本文關(guān)鍵詞：包絡(luò)跟蹤功率放大器技術(shù)研究　出處：《電子科技大學》2015年碩士論文　論文類型：學位論文

  更多相關(guān)文章： 包絡(luò)跟蹤 功率放大器 包絡(luò)調(diào)制器 神經(jīng)網(wǎng)絡(luò)

【摘要】：包絡(luò)跟蹤是一項用于設(shè)計高效率射頻功率放大器的技術(shù)。這項技術(shù)的基本原理是功放漏極或集電極偏置電壓隨著輸出信號功率的變化而實時地進行調(diào)整,以維持功放工作于效率較高的區(qū)域。盡管原理與概念由來已久并深為人知,包絡(luò)跟蹤技術(shù)的工程實踐卻并非易事。本文就包絡(luò)跟蹤技術(shù)中的技術(shù)要點進行了理論分析、仿真進實驗驗證。本文從功率放大器效率公式出發(fā),引出包絡(luò)跟蹤技術(shù)的實現(xiàn)形式;將技術(shù)難點一一呈現(xiàn),如包絡(luò)成形技術(shù)、包絡(luò)調(diào)制器實現(xiàn)技術(shù)、動態(tài)偏置功率放大器設(shè)計、數(shù)字預(yù)失真技術(shù)等。包絡(luò)成形技術(shù)根據(jù)側(cè)重點不同,可分為最大效率、固定壓縮點和固定增益三種。就功放效率指標而言,最大效率成形函數(shù)最高而固定增益函數(shù)最低;就功放線性指標而言,最大效率成形函數(shù)最差而固定增益函數(shù)最好。線性度太差會導(dǎo)致數(shù)字預(yù)失真技術(shù)無法對功放非線性進行修正,從而在工程實踐中無法運用。包絡(luò)調(diào)制器是包絡(luò)跟蹤技術(shù)中最關(guān)鍵的部分,在設(shè)計中必須兼顧帶寬、效率、噪聲、帶載能力等。包絡(luò)調(diào)制器的實現(xiàn)方式有直流-直流轉(zhuǎn)換器、線性放大器以及兩者合并的混合型放大器。本文中采用多階噪聲成形技術(shù)控制多電平直流轉(zhuǎn)換器,成功制作出一款跟蹤能力達到300KHz,效率達80%的包絡(luò)調(diào)制器。功率放大器本身即為非線性電路,在漏極偏置電壓變化的情況下,放大后的信號線性度將進一步惡化。從最佳阻抗匹配點出發(fā),本文分析了動態(tài)偏置對功放設(shè)計帶來的影響.只有效率而不考慮線性的功率放大器,在現(xiàn)有的通信系統(tǒng)中是沒有立足之地的。本文采用神經(jīng)網(wǎng)絡(luò)作為功率放大器的建模工具來研究包絡(luò)跟蹤功率放大器的數(shù)字預(yù)失真線性化技術(shù)。實驗結(jié)果表明,針對8載波GSM信號,互調(diào)改善達到26dB以上;針對5MHz帶寬的WCDMA信號,ACPR改善達到12dB以上。
[Abstract]:Envelope tracking is a technique used to design high efficiency RF power amplifiers. The basic principle of this technique is that the bias voltage of power amplifier drain or collector is adjusted in real time with the change of output signal power. In order to maintain the power amplifier work in the more efficient areas. Although the principles and concepts have a long history and is well known. The engineering practice of envelope tracking technology is not easy. In this paper, the main points of envelope tracking technology are analyzed theoretically and verified by simulation. The efficiency formula of power amplifier is used in this paper. The realization of envelope tracking technology is introduced. The technical difficulties are presented one by one, such as envelope shaping technology, envelope modulator realization technology, dynamic bias power amplifier design, digital predistortion technology, etc. It can be divided into three types: maximum efficiency, fixed compression point and fixed gain. In terms of power amplifier efficiency index, the maximum efficiency shaping function is the highest and the fixed gain function is the lowest. In terms of the linear index of power amplifier, the maximum efficiency shaping function is the worst and the fixed gain function is the best. The linearity is too poor, so the digital predistortion technology can not correct the nonlinear of power amplifier. The envelope modulator is the most important part of the envelope tracking technology. In the design, the bandwidth, efficiency and noise must be taken into account. The realization of envelope modulator includes DC-DC converter, linear amplifier and hybrid amplifier. In this paper, multilevel DC converter is controlled by multi-order noise shaping technology. An envelope modulator with a tracking capacity of 300kHz and an efficiency of 80% has been successfully fabricated. The power amplifier itself is a nonlinear circuit under the condition of leakage bias voltage change. The linear degree of the amplified signal will deteriorate further. Based on the optimal impedance matching point, this paper analyzes the influence of dynamic bias on the design of the power amplifier. Only the efficiency of the amplifier without consideration of the linear power amplifier. The neural network is used as the modeling tool of the power amplifier to study the digital predistortion linearization technology of the envelope tracking power amplifier. The experimental results show that there is no foothold in the existing communication system. For 8-carrier GSM signal, the improvement of intermodulation is more than 26dB. For WCDMA signal with 5 MHz bandwidth, the improvement of ACPR is more than 12 dB.
【學位授予單位】：電子科技大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TN722.75
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本文編號：1440794