Current-mode second-order notch filter using CDTA-based allpass sections

A circuit technique for realizing a current-mode second-order notch filter using CDTA-based first order allpass sections is presented in this paper. The proposed circuit employs only four CDTAs and two virtually grounded capacitors, and exhibit low-input and high-output impedances, which is suitable for cascading in current-mode operation. The circuit also has low passive and active sensitivities. Moreover, if the active and passive component values are properly chosen, the circuit permits the realization of second-order allpass current response. PSPICE simulation results are used to verify the theoretical analysis.