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通信原理与matlab仿真v3 第十一章 QPSK调制解调器仿真(4)

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继续讲解！！！实际中有产品使用QPSK调制方式吗？之前讲了美军的一些系统，相信大家已经有了初步印象。先看一段程序来近距离接触一下吧！

滤波器的问题是个好问题！通信和数字信号处理关系太紧密了，随处可见滤波器的身影！

fs = 9600 ;%%采样率

sr = 1200 ;%%符号率

br = 2400 ;%%比特率

fc = 2000 ;%%中频信号

inter_value = fs/sr ; %内插倍数

delay_cof = [zeros(1,82),1,zeros(1,82)];

%%延时滤波器

hilbert_cof =

[0,-0.00472345357205545,0,-0.00498252003664550,0,-0.00525314271392766,0,-0.00553612755366318,0,-0.00583237041501683,0,-0.00614286984176291,0,-0.00646874205769890,0,-0.00681123864607970,0,-0.00717176749105900,0,-0.00755191770591194,0,-0.00795348946292621,0,-0.00837852988795173,0,-0.00882937650905171,0,-0.00930871018200420,0,-0.00981961999584277,0,-0.0103656834469578,0,-0.0109510662440721,0,-0.0115806475914636,0,-0.0122601788768664,0,-0.0129964866398641,0,-0.0137977349408074,0,-0.0146737684533889,0,-0.0156365668248191,0,-0.0167008548105098,0,-0.0178849342692745,0,-0.0192118382139715,0,-0.0207109623924876,0,-0.0224204220072335,0,-0.0243905396505673,0,-0.0266891530221987,0,-0.0294099556164102,-0,-0.0326861051987813,0,-0.0367134382518456,0,-0.0417922559604959,0,-0.0484076818566803,0,-0.0573976823259233,0,-0.0703451144271719,0,-0.0906418556523782,0,-0.127106845056775,0,-0.212076288822662,0,-0.636576332324884,0,0.636576332324884,0,0.212076288822662,0,0.127106845056775,0,0.0906418556523782,0,0.0703451144271719,0,0.05739768230,0.0484076818566803,0,0.0417922559604959,0,0.0367134382518456,0,0.0326861051987813,0,0.0294099556164102,0,0.0266891530221987,0,0.0243905396505673,0,0.0224204220072335,0,0.0207109623924876,0,0.0192118382139715,0,0.0178849342692745,0,0.0167008548105098,0,0.0156365668248191,0,0.0146737684533889,0,0.0137977349408074,0,0.0129964866398641,0,0.0122601788768664,0,0.0115806475914636,0,0.0109510662440721,0,0.0103656834469578,0,0.00981961999584277,0,0.00930871018200420,0,0.00882937650905171,0,0.00837852988795173,0,0.00795348946292621,0,0.00755191770591194,0,0.00717176749105900,0,0.00681123864607970,0,0.00646874205769890,0,0.00614286984176291,0,0.00583237041501683,0,0.00553612755366318,0,0.00525314271392766,0,0.00498252003664550,0,0.00472345357205545,0;];

%% 希尔伯特滤波器

接着看代码！

[psf,den] = rcosine(1*sr,inter_value*sr,'fir/sqrt',0.25,5);

% 成型滤波

pre_data_len = 203 ;

%按照协议规定 203个数据

pre_data = [2 6 4 4 6 4 6 2 6 0 2 2 0 4 6 2 2 0 2 6

0 6 4 0 2 0 6 6 6 4 0 6 0 6 2 2 0 4 2 4

0 2 2 2 2 6 4 6 6 2 4 6 4 6 2 6 0 2 4 0

0 0 6 6 2 6 2 2 0 2 4 4 6 4 6 0 4 0 6 6

2 2 0 0 6 6 4 0 4 0 0 6 6 6 4 6 4 6 0 2

2 6 0 0 0 2 6 2 0 0 6 2 6 0 4 6 6 4 0 6