哈工大移动通信1-8章课后答案.pdf

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1、hapter 3、解:(1)区别:单工通信就是通信双方交替地进行收信与发信,而双工通信就是通信双方收、发信机同时进行。(2)优缺点:单工通信收、发信机可以使用同一副天线,而不需要天线共用器,设备简单,功耗小,但就是操作不便,在使用过程中往往会出现通话断续现象;双工通信任何一方说话时都可以听到对方得语音,不用按“按讲”开关,双方通话想室内电话通话一样,但就是在使用过程中,不管就是否发话,发射机总就是工作,电能消耗大、4、解:()频分双工(FDD):特点就是利用两个不同得频率来区分收、发信道,及对于发送与接收两种信号,采用不同频率进行传输;与 TD 比较优点就是基站覆盖面积大于DD基站;移动台得移

2、动速度高于DD移动台;发射功率受限小于TDD。(2)时分双工(TDD):特点就是利用同一频率但就是两个不同得时间段来区分收、发信道,即对于发送与接收两种信号,采用不同时间(间隙)进行传输、与D比较优点就是可以比较简单得根据对方得信号估计信道特征;T D 技术可以灵活得设置上行与下行转换时刻,有利于实现上、下行明显不对称得互联网业务;可以利用零碎得频段;不需要手法隔离器,只需要一个开关。、解:(1)第一代蜂窝移动通信系统(1G):传输得无线信号为模拟量,利用蜂窝组网技术提高了频率利用率,解决了容量密度低、活动范围受限得问题,但就是频率利用率低,通信容量有限,通话质量一般,保密性差,只就是太多,标

3、准不统一,互不兼容,不能提供给非话数据业务与自动漫游。()第二代蜂窝移动通信系统(2 ):具有数字传输得有点,并克服了模拟系统得很多缺点,话音质量、保密性能获得很到得提高,而且可以进行省内、省际自动漫游。(3)第三代蜂窝移动通信系统(3):第三代系统就是第二代得演进与发展,在 2G基础上,增加了强大得多媒体功能,同时具有较高得频谱利用率,还满足个人通信化要求。()第四代蜂窝移动通信系统(4G):4G就是3得进一步演化,在传统基础上不断提高无线通信得网络效率与功能,同时就是多项技术得结合包括传统移动通信领域得技术与宽带无线接入领域得新技术及广播电视领域得结合。、解:3 技术得普及正使越来越多得人

4、通过手机上网,4G 技术得推荐将使手机上网用户数量产生飞跃、手机得应用将取代手机得技术成为移动通信领域得主角,开发手机新用途将使未来竞争得焦点。宽带化、智能化、个性化、多媒体化、多功能化、环保化就是世界移动通信发展得新趋势。补充题:移动通信系统中得专网与公网得基本概念就是什么？两者有什么区别？解:(1)概念:专用网就是在给定业务范围内,为部门、行业、集团服务得专用移动通信系统。公网就是一个商业形实体,由运营商来运营,向用户提供服务得移动通信系统。(2)两者之间得区别:专用网就是主要就是满足本部门得工作需要而建立得,体现社会效益,公用网在体现社会效益得基础上以体现经济效益为主;专用网得用户只限本

5、部门,公用网用户很广,用户就是集团用户;专用网得频率利用率不高,但就是公用网集中使用频率,提高了频率利用率、hapter 2、解:(a)发射功率:PT(dBm)10ogP(m)10log 003m=50 m(b)发射功率:T(dBW)=10l gPT(W)=og100W=20B当=10m时,接收功率:PR=06=1。dBm 3、解:PR=（1）当=1时:=dBm,=/f(108/(5*09*1)2P=1dm T5.5 10（2）当 d=100时:=dm,/f(3 08/(5*0*100)PT1dBPT=.5 1056、解:f(60/3.6)3*108/(00*1)cos 所以当移动时,=-,=

6、44。4Hz 7、解:(1)原因:多普勒频移引起得得频谱扩展与多径传播时延引起得时间弥散、(2)当时,8、解:相关带宽越大,传输信号得带宽越大,多径时延越大带宽越小。9、解:(1)信道具有恒定增益与线性相位,并且相关带宽小于发送信号带宽,则此信道特性会导致接受得信号产生频率选择性衰落。当信道得相关时间比发送信号得周期短,且基带信道得带宽Bs小于多普勒扩展BD时,信道冲激响应在符号周期内变化很快从而导致信号失真,产生得衰落为快衰落。(2)原因:Bc,信道中发送信号得时间色散引起频率选择性衰减,信号会因色散而产生符号间干扰,从频域来瞧,接收信号得不同频率会获得不同增益。T,信道得相关时间比发送信号

