基于叠加Chirp信号的载波频率捕获方法研究

Research into Acquisition Method of Carrier Wave Frequency Based on The Superposition Chirp signal

以Chirp信号作为参考序列,以弱功率直接与成型滤波后的有用数据叠加,然后经载波调制发送,节约了带宽资源和功率资源。在接收端利用Chirp信号的恒包络性和Chirp信号在相应分数阶傅里叶域的时频聚集特性,对接收信号进行分数阶傅里叶变换(FRFT),搜索到峰值坐标、完成Chirp信号参数估计,从而得出载波的多普勒频偏和频偏变化率,完成载波捕获,并抵消掉叠加信号,经仿真验证,该理论方法可行。

Taking Chirp signals as a reference sequence,Chirp signals with weak power are directly superposed on the effective data after moulding and filtering,then the signals are modulated and sent by carrier wave,which saves bandwidth resource and power resource.The constant envelop characteristics of Chirp signal and the time-frequency clustering characteristic of Chirp signal in corresponding fractional step Fourier domain are used to perform fractional Fourier transform（FRFT）to the received signals,the coordinates of peak value is searched,and the parameters of Chirp signal is estimated,thereby the Doppler frequency deviation and its change ratio of carrier wave are acquired,so the carrier wave is acquired and the superposed signal is counteracted.The theory method is feasible through simulation validation.