A comparative simulation study of the real effect of PCM, DM and DPCM systems on audio and image modulation

摘要

In order for a message to be feasible for transmission, it has to pass through an essential process which is “modulation”. Through years, Pulse Code Modulation (PCM), Delta Modulation (DM) and Differential Pulse Code Modulation (DPCM), in digital communication systems, have proven their unlimited advantages over analog communication systems, in terms of error minimization and distances of transmission enhancements. However, Pulse Code Modulation system still has some weaknesses limiting its advantages; these limitations cause quantization error, slope overload distortion and granular noise which are results of negative communication process. Since Delta Modulation is a simplified version of Pulse Coded Modulation, it has to have the same negative points related to noise and quantization. Consequently, communication engineers have developed additional digital communication systems, one of which is the Differential Pulse Coded Modulation (DPCM) in order to solve the aforementioned problems. This paper discusses the implementation of the aforementioned systems using Simulink (The Math Works, Inc., USA) on a multithreaded processor computer. The systems are to be tested on both image and audio inputs, to prove the importance of DPCM over PCM system in eliminating such effects and ensuring a successful transfer of data.