通信原理教程11

1、1a2a4a1a3a5a7a6a8a1a3a5a7a2a6a4a8245輸入二進(jìn)制數(shù)字輸入二進(jìn)制數(shù)字相位改變相位改變1 1450 11350 0-1351 0-453)2cos()(kksktTattskTtTk ) 1(ssf21ka4)2cos()(kksktTattskTtTk ) 1(1),2cos(1),2cos()(01kkkkkatfatfts當(dāng)當(dāng)kTtTk ) 1()4/(1)4/(101TffTffss50)()0sin()()2sin()sin(2)sin(010101010101kkTT0)()sin()()sin()sin()sin(010101010101010101

2、01TT., 3, 2, 1,4nnTfssfnT4/6TmNTnfs1)4(4sfnT4/TmNTffTmNTffss141411414101014141TmNTmNT7014141TmNTmNT8kTtTkttsksk)1(),cos()(91kskskTkT)2cos()(kksktTattskTtTk )1(1122kkkkkTTakTTa時(shí)。當(dāng)時(shí)當(dāng)1k111,)(2kkkkkkkkkaakaaaak10時(shí)。當(dāng)時(shí)當(dāng)1k111,)(2kkkkkkkkkaakaaaak)2(mod,01或k)2cos()(kksktTattskTtTk )1()(cos)(tttskskkTtTk)1(k

3、kktTat2)(11kkktTat2)(T3T5T9T7T11T0(b)附加相位的可能路徑附加相位的可能路徑 k(t)T3T5T9T7T11T0(a)附加相位軌跡附加相位軌跡 k(t)T3T5T9T7T11T0(c)模模2運(yùn)算后的附加相位運(yùn)算后的附加相位 k(t)12)2cos()(kksktTattskTtTk )1(tTtqtTtptsskskksin2sincos2cos)(kTtTk )1(1coskkp1coskkkaq13k0 12345678T(-T, 0)(0, T)(2T, 3T) (3T, 4T) (4T, 5T) (5T, 6T) (6T, 7T) (7T, 8T) (

4、8T, 9T)ak+11+1-1-1+1+111 k(mod 2 )00 0pk11-1-1-1-1-1-11qk1-1-111-1-11114 k(mod 2 )akqkpk a0a1a2a3a4a5a6a7a8qksin( t/2T)pkcos( t/2T)0 T 2T 3T 4T 5T 6T 7T 8T15差分差分編碼編碼串串/并并變換變換振蕩振蕩f=1/4T振蕩振蕩f=fs移相移相 /2移相移相 /2 cos( t/2T)qkpkpkcos( t/2T)qksin( t/2T)sin( t/2T)cos stsin stpkcos( t/2T)cos stqksin( t/2T)sin

5、 stakbk帶通帶通濾波濾波MSK信號(hào)信號(hào)tTtqtTtptsskskksin2sincos2cos)(kTtTk )1(1690 相移相移模模2乘乘載波提取載波提取積分判決積分判決抽樣保持抽樣保持積分判決積分判決抽樣保持抽樣保持cos st-sin stMSK信號(hào)信號(hào)2iT, 2(i+1)T(2i-1)T, (2i+1)Tpq(MSK信號(hào)解調(diào)器原理方框圖信號(hào)解調(diào)器原理方框圖解調(diào)解調(diào)輸出輸出17 MSK信號(hào)解調(diào)波形圖信號(hào)解調(diào)波形圖ttt000pqp q11 11+1+1+1+1+1182222)(161)(2cos32)(TffTffTfPsss19)/)(2/2(lnexp)(2BffH2

6、0211, 1, 0)2cos()(NktfBtxkkkk10)2cos()(NkkkktfBts102)(NktfjkkkeBtskB22, 2, 1, 0,2mTmkfk0)2cos()2cos(0dttftfiiTkk, 2, 1,/|nTnffik23Tffkfk+1/T24HzsbMOFDMB/log2/HzsbMNNBTMNOFDMOFDMB/log11log22/)(1HzTNBOFDMMNTTMNMB22/log212log2510)/2()(1)(KknkKjeksKnS) 1, 2, 1, 0(Kn10)/2()(1)(KnnkKjenSKks) 1, 2, 1, 0(Kk

7、()*( )S KkSk) 1, 2, 1, 0(Kk26102)(NktfjkkkeBts102)(NktfjkkeBts10)/2()(1)(KnnkKjenSKks) 1, 2, 1, 0(KkkB271幀幀F(xiàn) 比特比特b3b2b1bN b3b2b1bN TNiibF128b3b2b1bN t1幀幀TB1B2B3 BN1幀幀TiBiB2910)/2()(1)(KnnkKjenSKks) 1, 2, 1, 0(Kk)(*) 1(kSkKS) 1, 2, 1, 0(KkiB kB1, 2, 1,*1NkBBkkK22, 2, 1,1NNNNkBBkkK)Re(00BB)Im(0121BBBN

