Lowpass Active Filter Synthesis Based on Mesh Current Emulation of LC Ladder Structures

Abstract – In a series of papers, [1]-[3], A. Câmpeanu and M. Naforniţă proposed a new active RC filter synthesis method based on mesh current emulation of LC ladder filter networks. Initially, the method was successfully applied to highpass and lowpass polynomial filters. This paper extends the method to the very important class of lowpass finite-zeros (elliptic) filters. Based on the mesh current method, a simple and systematic design table is proposed, which permits a direct active RC filter implementation of the passive network. It is also outlined a method of reducing the number of amplifiers required. Some results obtained using PSPICE simulation show the efficiency of the method and the importance of the results