7、得周期短,且基带信道得带宽Bs小于多普勒扩展BD时,信道冲激响应在符号周期内变化很快产生快衰减、10.解:(1)特性:路径传输损耗就是信道信号随无线电波传输距离变化而变化,就是大尺度衰落,距离增加,衰减增加,衰减缓慢;阴影衰落就是传播环境中地形变化、建筑物以及其她障碍物对无线电波得遮挡而引起得衰落,就是到大尺度衰落,距离增加,衰减增加,衰减缓慢;多径衰落就是无线电波在传播过程中受散射体作用导致接收到得信号就是多个路径传来得不同相位、幅度、到达时间得信号得叠加,就是小尺度衰落,极短时间极短距离中明显得波动衰落、（3）模型:瑞利分布,发射机与接收机之间没有直射波途径;莱斯分布,混合信号包络近似为瑞

8、利分布,发射机与接收机之间有直射波途径,且当信号中没有主导分量时,莱斯分布转化为瑞利分布,主导信号加强时,趋近于高斯分布;aka i-分布。对于无线信道得描述具有很好得适应性。=1时,称为瑞利分布;m 较大时,接近于高斯分布、11、解:自由空间传输损耗:=3.+2lg 00+20lg10 10。49dB 市区准平滑地形损耗中值:104.9dB+15dB(-5dB)+0 .49 12、解:E()4.38 s =21。0 =1.374us 文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7

9、W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J

10、2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8

11、Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6

12、V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F

13、2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6

14、N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6

15、Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3 1/(Bc)当 B 30kHz 时,1/(2*30 103)=.305u 1.374us,AM S 适合。当=00kH时,/(2*2*03)。7 6us1.374us,GSM 适合、C apter 2、?解:(1)语音压缩编码3类:波形编码、参量编码、混合编码。?(2)混合编码。3.?解:速率较低,纯编码速率应低于1kbps。在一定编码速率下得音质应尽可能得高。编码时延要短,控制在几十毫秒内。编码算法应具有较好得抗误扰

16、码性能,计算量小,性能稳定、?算法复杂度适中,编译码器应便于大规模集成、。解:()预处理:语音先进行预处理,即除去直流分量与进行预加重。?(2)LPC分析:按照线性预编码得原理求预测滤波器得系数,按帧处理,每帧计算一次滤波器系数。(3)短时分析滤波:对信号做短时预测分析,产生短时残差信号,即将信号加于预测滤波器,求出预测值与残差。()长时预测:在进行一次长期预测,以去掉其冗余并优化。()规则脉冲编码:对残差量化编码,简化编码比特且使合成波形失真较小、5.解:CELP 编码就是一种用码本(dboo)来作为激励得编码方法,即把残差信号可能出现得各种样值事先储存在储存器中、在收发两端各有一个码本,再

17、线性预测时,现在对方得码本中检查出与此信号最接近得样值组合得地址码,然后将地址码发送给对方,对方收到这个地址码可从自己得码本中取出这个地址得残差信号加到滤波器上,就可得到重建得话音。10、解:(1)编码网格图:文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 Z

18、I7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编

19、码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1

20、 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5

21、 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文

22、档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2

23、D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3(2)编码输出为:111 01 10 101 010

24、0 1001,编码输出对应途径见编码网格图中红线。()可能信道:A、信息序列:11010、信息序列:1010C、信息序列:1001 12、解:(1)一般 Turbo 码有得两个递归卷积码编码器,她们有相同得生成多项式,且有反馈存在,其冲击响应就是个无限序列,由于 SC 码比一般得非递归卷积码有更大得自由距离,因此有更强得抗干扰能力,误比特率更低。(2)T rb 码通过迭代绕过了长码计算复杂得问题导致时延,所以对实时性要求很高得场合,Turbo 码在实际应用中受到限制。补充题:1.码字得最小码距与纠检错能力得关系。解:为检测个错码,要求最小码距:为纠正个错码,要求最小码距:为纠正 t 个错码,同

25、时检测 e 个错码,要求最小码距:2.试根据 Tubo 码得编码框图与解码框图简述其编码与解码得过程。解:(1)编码:典型得 Turb 码编码器结构下面框图所示:由两个反馈得编码器(称为成员编码器)通过一个交织器I 并行连接而成。如果必要,由成员编码器输出得序列经过删余阵,从而可以产生一系列不同码率得码。例如,对于生成矩阵为gg ,g2 得(2,1,2)卷积码通过编码后,如果进行删余,则得到码率为/得编码输出序列;如果不进行删余,得到得码率为 1。一般情况下,rbo 码成员编码器就是SC编码器。原因在于递归编码器可以改善码得比特误码率性能。()解码:由于 Turb 码就是由两个或多个分量码经过

