Cascade approach for the realization of high order Voltage-Mode Filters using single CDBA-based first and second order sections

摘要

This study proposes single current differencing buffered amplifier (CDBA)-based first and second order basic filter blocks, so that, by cascading these individual filter blocks, a given higher order voltage transfer function can be realized. The cascaded and the single CDBA-based (direct realized) third order Butterworth lowpass filter circuits are analyzed using two (Schoeffler's and integrated sensitivity) measures for the multiparameter sensitivity performance comparison of both circuits. It is concluded that the cascade approach for the realization of a given voltage transfer function (VTF) is superior to the single CDBA-based (direct realized) configuration, because of its a) simplicity , b) practical implications regarding post design adjustments, and c) realization of less sensitive circuit structures. This method described here, offers a simpler and more economical alternative to other CDBA-based methods reported previously in literature, by keeping, a)the number of CDBAs, b)the effects of current and voltage tracking errors and, c)passive component sensitivities on the VTF of higher order filters, at reasonably low values.