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QPSK(四相绝对相移键控)是数字卫星电视系统采用的数字调制技术,它具有抗干扰能力强、频谱利用率高、电路实现简易等优势。在HFC网络架构中,从用户线缆调制解调器发往上行通道的数据亦采用QPSK调制方式。在QPSK信号调制解调体系中,载波同步是信号解调的关键技术,本文在论述QPSK调制原理及解调方案的基础上,研究、分析了QPSK信号的载波同步原理及实现方案,并在FPGA中仿真实现。
QPSK (Quadrature Absolute Phase Shift Keying) is a digital modulation technique used in digital satellite television systems. It has many advantages such as strong anti-interference ability, high spectrum utilization and simple circuit implementation. In the HFC network architecture, the data sent from the user cable modem to the uplink channel also uses QPSK modulation. In QPSK signal modulation and demodulation system, carrier synchronization is the key technology of signal demodulation. Based on the discussion of QPSK modulation principle and demodulation scheme, this paper studies and analyzes the carrier synchronization principle and implementation scheme of QPSK signal, In the simulation.