应用最为突出。

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。

Its ideal is that modulation mode can be adaptively adjusted by estimating such wireless parameters as fading degree,channel traffic and etc. Channel capacity will achieve a maximum and system performance will be best anytime. By this way,although mobile wireless channel broadband is more and more congesting today,adaptive modulation can be provided preferable spectral efficiency and can be increased the information transmission rate.

它的主要思想是通过研究无线信道的衰落程度、信道流量等参数动态地改变调制方式，在任何时刻都使信道容量达到最大或者使系统性能达到最佳，从而使移动无线信道频带日益拥挤的今天能得到较高的频谱利用率，有效地提高信息传输速率、从而提高传输系统的带宽。

In particular, zeros in the transmission bands often results in a loss in bit rate.

特别是当零点发生在传输频带时，会造成传输率的下降。

It possesses the advantages such as small volume , wide transmission belt of frequency , no saturation problem and without harmonic vibration point etc.

采用电阻分压器来替代电磁式电压互感器，可将初级电压直接转化为10 V 以内的微信号，具有体积小、传输频带宽、不存在饱和问题、无谐振点等优点。

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。

In digital communication, a transmitted carrier signal that consists of the12 single sidebands being sent over the transmission circuit.

在数据通信中，一种传输载波信号，由传输电路上发送的12个单边频带组成。

In addition, there are two strands of the head is also black, and are rust, rust can be seen because of lead wire resistance increases, resulting in the signal can not be smooth, telephone through the audio signal, the low band signal can also only phone, there is always the voice of flap, and the use of the ADSL band signal is relatively high, head through the rust on it is very difficult, leading to slow or stop signal transmission.

此外有两处绞合的线头处也发黑了，都是锈，可见正是因为导线生锈导致电阻增大，导致信号不能畅通，电话通过的音频信号，频带低，信号还能通过，只是电话里老是有啪啪的声音，而ADSL的信号使用的频带比较高，线头生锈了就很难通过，导致信号传输变慢或者断流。

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。