A Based On The Maximum Likelihood Algorithm Of Symbol Synchronization And Demoduation Of CPM Singal

Modulation and demodulation technology in wireless communication system is animportant technology, one of the key links.With the application of software radiotechnology and promotion, digital modulation techniques for digital communicationsystem affect the performance of the system gain.In engineering practice, select the modulation frequency spectrum characteristicsof efficient, excellent, which helps lower spectral bandwidth of the modulated signal,improved modulation spectrum utilization, improves the capacity of wirelesscommunication system, improving transport performance.Topics in this paper is the study of continuous phase modulation, modulationprinciple, as well as several representative, engineering analysis of continuous phasemodulation technique applied on a broader: CPFSK, GMSK, TFM.Topics first on FM modulation scheme for initial discussion, and has focused oncomparative analysis and non-continuous phase modulation technique of continuousphase modulation technology in a spectrum of differences, advantages anddisadvantages, as well as on the implementation.Stated that in the wireless communication, continuous phase modulation (CPM)channel fading resistance, on band utilization has great advantages, it is an advanced,merited in-depth study of modulation techniques. Papers focus on a CPM simulationdesign and realization of continuous phase modulation, demodulation using maximumlikelihood of demodulation method for signal processing, and finally afterimplementation of demodulation algorithm engineering, updated through the wholetesting way reflect algorithm performance advantages.Thesis work accomplished for CPM technologies mainly include: in-depthresearch and analysis on the principle of continuous phase modulation, modulation endof building and design system framework, modular design in simulation, divided intopseudo-random sequence generation, base-band filter, forming phase additivebaseband modulation. Use of hardware description language VHDL Design, block design, simulation output eventually modulated baseband IQ signal has beentransferred on the sending side. In-depth study and inference based on maximumlikelihood symbol detection algorithm for demodulation of CPM signals, from thefundamentals of algorithms to the specific design of engineering practice, taking intoaccount the performance and physical sexual, proposed and details of derivationoptimizing technology. At the same time, symbol detection based on maximumlikelihood techniques can also be applied to the symbol CMP signal synchronization,papers on the theory and design schema also has in-depth studies. CPM simulationperformance test system, study on demodulation algorithm brings the receivesignal-to-noise ratio/BER performance improvement. At the same time, algorithmtechnology applied to a military wireless microwave transmission equipment, up ondemodulation technique before, system gain significantly improved.