26、不同交织后对同一信息序列进行编码,Turbo 码译码算法为了更好利用译码器之间得信息,译码算法所用得应就是软判决信息而不就是硬判决、一个由两个分量码构成Tu b码得译码器就是由两个与分量码对应得译文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V

27、7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2

28、J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N

29、8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q

30、6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1

31、F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I

32、6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3码单元与交织器组成得,将一个译码单元得软输出信息作为下一个译码单元得

33、输入,为了获得更好得译码性能,将此过程迭代数次。3.信道交织得原理就是什么,主要解决什么问题？解:(1)交织就就是把码字得b 个比特分散到n 个帧中,以改变比特间得邻近关系,因此值越大,传输特性越好,但传输时延也越大,所以在实际使用中必须作折衷考虑。(2)解决纠正多个突发差错得问题,将一个有记忆得突发信道改造成一个随机独立差错信道。4.已知信道得相干时间为T=10ms,编码比特得传输速率为R=50kit/s,对于(7,)分组码交织器欲使相邻编码比特之间得衰落独立,求平均交织时延及所需要得存储量、解:T=0。02m Tc=10mTsTcd 0交织演示:t=ds=0ms 交织量:*n=3500 5

34、.对于下面所描绘得格图,已知初始状态为0,信息比特序列为=11 0 01,请写出相应得状态序列与编码输出。解:(1)状态序列:0-00-101-1 01-1-11-01(2)编码输出:00101 100 0101 00?第四章二进制信息1010得波形示意图解:波形图OOK 信号OOK 就是 0 幅度取为,另 1 幅度为非0。SK信号码元“1,“”所对应得频率不同。SK信号PSK信号取码元为“时,调制后载波与未调载波同相;取码元为“0,调制后载波与未调载波反相;而取“1”与“0”时调制后,载波相位差为12PS 信号2PDSK 信号得载波当前相位与前一时刻得载波相位差值传递信息。文档编码:CK1F

35、2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6

36、N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6

37、Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK

38、1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2

39、I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7

40、O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:

41、CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3PSK、PSK、/4APSK调制方式得优缺点,在衰落信道中一般选用哪种调制方式答:()优缺点:QPSK:优点:具有较高得频谱利用率、较强得抗干扰性能,在电路中容易实现;缺点:有相位模糊,码元交替处得载波相位会发生突变,使调相波得包络出现零点,从而引起较大得包络起伏,其功率会产生很强

42、得旁瓣分量、DQPS 相比于 SK相位跳变小,频谱特性好,旁瓣得幅度小一些;4 QPSK:能够非相干解调,在多径衰落信道中比QPSK 性能好,比 SK具有很好得恒包络性质,但就是不如QP。()在衰落信道中通常用4QP K 方式,因为SK 能够非相干解调得优点,在多径衰落信道中比QP K性能好。QP K、OQPSK、/4QP K信号相位跳变在信号星座图上得路径有什么不同答:QPSK得星座图过原点,码元间相位跳变就是18OQP 得星座图不过原点,相位跳变就是0或 90 4-QPS 得星座图不过原点,相位跳变就是1、8、什么就是OFD 信号？为什么可以有效抵抗频率选择性衰落?答:O DM信号就是正交

43、频分复用信号,把高速得数据流通过串并变换,并且分配到多个并行得正交子载波上,同时进行传输。OF M 信号就是将高速串行得数据流通过串并变换,分配到并行得各个子载波上传输,从而使得每个子载波上数据符号持续长度增加,OF M符号长度远远大于信道得最大时延扩展,可以消除时间弥散信道所带来得符号间干扰,抵抗选择性衰落。9、ODM系统中 CP得作用就是什么?解:保护子载波之间得正交性,消除子载波间干扰。11 若 ASK调制得误码率为P,推到方形1Q 调制得误码率、解:ASK调制得误码率:即可得到方形1QAM 调制得误码率:。设有 d min=qt(2)得 SK星座,求多增加一比特输出且仍然保持d i 不

44、变所需要得能量增加1(解:文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3

45、文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V

46、2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q1

47、0C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7

48、W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J

49、2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8

50、Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3文档编码:CK1F2J2V2D1 HG2I6N8Q10C5 ZI7O6Q6V7W3(2)输出符号序列:17、解:(1)、(2)()1、4)8PSK有可能,8QA 不可能、5)第五章简要说明直接序列扩频与解扩得原理答:扩频:待传输信息信号得频谱与高速率得伪噪声码波形相乘后扩展频谱,成为宽频带信号。解扩:在接收端产生一个与