A new lock detection algorithm for Gardner's timing recovery

This paper proposes a new lock detection algorithm for timing recovery, which can be used in the all-digital receiver of BPSK, QPSK or QAM. This lock detector needs only 2 signal samples, associated with the Gardner timing error detector (GA-TED).It can show whether the timing recovery loop is locked when GA-TED working. In the paper we represent that the new lock detector algorithm is just sensitive to signal-to-noise rate, but not to signal amplitude attenuation or carrier offset, by Matlab simulation and performance analysis. The new lock detector algorithm is especially suitable for the system that the timing recovery precedes the carrier synchronization and can be easily implemented in FPGA. The new lock detection algorithm has been applied to our project successfully.