DVCC Based Current-Mode First Order All-Pass Filter and Quadrature Oscillator

A current mode first-order all-pass filter configuration is proposed. The presented circuit uses a single differential voltage current conveyor (DVCC), a capacitor and resistors. High output impedance of the proposed filter enables the circuit to be cascaded without additional buffers. To demonstrate the performance of the proposed filter a new current mode quadrature oscillator is given as an application example. Oscillator is implemented through the proposed first order all-pass filter and integrator as the building blocks. Furthemore the effects of tracking errors of the DVCC on oscillation condition and frequency are investigated. The theoretical results are verified with PSPICE simulations using a new CMOS realization of DVCC.