An Improved Lock Detection Algorithm for Costas Loop
Zhu Nan, Wenquan Feng, Zhang Shilong, Liu Suxiao · 2012
The Costas loop is the most common carrier synchronization structure in receiver using BPSK modulation. Reliable detection of carrier lock condition is important to the BPSK receiver. In this paper, an improved lock detection algorithm for Costas loop is proposed. First, the mathematical model and the hardware structure of the algorithm are proposed, and then theoretical derivation is given. Through the analysis of performance, the criterion of choosing lock threshold is presented. Simulation results show that using the signal power in normalization can eliminate the impact of input signal power changes. The algorithm work reliably when Es/N0> 1dB, at this time, the estimation error of Es/N0 is less than 1dB. And it's verified through a number of model experiments with good results.