在研究数字信号处理的过程中,可以采用数字带阻滤波器方法来进行消除交流电产生的工频干扰,但是传统的数字滤波器在起始位置存在畸变。利用双线性变换的方法将模拟带阻滤波器转换为数字带阻滤波器,借助离散时间系统中Z变换后的系统函数设计相应的数字带阻滤波器,以此来去除被测信号中的干扰信号,并通过两种简单算法来消除数字滤波器在起始位置的畸变。对一仿真混合正弦信号进行测试,试验表明,该滤波器可以很好地消除50 Hz 的工频干扰,且该方法具有设计简单、应用方便、实用性强等特点。

In the study of digital signal processing,digital band-stop filter approach is used to resolve power frequency interference which is from the alternating current.However,distortion is generated in the starting position with traditional digital filter.Using the system function in the Z-transform of discrete-time system,and converting analog-stop filter to bilinear digital-stop filter,we design an appropriate digital band-stop filter to remove the signal interference.It can eliminate the digital filter distortion of the starting position.Simulation results of a mixed sinusoidal signal show that the interference signal could be eliminated at 50 Hz frequency by the designed filter.The method has the advantages of simple design,convenient application,strong practicability and so on.