Construction and Simulation Analysis of a QPSK Modulation and Demodulation Model

Phase shift keying (PSK) modulation is an important modulation method in signal processing, and it has many advantages compared with other modulation methods. QPSK transmits 2 bits per symbol which means the higher spectral efficiency. QPSK is also good trade-off between complexity and performance. In order to better understand the modulation mode of QPSK, this paper establishes a basic QPSK modulation and demodulation model. With the help of MATLAB simulation software, waveform diagram, spectrum diagram, power spectrum diagram, eye diagram and other graphics are used to visualize the changes of signals in each process of QPSK system. And the simulation results are consistent with the theory, which verifies the validity of the model and compare the advantages of QPSK modulation versus other modulation methods. QPSK modulation has wide applicability and can be applied to a variety of information transmission environments, such as cellular network, Wi-Fi, satellite communication and OFDM-based systems. QPSK is very useful for later research on more complex modulation methods.