Power Spectral Density and Constellation Diagrams of QPSK Modulation with Rectangular and Root Raised Cosine Pulses under Different SNR Channel Conditions

In this documentation, we implement QPSK modulation with rectangular pulses and root raised cosine (RRC) pulses using MATLAB. Our investigation focuses on analyzing their power spectral density characteristics and observing corresponding constellation diagrams under different signal-to-noise ratio (SNR) channel conditions. Key implementation aspects include: - Pulse shaping functions for rectangular and RRC pulse generation - QPSK modulator/demodulator with proper symbol mapping - AWGN channel simulation with configurable SNR levels - Power spectral density calculation using FFT-based methods - Constellation diagram visualization with scatter plots To obtain all results, simply execute the main function which integrates all modules sequentially. Through these experiments, we gain comprehensive insights into QPSK modulation performance characteristics and the impact of channel conditions on signal integrity. The code automatically generates comparative analyses between pulse shaping techniques and their behavior under varying noise conditions.