Design of Fourth Order Active Band-Pass Filter With Sallen and Key Topology

Abstract

Analog active filters can be found in most of the electronic circuits. One major application of active filters involve an important class of sharp cutoff filter used to condition analog input signals that are being sampled and converted to digital signal as real-time to the modem computers. In this paper, we present the design of active filter with the second and the fourth order Butterworth responses in the category of Sallen and Key filter architecture. This type of filter has voltage controlled voltage source topology that uses a unity-gain amplifier. The complex transfer function of the filter is obtained and the capacitor/ resistor values are calculated. The filter is simulated with the Multisim program and compared with the Matlab tool. The results of the frequency responses are very similar to each other.