【正文】 s numeral mobile munication to use the QPSK modulating Technology discussed which in 1986 ago international conference nearly all concentrated in the above permanent enveloping modulating technology modulating technique, the GMSK modulation received universal wele in particular. In recent years as a result of the amplifier design technology progress, realized the modulation method possibly to bee. In 1987 the intermediate stage, linear modulation technologies and so an QPSK only then started to be popular. Four phase shift keying signal hereinafter referred to as QPSK. Due to the absolutely phase shifting mode existing phase fuzzy problem, so in practice, mainly USES the relative phase shifting QDPSK way. It has a series of special advantages, at present has been used widely in wireless munication, modern munication bee a kind of very important demodulation method. QPSK is English Quadrature Phase Shift Keying as the abbreviations Body means is photograph shift keying, is a kind of digital modulation mode. QPSK digital demodulation including: modulus conversion, extraction or interpolation, matched filter, clock and carrier recovery. In the actual tuning demodulation circuit, the carrier is coherent demodulation, the vibration signal and the launch carrier signal frequency deviation and phase there shaking, and the simulation of demodulation out I, Q baseband signal is a carrier of the error signal. Such analog baseband signal even if the timing accurate clock sampling the judgment, the 石家莊鐵道大學(xué)四方學(xué)院畢業(yè)設(shè)計 。 Similarly, the high power efficiency also needs to sacrifice certain frequency spectrum efficiency. Along with the modulation technique in the unceasing development, the new modulation technology modulation technique might bring the better frequency and the higher power efficiency. FSK and PSK in the numeral mobile munication the find application, in which FSK already obtained the use in the simulation mobile munication digital signaling. QAM applies in the fixed pointtopoint digital microwave system widely, it has the very high frequency spectrum use factor. But the mobile munication environment regarding the traditional QAM modulation is the serious challenge, but in techs in the character mobile munication system also to have uses QAM. Exudes Europe39。 the liner modulation technology and the permanent enveloping modulation technology modulation technique linear modulation technology mainly has。 石家莊鐵道大學(xué)四方學(xué)院畢業(yè)設(shè)計 31 附 錄 附錄 A 外文資料 Modulation and demodulation technology In the last few year, in the mobile munication modulates the demodulation technology superiority in the development speed and the new application number aspect, for human extremely profound impression. Along with the social economy Development, the modulating technology modulating technique renews continuously again and is consummating, at the same