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ID:52472015
大小:493.05 KB
页数:19页
时间:2020-04-08
《CDMA2000码序列(短码、长码WALSH码.ppt》由会员上传分享,免费在线阅读,更多相关内容在教育资源-天天文库。
1、教学目标掌握CDMA2000中使用的三种码字的作用了解WALSH码和PN码是如何产生的掌握WALSH码和PN码的特点1教学重点掌握CMDA2000中使用的三种码字的作用掌握WALSH码和PN码的特点2教学难点WALSH码和PN码是如何产生的WALSH码和PN码的特点3一、walsh码字及相关性的概念二、PN码字的产生及作用4一、walsh码字及相关性的概念CDMA2000扩频码的选择Walsh码的定义Walsh码的产生相关性正交函数Walsh码在CDMA中的应用5扩频码速率:1.2288Mcps;扩频码:前向为Walsh码和PN短码,反向为PN长码。扩频码的使
2、用是扩频通信的关键点CDMA2000扩频码的选择6Walsh码的定义Walsh码的定义Walsh函数是一种非正弦波的完备正交函数系统,可用哈达玛矩阵H通过递推关系构成。由于它仅有可能的取值是+1和-1(或0和1),比较适合于用来表达和处理数字信号。Walsh函数具有理想的互相关特性。在Walsh函数中,两两之间的互相关函数为“0”,亦即它们之间是正交的。7WALSHCODES#----------------------------------64-ChipSequence------------------------------------------00
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4、0000111100001111000011110000111100001111501011010010110100101101001011010010110100101101001011010010110106001111000011110000111100001111000011110000111100001111000011110070110100101101001011010010110100101101001011010010110100101101001800000000111111110000000011111111000000001111111
5、1000000001111111190101010110101010010101011010101001010101101010100101010110101010100011001111001100001100111100110000110011110011000011001111001100110110011010011001011001101001100101100110100110010110011010011001120000111111110000000011111111000000001111111100000000111111110000130
6、1011010101001010101101010100101010110101010010101011010101001011400111100110000110011110011000011001111001100001100111100110000111501101001100101100110100110010110011010011001011001101001100101101600000000000000001111111111111111000000000000000011111111111111111701010101010101011010
7、1010101010100101010101010101101010101010101018001100110011001111001100110011000011001100110011110011001100110019011001100110011010011001100110010110011001100110100110011001100120000011110000111111110000111100000000111100001111111100001111000021010110100101101010100101101001010101101
8、0010110101010010110
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