Study On The Cycle Identification Techniques Of Digital Timing Receiver

Timing receiver is the terminal device which is to achieve the timing system functionality and performance, and has the main function of receiving standard time and frequency information from time?dissemination station to synchronize local time signal and standard time signal–UTC (NTSC). When timing receivers receive long and short wave timing signals separately to synchronize time, using cycle identification techniques to identify a specific cycle is necessary. The BPL timing receiver will bring 10us errors at least, and 1ms errors at least for BPM timing receiver if identification of cycle error happens. Obviously, stability and accuracy of time and frequency synchronization? of? timing receiver system depends greatly on accuracy of cycle identification. Based on the status, research on cycle identification technology of the digital timing receiver in this paper are made for the purpose of technique support on developing high performance of BPL and BPM timing receiver.Through the study on principle of operation of BPL and BPM timing receiver, this paper analyzes importance of cycle identification technique in BPL and BPM timing receiver. By studying existing identification techniques, problems are summarized as follows: poor anti-noise performance, cycle-skipping, signal energy waste and difficult selection of crude zero-crossing point, etc. Considering these, this paper proposes a new cycle identification method based on related delay accumulation which has good applicability, identification precision and anti-noise performance.In research of identification cycle, in order to avoid interference of sky wave, sky-wave and ground-wave detection are done based on the IFFT algorithm and MUSIC algorithm. Due to high sampling frequency of intermediate frequency of short wave signal, this paper extracts filtering for BPM through CIC filter. After this, by related delay accumulates method, identify cycle of pre-disposal long and short timing signals separately.Simulation results show that: the cycle identification accuracy of long-wave signal reaches 99% and the identification error is controlled in±5ns; the identification accuracy of short-wave signal reach 99%, and recognition control error in±1.6us. By analyzing and testing actual signal, feasibility and reliability in long and short timing receiver cycle identification using this algorithm are verified.