time, the mobile munication, the second generation of mobile munication and soon enter the third generation mobile munication, between this, the modulation technology modulation technique development is playing the extremely vital toile in inside. In recent years, our mobile munication service swift and violent development, perated into social life each aspect, facing the motion user group continually growth and new service emerging one after another incessantly, the mobile munication system must adapt promptly even in advance in the market demand step. But took of a digital modulating technology Modulating technique mobile munication core technology is the realization high speed, the highly effective mobile munication system important status on the digital modulation includes。 在我大學(xué)四年期問，許多老師和同學(xué)在生活、學(xué)習(xí)等方面給予我許多關(guān)心和幫助，在此表示感謝。 感謝我大學(xué)四年的任課老師、同學(xué)們，在這幾年的學(xué)習(xí)生活中，我們結(jié)下了深厚的友誼，在論文撰寫期間，他們給了我很大的支持和幫助，在他們創(chuàng)造的自由和諧的學(xué)術(shù)氛圍中我度過了愉快的時光。這 些在我今后的人生道路上將給我莫大的幫助。在他的諄諄教誨下，我得以順利地完成整個畢業(yè)設(shè)計。由于 QPSK優(yōu)越的性能，隨著 EDA技術(shù)的進一步發(fā)展，該設(shè)計有著一定的技術(shù)價值。 在信息時代的今天，軟件無線電的提出和發(fā)展，標志著無線通信質(zhì)的飛躍。 在數(shù)字信號的調(diào)制方式中 QPSK 四相移鍵控是最常用的一種衛(wèi)星數(shù)字信號調(diào)制方式，它具有較高的頻譜利用率、較強的抗干擾性、在電 路上實現(xiàn)也較為簡單。 QPSK這類調(diào)制信號具有循環(huán)平穩(wěn)性，在對循環(huán)平穩(wěn)信號進行分析檢測時，利用其譜相關(guān)特性較之傳統(tǒng)的功率譜密度相比有著很好的抗干擾和抗噪聲優(yōu)勢。 QPSK 數(shù)字電視調(diào)制器在對數(shù)據(jù)流的處理上采用能量擴散的隨機化處理、 RS 編碼、卷積交織、收縮卷積編碼、調(diào)制前的基帶成形處理等，保證了數(shù)據(jù)的傳輸性能。 QPSK 數(shù)字電視調(diào)制器采用了先進的數(shù)字信號處理技術(shù)技術(shù)，完全符 DVBS 標準，接收端可直接用數(shù)字衛(wèi)星接收機進行接收。 適合衛(wèi)星廣播。 QPSK 是一種頻譜利用率高、抗干擾性強的數(shù)調(diào)制方式，它被廣泛應(yīng)用于各種通信系統(tǒng)中。四相相移鍵控 (QPSK)是在數(shù)字蜂窩移動通信、衛(wèi)星通信、數(shù)字電視中廣泛應(yīng)用的一種線性數(shù)字調(diào)制技術(shù)。 石家莊鐵道大學(xué)四方學(xué)院畢業(yè)設(shè)計 26 第 5 章 QPSK 的應(yīng)用 現(xiàn)代移動通信技術(shù)所涵蓋的技術(shù)面廣闊，其中調(diào)制解調(diào)技術(shù)關(guān)系到信號傳輸?shù)男屎唾|(zhì)量，是移動通信的關(guān)鍵部分。在信噪比一定的情況下， 2PSK 系統(tǒng)的誤碼率比 2FSK 和 2ASK 系統(tǒng)的誤碼率都小。 比較圖 48(a)仿真誤碼率曲線和 48(b)Monte Carlo 誤碼率曲線可知：仿真誤碼率曲線基本上符合理想的誤碼 率曲線，驗證了仿真系統(tǒng)的正確性，符合設(shè)計要求。 Monte Carlo 仿真方法 的特點如下： (1)Monte Carlo 仿真分析是通過大量而簡單的重復(fù)抽樣實現(xiàn)的，故計算方法和程序結(jié)構(gòu)都很簡單； (2)收斂的概率性和收斂速度與問題的維數(shù)無關(guān)； (3)適應(yīng)性強，受問題條件限制的影響較??； (4)收斂速度較慢，不宜用來解決精度要求很高的實際問題 。它解決問題的基本思想是，首先建立與描述該問題有相似性的概率模型，然后對模型進行隨機模擬或統(tǒng)計抽樣，再利用所得的結(jié)果求出特征量的統(tǒng)計值作為原問題的近似解，并對解的精度作出某些估計。當(dāng)發(fā)送“ 11”時，接收信號矢 量的相位若超出這一范圍（圖中陰影區(qū)），則將發(fā)生錯判。在圖中對于矢量“ 11”來說，判決門限應(yīng)該設(shè)在 0176。則將錯判為“ 01”。例如，設(shè)發(fā)送矢量的相位為 45176。它表示數(shù)字系統(tǒng)傳輸質(zhì)量的式是“在多少位數(shù)據(jù)中出現(xiàn)一位差錯” [12][13]。噪音、交流電或閃電造成的脈沖、傳輸設(shè)備故障及其他因素都會導(dǎo)致誤碼 (比如傳送的信號是 1，而接收到的是 0； 反之亦然 )。如果有誤碼就有誤碼率。 QPSK 系統(tǒng)的誤碼率 誤碼率 (BER： Bit Error Ratio)是衡量 數(shù)據(jù) 在規(guī)定時間內(nèi)數(shù)據(jù)傳輸精確性的指標。 (6)橫軸對應(yīng)判 決門限電平。 (4)在抽樣時刻，陰影區(qū)的垂直寬度表示最大信號失真量。 (2)眼圖斜邊的斜率表示系統(tǒng)對定時抖動的靈敏度。 石家莊鐵道大學(xué)四方學(xué)院畢業(yè)設(shè)計 22 圖 43 眼圖系統(tǒng)模型 圖 44 信道有干擾時的眼圖 圖 45 信道無干