The main content of this dissertation includes: 1. Research on the theory of ultrasonic power supply, introduce its development process. On the basis of these, fix on the scheme of medical ultrasonic low-power supply. 2. According to the principle of modularized design, divide medical ultrasonic low-power supply into four parts. They are power amplify circuit, power control circuit, frequency automatic tracking circuit and matching circuit. Separately research on their theories and design their circuits and necessary programs, especially, effectively resolve the problem tracking the supersonic vibration system with a narrow syntony frequency bandwidth and a high swing. 3. The matching experiments gain good result, and prove that medical ultrasonic low-power supply is entirely up to the mustard on intellectualization, wide band of working frequency, steady output and high efficiency.

本文工作的主要內(nèi)容包括： 1、研究了超聲功率電源的原理在线色网站，并回顧了它的發(fā)展過程欧美好色aaa，在此基礎(chǔ)之上確定本文醫(yī)用小功率超聲電源的設(shè)計方案； 2国产日日操夜夜操、按照模塊化的設(shè)計原則爱爱网址，將醫(yī)用小功率超聲電源的設(shè)計分解為功率放大電路、功率控制電路韩国三级代理、頻率自動跟蹤電路和匹配電路等四個部分，分別研究了各部分的原理国内自拍53页，在此基礎(chǔ)之上進行了具體的電路設(shè)計和程序設(shè)計黄色网站18岁，尤其是有效地解決了對諧振頻率帶寬窄振幅高的超聲振動系統(tǒng)的頻率跟蹤問題4455www看片； 3、通過與超聲振動系統(tǒng)的各項配合實驗人人肏人人干人人肏，取得了很好的實驗結(jié)果免费中文字幕爱爱小视频，驗證了醫(yī)用小功率超聲電源完全滿足智能化、工作頻帶寬搜索超碰在线操人妻。、輸出功率穩(wěn)定欧美精选1、輸出效率高的設(shè)計要求。

Ricker wavelet whose predominant frequency is 200Hz was chosen as the exciting wave, and the character parameters (predominant amplitude, predominant frequency and frequency bandwidth) of its reflected wave were calculated.

選擇主頻為200Hz的雷克子波网站在线观看视频免黄，理論計算原始地震反射波的特征參數(shù)（主振幅国产一级a、主頻率、頻帶寬度）人操人操人操人操人操人操人操。

In wireless broadband digital communication, Inter-Symbol Interference caused by time disperse of radio channel is one of main factors that limit bandwidth of communicated information and system performance of communication. In receiver, Orthogonal Frequency Division Multiplexing system can easily cancel ISI and equalize frequency-selective fadings that are both caused by time disperse of radio channel.

在這一系統(tǒng)中亚洲天堂的无码在线视频，無線信道時延擴展引起的符號間干擾是限制傳輸性能和信息速率的主要因素之一；而在消除符號間干擾和均衡由無線信道時延擴展引起的頻率選擇性衰落方面国产嫖娼妓院视频网站，正交頻分復(fù)用(Orthogonal Frequency Division Multiplexingsansansy.com，OFDM)技術(shù)具有明顯優(yōu)勢。

bandwidth：頻帶寬度

D."頻帶寬度"(Bandwidth)欧美精品理论片大全、"頻差容限"(frequency tolerance) 具有電信公約給予該等詞的涵義. A.有效輻射功率(ERP)是將供應(yīng)天線的功率乘以該天線在某特定方向的相對增益. 有效輻射功率在顧及所使用的發(fā)射類別下,

Directivity：指向性

輸出阻抗不一定會是50奧姆,此時便需在收發(fā)機電路與天線輸入端之間設(shè)計一個外加的阻抗匹配網(wǎng)絡(luò)來將天線的輸入阻抗值轉(zhuǎn)換到收發(fā)機的輸出阻抗值. 操作頻率(Operating Frequency)與頻寬(Bandwidth, BW)指向性(Directivity)與天線增益(Gain)