Design and Simulation of Butterworth Low-pass Filter

Abstract

Filters are required to filter the signal to improve the signal-to-noise ratio. It is known that the maximum frequency of the human ear is about 20 kHz, and filtering out the signal components above 20 kHz can greatly improve the audio signal quality. Therefore, the design requires the cut-off frequency of 20 kHz. In this design, the normalized transfer function of the fourth-order Butterworth filter is obtained by using the normalization process, and the denormalization process is carried out according to the cutoff frequency of 20kHz, the transfer function of the fourth-order Butterworth filter is obtained.The idea of circuit cascade is applied to derive the parameters of the components, so that a filter that meets the design requirements is obtained, and the filter is used in the Multisim and Matlab simulation software to verify the filtering effect.