The frequency of the input signal is selected specially to ensure that the input frequency just exceeds the cut-off frequency of analog filters. Because input signal is restrained partly by the attenuation of analog filters, output signal is sensitive to the variation of fault components. The peak voltage of key points is measured to construct fault samples of analog filters. The relationship between fault components and fault samples is analyzed to verify that fault samples have strong fault information of analog filters. The experimental results show that high-quality fault samples can be acquired efficiently, and fault feature of samples can be verified objectively by the present method.