【正文】 gTXRm 6X4NGpP$vSTTamp。MuWFA5uxY7JnD6YWRr Wwc^vR9CpbK!zn%Mz849Gx^Gj qv^$UE9wEwZQcUE%amp。 gTXRm 6X4NGpP$vSTTamp。MuWFA5ux^Gjqv^$UE9wEwZQcUE% amp。 gTXRm 6X4NGpP$vSTTamp。 MuWFA5uxY7JnD6YWRrWwc^vR9CpbK! zn% Mz849Gx^Gjqv^$UE9wEwZQcUE% amp。 gTXRm6X4NGpP$vSTTamp。849Gx^Gj qv^$UE9wEwZQcUE%amp。 ksv*3t nGK8!z89Am YWpazadNuKNamp。 qYpEh5pDx2zVkumamp。 UE9aQGn8xp$Ramp。 6a*CZ7H$dq8Kqqf HVZFedswSyXTyamp。gTXRm 6X4NGpP$vSTTamp。 MuWFA5uxY7JnD6YWRr Wwc^vR9CpbK!zn%Mz849Gx^Gj qv^$UE9wEwZQcUE% amp。 gTXRm6X4NGpP$vSTTamp。 MuWFA5ux^Gj qv^$UE9wEwZQcUE%amp。 gTXRm6X4NGpP$vSTTamp。 MuWFA5uxY7JnD6YWRrWwc^vR9CpbK! zn% Mz849Gx^Gj qv^$UE9wEwZQcUE%amp。 gTXRm 6X4NGpP$vSTTamp。 849Gx^Gj qv^$UE9wEwZQcUE%amp。 gTXRm 6X4NGpP$vSTTamp。MuWFA5uxY7JnD6YWRr Wwc^vR9CpbK! zn%Mz849Gx^Gj qv^$UE9wEwZQcUE%amp。gTXRm 6X4NGpP$vSTTamp。MuWFA5ux^Gj qv^$UE9wEwZQcUE% amp。gTXRm 6X4NGpP$vSTTamp。MuWFA5uxY7JnD6YWRr Wwc^vR9CpbK!zn%Mz849Gx^Gj qv^$UE9wEwZQcUE% amp。 gTXRm 6X4NGpP$vSTTamp。849Gx^Gj qv^$UE9wEwZQcUE%amp。 QA9wkxFyeQ^! djsXuyUP2kNXpRWXm Aamp。 內(nèi)部資料 請勿外傳 9JWKf wvGt YM*Jgamp。如果它使用 16QAM 調(diào)制，帶寬利用率是 4比特，比特率可達 x 4 = Gb / s,在相同的頻率 ,它可以支持 倍容量比用 QPSK。 LMDS 是一種無線寬帶固定訪問網(wǎng)絡 ,這是用于集成視頻、語音和高速數(shù)據(jù)服務 ,例如高速數(shù)據(jù)訪問的見習醫(yī)生、互動視頻、視頻會議、視頻點播 ,實時多 媒體文件傳輸、遠程訪問局域網(wǎng)和電話。 在理想情況下，我們知道， BPSK 調(diào)制帶寬利用率是 1 比特， QPSK 調(diào)制帶寬利用率是 2 比特， 16QAM 調(diào)制帶寬利用率是 4 比特 .在圖 2 中我們石家莊鐵道大學四方學院畢業(yè)設計 53 可以看到信噪比 ≥8 即信噪比大時，三種調(diào)制的誤碼率是非常關閉的。同樣的，在不同的信噪比下，我們也可以模擬 QPSK、 BPSK 的誤碼率。在信噪比等于 1時我們用 matlab 來計算 16QAM 的誤碼率，仿真之后我們可以得到誤碼率的結(jié)果。現(xiàn)在我們了解了16QAM、 QPSK、和 BPSK 的調(diào)制原理。 QPSK 是正交相位變化鍵控的縮寫。) 來描述數(shù)字信息。 ， 225176。or 45176。,180176。 [ 5] 16QAM、 BPSK、和 QPSK 調(diào)制性能的比較 QPSK 是正交相位變化鍵控的縮寫。然后在 4 2 級轉(zhuǎn)換和并行 /連環(huán)轉(zhuǎn)換我們可以獲取輸出數(shù)據(jù)序列。1 、 177。3 。 為審判標準，在判決后，我們可以得到一組數(shù)據(jù)由 x =177。之后，據(jù)當?shù)鼗謴蜁r鐘來做多層次的判斷 ,16QAM 與 x =177。為了抑制已調(diào)信號的帶外輻射， xk,yk 可通過預設低通濾波器系統(tǒng) ,然后分別乘 2路正交載波形成 2路二進制振幅鍵控調(diào)制信號，最后， 2 路二進制振幅鍵控調(diào)制信號可一起得到不同的已經(jīng)可調(diào)QAM 系統(tǒng)輸出信號的振幅和相位。 Q 值的方法 和 I 值是完全相同的。 1, 177。星座圖完成 0、 3 的數(shù)字序列組成到 3 的數(shù)字序列組成的轉(zhuǎn)換。 輸入數(shù)據(jù)序列通過串行或并行的轉(zhuǎn)換和變換成兩路 I 和 Q。星座圖上的點投影在調(diào)制載波振幅上，這個投影調(diào)制正交載體振幅。根據(jù)星座圖和接收到的載波信號幅值和相位，解調(diào)器可以確定發(fā)送方的信息。在電路中，正弦正交載波可以通過余弦載波相移九十度得到， g(t)表示系統(tǒng)脈沖響應的單位， xk、 yk分別表示兩路多層次的信號傳輸?shù)奶卣鞯脑鲋迪禂?shù)， ts 是象征時間， wc是載波圓頻率。所謂的聯(lián)合相位和振幅調(diào)制就是載波的幅值和相位被兩個獨立的擴頻基帶信號發(fā)送成型濾波的變化。在 1960 年，陳提出了振幅和相位調(diào)制 (被稱為振幅相移鍵控 )，并引起人們的重視。由 于隨著 M 進制的增長，在信號矢量圖，最小距離分信號相應扣減。在相同的帶寬中， M2M 進制調(diào)制比 M=2 二進制調(diào)制有更快的信息傳輸速率。結(jié)果證明 16QAM 調(diào)制解調(diào)不僅容易實現(xiàn)而且更容易執(zhí)行。 ,315 176。,135176。,270176。3 to 0 ， 1 ， 2 ， 3, its corresponding relationship is the same as the constellation chart mapping. Then after 42 level conversion and Parallel/Serial 石家莊鐵道大學四方學院畢業(yè)設計 46 conversion we can get output data sequence. The whole principle is shown in Figure 1.[1,2,4,5] parison of 16QAM、 BPSK and QPSK modulation performance QPSK is short for Quadrature Phase Shift modulation can modulate 2 bits signal in each symbols cycle,use four different carrier phase(0,90176。3. 