Subcarrier Modulation Of Carry Recovery In Wireless Communication

Today there are a lot of different kinds of communication mode,and under the different conditions need different type of communication.With the constant improvement of the social demand,different type communications are demanded improvement by different requirement.When the transmitter emission high frequency or high power optical signals,the receiver can not received accurate signal under the constraints conditions,so we should receive the signal by the way of sub-carrier modulation,this way has the advantage that we can receive some of the high frequency signal which we can not receive under the normal condition,expand the scope of communication mode,satisfy the needs of social communication.The signal pass in space,due to the receiver hardware or transmission medium about main or guest factors,which can lead to the signal frequency offset and phase offset when receive the signal,and received signals do not agree with the original signal,affect the normal work and life.In order to correct the frequency offset and phase offset,and received signal accurately,carrier synchronization is necessary step into the receiving part which also called carrier recovery.This paper mainly studied the sub-carrier modulation of carrier recovery and the structure of carrier recovery and simulation implementation.The carrier recovery method in the article are corresponding digital simulation implementation,which ensure we can improve compute function.In this paper related work are listed below:First,introduce the background to sub-carrier and sub-carrier modulation.In this paper,the subcarrier physical diagram and conversion principle of photoelectric conversion are introduced. Introduce the DPSK signal and 16 PSK signal modulation and demodulation process,and using MTALAB simulation and comparison.Second: Described the development history of carrier recovery method and the research background.Introduce previous carrier recovery method,and points out that under different circumstances different methods in the high and low signal-to-noise ratio, the advantages and disadvantages of excessive frequency on the cases and comparison.Separate the recovery method of carrier phase and frequency,The phase shift of maximum likelihood method andhistogram method simulation analysis and comparison, use a decision auxiliary frequency offset,Auxiliary and M&M algorithm for recovery simulation data analysis and comparison.Third:Using photoelectric conversion equipment and hardware equipment,Link up with a set of 16 PSK subcarrier to send and receive equipment,the related introduction of the device hardware, prepared to hardware for after 16 PSK subcarrier recovery.Fourth:On the basis of the previous step,after obtaining contains noise 1 PSK subcarrier signal,in this paper, the use of fast Fourier transform and joint Coleman filter is carrier recovery method will be acceptable to the subcarrier carrier recovery,Proved that the method in the frequency and under the condition of high SNR has a stable performance,Comparing with other ideas and simulation.