In this work, we presenta current-mode and voltage-mode quadrature oscillator circuit using a voltagedifferencing buffered amplifier (VDBA), two grounded capacitors, and a groundedresistor. The oscillation condition and frequency are orthogonally (orindependently) controllable. The current-mode and voltage-mode quadraturesignals can be simultaneously obtained from the proposed circuit. The use ofonly grounded capacitors and resistors makes the proposed circuits ideal forintegrated circuit implementation. The quadrature oscillator is simulated withSPICE simulation program using 0.35-µm technology parameters.