不同方式解调下FSKPSKDPSK的误码率比较.doc

摘要 一般来说，数字解调与模拟调制的基本原理相同，但是数字信号有离散取值的特点。因此数字调制技术有两种方法：1 利用模拟调制的方法去实现数字式调制，即数字调制看成是模拟调制的一个特例，把数字基带信号当做模拟信号的特殊情况处理；2 利用数字信号的离散取值特点通过开关键控载波，从而实现数字调制。这种方法通常称为键控法，比如对载波的振幅，频率和相位进行键控，便可获得振幅键控（Ampolitude shift keying, ASK）、频移键控（Frequency shift keying,FSK）、和相移键控（Phase shift keying，PSK）三种基本的数字调制方式。这次为期一周的通信传输课程设计的实习,就是通过MATLAB编程仿真,来更好的理解FSK、PSK、DPSK的调制和解调过程。在这次的实习中，主要是应用MATLAB进行编程仿真并显示结果。仿真的是FSK的相干、非相干和过零解调，PSK的相干解调及DPSK的相干和差分解调。并比较相同调制后的信号不同的解调方式和不同调制后的信号相同的解调方式。 关键字：频移键控，相移键控，误码率，信噪比 ABSTRACT Generally speaking, digital demodulation and analog modulation of the basic principles of the same, but the digital signal has the characteristics of discrete values. Therefore, digital modulation techniques, there are two methods: one using analog modulation methods to achieve digital modulation, digital modulation that is seen as a special case of analog modulation to digital baseband signal as an analog signal a special case; 2 using digital signal characteristics of discrete values by keying switch carrier in order to achieve digital modulation. This method is usually referred to as keying method, such as the right carrier amplitude, frequency and the phase shift keying, can receive amplitude shift keying (Ampolitude shift keying, ASK), frequency shift keying (Frequency shift keying, FSK), and the phase shift keying (Phase shift keying, PSK) digital modulation of three basic ways. The week-long internship curriculum design communication transmission is through MATLAB simulation program, to a better understanding of FSK, PSK, DPSK modulation and demodulation process. In this attachment, the main is the application programming MATLAB simulation and displays the results. Simulation is the FSK coherent, non-coherent and zero-crossing demodulation, PSK and DPSK coherent demodulation of coherent and differential demodulation. And compare the same modulated signal demodulation in different ways and different modulated signal demodulation the same way. Keywords: Frequency shift keying,