Simulation on the design of digital pulse position modulation system

Abstract

Pulse Position Modulation (PPM) is an important modulation method in communication systems, which plays an important role in many branches. This paper is designed to investigate the basic principles and processes of PPM modulation, to derive the results of each branch of this project, to analyze the advantages and disadvantages of Pulse Position Modulation, and to determine the appropriate application direction for PPM and the scope for remediation. This project is based on the MATLAB software and uses a PPM signal with only four symbols to carry out modulate and demodulate it in four steps, thus completing this project. In the first part, PPM signals are generated in the form of a random sequence of Gray codes, resulting in a large number of points; Then, the generated signal passes through a Gaussian white noise channel, and the modulation points are placed on a constellation diagram of the PPM plane for observation. After that, demodulation is performed by using the minimum distance discrimination method, and some error points are listed. Finally, the SER vs SNR curve is plotted. This project can basically explain the working principle of PPM, help researchers to get familiar with the PPM modulation process, and make it easier to choose how to work with communication in practice. It will guide the research direction on how to improve the accuracy of PPM in the future to broaden the application of this method.