All-digital Msk Modulation And Demodulation Algorithm Research

The purpose of communication is transmit the information.Informations have much kinds such as voice.letter,data,symbol and picture etc.Originally data signal has two base kinds,analog and digital.The digital communication has been the important way of modern communication because digital data is more easier to store,process and transmit.Analog data can be filtered and sampled to be the digital data.So the way of signal's modulation was converted from analog to digital continually and widely.This thesis mainly discusses the method of MSK modulation and demodulation.The traditional way of modulation and demodualtion is using the way of analog.But in this thesis,a digital method of accomplishing MSK modulation and demodulation was realized.And the mainly content of this thesis are presented as follows:1.Studying the method of MSK modulation. It is a spcecial type of constant envelope-continuous phase FSK. The rolloff velocity and use rate of the MSK spectrum was improved greatly.2.Realization of signal's digital MSK modulation.The thesis used the priciple of direct digital frequency synthesis to realize the modulation.3.Realization of MSK modulated signals' digital demodulation.The digital MSK demodulation employed the theory of power spectral analysis to demodulate the digital MSK modulated signal.The significance of this thesis is that it employs the most advanced digital technology in the field of communication to realize MSK modulation and demodulation.It is a "SOFT" way.The "SOFT" way used in this thesis is not same as the traditional analog way.It is a fully digital method and has more flexibility:1.It can change some performance if some parameter was altered or the software was upgraded on the same platform.For example,different data tranmmission rate was realized if the sampling frequency was changed in this thesis.2.In the same system,the software's modification can realized modulation of different ways,such as FSK and PSK.3.It isn't easy to be influenced and has strongly credibility,because the digital system only has two tones(high and low).So this method has some practice meaning to the research of nowadays communication technology.