【正文】 外墻水泥砂漿抹面，外刷淺灰色墻漆。 以絕對標高 m 為準，總長 27樓 ； 30樓 m。 本工程耐火等級二級，屋面防水等級三級，地震防烈度為 8度，設(shè)計使用年限 50 年。下文為附加文檔，如不需要，下載后可以編輯刪除，謝謝！ 施工組織設(shè)計 本施工組織設(shè)計是本著“一流的質(zhì)量、一流的工期、科學(xué)管理”來進行 編制的。 仿真結(jié)果分析 加入噪聲和干擾后 ,取 CL = 10 ,用 3 個不同的正弦信號干擾 ,其振幅分別為 2 ,3 ,7. 在誤碼率運算中加性噪聲的方差是固定的 ,總共進行了 1萬次運算 ,而且在每次運算中 ,信號能量取值都滿足所需的信噪比要求 ,從而得到了圖 3 所示的仿真曲線 . 可見 ,正弦干擾信號的振幅越大 ,誤碼率越大 .同樣，在相同信噪比下 ,處理增益越大 ,誤碼率越小 ,而在大信噪比時 ,這種差別尤為明顯。 F 為信號的頻率 。所以 ,擴頻系統(tǒng)可實現(xiàn)隱蔽通信 。這些反射或散射信號同直達路徑信號在接收端相互干涉造成干擾。由于擴頻通信系統(tǒng)在傳輸過程中擴展了信號帶寬 ,所以即使信噪比很低 ,甚至是有用信號功率低于干擾信號功率的情況下仍能夠高質(zhì)量地不受干擾地進行通信 ,擴展的頻譜越寬 ,其抗干擾性越強。這兩個序列發(fā)生器產(chǎn)生偽隨機噪聲（ PN）二值序列，在調(diào)制端將傳送信號在頻域進行擴展，在解調(diào)端解擴該擴頻發(fā)送信號。 2）抗干擾容限 是指擴頻通信系統(tǒng)能在多大干擾環(huán)境下正常工作的能力，定義為： ]s)/[( outj LNSGM ??? （ 6） 其中： jM 抗干擾容 G 處理增益 out)/( NS 信息數(shù)據(jù)被正確解調(diào)而要求的最小輸出信噪比 sL 接收系統(tǒng)的工作損耗 擴頻通信系統(tǒng)的工作原理 數(shù)字擴頻通信的一般工作原理如圖 1 所示。這就是擴展頻譜通信的基本思想和理論依據(jù)。擴展頻譜換取信噪比要求的降低，正是擴頻通信的重要特點，并由此為擴頻通信的應(yīng)用奠定了基礎(chǔ)。而擴頻通信的 Gp 值，高達數(shù)百、上千，稱為 “寬帶通信”。為什么要用這樣寬頻帶的信號來傳送信息呢 ? 簡單的回答就是主要為了通信的安全可靠。即把擴展以后的信號又恢復(fù)成原來所傳的信息。 3）在接收端用相關(guān)解調(diào)來解擴。如下面介紹的直接序列擴頻系統(tǒng)就是采用這種方法獲得擴頻信號。例如很窄的脈沖信號，其頻譜則很寬。一般的調(diào)頻信號，或脈沖編碼調(diào)制信號，它們的帶寬與信息帶寬之比也只有幾到十幾。為了充分利用頻率資源，通常都是盡量采用大體相當?shù)膸挼男盘杹韨鬏斝畔ⅰ? 2 擴頻通信的基本原理 擴頻通信的定義 所謂擴展頻譜通信，可簡單表述如下：“擴頻通信技術(shù)是一種信息傳輸方式，其信號所占有的頻帶寬度遠大于所傳信息必需的最小帶寬；頻帶的擴展是通過一個獨立的碼序列來完成，用編碼及調(diào)制的方法來實現(xiàn)的，與所傳信息數(shù)據(jù)無關(guān)；在接收端則用同樣的碼進行相關(guān)同步接收、解擴及恢復(fù)所傳信息數(shù)據(jù)”。 研究擴頻通信的目的和意義 擴頻通信是通信的一個重要分支和信道通信系統(tǒng)的發(fā)展方向。 頻譜擴展的方式主要有以下幾種 :直序擴頻 (DSSS)使用高速偽隨機碼對要傳輸?shù)牡退贁?shù)據(jù)進行擴頻調(diào)制；跳頻系統(tǒng)則利用偽隨機碼控制載波頻率在一個更寬的頻帶內(nèi)變化；跳時則是數(shù)據(jù)的傳輸時隙是偽隨機的；線性調(diào)頻系統(tǒng)中的頻率擴展則是一個線性變化的過程。 關(guān)鍵詞 ： 擴頻；通信； MATLAB。 0N For the noise power spectral transmission bandwidth W ,Signal power TES /? ,Noise Power 0WNN? ,Signal duration T ,Information signal bandwidth TF /1?? ,Into the type(8) ,a： FWNSNST WNE ???0 (9) Style (9) Description, eP By FWNS? Decision,In other words, a certain bandwidth transmission F? Information,SNR NS And bandwidth can beW Exchange. Binary sequences for spread spectrum munication of information, assuming that the information rate of R , Symbol interval is SRT /1b? ,Effective bandwidth to transmit information to )m( RBB CC .In the DS system, the use of MatLab toolbox function of the pseudorandom sequence to generate pseudorandom code sequence. There is the PN code is a 9 bit more than 0,1 code sequences, which undergo a rigorous selection process, and has a good autocorrelation, but similar to each other but are mutually orthogonal, linearly independent and, in many key type, they can easily identify with their own code the same type, and not easily confused with other codebased. The use of PN sequences in the transmitter, the message sequence will be the expansion of narrowband wideband signal for transmission into the channel, the receiver will receive the broadband signal synchronized with the