8、K kB3010)/2(1)(KnnkKjKeBKks kB) 1, 2, 1, 0(Kk)/()(KnTsks10)/2(1)(KnntTjKeBKts)0 (Tt 31分幀分幀分組分組串串/并并變換變換 編碼編碼映射映射.IDFT.并并/串串變換變換 D/A變換變換上上變變頻頻OFDM信號(hào)信號(hào)二進(jìn)制二進(jìn)制輸入信號(hào)輸入信號(hào)32d0 = 2sin( /8) = 0.765d1 = 213334卷積碼卷積碼編碼器編碼器選擇選擇子集子集選擇選擇子集子集中的點(diǎn)中的點(diǎn)k1k2n1信號(hào)點(diǎn)信號(hào)點(diǎn)b112b2未編碼比特未編碼比特c2c1c3編碼輸出編碼輸出輸入輸入k1k2350010圖圖11.5.5 8PS

9、K編碼器網(wǎng)格圖編碼器網(wǎng)格圖0111c1 c2 c30 0 0011010011010101000 001100 100 110111110111101b1 b2ti +1時(shí)刻時(shí)刻ti 時(shí)刻時(shí)刻abcd0 0 1狀態(tài)狀態(tài)k1b1b2狀狀 態(tài)態(tài)c1c200a00000a00100a01110b11011d11101c00010b10001c01000a00實(shí)線表示輸入信息位實(shí)線表示輸入信息位k1為為“0”，虛線表示輸入信息位虛線表示輸入信息位k1為為“1”。 360010圖圖11.5.5 8PSK編碼器網(wǎng)格圖編碼器網(wǎng)格圖0111c1 c2 c30 0 0011010011010101000 001

10、100 100 110111110111101b1 b2ti +1時(shí)刻時(shí)刻ti 時(shí)刻時(shí)刻abcd0 0 1狀態(tài)狀態(tài)3710011100b1 b2abcd狀態(tài)狀態(tài)U0U1U2U3U4V0V1V2V3V4W3810011100b1 b2abcd狀態(tài)狀態(tài)U0U1U2U3U4V0V1V2V3V4W585. 42585. 022)765. 0(2)010000()100000()010000(),(),(),(2222223322221122，dddVUdVUdVUdd14. 2585. 4d40)2(0)010000()001000()000000(),(),(),(2222332221122，ddd

11、UUdWUdUUddd = 2dFed = 2 39d0 = 2sin( /8) = 0.765d1 = 2121 ddref01. 3)/(log2010/8refFedQPSKPSKddG40狀態(tài)數(shù)目狀態(tài)數(shù)目kG8PSK/QPSK413.01823.601624.133224.596425.0112825.1725625.7541424344(b) 解擴(kuò)后的功率譜解擴(kuò)后的功率譜f有用信號(hào)有用信號(hào)s1(t)功率譜密度功率譜密度窄帶干擾功率譜密度窄帶干擾功率譜密度白噪聲功率譜密度白噪聲功率譜密度寬帶干擾功率譜密度寬帶干擾功率譜密度2BcBcf寬帶干擾功率譜密度寬帶干擾功率譜密度白噪聲功率譜密度

12、白噪聲功率譜密度窄帶干擾功率譜密度窄帶干擾功率譜密度有用信號(hào)有用信號(hào)s1(t)功率譜密度功率譜密度Bc2Bc(a) 解擴(kuò)前的功率譜解擴(kuò)前的功率譜f04546474810)(cos)(njiijjtjtMA49窄帶窄帶濾波濾波帶通帶通濾波濾波中頻信號(hào)中頻信號(hào)輸入輸入sj(t)c(t)g(t)f(t) )(cos)()(iijjjtjtMAts)cos()(0ttc)cos()(cos)()()(0tjtjtMAtctsiijj)cos)(0iiijjtAtg()cos()()(02tjtMAtfj501002)cos()()(njjtjtMAtf51. . . . . . . . . . . . . i 抽抽 頭頭 延延 遲遲 線線AFAFAFAFAF 相相 加加 器器中頻信號(hào)中頻信號(hào)輸入輸入本地本地m序列序列產(chǎn)生器產(chǎn)生器積分積分)cos()(0ttc52. . . . . . . . . . . . . i 抽抽 頭頭 延延 遲遲 線線AFAFAFAFAF 相相 加加 器器中頻信號(hào)中頻信號(hào)輸入輸入本地本地m序列序列產(chǎn)生器產(chǎn)生器積分積分)cos()(0t