Synthesis of an LC filter suitable for LC simulation-type RC active filters and its application

Abstract

One of the most important measures for the construction of the active RC filter is the element sensitivity. One of the effective means to reduce the element sensitivity is the method to simulate the conventional LC filter with both ends terminated by resistors. This paper considers the realization of the low-pass filter by LC simulation using GIC or by the node-voltage simulation. The prototype LC filter is discussed to solve the bias instability problem, which is a problem in the realization. First, an LC filter is proposed which is obtained by adding an inductor in parallel with the input resistor of the conventional doubly terminated LC filter. The method of constructing the filter is discussed. Then a method is presented to simulate the filter using GIC. Finally, the 5th-order Chebyshev low-pass filter is constructed and its characteristics are measured. The element sensitivity is analyzed using a computer, and it is verified that the proposed circuit has a low element sensitivity.