中圖分類號：TN929.5 文獻標志碼：A DOI: 10.16157/j.issn.0258-7998.245420
中文引用格式： 秦晴，才智，樂志煒. 一種數(shù)字集群系統(tǒng)中GMSK信號的相偏跟蹤算法[J]. 電子技術(shù)應(yīng)用，2024，50(8)：67-70.
英文引用格式： Qin Qing，Cai Zhi，Le Zhiwei. A phase offset tracking algorithm for GMSK signal in digital trunking system[J]. Application of Electronic Technique，2024，50(8)：67-70.

A phase offset tracking algorithm for GMSK signal in digital trunking system

Abstract： In this paper, the frequency synchronization problem encountered by a domestic trunking system using quasi-coherent demodulation is studied and discussed, and the solution is proposed. Because quasi-coherent demodulation requires very high frequency synchronization accuracy of transceiver systems, it is difficult to meet the requirements by using conventional frequency offset estimation and compensation scheme, which makes the performance advantages of quasi-coherent demodulation unable to be reflected. In order to solve this problem, this paper proposes a segmented phase tracking algorithm. By tracking and compensating the large phase error caused by residual frequency offset after frequency offset compensation, the influence of residual frequency offset on the demodulation performance of the system is reduced, and the obtained demodulation performance is basically consistent with the performance under ideal frequency synchronization. The algorithm proposed in this paper is especially suitable for systems with large frequency offset estimation errors.

Key words : Gaussian Filtered Minimum Shift Keying （GMSK）；digital trunking；quasi-coherent demodulation；frequency offset estimation；phase tracking