Abstract: A filter system includes: a first mixer, converting an input signal into a first signal according to a reference frequency signal, wherein the reference frequency signal corresponding to a target frequency band; an analog-to-digital converter, coupled to the first mixer, converting the first signal into a first digital signal; a digital filter, coupled to the analog-to-digital converter, filtering the first digital signal according to a first frequency band and generating a second digital signal, wherein the first frequency band corresponding to the first signal; a digital-to-analog converter coupled to the digital filter, converting the second digital signal into a second signal; and a second mixer, coupled to the digital-to-analog converter, converting the second signal into an output signal according to the reference frequency signal, wherein the output signal corresponds to the input signal filtered by the target frequency band.

Abstract: A filter system includes: a first mixer, converting an input signal into a first signal according to a reference frequency signal, wherein the reference frequency signal corresponding to a target frequency band; an analog-to-digital converter, coupled to the first mixer, converting the first signal into a first digital signal; a digital filter, coupled to the analog-to-digital converter, filtering the first digital signal according to a first frequency band and generating a second digital signal, wherein the first frequency band corresponding to the first signal; a digital-to-analog converter coupled to the digital filter, converting the second digital signal into a second signal; and a second mixer, coupled to the digital-to-analog converter, converting the second signal into an output signal according to the reference frequency signal, wherein the output signal corresponds to the input signal filtered by the target frequency band.