Odd- and even-order electronically controlled wave active filter employing differential difference trans-conductance amplifier (DDTA)

ABSTRACT

In recent years, several current mode wave active filters have been reported in literature. However, most schemes only have a few higher-order filters that employ a wave-equivalent inductor in a series branch as well as a wave-equivalent capacitor in the shunt branch. As a result, it is very difficult to design wave active filters with all the filter frequency responses using lower – to higher-order filters. Hence, in this research work, we propose to construct a uniform framework for the design of a wave active filter using a complementary metal oxide semiconductor (CMOS) differential difference transconductance amplifier (DDTA) for lower and higher-order filter configurations. A traditional wave-equivalent method is incorporated for the reflected and incident waves of series and shunt inductors and capacitors. The theoretical verification of the proposed wave active filter uses second-order, third-order, fourth-order, fifth-order, and sixth-order filter designs. Technical verification is conducted through Simulation Program with Integrated Circuit Emphasis (SPICE) simulations using the Cadence Virtuoso tool with 0.18 µm CMOS (Taiwan Semiconductor Manufacturing Company, TSMC) parameters for the DDTA. In addition, experimental validation of the proposed wave active filter is performed with the operational transconductance amplifier as CA3080 for the implementation of DDTA.

KEYWORDS:

• Wave active filter
• Wave active equivalent
• Differential difference transconductance amplifier
• Scattering matrix
• Ladder filter

Disclosure statement

No potential conflict of interest was reported by the authors.