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为实现在低信噪比以及大频率偏移条件下,恢复出较为准确稳定的原信号,并在实际生活中提高通信质量,提出基于快速傅里叶(FFT)联合卡尔曼滤波器的载波恢复法。首先通过正交变换将所需恢复信号分解为信号单元,将信号分解之后有助于对信号更灵活地去使用,有助于完成下一步算法的进行。将所得信号分解之后的两路信号分别进行快速傅里叶(FFT)和卡尔曼滤波器联合的算法,该方法用快速傅里叶变换(FFT)通过峰值检测来估计频率偏移,用卡尔曼滤波器追踪相位。实验结果表明基于快速傅里叶联合卡尔曼滤波器的载波恢复法对信号的恢复信号有较高的准确性以及稳定性,复杂度低,在硬件上易于实现。仿真结果显示该方法对大频偏和低信噪比信号载波恢复的实现有良好的性能。
In order to recover the original signal with good accuracy and stability under low signal-to-noise ratio (SNR) and large frequency offset (SNR), and to improve communication quality in real life, a carrier recovery based on fast Fourier transform (FFT) combined with Kalman filter law. First of all, through the orthogonal transformation, the required recovery signal is decomposed into signal units. After the signal is decomposed, it helps to use the signal more flexibly and helps to complete the next algorithm. The two signals after the decomposition of the signal are respectively subjected to a combination of Fast Fourier (FFT) and Kalman filter. The method estimates the frequency offset by fast Fourier transform (FFT) through peak detection, Filter tracking phase. The experimental results show that the carrier recovery method based on fast Fourier joint Kalman filter has high accuracy, stability and complexity for the signal recovery signal, and is easy to implement in hardware. The simulation results show that this method has good performance for the carrier recovery with large frequency offset and low signal-to-noise ratio.