通信原理教程11

1、1a2a4a1a3a5a7a6a8a1a3a5a7a2a6a4a82453)2cos()(kksktTattskTtTk ) 1(ssf21ka4)2cos()(kksktTattskTtTk ) 1(1),2cos(1),2cos()(01kkkkkatfatfts当当kTtTk ) 1()4/(1)4/(101TffTffss50)()0sin()()2sin()sin(2)sin(010101010101kkTT0)()sin()()sin()sin()sin(01010101010101010101TT., 3, 2, 1,4nnTfssfnT4/6TmNTnfs1)4(4sfnT4/

2、TmNTffTmNTffss141411414101014141TmNTmNT7014141TmNTmNT8kTtTkttsksk)1(),cos()(91kskskTkT)2cos()(kksktTattskTtTk )1(1122kkkkkTTakTTa时。当时当1k111,)(2kkkkkkkkkaakaaaak10时。当时当1k111,)(2kkkkkkkkkaakaaaak)2(mod,01或k)2cos()(kksktTattskTtTk )1()(cos)(tttskskkTtTk)1(kkktTat2)(11T3T5T9T7T11T0(c)模2运算后的附加相位kkktTat2)

3、(T3T5T9T7T11T0(b)附加相位的可能路径k(t)T3T5T9T7T11T0(a)附加相位轨迹k(t)12)2cos()(kksktTattskTtTk )1(tTtqtTtptsskskksin2sincos2cos)(kTtTk )1(1coskkp1coskkkaq1314k(mod 2)akqkpka0a1a2a3a4a5a6a7a8qksin(t/2T)pkcos(t/2T)0 T 2T 3T 4T 5T 6T 7T 8T15差分编码串/并变换振荡f=1/4T振荡f=fs移相/2移相/2cos(t/2T)qkpkpkcos(t/2T)qksin(t/2T)sin(t/2T)

4、cosstsinstpkcos(t/2T)cosstqksin(t/2T)sinstakbk带通滤波MSK信号tTtqtTtptsskskksin2sincos2cos)(kTtTk )1(1690相移模2乘载波提取积分判决抽样保持积分判决抽样保持cosst-sinstMSK信号2iT, 2(i+1)T(2i-1)T, (2i+1)Tpq(MSK信号解调器原理方框图解调输出17 MSK信号解调波形图tttOOOpqp q11 11+1+1+1+1+1182222)(161)(2cos32)(TffTffTfPsss19)/)(2/2(lnexp)(2BffH20211, 1, 0)2cos()

5、(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)(*) 1(kSkKS) 1,

6、2, 1, 0(Kk26102)(NktfjkkkeBts102)(NktfjkkeBts10)/2()(1)(KnnkKjenSKks) 1, 2, 1, 0(KkkB271帧F 比特b3b2b1bN b3b2b1bN TNiibF128b3b2b1bN t1帧TB1B2B3 BN1帧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(0121BBBNK kB3010)/2(1)(KnnkKjK

7、eBKks kB) 1, 2, 1, 0(Kk)/()(KnTsks10)/2(1)(KnntTjKeBKts)0 (Tt 31分帧分组串/并变换 编码映射.IDFT.并/串变换 D/A变换上变频OFDM信号二进制输入信号32d0 = 2sin(/8) = 0.765d1 = 213334卷积码编码器选择子集选择子集中的点k1k2n1信号点b112b2未编码比特c2c1c3编码输出输入k1k2350010图11.5.5 8PSK编码器网格图0111c1 c2 c30 0 0011010011010101000 001100 100 110111110111101b1 b2ti +1时刻ti 时

8、刻abcd0 0 1状态实线表示输入信息位k1为“0”，虚线表示输入信息位k1为“1”。 360010图11.5.5 8PSK编码器网格图0111c1 c2 c30 0 0011010011010101000 001100 100 110111110111101b1 b2ti +1时刻ti 时刻abcd0 0 1状态3710011100b1 b2abcd状态U0U1U2U3U4V0V1V2V3V4W3810011100b1 b2abcd状态U0U1U2U3U4V0V1V2V3V4W585. 42585. 022)765. 0(2)010000()100000()010000(),(),(),(

9、2222223322221122，dddVUdVUdVUdd14. 2585. 4d40)2(0)010000()001000()000000(),(),(),(2222332221122，dddUUdWUdUUddd = 2dFed = 2 39d0 = 2sin(/8) = 0.765d1 = 2121 ddref01. 3)/(log2010/8refFedQPSKPSKddG4041424344(b) 解扩后的功率谱f有用信号s1(t)功率谱密度窄带干扰功率谱密度白噪声功率谱密度宽带干扰功率谱密度2BcBcf宽带干扰功率谱密度白噪声功率谱密度窄带干扰功率谱密度有用信号s1(t)功率谱密

10、度Bc2Bc(a) 解扩前的功率谱f04546474810)(cos)(njiijjtjtMA49窄带滤波带通滤波中频信号输入sj(t)c(t)g(t)f(t)(cos)()(iijjjtjtMAts)cos()(0ttc)cos()(cos)()()(0tjtjtMAtctsiijj)cos)(0iiijjtAtg()cos()()(02tjtMAtfj501002)cos()()(njjtjtMAtf51. . . . . . . . . . . . .i抽 头 延 迟 线AFAFAFAFAF相 加 器中频信号输入本地m序列产生器积分)cos()(0ttc52. . . . . . . . . . . . .i抽 头 延 迟 线AFAFAFAFAF相 加 器中频信号输入本地m序列产生器积分)cos()(0ttc A02M(t ) + A12M(t- ) + A22M(t-2 )