Current conveyors based allpass filters and quadrature oscillators employing grounded capacitors and resistors

Six quadrature oscillator (QO) circuits are proposed. They are implemented through the proposed second-generation current conveyors (CCIIs) based high input impedance first-order allpass filters and the integrators as the building blocks. Outputs of two sinusoids with 90° phase difference are available in each of the proposed quadrature oscillators. The oscillation condition and oscillation frequency of each proposed quadrature oscillator are independently controllable through grounded resistors. All proposed circuits employ only grounded capacitors and resistors. The use of only grounded capacitors and resistors is ideal for integration. Experimental results are also included.