Carrier phase lock loop based on four-way signal processing

Under a certain carrier noise ratio (CNR), the threshold of carrier tracking loop is mainly affected by the dynamic stress. Costas phase lock loop (PLL) is one of the most common carrier tracking loop, but it is too sensitive to the dynamic stress because of the limited frequency pull-in range. The frequency pull-in range of phase lock loop is determined by the maximum phase pull-in range. The phase pull-in range of classic Costas PLL based on two-way signal processing is just[-π/2, π/2], which is not good enough to track the carrier in dynamic environment. Therefore, a new four-way signal processing was proposed and applied into the Costas PLL, which can improve the phase pull-in range to[-3π/4, 3π/4]. In the proposed method, the π/4 and 3π/4 way signal processing were added to the classic Costas PLL to construct four-way signal processing. The simulation results show that the proposed four-way signal processing PLL can significantly improve the dynamic performance of the receiver.