基于频域块LMS算法的实时虚拟暗室测试方法

A Real-time Virtual Chamber Test Method Based on Frequency-domain Block LMS Algorithm

针对电磁辐射现场测试被测设备信号和干扰未知的情况,提出了一种基于频域块最小均方算法的实时虚拟暗室测试方法。该方法采用双通道接收机,根据测试通道和背景通道中干扰信号的相关性设计自适应滤波器,在频域对背景通道信号滤波以趋近测试通道中的干扰分量,采用瞬时双通道信号迭代更新滤波器系数,滤波器系数收敛后系统输出中只有被测设备信号。仿真与分析表明,该方法在背景通道有无被测设备信号泄露的情况下都能有效抑制干扰,与基于时域最小均方算法的方法相比,在滤波器长度相同的情况下其计算复杂度更低,适用于实时现场测试。

Equipment under test(EUT) signal and interference are usually unknown in electromagnetic radiation site test.In order to solve this problem,a real-time virtual chamber test method based on frequency-domain block least mean square(FBLMS) algorithm is proposed.In this method,a dual-channel receiver is used.The correlation of interference signals between test channel and background channel is utilized for adaptive filter design.Background channel signal is filtered in frequency-domain to reach the interference signal in test channel.The filter coefficients are iteratively updated by instant value of input signals in both channels.When the coefficients are converged,the system output only contains EUT signal.The simulation and analysis results indicate that interference can be suppressed effectively by this method,no matter EUT signal leaks in background channel or not.Compared with the method based on time-domain least mean square(TDLMS) algorithm,this method has lower computation complexity with the same filter length,so it is more suitable for real-time site test.