移动通信原理C1型实验指导书

目录第一章实验系统介绍······························错误!未定义书签。1.1系统组成···········································································错误!未定义书签。1.2调制解调模块·····································································错误!未定义书签。1.3无绳电话系统·····································································错误!未定义书签。1.4CDMA系统········································································错误!未定义书签。第二章调制解调实验··················································-1-实验一MSK调制解调实验·············································································-1-实验二GMSK调制解调实验······················································错误!未定义书签。实验三QPSK调制解调实验···········································································-6-实验四OQPSK调制解调实验·····················································错误!未定义书签。实验五DQPSK调制解调实验·····················································错误!未定义书签。实验六Π/4DQPSK调制解调实验·················································错误!未定义书签。第三章无绳电话实验······························错误!未定义书签。实验一信道分配实验································································错误!未定义书签。实验二用户线信令与无绳电话实验··············································错误!未定义书签。实验三接收机实验···································································错误!未定义书签。实验四发射机实验···································································错误!未定义书签。实验五锁相频率合成器实验·······················································错误!未定义书签。实验六双工器实验···································································错误!未定义书签。实验七无绳电话移动通信系统实验··············································错误!未定义书签。第四章CDMA实验··················································-11-实验一GOLD序列特性实验··········································································-11-实验二GOLD序列的捕获与跟踪实验······························································-16-实验三扩频与解扩实验················································································-20-实验四载波提取实验···················································································-25-实验五PSK调制与解调实验··········································································-29-实验六位同步提取实验················································································-36-实验七帧同步提取实验················································································-42-实验八纠错编码实验···················································································-50-实验九CDMA移动通信系统实验···································································-54-参考书目································································-60-移动通信原理实验指导书-1-第二章调制解调实验实验一MSK调制解调实验一、实验目的1、掌握MSK调制和解调的原理。2、理解MSK的优缺点。二、实验内容1、观察MSK调制过程中各信号的波形。2、观察MSK解调过程中各信号的波形。三、预备知识1、MSK调制和解调的基本原理。2、MSK调制和解调部分的工作原理及电路说明。四、实验器材1、移动通信原理实验箱一台2、20M双踪示波器一台五、实验原理1、MSK调制原理MSK称为最小移频键控，是移频键控（FSK）的一种改进型。这里“最小”指的是能以最小的调制指数（即0.5）获得正交信号，它能比PSK传送更高的比特速率。二进制MSK信号的表达式可写为：costSMSKkkctTsat2kTstTsk)1(c——载波角频率；Ts——码元宽度；ka——第k个码元中的信息，其取值为±1；k——第k个码元的相位常数，它在时间kTstTsk)1(中保持不变；移动通信原理实验指导书-2-当ka＝＋1时，信号的频率为：2f＝cf＋Ts41当ka＝－1时，信号的频率为：1f＝cf－Ts41由此可得频率之差为：f＝2f－1f＝Ts21那么MSK信号波形如图2.1-1所示：＋－－＋＋＋－－图2.1-1MSK信号波形为了保持相位的连续，在t=kTs时间内应有下式成立：k=1k＋（1ka－ka）2（1k）即：当ka＝1ka时，k=1k；当ka≠1ka时，k=1k±（1k）π；若令0＝0，则k＝0或±π，此式说明本比特内的相位常数不仅与本比特区间的输入有关，还与前一个比特区间内的输入及相位常数有关。costSMSKkkctTsat2=kcos）（tTs2costccos－kakcos）（tTs2sintcsinkTstTsk)1(令kcos＝kI，－kakcos＝kQ则：tSMSK＝kI）（tTs2costccos＋kQ）（tTs2sintcsinkTstTsk)1(为了便于理解如图2.1-2所示：移动通信原理实验指导书-3-1234567891011121314151617181920212223240+1+1+1+1+1+1+1+1+1+1+1+1+1+1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1+1+1+1+1+1+1+1+1+1+1+1+1+1kakkdkcoskkacos)2sin(cosTstakk000000000000000+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1)2cos(cosTstkk图2.1-2码元变换及成形信号波形图根据上面描述可构成一种MSK调制器，其方框图如图2.1-3所示：差分编码串/并转换波形选择地址生成器CosωctSinωctMSK信号波形选择地址生成器EEPROMEEPROMD/A转换器乘法器乘法器加法器（运放）D/A转换器CPLD时序电路低通滤波器时序电路低通滤波器IkQk延时TsNRZ图2.1-3MSK调制原理框图输入数据NRZ，然后通过CPLD电路实现差分编码及串/并转换，得到Ik、Qk两路数据。波形选择地址生成器是根据接受到的数据（Ik或Qk）输出波形选择的地址。EEPROM（各种波形数据存储在其中）根据CPLD输出的地址来输出相应的数据，然后通过D／A转换器得到我们需要的基带波形，最后通过乘法器调制，运放求和就得到了我们需要的MSK调制信号。MSK基带波形只有两种波形组成，见图2.1-4所示：移动通信原理实验指导书-4-波形1波形2图2.1-4MSK成形信号在MSK调制中，成形信号取出原理为：由于成形信号只有两种波形选择，因此当前数据取出的成形信号只与它的前一位数据有关。如果当前数据与前一位数据相同，输出的成形信号就相反（如果前一数据对应波形1，那么当前数据对应波形2）；如果当前数据与前一位数据相反，输出的成形信号就相同（如果前一数据对应波形1，那么当前数据仍对应波形1）。2、MSK解调原理MSK信号的解调与FSK信号相似，可以采用相干解调，也可以采用非相干解调方式。本实验模块中采用一种相干解调的方式。已知：tSMSK＝kI）（tTs2costccos＋kQ）（tTs2sintcsin把该信号进行正交解调可得到：Ik路[kI）（tTs2costccos＋kQ）（tTs2sintcsin]tccos=21kI）（tTs2cos+41kItTsc）（22cos+41kItTsc）－（22cos－41kQtTsc）（22cos+41kQtTsc）（22cosQk路[kI）（tTs2costccos＋kQ）（tTs2sintcsin]tcsin=21kQ）（tTs2sin+41kItTsc）（22sin+41kItTsc）－（22sin－41kQtTsc）（22sin+41kQtTsc）（22sin我们需要的是21kI）（tTs2cos、21kQ）（tTs2sin两路信号，所以必须将其它频率成份）（Tsc22、）（Tsc22通过低通滤波器滤除掉，然后对21kI）（tTs2cos、移动通信原理实验指导书-5-21kQ）（tTs2sin采样即可还原成kI、kQ两路信号。根据上面描述可构成一种MSK解调器，其方框图如图2.1-5所示：MSK信号乘法器乘法器时序电路低通滤波器低通滤波器电平比较器电平比较器抽样判决抽样判决数据还原数据还原时序电路并/串转换差分译码S