Single‐differential difference current conveyor‐based first‐order VM/TAM universal filter and its applications

Abstract

A new first‐order universal filter structure is presented in this article using a single differential difference current conveyor (DDCC). The proposed circuit can provide three first‐order filter functions namely, high‐pass filter (HPF), low‐pass filter (LPF), and all‐pass filter (APF) in voltage mode (VM) and transadmittance mode (TAM) both. A voltage amplifier with a gain of 2 is required for the realization of the APF functions in both the modes while for LPF and HPF, no condition is required. The pole frequency and gain of the proposed circuit can be controlled separately. The effect of the parasitic impedances of the DDCC has been modeled in the nonideal equivalent circuit from which nonideal parameters have been evaluated and compared with their ideal ones. Application examples of the proposed circuits configured as amplitude equalizer (in both modes) and in the realization of a simple wideband band‐pass filter are also discussed. The functionality of the proposed circuit as well as its mentioned application circuits is verified using complementry metal oxide semiconductor DDCC to support the theoretical propositions. Some experimentally observed frequency responses and transient responses of the various VM filters have also been corroborated using DDCC implemented using AD844 ICs.