Quaternary Differential Phase Shift Keying (DQPSK Modulation Method)

This article explores Quaternary Differential Phase Shift Keying (DQPSK), a widely adopted digital modulation technique. Commonly deployed in digital communications and radio systems, DQPSK enhances data transmission reliability and efficiency by exhibiting robustness against noise and interference during signal propagation. In his seminal work "Communication Principles," Fan Changxin provides comprehensive coverage of DQPSK's theoretical foundations and practical applications. The text illuminates its comparative advantages, limitations, and guidelines for optimizing parameters in real-world implementations. From a coding perspective, DQPSK implementation typically involves phase difference encoding where information bits (00, 01, 10, 11) map to relative phase shifts (0°, 90°, 180°, 270°) rather than absolute phases. Key algorithmic components include differential encoding logic, constellation mapping, and coherent detection with phase comparator circuits. Overall, DQPSK represents a crucial modulation scheme warranting in-depth study for modern communication system design.