All grounded passive elements current-mode all-pass filter

Abstract

In this paper, a new current-mode (CM) all-pass filter employing two Dual-Output Second-Generation Current Conveyors (DO-CCIIs), one grounded resistor and one grounded capacitor is presented. The proposed circuit exhibits low input impedance and high output impedance, which makes it suitable for cascading. Moreover, adding two extra resistors to the proposed circuit, a new gain-variable voltage-mode (VM) all pass filter is obtained. A quadrature oscillator employing minimum number of grounded passive components is derived from the developed CM filter as an application of the first-order all-pass filter. Both of the proposed all-pass filters do not require matching of passive components. The effects of the parasitic impedances of the DO-CCIIs on the transfer function (TF) of the proposed CM filter as an example are investigated. In addition, the proposed CM all-pass filter and oscillator circuit are simulated using SPICE simulation program to confirm the theory.