基于costas环路的载波同步，使收发时钟频率和相位一致，环路包括四个部分乘法器和低通滤波、鉴相器、环路滤波器和数字振荡器组成-Based on the carrier synchronization of Costas loop, the frequency and phase of the transmit and receive clock is the same. The loop consists of four parts, including the multiplier and low-pass filter, phase detector, loop filter and digital oscillator.