MATLAB Implementation of QPSK Simulation with COSTAS Loop Carrier Recovery

This QPSK simulation program employs a COSTAS loop for carrier recovery and is designed for seamless integration with SIMULINK. The implementation provides a robust framework for simulating and evaluating QPSK modulation performance through systematic demodulation processes that recover both carrier signals and transmitted data. The simulation architecture includes configurable parameters such as signal-to-noise ratio (SNR), multipath fading scenarios, and phase error adjustments, allowing engineers to analyze their impact on system performance. The code implementation features real-time waveform visualization and spectral analysis displays, enabling intuitive observation of signal characteristics. Key algorithmic components include: - Quadrature Phase Shift Keying modulation/demodulation algorithms - COSTAS loop implementation with phase detector and voltage-controlled oscillator (VCO) - Error vector magnitude (EVM) calculations for performance metrics - Bit error rate (BER) analysis modules This simulation serves as a powerful analytical tool for deep investigation and optimization of QPSK systems, providing valuable insights for communication system design and performance enhancement. The modular structure allows for easy parameter modification and extension to more complex modulation schemes.