【正文】 nearby cell. Since adjacent cell use the same frequencies, CDMA systems have the ability to perform soft handoffs. Soft handoffs allow the mobile telephone to munication simultaneously with two or more cells. The best signal quality in selected until the handoff is plete. This is different from hard handoffs utilized in other cellular systems. In a hard handoff situation, as the mobile telephone approaches a handoff, signal strength may vary abruptly. In contrast, CDMA systems use the soft handoff, which is undetectable and provides a more reliable and higher quality signal. Concluding remarks spreadspectrum technology in the initial stages of development, it has bee a theory and a major technological breakthrough. Later in the development process is the improvement and hardware performance improved. Development to the present,spreadspectrum technology and the theory has been almost perfect,mainly from the point of view of overall performance, and the other new technology applications. Therefore, the application has been driven by the development of spreadspectrum technology is a power driving force, the future wireless munication systems, such as mobile munication. Wireless LAN, global personal munications, spreadspectrum technology will certainly play an important role. 譯文正文 擴(kuò)頻通信，即擴(kuò)展頻譜通信（ Spread spectrum munication)，它與光纖通信、衛(wèi)星通信，一同譽(yù)為進(jìn)入信息時(shí)代的三大高技術(shù)通信傳輸方式，擴(kuò)頻通信是將待傳送的信息數(shù)據(jù)被偽隨機(jī)碼調(diào)制，實(shí)現(xiàn)頻譜擴(kuò)展后再傳輸；接收端則采用相同的編碼進(jìn)行解調(diào)及相關(guān)處理，恢復(fù)原始信息數(shù)據(jù)。擴(kuò)頻通信容易采用碼分多址、語音壓縮等多項(xiàng)新技術(shù)，更加適用于計(jì)算機(jī)網(wǎng)絡(luò)以及數(shù)字化的語音、圖像信息傳輸。 CDMA 還耐干擾。在 FDMA 和 TDMA 系統(tǒng)中頻率規(guī)劃是重要的考慮因素。 。 RAKE 接收器整合多個(gè)相關(guān)器的信息，每一個(gè)調(diào)諧到不同的路徑延遲，產(chǎn)生一個(gè)比相關(guān)的簡(jiǎn)單調(diào)整，以最強(qiáng)的信號(hào)路徑延遲接收的信號(hào)更強(qiáng)的信號(hào)版本。異步 CDMA 有一些內(nèi)置的隱私級(jí)別，因?yàn)樾盘?hào)傳 播使用偽隨機(jī)碼，這個(gè)代碼使擴(kuò)頻信號(hào)出現(xiàn)隨機(jī)或有噪聲性能。 由于擴(kuò)頻通信又采取了相關(guān)接收這一技術(shù)，信號(hào)發(fā)送功率極低（＜ 1W，一般為1~100mW），且可工作在信道噪聲和熱噪聲背景中，易于在同一地區(qū)重復(fù)使用同一頻率，也可以在現(xiàn)今各種窄帶通信共享同一頻率資源。 chirp frequency system is a linear extension of the process of change. Combination of a number of ways of hybrid systems are often applied. The most important measure pf spreadspectrum system is an indicator of spreading gain, also known as processing gain. It is precisely because of the spread spectrum system itself with its performance characteristics with a series of advantages. Code division multiple access Code division multiple access (CDMA) is a channel access method used by various radio munication technologies. It should not be confused with the mobile phone standards called cdmaOne, CDMA2021(the 3G evolution of cdmaOne) and WCDMA (the 3Gstandard used by GSM carrier), which are often referred to as simply CDMA, and use CDMA as an underlying channel access method. One of the concepts in data munication is the idea of allowing several transmitters to send information simultaneously over a signal munication channel. This allows several users to share a band of frequencies (see bandwidth). This concept is called multiple access. CDMA employs spread