数字GFSK调制解调的算法与实现

摘要

Gaussian frequency shift keying（GFSK） modulation is widely used in low data-rate wireless audio/video transmission and personal communication standards like Bluetooth.For the purpose of low power and low cost,GFSK transceivers are usually designed in the analog domain.To improve bit error rate（BER）performance and the integration capability for diverse and complicated applications,the digital GFSK demodulation technology becomes attractive.In this letter,least squares（LS） and maximum likelihood（ML） methods are exploited for decision-aided carrier recovery in a GFSK receiver.Through the analysis of estimation error variance,we show that the LS/ML carrier frequency offset estimation method outperforms the conventional method using the DFT approach.Besides,the new method is also effective to deal with non-DC-free data sources.The complete GFSK transmission simulation is performed and almost ideal BER performance is achieved in the additive white Gaussian noise environment through the MATLAB simulation.%高斯频移键控（Gauss frequencyShift Keying,GFSK）是一种广泛应用于低数据速率的个人通信标准（如蓝牙）的调制方式。限于低功耗和低成本,GFSK收发机通常在模拟域设计。为了改进误比特率和提高不同的复杂设备之间的综合能力,数字GFSK调制解调技术应运而生。在该文,将着重讨论最小平方（LS）与最大似然估计法（MS）是利用计算机辅助技术来实现GFSK载波恢复。通过估测误差方差的分析,我们发现LS/ML载波频率偏移估计法优于传统DFT法。除此之外,本方法也能有效地处理直流的数据源。通过在MATLAB上进行仿真,在高斯白噪声环境中实现了理想误码率的GFSK传输仿真。