通频带

Later, it makes some comparison with four kinds of modulation technique, and finally, it implements the three-level PWM switching power amplifier with the PWM technique. The power of the amplifier is 2kVA, and the frequency bandwidth is 10～3kHz. In the thesis, the author designs and makes the hardwares of the switching power amplifier. The hardwares contain power inverter rank circuit, control system circuit based on DSP, drive and isolation circuit, and protective circuit. The thesis also analyses the potential safety problems and put forward some solutions for the problems. Furthermore, the thesis accomplishes the software design of the control system, and successfully debugs it. The methods of designing higher power ampilfier are also discussed in the thesis. It analyses the feasibility of the methods, outlines the way of how to design higher power switching power amplifier, and does some experiments with the method of switches-parallelling.

根据电动振动试验系统对开关功放的要求，提出了以电感电流瞬时值控制技术为基础的三电平脉宽调制开关功放的设计方案，并通过系统仿真进行了原理性论证；然后设计并制作了开关功放的硬件，包括功率转换电路，基于DSP的控制电路，驱动、隔离电路以及保护电路；针对开关功放数学模型不易得出的特点，细致分析了模糊自适应PID控制方法，在此基础上编写了控制程序；研制出一台功率为2kVA，通频带为10～3kHz的三电平脉宽调制开关功放；论文中还探讨了实现大功率开关功放的方法，分析了各种方法的可行性，给出了实现大功率开关功放的思路，并进行了并联开关管实现大功率开关功放的实验。

This formula indicates that the resolution of the panoramic receiver is pro-portional to its bandwidth,and the factor of proportionality ζ depends upon the typeof the IF filter and the detector.

公式表明，全景接收机的分辨能力与其通频带成正比，比例系数ξ取决于中频滤波器和检波器的程式。

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。

Output of each filter reflects quantity of signal at that transmission band.

率不同的带通滤波器实现，各个滤波器的输出反映了信号在该通频带内的量值。

First of all, the circuit output waveform in the case of losing it by measuring the input voltage and output voltage in order to detect amplification of analog circuits, and then by adjusting the frequency of AC voltage source to reduce the output gain make 3db analog circuits in order to measure the maximum cut-off frequency, pass band can be obtained.

本电路首先在输出波形不失真的情况下通过测量输入电压和输出电压从而测出模拟电路的放大倍数，然后通过调节交流电压源的频率使得输出增益减少3db从而测量出模拟电路的上限截止频率，即可求出通频带。

And can be easily used to analyze the diaphragm pump axis' vibration signal.

由于隔膜泵主轴振动信号非常丰富，在通频带上有大量的能量分布，所以单从频谱上很难识别故障。

Being characteristics of the broad transmission bands an...

由于传输线变压器具有通频带宽、易于制作的特点，在功率超声领域将有可能得到广泛的应用。

This paper presented the main functions and characteristics of Multisim8.0, and the main qualities of high frequency tunable amplifier such as voltage gain, transmission bands and selectivity were studied using simulation analysis and testing technologies of Multisim 8.0. The results are visual and precise, and prove the theory very well. This software has powerful simulation and analysis function, by which the analysis and design of high frequency circuit are not only more precise and credible, but also more closed to the real circuit running status.

本文介绍了Multisim8.0仿真软件的主要功能及特点，并结合该软件对高频单调谐放大电路的电压增益、通频带、选择性等主要质量指标进行了测试与仿真分析，结果直观、精确，很好地验证了理论，表明该软件有强大的仿真和分析功能，在实现高频电路分析和设计方面不仅高效、可靠，而且具有逼近真实电路的效果。

Transmission bands; ultimate gain; output-power; output voltage RMS

通频带；最大增益；功率输出；输出电压有效值

The paper extended researches the microstrip six-port net project deeply, ADS tools are adopted to model and simulate this project, and then the paper analyses the characteristic of radio channel both transmitter and receiver, analyses the extended transmission bands and simulates the adaptability, then designs lumped-distributed microstrip filter.

文中对微带六端口射频通道方案进行深入的扩展分析，采用ADS建模及仿真研究，分析了发射通道和接收通道的特性，通过对通频带扩展及适应性仿真的分析，设计了集总—分布式微带滤波器，最后也与零中频混频方案比较了各自的差异性。

What are your goals and strategies for growth?

你的成长目标和策略是什么？

And unto the angel of the church in Sardis write; These things saith he that hath the seven irits of God, and the seven star I know thy works, that thou hast a name that thou livest, and art dead.

3：1 你要写信给撒狄教会的使者，说，那有神的七灵和七星的，说，我知道你的行为，按名你是活的，其实是死的。