Active and passive filter synthesis using MATLAB

Analog filters play a significant role in every electronic system. There are two different ways to implement analog filters. The first one uses cascade connection of second-order circuits. These types of filters are easy to design, but they are relatively sensitive to the tolerance of elements. The second method uses passive ladder prototypes and practical VLSI implementation needs a series of integrators. This type of design is much less sensitive to the tolerance of elements, but also it is more difficult to design. The second method is rarely taught in basic analog filter courses. Both cascade as well as ladder-based filter implementation designs are complex and computationally intensive. Therefore, computer software could be very helpful to assist students and engineers in their design effort. This paper describes an educational MA TLAB tool which simplifies the process of analog filter design. The software allows the use of four approximation methods: Butterworth, Chebyshew, Inverse Chebyshev and Cauer. In addition, several types of filters can be designed such as lowpass, highpass, bandpass and bandstop. In comparison to other tools this software also generates actual circuit implementation.