『摘 要』随着社会的不断发展,通信对我们来说越来越显的重要.对于通信技术来讲,通信的质量也就显的非常的关键.通信的根本任务是如何保证远距离传输信息的正确性，在这方面数字通信系统具有先天的优势。这主要是因为数字通信系统中传输的是离散的数字信号，由于信号是离散的，被噪声干扰后的信号只要没有超过门限，接收端就能够完全正确地判断出传输的信息；而对于模拟传输系统，只要有稍微的干扰都会使传输的信息产生错误。也正是由于这样的原因，数字通信系统才能在各方面逐渐代替模拟通信系统成为现代通信的最基本方式。为了便于区别信号与噪声，使通信不失真和不受干扰,往往给测量信号赋以一定特征，这就是调制的主要功能。调制就是用一个信号（称为调制信号）去控制另一作为载体的信号（称为载波信号），让后者的某一特征参数按前者变化。再将测量信号调制，并将它和噪声分离，放大等处理后，还要从已经调制的信号中提取反映被测量值的测量信号，这一过程称为解调。为了更好地利用通信信道的带宽并使信号能够传送更大的距离, 在数字载波通信中,我们采用了三种解调方式: 幅移键控（ASK）频移键控（FSK）和相移键控（PSK）。调制信号为二进制信号的调制称为二进制数字调制, 二进制调制又分为二进制幅移键控（2ASK）、二进制频移键控（2FSK）、二进制相移键控（2PSK）和差分二进制相移键控（2DPSK）等多种基本的类型，本课题主要是数字频率调制又称频移键控（FSK）。同时利用system view软件实现对FSK系统的仿真和分析，从而通过运用模拟的视觉化的手段来实现达到解调调制的目的。
『关键词』数字通信；FSK信号；非相干数字解调
Summary
Along with society of continuously development, correspondence more and more show to us of importance.Speak for the correspondence technique, the quality of the correspondence also show very of key.Correspondence of root mission is how assurance long-distance leave to deliver an information of accuracy, in this aspect numeral correspondence the system have inborn of advantage.This main is because of numeral correspondence what to deliver be long-lost in the system of numeral signal, because of the signal be long-lost, drive Zao voice interference empress of signal want ～only have no exceed threshold, receive to carry can complete with accuracy judgment the information for deliver;But for imitate to deliver system, as long as have a little bit of the interference will make the information creation for deliver false.Is exactly also because of so of reason, numeral correspondence system then can in everyone's noodles gradual replace imitate correspondence system to become modern correspondence of the most basic way.For the sake of easy to differentiation signal and Zao voice, make correspondence don't lose true with be free from interference, usually give diagraph signal to endow with with certain characteristic, this be the main function for make.Make is the signal(be called to carry a signal) which use a signal(be called to make signal) to carry a body to control's another a conduct and actions, let the latter of some characteristic parameter press the former variety.Will measure signal to make again, and will it with Zao voice separate, after enlarge etc. processing, return want to withdraw reflection from have already make of the signal quilt measured value of measure signal, this process be called solution to adjust.The bandwidth using correspondence letter way for the sake of better land utilization also make signal can transmission larger of distance, in the numeral carry the wave the correspondence, we adoption three kinds of solution adjust a way: Move key to control(ASK) Pin to move key to control(FSK) with mutually move key to control(PSK).Make signal be called binary system numeral to make for the make of binary system signal, the binary system make and is divided into a binary system to move key to control(2 ASK), the binary system Pin move key to control(2 FSK), the binary system mutually move key to control(2 PSK) with bad cent the binary system mutually move key to control(2 DPSK) etc. variety basic type, this topic main is numeral the frequency make and call Pin to move key to control(FSK).In the meantime make use of system view software realization to imitate FSK system true with analysis, pass an usage imitate thus of the sense of vision turn of means to realization attain solution to adjust of purpose.
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