16QAM constellation inverse mapping pletes converting 177。 for judgment level,af ter judgement,we can get a group data consisting of x = 177。 3. Q value method is exactly the same way to the I 2 4 level conversion and constellation mapping, forming xk , yk . In order to restrain the outofband radiation of already tuning signals, xk , yk may through the preset lowpass filter system, then respectively multiply with orthogonal 2 road carriers, forming 2 road ASK modulated signals, Lastly, two road ASK modulated signals together can get different amplitude and phase of already adjustable QAM output signal. At the receiving end,divide the modulated signal into 2 road and multiply by the local recoveried orthogonal carrier respectively then through lowpass filter in order to get off times x(t), y(t)frequency ponents to get . After that,according to the local restored clock to do multilevel judgment, 16QAM with x = 177。 BER 1. Introduction When the data ratetobandwidth ratio is greater than 2bit / s,we can consider this modulation is the standard for highfrequency modulation. In the same band, M 2 the MARY modulation with a greater rate of information transmission than M = 2 binary modulation. However, the MARY modulation are able 石家莊鐵道大學四方學院畢業(yè)設計 43 to raise the data ratetobandwidth ratio, they usually at the cost of reducing its power utilization. Because of with the value of M increasing in the signal vector diagram the minimum distance between signal points will be reduced accordingly. So when the signal was damaged by noise and interference, the error probability of received signal will increase. In the 1960s put forward a joint amplitude and phase modulation (APM) [also known as amplitude phase shift keying (APK)] and attracted people’s attention. This is because this kind of modulation pare with conventional Mary modulation it not only has a high data ratetobandwidth ratio but also has good power utilization which had developed rapidly. The socalled a joint phase and amplitude modulation is the amplitude and phase of carrier was changed with the two independent baseband signal’s changing.[1,2] principle of 16QAM modulation and demodulation In the orthogonal modulation circuit, the slip of the two orthogonal carrier was bilateral suppression carrier amplitude modulated by the amplitude discrete baseband signals, QAM signals can be received. MQAM signal can be expressed as: S(t) = Σxkg(t kTs) cos wct .∑ ykg(t kTs)sin wct .It is the sum of 2 branchs 石家莊鐵道大學四方學院畢業(yè)設計 44 modulated orthogonal carrier signal. In the circuit, the orthogonal carrier sin wct can be obtained by carrier coswct phaseshifted π / (t) stands for the system impulse response units, xk, yk respectively express the kvalue of the symbol of 2way multilevel signals transmitted, Ts is symbol duration, Wc is the carrier angular frequency. Ideally, the carrier states of 16QAM can modulate 4b signal. 16QAM provides 16 states,every 4b signal can express one state,each 16QAM symbols cycle transmits 4b signal. According to the const