MATLAB-Based Modulation and Demodulation

This article provides a detailed exploration of MATLAB-based modulation and demodulation techniques. We begin by introducing fundamental concepts of modulation and demodulation, then delve into various modulation schemes including amplitude modulation (AM), frequency modulation (FM), and phase modulation (PM). The implementation typically involves MATLAB's Communication Toolbox functions such as ammod() for amplitude modulation and amdemod() for demodulation, where users can specify carrier frequencies and modulation indices.

We further examine the concept of Signal-to-Noise Ratio (SNR) and demonstrate how to simulate and analyze modulation system performance in MATLAB using functions like awgn() to add white Gaussian noise and berawgn() to calculate bit error rates. The analysis includes studying the impact of different noise types (additive white Gaussian noise, phase noise, etc.) on system performance through Monte Carlo simulations.

The article also covers optimization techniques for improving system performance, such as implementing matched filters using fir1() function and employing error correction codes with MATLAB's Error Correction Coding toolbox. Practical implementation case studies include digital communication systems using QAM modulation with qammod() function and frequency-shift keying (FSK) implementations using fskmod(), demonstrating real-world applications in wireless communications and signal processing.