Abstract:Anti-aliasing filters have been widely used in electronic instruments. The cut-off frequency and resonance coefficient of the filter are the two main parameters of the design, and the other important parameter, the transient process of the dynamic response, also needs to be considered. However, an important factor affecting the data acquisition rate of ECT system is the time delay of the filter. Therefore, the design of anti - aliasing filter is discussed. The step response of LPF is studied by theoretical analysis, simulation and experiment. The effects of resonance factor, element parameters and LPF order on the delay are discussed respectively. The fourth-order anti-aliasing filter is designed and tested. The experimental results show that the improved filter has faster response speed and shorter stability time.