通信原理第6章 多路復(fù)用和多址技術(shù)

1、(a) 頻分制(b) 時(shí)分制(c) 碼分制fNf1f2t2tNt1tNt1t2I 2 21 1t t1212t tf(t)f(t)dt0f(t)f(t)dt0 (a) 發(fā)送端原理方框圖4.3 7.4 kHz8.3 11.4 kHz4 kHz12 kHz8 kHz多路信號(hào)輸出相乘帶通低通話音輸入1f1相乘帶通低通話音輸入2f2相乘帶通低通話音輸入3f3300 3400 Hz300 3400 Hz300 3400 Hz12.3 15.4 kHz4 kHz8 kHz12 kHz基帶語音信號(hào)300 3400 Hz4.3 7.4 kHz8.3 11.4 kHz12.3 15.4 kHzf0(1)ttcc

2、mgffff多路信號(hào)輸入(b)接收端原理方框圖話音輸出1話音輸出2話音輸出3相乘低通帶通f1相乘低通帶通f1相乘低通帶通f14.3 7.4 kHz8.3 11.4 kHz12.3 15.4 kHz3400 Hz3400 Hz3400 Hz8 kHz12 kHz4 kHz 1(1)(1)()(1)nmgmgmmBnfnfnfffnBf4 kHz8 kHz12 kHz基帶語音信號(hào)300 3400 Hz4.3 7.4 kHz8.3 11.4 kHz12.3 15.4 kHzf0 LRLR下 邊 帶LR上 邊 帶輔 助通 信 通 道導(dǎo) 頻載 頻DSB-SC01915233853 5975f / kHz

3、38 kHz振蕩器2衰減L RL R左聲道L右聲道R去調(diào)頻發(fā)射機(jī)(a)LPF0 15 kHzBPF23 53 kHzLPF0 15 kHz導(dǎo)頻濾波19 kHz2LR來自鑒頻器立體聲指示(b)12(L R)12(L R) m1(t)m2(t)NNsi(t)低通1低通2低 通N信道低通1低通2低 通Ns1(t)s2(t)1幀T/NT+T/N2T+T/N3T+T/N同步旋轉(zhuǎn)開關(guān)s1(t)s2(t)s2(t)s1(t)sN(t)sN(t)時(shí)隙1旋轉(zhuǎn)開關(guān)采集到的信號(hào)信號(hào)s1(t)的采樣信號(hào)s2(t)的采樣時(shí)分多路復(fù)用原理1PAMsTTNNfQuantizerandencoderChannelDecode

4、rLPFLPFLPFAnalog input signalsChannel 1(from source 1)Channel 2(from source 2)Channel 3(from source 3)TransmitterSamplerTDMPAMsignalTsTstTDMPCMsignalSynchronizationSamplerTDMPAMReceiverReceivedTDM PCMplus noiseChannel 1Channel 2Channel 3Output analog signalsfsfs),(21Nixxxxx),(21Niyyyyy)1, 1(,iiyxNii

5、iyxNyx11),(0),(yx0000-1+1+1+1+1-1-1-1s3s1s2s4正交碼組tttt)1,1,1,1()1,1,1,1()1,1,1,1()1,1,1,1(4321ssssDADAyx),()1 ,0, 1 ,0()0, 1 , 1 ,0()1 , 1 ,0,0()0,0,0,0(4321ssss) 1, 1, 1, 1() 1, 1, 1, 1() 1, 1, 1, 1() 1, 1, 1, 1(4321ssss 01001110 +1-1+1+1-1-1-1+1NijiixNjxxNj1) 1(, 1, 01)(141)0(412iixx0)1111(41)(4141

6、)1xxxxxxxxxiiix1)1111(41)(4141)2(2434231412xxxxxxxxxxiiix0)1111(41)(4141)3(34231241413xxxxxxxxxxiiix(0, 0, 0, 0)(1, 1, 1, 1)(0, 0, 1, 1)(1, 1, 0, 0)(0, 1, 1, 0)(1, 0, 0, 1)(0, 1, 0, 1)(1, 0, 1, 0)DADAxxjii),(11) 1 , 0 , 1 (),0 , 1 , 1 (),1 , 1 , 0 (321sssmisis1m4s2m4s3m4s4m4積分m1m2m3m4s4

7、s2s1s3積分積分積分TTTTTTttt(c) mi(t)si(t)(b) si(t)(a) mi(t)t(d) misi(e) (misi)sit(f) (misi)sidttttttttttttttttt11112H2H2HHH2 / NN 2222224HHHHHHH4444248HHHHHHH 8Wa1a0+a2a3 a1a0+a2a3a3a2a1a0100011001110111101111011010110101101011000111001010000100001-1000初始狀態(tài)初始狀態(tài) 周期周期24 1 = 15c1c2cn-1+ak-1cn = 1ak-2輸出輸出c0 =

8、 1ak-n+1ak-nc1c2cn-1+ak-1cn = 1ak-2輸出輸出c0 = 1n 級(jí)線性反饋移存器級(jí)線性反饋移存器ak-n+1ak-nniikinknnknkkkacacacacaca1112211)2(mod c1c2cn-1+ak-1cn = 1ak-2輸出輸出c0 = 1n 級(jí)線性反饋移存器級(jí)線性反饋移存器ak-n+1ak-nniiinnxcxcxcxccxf02210)(41)(xxxfa1a0+a2a3) 1)(1)(1)(1)(1() 1(223434415xxxxxxxxxxxx) 1)(1)(1)(1)(1() 1(223434415xxxxxxxxxxxx) 1() 1)(1(5234xxxxxxn本原多項(xiàng)式本原多項(xiàng)式代數(shù)式代數(shù)式8進(jìn)制表示進(jìn)制表示2x2 + x + 173x3 + x + 1134x4 + x + 1235x5 + x2 + 1456x6 + x + 11037x7 + x3 + 12118x8 + x4 + x3 + x2 + 14359x9 + x4 + 1102110X10 + x3 + 1201111X11 + x2 + 1400512x12 + x6 + x4 + x + 11012313x13 + x4 + x3 + x + 1200338進(jìn)制數(shù)字進(jìn)制數(shù)字232進(jìn)制數(shù)字進(jìn)制數(shù)字0 1 00 1 1抽頭系數(shù)抽頭系數(shù) c5