In this work, we present a current-mode and voltage-mode quadrature oscillator circuit using a voltage differencing buffered amplifier (VDBA), two grounded capacitors, and a grounded resistor. The oscillation condition and frequency are orthogonally (or independently) controllable. The current-mode and voltage-mode quadrature signals can be simultaneously obtained from the proposed circuit. The use of only grounded capacitors and resistors makes the proposed circuits ideal for integrated circuit implementation. The quadrature oscillator is simulated with SPICE simulation program using 0.35-mu m technology parameters.