transmitter PN sequence multiplied, the narrowband despread the message sequence, and the types of interference signals are multiplied with the PN sequence to the expansion of the form for broadband,Will eventually weaken the energy of interference signal W / R times. In the modulator, the message sequence for the bandwidth expansion CBW? ,Prevalent as a result of transmission interference, and therefore must be taken into account in the simulation of the interference signal of the decision ruling the impact of device. Assuming that the process of signal transmission by the cosine form of interference with the role of signal, the signal current of )2co s()( tfAti jj ?? (10) Type (10): jf In order to send the signal interference within the frequency bandwidth. )(ti and )(tc Multiplied so that cosine form of interference into the broadband interference，Its energy density spectrum WPJ J /0 ? ,Where: 2/2JJ AP ? For the average energy of interference order to more intuitive analysis of DSsinusoidal interference signal suppression effects,The establishment of a Monte Carlo simulation model, Figure 2 DS Monte Carlo simulation model system 10 As can be seen from Figure 2, by the random number generator produce a series of binary (177。 At the same time, different users use different code, others can not be tapping their munications, thus spreadspectrum system with high confidentiality. 4 Spread Spectrum Communication in the MATLAB simulation Direct Sequence Spread Spectrum system BER simulation According to Shannon theorem, we can see: ）（ NSWLC /1og ?? （ 7） Where: W for the transmission bandwidth。s main performance indicators 1) The processing gain is the tolerance and antijamming spreadspectrum munication systems are two important performance , also known as processing gain spread spectrum gain (Spreading Gain) it is defined as the information before spread spectrum 6 bandwidth expansion band DF and the signal bandwidth W ratio: FWGP ?? / （ 5） In spread spectrum munication system. Demodulation for spreadspectrum receiver, the only pseudorandom code extract treatment, the bandwidth related to the information DF, and ruled out the external Wwideband interference, noise and its impact to the user39。Chirp frequency system is a linear extension of the process of 2 of a number of ways of hybrid systems are often applied. The most important measure of spreadspectrum system is an indicator of spreading gain, also known as processing is precisely because of the spread spectrum system itself with its performance characteristics with a series of advantages. The purpose of spread spectrum munication studies and significance Spread spectrum munication is an important branch of munication and channel the direction of development of munication technology, with strong antiinterference ability, confidentiality, and is easy to realize the advantages of multipleacc